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GI Joe Medical Boards
Joseph Kumka
12 episodes
22 hours ago
I'm Dr. Joseph Kumka, Gastroenterology Fellow, educator, and host of evidence-based, board-oriented medical podcasts. Whether you're a resident gearing up for the boards, a fellow diving deep into subspecialty topics, or a practicing clinician hungry for high-yield updates—you’re in the right place.
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Medicine
Education,
Health & Fitness
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All content for GI Joe Medical Boards is the property of Joseph Kumka and is served directly from their servers with no modification, redirects, or rehosting. The podcast is not affiliated with or endorsed by Podjoint in any way.
I'm Dr. Joseph Kumka, Gastroenterology Fellow, educator, and host of evidence-based, board-oriented medical podcasts. Whether you're a resident gearing up for the boards, a fellow diving deep into subspecialty topics, or a practicing clinician hungry for high-yield updates—you’re in the right place.
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Medicine
Education,
Health & Fitness
Episodes (12/12)
GI Joe Medical Boards
Cardiology - Cardiovascular Disease and Cancer

Cardiovascular Disease in Cancer

I. Cardiotoxicity of Radiation Therapy to the Thorax

  • Prevalence and Significance: Radiation therapy, while improving survival in patients with thoracic malignancies (e.g., Hodgkin lymphoma, early-stage breast cancer), has led to cardiovascular disease becoming "the most common nonmalignant cause of death in patients treated with chest radiation therapy, accounting for 25% of deaths in survivors of Hodgkin lymphoma."
  • Mechanism and Onset: Thoracic irradiation damages all cardiac cells and structures, including the "pericardium, myocardium, valves, coronary and peripheral vasculature, and conduction system." Clinical disease typically presents "two to three decades after treatment," though some manifestations can occur earlier.
  • Increased Risk Factors: The risk of radiation-induced cardiac injury is heightened in patients receiving "concomitant anthracyclines or trastuzumab." Contemporary radiation techniques aim to "limit total dosage and field size" to decrease complications.
  • Spectrum of Cardiovascular Diseases (Table 42):
  • Pericardial Disease:
  • Acute pericarditis: "Most common early manifestation," affecting 2.5% of patients.
  • Chronic or constrictive pericarditis: Develops in "10% to 20% of patients 5 to 10 years after radiation therapy." Pericardial calcification is not always present, and late constriction can occur without prior acute pericarditis.
  • Cardiomyopathy: Radiation damages microvasculature, leading to "endothelial dysfunction and ischemia that result in myocardial fibrosis, diastolic dysfunction, and restrictive physiology." Differentiating it from pericardial constriction is crucial for treatment.
  • Valvular Disease: Affects all valves, predominantly left-sided. "Valvular regurgitation due to tissue retraction is the most common valvular lesion in the first two decades after therapy," evolving to "mixed regurgitation and stenosis" with later fibrosis and calcification.
  • Conduction Defects: Common in long-term survivors, including "atrioventricular block, bundle branch block." Increased need for permanent pacing after valve replacement surgery in irradiated patients.
  • Coronary Artery Disease (CAD): Occurs "earlier and with increased incidence." Lesions are typically "ostial, long, smooth, and concentric and have higher fibrotic content than typical atherosclerotic lesions." Traditional risk factors (smoking, dyslipidemia, hypertension) exacerbate incidence, requiring aggressive management.
  • Surgical Outcomes: Surgical outcomes for radiation-associated cardiovascular disease are "significantly worse than in matched cohorts." Percutaneous approaches, such as percutaneous aortic valve replacement, "may be preferable" for aortic stenosis in this group.
  • Surveillance and Prevention:
  • No consensus on cardiac testing in asymptomatic patients, but "baseline evaluation including echocardiography is reasonable."
  • Some organizations recommend "stress echocardiography at 5 to 10 years after completion of therapy or at age 30 years, whichever comes first."
  • Serum biomarkers, nuclear medicine testing, and coronary CT are "not recommended" for routine screening.
  • Statins, ACE inhibitors, and aldosterone antagonists have "not been proved to prevent radiation-induced cardiovascular disease," despite their role in risk factor reduction.

II. Cardiotoxicity of Chemotherapy

  • General Principles: Chemotherapy can cause "reversible or dose-dependent, irreversible cardiac injury" (Table 43). Strategies to minimize risk include optimizing traditional risk factors and identifying high-risk patients (Table 44) before treatment.
  • Key Cardiotoxic Agents and Effects (Table 43 & associated text):
  • Left Ventricular Dysfunction (LVD):
  • Anthracyclines (Doxorubicin, Epirubicin, Idarubicin):
  • Acute toxicity: Rare (<1%), reversible, presenting as heart block, arrhythmias, heart failure, myocarditis, or pericarditis.
  • Chronic progressive toxicity: Typically irreversible, presenting as dilated cardiomyopathy. "Most closely linked with doxorubicin."
  • Onset: Early (within 1 year) in 1.6% to 2.1%; late (after 1 year) in up to 5%.
  • Dose-dependent: "Late-onset chronic progressive toxicity is related to total cumulative dose." Incidence of heart failure up to 26% at 550 mg/m2 doxorubicin, with clinical evidence appearing "10 to 20 years after treatment."
  • Mitigation strategies: Dexrazoxane (iron chelator) for high-risk patients; continuous infusion vs. bolus; liposomal formulations of doxorubicin. ACE inhibitors, ARBs, and beta-blockers have not been proven to prevent toxicity.
  • Trastuzumab: Causes "LV systolic dysfunction, with symptoms of heart failure in 3% to 7% of patients." More common in patients older than 50 and with concomitant anthracycline use. Toxicity often reversible.
  • Other Agents: Alkylating agents (cyclophosphamide, ifosfamide), antimicrotubular agents (paclitaxel, docetaxel), proteasome inhibitors (bortezomib, carfilzomib), tyrosine kinase inhibitors (sunitinib).
  • Ischemia: Antimetabolites (5-fluorouracil, capecitabine), antimicrotubular agents (paclitaxel, docetaxel), monoclonal antibody (bevacizumab), tyrosine kinase inhibitors (erlotinib, sorafenib).
  • Hypertension: Monoclonal antibody (bevacizumab), tyrosine kinase inhibitors (sorafenib, sunitinib). Sunitinib can cause up to "50% incidence of new or worsened hypertension" and up to "15% incidence of decreased LV ejection fraction (LVEF)," often reversible with early recognition. Bevacizumab-associated hypertension is "significant but reversible."
  • Arrhythmias:
  • Bradycardia/AV block: Thalidomide, paclitaxel.
  • QT prolongation/Torsades de pointes: Oxaliplatin, aclarubicin, arsenic, vandetanib.
  • Atrial fibrillation: Cyclophosphamide, ifosfamide, doxorubicin, mitoxantrone, 5-fluorouracil, trastuzumab, sunitinib, sorafenib, ibrutinib, and others.
  • Monomorphic ventricular tachycardia: Doxorubicin, 5-fluorouracil, arsenic, nivolumab, trastuzumab.
  • Factors Increasing Long-Term Cardiovascular Risk (Table 44): High-dose anthracyclines (≥250 mg/m2 doxorubicin or ≥600 mg/m2 epirubicin), combination anthracycline and trastuzumab, combination anthracycline and radiation, radiation of ≥30 Gy with heart in field, and anthracycline or trastuzumab in patients with multiple pre-existing cardiovascular risk factors.
  • Monitoring and Management:
  • Baseline Evaluation: "Baseline echocardiography is recommended" for patients receiving chemotherapy with possible LV dysfunction.
  • Surveillance:
  • Global Longitudinal Strain (GLS): Recommended by some experts as a more sensitive marker for "early myocardial dysfunction." A "relative decline in GLS of greater than 15% is considered subclinical LV dysfunction and should prompt consultation with a cardiologist."
  • Echocardiography Frequency: For anthracyclines, reasonable to repeat at a cumulative dose of 250 mg/m2 and "before each dose in patients with pre-existing LV dysfunction or those receiving higher cumulative doses." For trastuzumab, frequency is based on clinical judgme...
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3 months ago
32 minutes

GI Joe Medical Boards
Cardiology - Cardiomyopathies in Pregnancy

Cardiovascular Disease

Executive Summary

This briefing document summarizes key information regarding cardiovascular health during pregnancy, drawing insights from "Pregnancy and Cardiovascular Disease - Cardiovascular Medicine Text - MKSAP 19.pdf". It highlights the increasing maternal mortality in the US due to cardiovascular disorders, the physiological changes during normal pregnancy, and the critical importance of prepregnancy evaluation, multidisciplinary management, and careful consideration of medication and anticoagulation therapies for women with pre-existing or pregnancy-related cardiovascular conditions. Special attention is given to high-risk conditions like peripartum cardiomyopathy and Marfan syndrome.

I. Maternal Mortality Trends and Primary Causes

Maternal mortality in the United States has increased over the past two decades, a trend contrasting with decreasing rates in other Western countries. The leading cause of maternal mortality is acquired cardiovascular disorders, specifically "cardiomyopathy, coronary artery disease, and aortic disorders."

II. Cardiovascular Changes During Normal Pregnancy

Understanding normal physiological changes is crucial for distinguishing between healthy and pathologic signs. Key cardiovascular adaptations during a normal pregnancy include:

  • Relative Anemia: Due to a greater increase in plasma volume compared to erythrocyte mass.
  • Decreased Mean Arterial Pressure: Resulting from "reduced systemic vascular resistance and increased heart rate and cardiac output."
  • Increased Heart Rate and Cardiac Output: Maternal cardiac output "peaks at approximately 40% to 50% above the prepregnancy level by the 32nd week," and can further increase to "as much as 80% above the prepregnancy level" during delivery.
  • Common Normal Symptoms/Signs: Mild dyspnea, dyspnea with exertion, atrial and ventricular premature beats, heart rate increased by 20-30%, modest blood pressure decrease (~10 mm Hg), and a "basal systolic murmur grade 1/6 or 2/6 present in 80% of pregnant patients, S3."

Table 45 (Normal Versus Pathologic Signs and Symptoms in Pregnancy) provides a detailed comparison, distinguishing normal physiological changes from symptoms like orthopnea, chest pain, atrial fibrillation, heart rate >100/min, high blood pressure (≥140/90 mm Hg), systolic murmur grade ≥3/6, or any diastolic murmur/S4, which are considered pathologic.

III. Prepregnancy Evaluation and Risk Stratification

Mandatory Prepregnancy Counseling: "All women with cardiovascular disease should receive pregnancy counseling," including genetic counseling and testing if appropriate. Multidisciplinary Approach: A comprehensive evaluation involving a "cardiologist, a maternal-fetal medicine specialist, and an obstetric anesthesiologist" is essential to assess risks and formulate a management plan for labor and postpartum. Risk Assessment Tool: The modified World Health Organization pregnancy risk classification is currently the "most accurate system of risk assessment."

A. Low-Risk Conditions

Women with certain conditions generally experience no increased morbidity or mortality:

  • Uncomplicated small patent ductus arteriosus
  • Mild pulmonary stenosis
  • Mitral valve prolapse
  • Successfully repaired simple lesions (atrial or ventricular septal defect, patent ductus arteriosus, anomalous pulmonary venous drainage)
  • Isolated atrial or ventricular ectopic beats
  • Tetralogy of Fallot, most supraventricular arrhythmias, and Turner syndrome without aortic dilatation. These patients can typically be managed and deliver in a local hospital.

B. Extremely High-Risk Conditions (Require Expert Center Care)

Conditions conferring "extremely high risk for maternal mortality or severe morbidity" necessitate care and delivery at "an expert center for pregnancy and cardiac disease":

  • Pulmonary hypertension
  • Previous peripartum cardiomyopathy with residual left ventricular dysfunction
  • Severe left ventricular dysfunction (ejection fraction <30% or NYHA functional class III-IV symptoms)
  • Severe mitral stenosis
  • Symptomatic severe aortic stenosis
  • Marked ascending aorta dilatation

IV. Management of Cardiovascular Disease During Pregnancy

A. Valvular Lesions

  • Obstructive: Symptoms may arise due to increased blood volume/cardiac output; intervention before pregnancy should be considered.
  • Regurgitant: Generally well-tolerated during pregnancy.

B. Hypertrophic Cardiomyopathy

  • Symptomatic obstructive hypertrophic cardiomyopathy: Treated with "nonvasodilating β-blockers, with monitoring of fetal growth."

C. Arrhythmias

  • Most arrhythmias are benign.
  • Shared decision-making is crucial for antiarrhythmic drugs, considering maternal and fetal risks/benefits.
  • Most β-blockers (except atenolol) are safe for pregnancy and breastfeeding.
  • Adenosine is the drug of choice for acute symptomatic supraventricular tachycardia.
  • Amiodarone is rarely used due to toxicity.

D. Delivery Method

  • Vaginal delivery is generally preferred due to "less blood loss, quicker recovery, and lower risk for thrombosis."
  • Cesarean delivery is recommended for:Obstetric reasons in women with severe decompensated cardiovascular disease.
  • Some patients with a markedly dilated aorta.
  • Women on warfarin therapy to reduce fetal intracranial hemorrhage risk due to fetal anticoagulation.

V. Specific Cardiovascular Disorders

A. Peripartum Cardiomyopathy (PPCM)

  • Definition: "New onset of heart failure in the last month of pregnancy or within 5 months of delivery in the absence of an identifiable cause."
  • Risk Factors: Multiparity, age >30 years, multifetal pregnancy, gestational hypertension, preeclampsia, previous PPCM, tocolytic therapy.
  • Causes of Death: Heart failure, thromboembolic events, or arrhythmias.
  • Prognosis: Most women recover fully, but 13% may have major cardiovascular events or persistent severe cardiomyopathy. Recovery timeframe is typically 6 months. Worse outcomes are linked to severe LV dysfunction/dilatation at presentation, older maternal age, and multiparity.
  • Management: Prompt medical therapy (β-blockers, digoxin, hydralazine, nitrates, diuretics). ACE inhibitors, ARBs, and aldosterone antagonists are teratogenic and must be avoided until after delivery.
  • Anticoagulation: Recommended for LVEF <35% due to high thromboembolism risk. Duration is at least 8 weeks or until ejection fraction normalizes.
  • Severe Refractory Cases: Referral to a specialty center for advanced treatments (ventricular assist device, advanced arrhythmia management, heart transplantation).
  • Future Pregnancy: Women with a previous PPCM episode and persistent LV dysfunction "should be advised to avoid future pregnancy" due to high risk of recurrence or deterioration.

B. Other Cardiovascular Disorders

  • Adverse Pregnancy Outcomes: Linked to the acquisition of cardiovascular risk factors (e.g., hypertensive disorders of pregnancy, preterm delivery).
  • Marfan Syndrome: Increased risk for pregnancy-rela...
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3 months ago
36 minutes

GI Joe Medical Boards
Cardiology - Congenital Disease

Adult Congenital Heart Disease (ACHD)


Date: October 26, 2023

Purpose: This briefing document summarizes key themes, important ideas, and facts regarding Adult Congenital Heart Disease (ACHD) based on the provided source material.

Executive Summary

Medical and surgical advancements have led to a growing population of adults with congenital heart disease (CHD). This demographic requires specialized, multidisciplinary care due to common cardiovascular "residua" from previous interventions. The document highlights various specific CHD conditions, including Patent Foramen Ovale (PFO), Atrial Septal Defect (ASD), Ventricular Septal Defect (VSD), Patent Ductus Arteriosus (PDA), Pulmonary Stenosis (PS), Aortic Coarctation, and Tetralogy of Fallot (TOF), detailing their pathophysiology, clinical presentation, diagnostic evaluation, treatment, and post-closure follow-up. A significant theme across all conditions is the importance of specialized cardiology follow-up, careful consideration of activity restrictions, and comprehensive reproductive health counseling, especially regarding pregnancy risks and contraception. Additionally, the document addresses the unique challenges and management strategies for patients with cyanotic CHD, including Eisenmenger syndrome, emphasizing the need for highly specialized care for these complex cases.

Main Themes and Key Insights

1. Growing ACHD Population and the Need for Specialized Care: * Key Fact: "Medical and surgical advances have resulted in more adults than children with congenital heart disease (CHD) in North America." * Importance: This highlights a fundamental shift in patient demographics, necessitating a focus on adult-specific management strategies and long-term care. * Implication: The specialized nature of ACHD management underscores the "importance of periodic follow-up by a team ideally consisting of the internist and a cardiologist trained in adult CHD." * Specifics: "Specialized care is critical for patients born with complex and cyanotic congenital cardiac disease, symptomatic patients, and patients who desire pregnancy."

2. Comprehensive Patient Counseling and Holistic Care: * Reproductive Health: "Patients with CHD should be offered reproductive health counseling." This includes discussions on contraception, balancing its use against pregnancy risks, and pre-pregnancy counseling for those on anticoagulation due to associated "maternal and fetal risks." * Psychological Well-being: "Anxiety and depression are prevalent but underrecognized in patients with CHD, and screening for these mood disorders should be a routine aspect of care." This emphasizes a holistic approach to patient management beyond purely cardiac issues. * Infectious Disease Prevention: Hepatitis C screening is recommended, and Hepatitis B vaccination is advised for non-immune individuals.

3. Common Cardiovascular Residua and Long-Term Follow-up: * General Principle: "Cardiovascular residua are common in patients with previous intervention for congenital cardiac lesions." This necessitates lifelong monitoring. * Condition-Specific Examples: * ASD: Atrial fibrillation risk persists after closure, and "Rare complications after device closure include device migration, erosion into the pericardium or aorta, and sudden death." * VSD: "Residual or recurrent VSD, arrhythmias, PH, endocarditis, and valve regurgitation are recognized complications following VSD closure." * PS: "Patients with previous PS intervention (balloon or surgical) often have severe pulmonary regurgitation; thus, long-term clinical and TTE follow-up is recommended." * Aortic Coarctation: "Following coarctation repair, hypertension occurs in up to 75% of patients and should be treated." * TOF: "Severe long-standing pulmonary regurgitation causes right heart enlargement, tricuspid regurgitation, exercise limitation, and both atrial and ventricular arrhythmias and is the most common reason for reoperation after TOF repair." The incidence of sudden cardiac death after TOF repair is "approximately 2% per decade."

4. Condition-Specific Management Strategies:

* **Patent Foramen Ovale (PFO):**

    * **Diagnosis:** Typically by transesophageal echocardiography (TEE) with color flow Doppler or agitated saline injection.

    * **Treatment:** Antiplatelet therapy for embolic stroke of undetermined source. PFO closure is recommended for patients under 60 with embolic-appearing infarcts and no other stroke mechanism, offering a "3.4% at 5 years" recurrent stroke risk reduction, but with a "3.9%" periprocedural complication rate and increased atrial fibrillation risk (0.33% per year). No treatment is needed for asymptomatic, incidentally detected PFO.

    * **Associated Conditions:** Platypnea-orthodeoxia syndrome and Atrial Septal Aneurysm (ASA), which "reportedly increases the risk for stroke compared with PFO alone."


* **Atrial Septal Defect (ASD):**

    * **Types:** Ostium secundum (most common), ostium primum, sinus venosus, and coronary sinus.

    * **Clinical Features:** Suspected with unexplained right heart enlargement or atrial arrhythmias; "Atrial fibrillation is a common finding, particularly in older patients with an ASD."

    * **Diagnosis:** TTE is preferred for secundum and primum defects; TEE, CMR, or CT for sinus venosus and coronary sinus defects.

    * **Treatment:** Closure indicated for right-sided cardiac chamber enlargement and dyspnea. Percutaneous device closure for isolated ostium secundum ASDs; surgical closure for nonsecundum, large secundum, or anatomically unfavorable defects, or coexistent cardiovascular disease.

    * **Pregnancy:** "Generally well-tolerated in patients with an ASD in the absence of PH."


* **Ventricular Septal Defect (VSD):**

    * **Types:** Membranous (most common, 80%), muscular (often close spontaneously), subpulmonary, and inlet.

    * **Presentation:** Small VSDs are asymptomatic with a "loud (often palpable) holosystolic murmur"; moderate shunts can cause LV volume overload and PH. Large, unrepaired VSDs can lead to "fixed PH within several years with subsequent development of Eisenmenger syndrome."

    * **Treatment:** Closure indicated for Qp:Qs ≥ 1.5 with LV volume overload and no PH. Surgical closure is most common, but percutaneous options exist. Closure is *not* indicated for small shunts or for Eisenmenger syndrome due to risk of "clinical deterioration."

    * **Pregnancy:** "Generally well-tolerated in the absence of PH; patients with VSDs and associated fixed PH should be counseled to avoid pregnancy."


* **Patent Ductus Arteriosus (PDA):**

    * **Presentation:** Typical "continuous 'machinery' murmur." Large unrepaired PDAs can cause PH and "Eisenmenger syndrome; characteristic features... are clubbing and oxygen desaturation affecting the feet but not the hands (differential cyanosis)."

    * **Treatment:** Closure indicated for left-sided cardiac chamber enlargement if pulmonary artery systolic pressure is less than 50% systemic. Percutaneous closure is usual.


* **Pulmonary Stenosis (PS):**

    * **Associated Syndrome:** Noonan syndrome.

  ...

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3 months ago
1 hour 11 minutes

GI Joe Medical Boards
Cardiology - Peripheral Arterial Disease

Peripheral Arterial Disease

I. Overview and Epidemiology

Peripheral Artery Disease (PAD) is primarily characterized by the narrowing of the aortic bifurcation and arteries of the lower extremities, including the iliac, femoral, popliteal, and tibial arteries. The most common cause is atherosclerosis. PAD is a significant health concern, considered a "coronary heart disease risk equivalent," meaning both asymptomatic and symptomatic patients face an elevated risk for ischemic events such as myocardial infarction, stroke, and cardiovascular death. Early detection is crucial for risk factor modification.

Key Facts:

  • Definition: Narrowing of arteries, predominantly in the lower extremities, due to atherosclerosis.
  • Prevalence: Incidence increases from age 40, reaching approximately 10% by age 70.
  • Gender Differences: Occurs later in life for women but has a higher overall prevalence in women due to their longer lifespan.
  • Cardiovascular Risk: PAD is a "coronary heart disease risk equivalent," placing patients at high risk for myocardial infarction, stroke, and cardiovascular death.

Risk Factors:

  • Smoking (current or past)
  • Diabetes mellitus
  • Hypertension
  • Hyperlipidemia
  • Increasing age
  • Family history of atherosclerosis

Screening Guidelines (AHA/ACC):

Screening with an Ankle-Brachial Index (ABI) is "reasonable in asymptomatic persons" with specific risk factors:

  1. Age 65 years or older.
  2. Age 50-64 years with atherosclerosis risk factors (e.g., smoking, diabetes, hypertension, dyslipidemia) or family history of PAD.
  3. Age younger than 50 years with diabetes and one additional atherosclerosis risk factor.
  4. Known atherosclerotic disease in another vascular bed (coronary, carotid, subclavian, renal, or mesenteric artery stenosis, or abdominal aortic aneurysm).

Note: The U.S. Preventive Services Task Force finds insufficient evidence to support routine ABI screening for lower extremity PAD.

II. Clinical Presentation

PAD presents with a wide spectrum of clinical manifestations, as it is defined by an abnormal ABI rather than solely by symptoms.

A. Intermittent Claudication (IC)

  • Description: "Exertional leg pain relieved by rest."
  • Symptoms: Cramping, tightness, aching, fatigue in buttock, hip, thigh, calf, or foot, consistent walking distance at onset, not occurring with standing still, relief within <5 minutes by standing or sitting.
  • Progression: Most patients have stable symptoms, but approximately 25% worsen, and 10-20% undergo revascularization within 5 years.
  • Complications: Annual risk for myocardial infarction, stroke, or cardiovascular death is approximately 5% to 7%.

B. Atypical Exertional Leg Pain

  • Patients may experience pain that does not fit the classic description of claudication.

C. Asymptomatic PAD

  • Defined solely by an abnormal ABI value without noticeable symptoms.

D. Chronic Limb-Threatening Ischemia (CLTI) / Critical Limb Ischemia

  • Severity: The "most severe form of PAD," affecting fewer than 5% of patients.
  • Manifestations: Ischemic rest pain, tissue ulceration, and gangrene.
  • Ulcer Characteristics: Commonly on distal toes, plantar aspect of the foot, anterior lower leg, or trauma sites. Usually painful with "sharply demarcated borders with a dry, pale gray or yellow wound base without evidence of granulation tissue."
  • Prognosis: High rates of major amputation (30%) and mortality (20%) within 1 year of diagnosis.
  • Treatment: Surgical or endovascular revascularization is usually necessary for limb salvage.

III. Evaluation

A comprehensive evaluation, including history, physical examination, and diagnostic testing, is essential for suspected PAD.

A. History and Physical Examination

  • History: Inquire about walking impairment, claudication vs. pseudoclaudication (see Table 38 for distinguishing characteristics), skin breakdown, foot ulcers, and education on foot protection.
  • Physical Exam Components (Table 39):Measure blood pressure in both arms (difference >15 mm Hg suggests subclavian stenosis).
  • Auscultate for arterial bruits (e.g., femoral artery).
  • Palpate for abdominal aortic aneurysm.
  • Palpate and record pulses (radial, brachial, carotid, femoral, popliteal, posterior tibial, dorsalis pedis).
  • Evaluate for elevation pallor and dependent rubor of foot.
  • Inspect feet for ulcers, fissures, calluses, tinea, and tendinous xanthoma; evaluate overall skin care.
  • Distinguishing CLTI: Differentiate CLTI from chronic venous disease (leg edema, pigmented/brawny induration of gaiter zone, shin/ankle ulceration).

B. Diagnostic Testing

  • Ankle-Brachial Index (ABI):Description: "The most commonly used diagnostic modality" for lower extremity PAD, measuring the ratio of lower extremity to upper extremity systolic blood pressures.
  • Guidelines: Recommended for "all patients with history or physical examination findings suggestive of PAD."
  • Advantages: Simple, inexpensive, noninvasive, sensitivity/specificity approaching 90%.
  • Procedure: Measure blood pressures in both arms and at dorsalis pedis and posterior tibial ankle locations. ABI for each leg is calculated as the higher ankle pressure divided by the higher brachial artery pressure.
  • Interpretation (Table 40):Normal: 1.00-1.40
  • Borderline: 0.91-0.99
  • Mild to Moderate PAD: 0.41-0.90 (typical for claudication)
  • Severe PAD: 0.00-0.40 (typical for ischemic rest pain, ulceration, gangrene)
  • Noncompressible (calcified) vessel: >1.40 (uninterpretable); Toe-brachial index (<0.70 indicates PAD) is used in these cases.
  • Segmental Pressure Measurements: Used to localize diseased vessels, involving pulse volume recordings and blood pressure measurements at various lower extremity locations.
  • Imaging Modalities (Table 41): Primarily used for planning revascularization.
  • Arterial duplex ultrasonography: Non-invasive, no contrast, inexpensive; limitations in pelvis, severe calcifications, and infrapopliteal stenosis.
  • CT angiography: Widely available, defines severity; risk of contrast-induced nephropathy, expensive.
  • Magnetic resonance angiography (MRA): Defines severity; contraindicated with pacemakers/defibrillators, risk of nephrogenic systemic fibrosis in severe kidney disease, expensive.
  • Invasive angiography: Often preferred as endovascular revascularization can be performed concurrently.

IV. Medical Therapy

Treatment of PAD focuses on "reducing cardiovascular risk, improving functional status and quality of life, decreasing claudication symptoms, and preventing tissue injury and amputation."

A. Risk Factor Modification

  • Smoking Cessation: "The most effective intervention for improving overall survival" and is associated with decreased major amputation risk, improved revascularization patency rates, and less disease progression.
  • Diabetes Management: Intensive glucose control has not shown a reduction in ma...
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3 months ago
27 minutes

GI Joe Medical Boards
Cardiology - Aortopathies

Aortic Diseases: A Comprehensive Briefing

Date: October 26, 2023

Purpose: This briefing document provides a detailed overview of various aortic diseases, including chronic conditions like aneurysms and acute, life-threatening syndromes such as dissection and rupture. It consolidates key information on definitions, causes, risk factors, symptoms, diagnosis, surveillance, and treatment strategies, drawing from provided medical sources.

1. Introduction to Aortic Diseases

Aortic diseases encompass a spectrum of conditions affecting the aorta, the body's largest artery. These conditions range from chronic issues like thoracic and abdominal aortic aneurysms and aortic atheromas to acute, highly perilous events such as aortic dissection and aneurysm rupture. Prompt diagnosis, appropriate treatment, and vigilant surveillance are crucial for preventing disease progression, complications, and mortality.

2. Thoracic Aortic Aneurysm (TAA)

2.1. Definition and Characteristics

TAA is defined as an increase in the thoracic aortic diameter greater than 50% relative to the expected or normal dimension, which varies by age, sex, and body type. TAAs can occur at the aortic root, ascending aorta, aortic arch, or descending aorta, most commonly affecting the root and ascending aorta, often linked to atherosclerosis.

2.2. Causes and Risk Factors

  • Cystic medial degeneration: The primary cause, involving weakening of the aortic wall due to loss of smooth muscle fibers and elastic fiber degeneration.
  • Connective tissue disorders: Common in patients younger than 50 years, including Marfan syndrome, Ehlers-Danlos syndrome, and Loeys-Dietz syndrome.
  • Bicuspid aortic valve: A significant risk factor, occurring in approximately 50% of affected individuals.
  • Other risk factors: Hypertension, smoking, and advanced age.
  • Other listed causes: Atherosclerosis, other genetic/congenital conditions (e.g., Turner syndrome, coarctation of the aorta), vasculitis (e.g., Takayasu arteritis, Giant cell arteritis), infectious causes (e.g., septic embolism, syphilis), and prior aortic injury or acute aortic syndrome.

2.3. Symptoms

TAAs are frequently asymptomatic and detected incidentally. When symptoms occur, they may include:

  • Infrequent: Dysphagia (difficulty swallowing) and hoarseness due to compression of surrounding structures.
  • Rupture: Severe chest pain, back pain, sudden shortness of breath, or sudden death.
  • Associated with aortic regurgitation: Diastolic heart murmur, wide pulse pressure, or symptoms of heart failure.

2.4. Diagnosis and Surveillance

  • Screening: Recommended only for patients with known genetic conditions predisposing to aortic aneurysms and dissections (e.g., Marfan syndrome, Ehlers-Danlos syndrome), or a family history of TAA or aortic dissection.
  • Imaging Modalities (Table 36):Transthoracic echocardiography (TTE): Good for aortic root/proximal ascending aorta; no radiation/contrast. Limited visualization of distal ascending aorta, arch, and branches.
  • Transesophageal echocardiography (TEE): Excellent visualization from root to descending aorta; no radiation/contrast. Invasive, operator dependent.
  • CT angiography (CTA): Visualizes entire aorta and side branches; rapid; high sensitivity/specificity. Exposes patient to radiation and iodinated contrast.
  • Magnetic resonance angiography (MRA): Visualizes entire aorta and side branches; high sensitivity/specificity; no radiation. Prolonged acquisition, contraindications (pacemakers, defibrillators, some kidney disease).
  • Aortography: Provides exact information on size/shape of aortic lumen and side branches. Invasive, requires dye, potential for nephrotoxicity and worsening dissection. Poor for intramural hematoma.
  • Measurement: Aortic diameter should be measured perpendicular to the long axis.
  • Surveillance Frequency:3.5 to 4.4 cm diameter: Annual imaging.
  • 4.5 to 5.4 cm diameter: Imaging every 6 months.
  • Marfan syndrome: Repeat assessment 6 months after initial diagnosis, then annually if stable.
  • Rapid expansion (>0.5 cm/year) or approaching repair threshold: More frequent imaging.

2.5. Treatment

  • Medical Therapy:For TAAs <5.0 cm.
  • Aggressive blood pressure control: Goal <130/80 mm Hg.
  • β-Blockers: Preferred antihypertensive agents; associated with reduced aneurysm growth, especially in Marfan syndrome.
  • Losartan: Also associated with reduced aneurysm growth in Marfan syndrome.
  • Surgical Repair: Warranted to prevent rupture, the leading cause of death in TAA patients.
  • Degenerative ascending aortic aneurysm: >5.5 cm in diameter or rapid growth (≥0.5 cm/year or ≥0.3 cm/year over 2 years).
  • Sporadic aneurysms: 5.0 cm or larger may be considered.
  • Nonsyndromic hereditary TAA: ≥4.5 cm with high-risk family history; ≥5.0 cm without high-risk family history.
  • Marfan syndrome/genetically mediated disorders: Lower threshold for elective repair (4.0-5.0 cm).
  • Bicuspid aortic valve with ascending aortic aneurysm: >5.5 cm, or 5.0 cm if additional dissection risk factors or low operative risk.
  • Concomitant cardiac surgery: Aortic repair should be performed if ascending aorta or aortic root >5.0 cm (or 4.5 cm for tricuspid aortic valve repair/replacement).
  • Types of Repair:Open surgical repair: Indicated for TAAs involving the aortic root, ascending aorta, and aortic arch.
  • Thoracic endovascular aortic repair (TEVAR): Used for descending aortic aneurysms. Associated with complications like endoleaks.

3. Abdominal Aortic Aneurysm (AAA)

3.1. Definition and Risk Factors

AAA is an abnormal dilatation of the abdominal aorta with an anteroposterior diameter greater than 3.0 cm.

  • Risk factors: Male sex (6:1 male-to-female ratio), advanced age, smoking, atherosclerosis, hypertension, and family history of AAA.

3.2. Screening and Surveillance

  • Diagnosis: Most often incidental via CTA or abdominal ultrasonography; 75% are asymptomatic at diagnosis.
  • Screening Recommendation (U.S. Preventive Services Task Force): One-time screening with duplex ultrasonography for men aged 65 to 75 years who have smoked at least 100 cigarettes. Selective screening for non-smoking men in the same age group.
  • Surveillance Frequency (by diameter):<4.0 cm: Every 2-3 years with duplex ultrasonography.
  • 4.0 to <5.5 cm: Every 6-12 months with CTA or duplex ultrasonography.
  • ≥5.5 cm (repair threshold): CTA or MRA to determine exact location (suprarenal, juxtarenal, or infrarenal) for planning repair.
  • Annual Rupture Risk (Table 37):<4.0 cm: <0.5%
  • 4.0-4.9 cm: 0.5%-5%
  • 5.0-5.9 cm: 3%-15%
  • 6.0-6.9 cm: 10%-20%
  • 7.0-7.9 cm: 20%-40%
  • ≥8.0 cm: 30%-50%

3.3. Treatment

  • Medical Treatment: Risk factor reduction to decrease rup...
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3 months ago
25 minutes

GI Joe Medical Boards
Cardiology - Pericardial Disease

Pericardial Disease Briefing Document

1. Acute Pericarditis

Definition: Acute pericarditis is the inflammation of the pericardium, the fibrous sac surrounding the heart.

Key Characteristics & Diagnosis (at least two of four criteria):

  • Chest Pain: Typically "sharp, severe, and positional." It is worse when supine and improves with sitting up and leaning forward. Unlike angina, it is "not exacerbated by exertion nor relieved by rest or nitroglycerin."
  • Pericardial Friction Rub: A "hallmark of acute pericarditis," described as a "harsh, scratchy sound" with classically three components corresponding to atrial systole, ventricular systole, and ventricular filling. It is not affected by respiration, differentiating it from a pleural rub.
  • ECG Changes: "Concave ST-segment elevation in multiple leads" that does not follow a single coronary artery distribution. "PR-segment depression in lead II or reciprocal PR-segment elevation in lead aVR" may also be present. This contrasts with acute myocardial infarction ECG findings.
  • New Pericardial Effusion: Presence of fluid around the heart. The absence of an effusion, however, "does not exclude acute pericarditis."

Causes (most often idiopathic or presumed viral):

  • Infectious: Viral (Enterovirus, herpesvirus, adenovirus, parvovirus), Bacterial (Mycobacterium tuberculosis, Pneumococcus spp., Staphylococcus spp.), Fungal.
  • Noninfectious: Autoimmune diseases, Cancer (metastatic lung/breast cancer, melanoma, lymphoma, leukemia), Metabolic conditions (uremia, myxedema), Drug-related (hydralazine, procainamide), Iatrogenic (cardiac surgery - postpericardiotomy syndrome, coronary perforation, pacemaker lead penetration), Other (irradiation, aortic dissection). Tuberculosis is a significant concern in endemic areas and specific patient populations.

Evaluation Support:

  • Echocardiography: Used to evaluate for pericardial effusion.
  • CMR imaging/Gated Cardiac CT: Identifies "pericardial inflammation, characterized by pericardial thickening and late gadolinium enhancement."
  • Serologic Evidence: Elevated erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and leukocytosis. Serum cardiac troponin levels may be "normal or may be slightly elevated if there is a component of myopericarditis."

Management:

  • Outpatient vs. Hospitalization: Most managed as outpatients, but hospitalization is required for high-risk features like temperature >38°C, subacute onset, large effusion/tamponade, oral anticoagulation, or lack of response to treatment.
  • First-line Therapy: Aspirin (750-1000 mg every 8 hours for 1-2 weeks) or NSAIDs (ibuprofen 600 mg every 8 hours for 1-2 weeks).
  • Adjunctive Therapy: "Colchicine (0.5 mg once or twice daily for 3 months) is recommended as adjunctive therapy to shorten symptom duration and reduce treatment failure and recurrence."
  • Glucocorticoids: Reserved for specific cases (recurrent, incessant, or chronic pericarditis despite standard therapy; uremic pericarditis unresponsive to dialysis; contraindications to NSAIDs; autoimmune-mediated pericarditis). Prednisone is added to standard therapy. CRP can guide tapering.
  • Activity Restriction: Athletes should not return to competitive exercise for 3 months. Non-athletes restrict strenuous activity until symptoms resolve.

2. Pericardial Effusion and Cardiac Tamponade

2.1. Pericardial Effusion

Definition: Accumulation of fluid within the pericardial space. Causes: Often idiopathic, but malignancy, infections (tuberculosis in endemic areas), autoimmune disease, hypothyroidism, and iatrogenic causes should be considered. Management:

  • Pericardiocentesis: Considered for diagnostic and therapeutic purposes if cancer or bacterial infection is suspected, or for large idiopathic effusions of >3 months' duration (due to 1 in 3 patients progressing to tamponade).
  • Empiric Treatment: Reasonable for effusions of unknown cause with elevated inflammatory markers.

2.2. Cardiac Tamponade

Definition: "Cardiac tamponade occurs when fluid accumulation within the pericardial space compresses the heart and impedes diastolic filling." It can arise rapidly with low volumes (trauma, aortic dissection) or slowly with large volumes (neoplastic disease, hypothyroidism).

Clinical Presentation & Evaluation:

  • Signs: Tachycardia, muffled heart sounds, and elevated central venous pressure (CVP). Hypotension may occur as pressures rise. The "y descent of the jugular venous pulse may be absent."
  • Pulsus Paradoxus: A "key clinical feature," characterized by a "fall in systolic pressure of greater than 10 mm Hg during inspiration." It is not specific to tamponade.
  • ECG: Sinus tachycardia, "electrical alternans (related to a swinging motion of the heart within the pericardial fluid)," or low voltage.
  • Chest Radiography: "Typically enlarged cardiac silhouette (water bottle heart)" if fluid accumulated slowly.
  • Echocardiography: Essential for diagnosis, defining fluid presence, distribution, and volume. Key findings include "Early diastolic collapse of the right ventricle, late diastolic collapse of the right atrium, abnormal interventricular septal motion, inspiratory decrease in mitral inflow velocity, and IVC plethora."
  • Cardiac Catheterization (rarely necessary): Hemodynamic hallmarks include "blunting or loss of the y descent within the right atrial pressure waveform and elevated and equalized diastolic pressures."

Management:

  • Pericardiocentesis: Primary treatment, often guided by echocardiography or fluoroscopy.
  • Surgical Therapy: Indicated when pericardiocentesis is unsafe, for tissue diagnosis, or to prevent recurrence (e.g., pericardial window for malignant effusions).
  • Hemodynamic Stabilization: Intravenous normal saline as a temporizing measure.
  • Effusive Constrictive Pericarditis: If constriction is revealed after drainage and active inflammation is suspected, medical therapy for acute pericarditis may be considered.

3. Constrictive Pericarditis

Definition: Characterized by "pericardial thickening, fibrosis, and sometimes calcification that impair diastolic filling and limit total cardiac volume."

Causes: Most commonly idiopathic in developed countries. Other causes include cardiac surgery, chest irradiation, autoimmune disease, and tuberculosis (major cause in developing countries).

Clinical Presentation & Evaluation:

  • Symptoms: Indolent progression of right-sided heart failure symptoms (peripheral edema, abdominal swelling), exertional dyspnea, and fatigue.
  • Physical Examination: "Elevated central venous pressure in nearly all patients, with prominent x and y descents." Kussmaul sign (CVP height does not fall or may increase during inspiration). "Pericardial knock" (high-frequency early diastolic sound). Pulsus paradoxus is less common than in tamponade.
  • ECG: May reveal low voltage; no specific findings....
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3 months ago
22 minutes

GI Joe Medical Boards
Cardiology - Cardiomyopathies

Myocardial Disease

1. Hypertrophic Cardiomyopathy (HCM)

1.1 Overview and Clinical Presentation

  • Definition: HCM is an "autosomal dominant heritable disorder related to mutations in the genes that primarily encode sarcomeric proteins." It is characterized by increased left ventricular (LV) wall thickness without other underlying causes (e.g., hypertension).
  • Prevalence: Affects approximately "1 in 500 persons" and can be identified in all age groups, though "index cases typically present within the third to fourth decades of life" in the U.S.
  • Asymptomatic Nature: "Most patients with HCM are asymptomatic and have normal life expectancy," often diagnosed during evaluation for a heart murmur or abnormal ECG.
  • Symptomatic Presentation: Symptomatic individuals typically present with "signs and symptoms of heart failure (dyspnea, fatigue) or arrhythmias (palpitations, syncope)."
  • Sudden Cardiac Death (SCD): SCD "may be the initial manifestation in some patients."
  • Pathophysiology of Symptoms: Heart failure symptoms are due to "abnormal LV filling (diastolic dysfunction)" and "dynamic left ventricular outflow tract (LVOT) obstruction."
  • Diastolic Dysfunction: Involves "increased chamber stiffness, progressive fibrosis, and myocardial ischemia."
  • Dynamic LVOT Obstruction: The "classic form of HCM," characterized by "asymmetric LV hypertrophy with prominent interventricular septal thickening." Found in 30% of patients at rest and an additional 40% with provocation.
  • "Eject-obstruct-leak" triad: During systole, "anterior motion of the mitral valve results in early to midsystolic obstruction of the LVOT and subsequent mitral regurgitation related to leaflet malcoaptation."

1.2 Evaluation

  • Physical Examination: May be normal without LVOT obstruction. A cardiac murmur is common with LVOT obstruction. Dynamic maneuvers (Valsalva, standing from squat, peripheral pulse after PVC) help differentiate HCM from fixed valvular aortic stenosis (see Table 27 in original source).
  • Murmur Characteristics: Ejection-quality, usually best heard at the left lower sternal border, "generally does not radiate to the carotid arteries."
  • Valsalva Maneuver: "Increase in intensity of murmur during strain phase."
  • ECG: Abnormal findings in 75% to 95% of patients, including "increased QRS voltage, evidence of left atrial enlargement, LV conduction abnormalities, pathologic Q waves, and significant repolarization abnormalities."
  • Echocardiography (TTE): Most common diagnostic tool. Demonstrates hypertrophy (≥15 mm LV region or 13-14 mm with first-degree relative with HCM), LVOT obstruction, and mitral regurgitation. Provocative maneuvers (Valsalva, squatting) and exercise echocardiography may be used.
  • Cardiac Magnetic Resonance (CMR) imaging: Indicated for inconclusive echocardiographic findings to clarify diagnosis. Useful for differentiating HCM from other conditions causing increased LV wall thickness.
  • Ambulatory ECG Monitoring: "24- to 48-hour ambulatory ECG monitoring should be performed to evaluate for arrhythmias." Nonsustained ventricular tachycardia indicates higher SCD risk.
  • Exercise Stress Testing: Reasonable for functional status and prognostic information.
  • Differential Diagnosis (Table 28): Must differentiate from other conditions with increased LV wall thickness like "Hypertension," "Athlete heart," "Amyloidosis," "Fabry disease," and "Friedreich ataxia."

1.3 Risk Stratification and Management

  • Annual Mortality Risk: "Patients with HCM have an annual risk for death of 1%, primarily related to fatal arrhythmia and heart failure."
  • SCD Risk Factors (Table 29):Previous SCD or sustained ventricular tachycardia
  • LV wall thickness ≥30 mm
  • ≥1 Episode of syncope thought to be arrhythmic in nature
  • LV apical aneurysm
  • LVEF <50%
  • Implantable Cardioverter-Defibrillator (ICD):Secondary Prevention: Recommended for patients with previous SCD or sustained ventricular tachycardia.
  • Primary Prevention: "Reasonable" for patients with one or more established risk factors.
  • CMR in Risk Assessment: Beneficial for assessing maximum LV wall thickness, ejection fraction, LV apical aneurysm, and extent of myocardial fibrosis with late gadolinium enhancement (LGE). LGE ≥15% can serve as a risk modifier for ICD placement in indeterminate cases.
  • Lifestyle Interventions: For overweight/obese patients, weight loss to decrease LVOT obstruction, heart failure, and atrial fibrillation risk. Avoid dehydration, excessive alcohol, and exposures causing vasodilation/decreased preload (e.g., saunas, hot tubs).
  • Exercise: "Mild- to moderate-intensity exercise is generally safe and beneficial." Athletes require comprehensive evaluation and shared decision-making.
  • Pharmacologic Therapy for Symptomatic Patients:First-line: Nonvasodilating β-blockers (avoid carvedilol, labetalol, nebivolol).
  • Alternatives: Verapamil or diltiazem if β-blockers are contraindicated/intolerated.
  • Persistent Symptoms with LVOT Obstruction: Adding a cardiac myosin inhibitor or disopyramide.
  • Caution with Diuretics: Use cautiously for dyspnea, as small changes in volume can impact cardiac output.
  • Avoid: Nitrates and phosphodiesterase-5 inhibitors due to LVOT obstruction exacerbation.
  • Invasive Treatment for Obstruction: Recommended for severe obstructive symptoms refractory to maximal medical therapy and LVOT gradient ≥50 mm Hg.
  • Surgical Septal Myectomy: "Associated with a higher likelihood of complete symptom resolution, greater obstruction relief, and a lower rate of repeat procedures." Favored in young patients.
  • Catheter-based Alcohol Septal Ablation: Carries a higher risk for atrioventricular block requiring pacemaker. More appropriate for older patients with comorbidities.
  • Atrial Fibrillation (AFib) Management:Rate control and anticoagulation (regardless of CHA2DS2-VASc score). Direct oral anticoagulants are first-line.
  • Anticoagulation for subclinical AFib >24 hours detected by ambulatory monitoring.
  • Consider rhythm control early for symptomatic patients.
  • Avoid digoxin due to positive inotropic effects worsening LVOT gradient.
  • End-Stage HCM: Fewer than 5% progress to dilated cardiomyopathy with systolic dysfunction. Guideline-directed therapy and ICD for primary prevention are recommended if LVEF <50%.

1.4 Surveillance

  • Asymptomatic Patients: ECG every 1-2 years; 24-48-hour ambulatory ECG monitoring at diagnosis and every 1-2 years.
  • Repeat TTE: Recommended with any change in clinical status or new cardiac event; every 1-2 years in asymptomatic patients to assess for mitral regurgitation, LV hypertrophy, function, and obstruction.

1.5 Role of Genetic Testing and Counseling

  • Recommendation: Genetic testing is recommended for patients meeting the clinical definition of HCM to identify the causative mutation.
  • Family Screening: First-degree relatives should undergo screening with ECG and echocardiography (every 1-2 years in children/adolescent...
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3 months ago
26 minutes

GI Joe Medical Boards
Cardiology - Vavulopathies

Valvular Heart Disease

1. Summary

Valvular Heart Disease (VHD) is a significant cardiac condition affecting approximately 20 million people in the United States, primarily age-dependent. It involves structural or functional valve abnormalities leading to either regurgitation (failure to close competently) or stenosis (failure to open effectively). VHD progression is slow, often causing patients to unconsciously limit activity, emphasizing the need for careful history and detailed physical examination. Diagnosis relies on ECG, chest radiography, and transthoracic echocardiography (TTE), with classification into four stages (A-D) to guide monitoring and intervention. While medical therapy offers symptom palliation, surgical or transcatheter interventions are crucial for improving long-term survival, especially in severe cases. A multidisciplinary "heart team" approach is recommended for intervention considerations. Specific VHDs discussed include Aortic Stenosis, Aortic Regurgitation, Bicuspid Aortic Valve Disease, Mitral Stenosis, Mitral Regurgitation, Tricuspid Valve Disease, and conditions related to Prosthetic Valves and Infective Endocarditis (IE).

2. General Principles of Valvular Heart Disease (VHD)

  • Definition and Prevalence: VHD is characterized by cardiac dysfunction due to "structural or functional valve abnormalities resulting from failure of the valves to either competently close (regurgitation) or effectively open (stenosis)." It affects around 20 million people in the U.S., with prevalence increasing with age (3-6% in those ≥65 years).
  • Clinical Presentation: Patients often "limit their activity unconsciously in response" to slow progression. "Exertional dyspnea is the most common symptom," accompanied by others such as angina, syncope, palpitations, and edema, depending on lesion and severity.
  • Diagnosis and Evaluation: Essential tests include "Twelve-lead ECG, chest radiography, and transthoracic echocardiography (TTE)."
  • Staging: VHD is classified into four stages (A-D) based on risk factors, symptoms, lesion severity, ventricular response, pulmonary/systemic circulation effects, and rhythm changes (Table 22):
  • Stage A (At risk): Patients with VHD risk factors.
  • Stage B (Progressive and asymptomatic): Asymptomatic with progressive VHD.
  • Stage C (Asymptomatic severe): Asymptomatic with severe VHD, categorized by compensated (C1) or decompensated (C2) ventricular function.
  • Stage D (Symptomatic severe): Patients with VHD-related symptoms.
  • Management Philosophy: "Medical therapy, although often effective for symptom palliation, has not been shown to prevent VHD progression or improve long-term survival." Surgery is "life-saving in select patients," requiring careful surgical risk calculation (age, morbidities, frailty, procedure-specific impediments). A "multidisciplinary approach with a heart team consisting of a cardiologist, a surgeon, and an interventional cardiologist is recommended" for intervention.

3. Specific Valvular Heart Diseases

3.1. Aortic Stenosis (AS)

  • Etiology: Most commonly "degeneration of the valve that occurs with aging," or congenital (bicuspid aortic valve). Rheumatic disease and chest irradiation are other acquired causes.
  • Pathophysiology: Chronic pressure overload of the left ventricle (LV) leads to concentric LV hypertrophy, myocardial interstitial fibrosis, diastolic dysfunction, and eventual systolic heart failure.
  • Symptoms & Prognosis: "Exertional dyspnea, syncope, and angina are the most common symptoms," often not appearing until severe. "Among asymptomatic patients with severe aortic stenosis, 75% will die or develop symptoms within 5 years. Once symptoms occur, life expectancy is generally only 1 to 2 years."
  • Diagnosis: TTE is the primary imaging modality. Severe AS is typically defined by "a small valve area (≤1.0 cm2), high peak velocity (>4 m/s), and/or high mean gradient (>40 mm Hg)." Subsets like low-flow, low-gradient AS require further evaluation (dobutamine echocardiography).
  • Management: "Aortic valve replacement is a life-prolonging procedure." Indications include symptoms, LV systolic dysfunction (<50% ejection fraction) in asymptomatic patients, or concomitant cardiac surgery.
  • Surgical Aortic Valve Replacement (SAVR) vs. Transcatheter Aortic Valve Implantation (TAVI): Both have similar survival rates (1-3% operative mortality). Choice depends on symptoms and surgical risk. TAVI is recommended for symptomatic patients >80 years or younger patients with life expectancy <10 years, and for high/prohibitive surgical risk patients with good post-procedure survival prospects. For 65-80 years, either is appropriate with shared decision-making.
  • Medical Therapy: Statins are ineffective in slowing progression. Guideline-directed medical therapy is for coexistent hypertension or heart failure, with caution for vasodilators.

3.2. Aortic Regurgitation (AR)

  • Etiology: Can be acute or chronic, stemming from aortic root pathology or valve pathology (e.g., endocarditis, bicuspid valve, rheumatic disease, trauma, dissection).
  • Pathophysiology (Chronic): Volume overload leads to "progressive LV dilatation and eccentric hypertrophy," eventually causing symptoms like shortness of breath, fatigue, or angina.
  • Clinical Findings (Chronic): Result from large stroke volume and LV dilatation, including "bounding peripheral pulses, displacement of the LV apex, and a diastolic decrescendo murmur."
  • Clinical Findings (Acute): Abrupt volume overload can cause acute heart failure or cardiogenic shock. Bounding pulses may be absent, and murmurs softer/shorter.
  • Diagnosis: TTE is indicated. Criteria for severe AR include specific jet width, vena contracta, regurgitation volume, and effective regurgitant orifice area. Aortic root abnormalities require CMR, CT, or TEE.
  • Management:Chronic AR: Surgery (SAVR) is advised for symptomatic patients or those with LV dysfunction (EF ≤50% or indexed end-systolic dimension >25 mm/m2). TAVI is generally not performed for isolated severe AR.
  • Medical Therapy: Dihydropyridine calcium channel blockers, ACE inhibitors, or ARBs for concomitant hypertension. ACE inhibitors/ARBs and β-blockers if surgery is not an option.
  • Acute AR: Due to aortic dissection is a "surgical emergency." Other acute causes require surgery based on severity, symptoms, and hemodynamic stability.

3.3. Bicuspid Aortic Valve (BAV) Disease

  • Prevalence: Affects 1-2% of the population.
  • Pathology: Abnormal shear forces lead to "early degeneration of the valve, resulting in stenosis in most patients (up to 75%) and pure regurgitation in a small minority."
  • Associated Abnormalities: Often accompanied by "aortic abnormalities, independent of the severity of aortic stenosis or regurgitation, and may be associated with aneurysm, dissection, or coarctation." Lifelong serial imaging of the ascending aorta and aortic arch is indicated if abnormalities are detected.
  • Heritability: BAV is a "heritable abnormality," recommending screening for first-degree relatives.
  • Management: Determined by predominant lesion and severity. Surgical repair of the ascending aorta is reasonable for patients undergoing valve surgery if t...
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3 months ago
37 minutes

GI Joe Medical Boards
Cardiology - Arrhythmias

Arrhythmias

I. Introduction to Arrhythmias

Cardiac arrhythmias are disruptions in the heart's rhythm or rate, manifesting in seven basic patterns: early beats, bigeminal beats, grouped beats, pauses, bradycardia, tachycardia, and chaotic rhythms. This document will detail the diagnosis and management of specific rhythm disorders.

II. Approach to the Patient With Bradycardia

Bradycardia is defined as a heart rate below 50 beats per minute (<50/min). While it can be a normal finding in trained athletes or during sleep, it can also be symptomatic, presenting as "light-headedness, syncope, exertional intolerance, dyspnea, or fatigue."

Clinical Presentation and Evaluation

Diagnosis involves a "thorough history, physical examination, focused laboratory testing (electrolyte levels, thyroid function testing), and resting 12-lead ECG." It's crucial to identify severe or unstable conduction abnormalities requiring urgent intervention and to investigate "extrinsic and reversible causes," such as ischemia, hypothyroidism, infections, electrolyte imbalances, and medication use (e.g., AV nodal blockers). Echocardiography, exercise stress testing, and ambulatory ECG monitoring may also be helpful. Sleep apnea should be considered for nocturnal bradycardia.

Types of Bradycardia

  • Sinus Bradycardia: Sinus rhythm with a heart rate below 50/min. Pathologic causes often include "sinus node dysfunction due to age-related myocardial fibrosis." Extrinsic causes commonly involve "medication use (β-blockers, donepezil, neostigmine, pyridostigmine)."
  • Atrioventricular (AV) Block: Classified into three degrees:
  • First-degree AV Block: "Delay in AV conduction (PR interval >200 ms)." Often benign.
  • Second-degree AV Block:Mobitz type 1 (Wenckebach): Progressive PR prolongation until a QRS complex is dropped.
  • Mobitz type 2: Intermittent nonconducted P waves with unchanging PR intervals. This type "usually occurs below the AV node and has a higher risk for progression to complete heart block."
  • Third-degree AV Block (Complete Heart Block): "No P waves conduct to the ventricles. AV dissociation is observed on the ECG."

Management of Bradycardia

  • Acute Management: For hemodynamically unstable bradycardia, "intravenous atropine should be administered." If ineffective, "chronotropic drug infusions (e.g., dopamine or epinephrine)" can be used until temporary pacing is implemented. "Temporary pacing is indicated for transient conditions causing hemodynamically unstable bradycardia or asystole."
  • Long-Term Management (Permanent Pacing):Reversible and extrinsic causes should always be addressed first.
  • Common indications for permanent pacing include:
  • "Symptomatic bradycardia without reversible cause"
  • "Permanent AF and symptomatic bradycardia"
  • "Alternating bundle branch block"
  • "Complete heart block, high-degree AV block, or Mobitz type 2 second-degree AV block, regardless of symptoms."
  • Patients with stable left or right bundle branch block without prolonged PR interval generally do not require pacing due to low risk of progression to complete heart block (1%-3% per year).
  • Cardiac Implantable Electronic Devices (CIEDs): Various devices offer functions beyond pacing, including antitachycardia pacing and defibrillation. These include Transvenous pacemakers, Leadless pacemakers, Implantable cardioverter-defibrillators (ICDs), Subcutaneous ICDs, Cardiac resynchronization therapy–pacing (CRT-P), and Cardiac resynchronization therapy–defibrillator (CRT-D).

III. Approach to the Patient With Tachycardia

Tachycardia is defined as a heart rate above 100 beats per minute (>100/min). Symptoms range from "tachypalpitations" to "syncope," or it may be discovered incidentally.

Clinical Presentation and Evaluation

"Documentation of tachycardia on ECG and correlation with symptoms is the key component of the diagnostic evaluation." Tachyarrhythmias are broadly categorized as supraventricular (originating above the AV node, normal QRS) or ventricular (originating below the AV node, widened QRS). History, medication review, physical exam, thyroid function testing, and echocardiography are part of the evaluation.

Antiarrhythmic Drugs

Antiarrhythmic agents are often classified by the Vaughan-Williams system (Classes I-IV), though many have multiple mechanisms. "Class I and class III agents are the most effective antiarrhythmic drugs; however, due to their membrane-active effects, they carry some paradoxical risk of inducing arrhythmia."

  • Class I (Sodium Channel Blockers):Class IB (Lidocaine, Mexiletine): Primarily for ventricular arrhythmias.
  • Class IC (Flecainide, Propafenone): Used for atrial fibrillation and SVT. "Contraindicated in patients with ischemic or structural heart disease because of the risk for promoting ventricular arrhythmias and death."
  • Class II (β-Adrenergic Blockers): (e.g., Metoprolol, Propranolol) Decrease heart rate, prolong PR interval. Used for rate control in atrial arrhythmias and SVT.
  • Class III (Potassium Channel Blockers): (e.g., Sotalol, Dofetilide, Amiodarone, Dronedarone) Prolong QT interval. Used for atrial and ventricular arrhythmias. "Class III antiarrhythmic therapy typically is initiated in an inpatient setting" with QTc monitoring. Amiodarone is widely used but has significant toxicities (thyroid, liver, lung, eye) requiring regular monitoring.
  • Class IV (Calcium Channel Blockers - nondihydropyridines): (e.g., Verapamil, Diltiazem) Decrease heart rate, prolong PR interval. Used for SVT and rate control of atrial arrhythmias.
  • Other Agents:Adenosine: An A1-receptor agonist causing brief AV block, used for "termination of SVT."
  • Digoxin: Increases vagal activity, slowing AV node conduction, used for "rate control of atrial fibrillation."

Types of Tachycardia

  • Sinus Tachycardia: Elevated heart rate due to "physiologic demand or distress," such as exercise, pain, or anxiety.
  • Inappropriate Sinus Tachycardia (IST): Elevated resting heart rate with exaggerated increases during activity, often in women aged 20-40. Diagnosis requires exclusion of secondary causes.
  • Postural Orthostatic Tachycardia Syndrome (POTS): A dysautonomia with orthostatic intolerance and excessive tachycardia upon standing (increase of ≥30/min or to >120/min within 10 minutes).

Supraventricular Tachycardias (SVTs)

Rapid heart rhythms originating from the atrium or requiring AV node conduction. They are common, often in younger patients and women, and typically occur without structural heart disease. ECG usually shows a narrow-complex tachycardia.

  • Acute Management of SVT: "Vagal maneuvers, including the Valsalva maneuver or carotid sinus massage, are first-line therapy." "Adenosine can be used to terminate SVT and simultaneously help diagnose its mechanism."
  • Atrioventricular Nodal Reentrant Tachycardia (AVNRT): Accounts for two-thirds of SVT cases (excluding AF/flutter). Caused by a reentrant circuit within the AV node. "AV nodal blockers (β-blockers or calcium channel blockers) are used to prevent recurrent AVNRT." "Catheter ablation of AVNRT has a high success rate."
  • Atrioventricular Reciprocating Tachycardia (AVRT): Accessory p...
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3 months ago
38 minutes

GI Joe Medical Boards
Cardiology - Heart Failure

Heart Failure

I. Overview of Heart Failure

Heart failure (HF) is a complex clinical syndrome resulting from structural or functional impairment in blood ejection or ventricular filling. It manifests with signs of fluid overload and/or decreased cardiac output.

Key Characteristics:

  • Fluid overload symptoms: Dyspnea (shortness of breath), paroxysmal nocturnal dyspnea (PND), orthopnea (difficulty breathing when lying flat), peripheral edema, crackles in lungs, elevated central venous pressure, and an S3 heart sound.
  • Decreased cardiac output symptoms: Hypotension, low pulse pressure, cool extremities, reduced cognition, and worsening kidney or liver function.

Types of Heart Failure based on Left Ventricular Ejection Fraction (LVEF):

  • Heart failure with reduced ejection fraction (HFrEF): LVEF of 40% or less.
  • Common Causes: Coronary artery disease (CAD), hypertension, obesity, diabetes mellitus, and valvular heart disease.
  • Pathophysiology: Reduced LVEF triggers neurohormonal system activation (Renin-Angiotensin-Aldosterone System (RAAS) and sympathetic nervous system). Initially adaptive, this becomes "chronic and maladaptive in the long term," leading to vasoconstriction, fluid overload, and "ventricular remodeling" (structural and functional changes in myocytes that worsen LV function).
  • Heart failure with preserved ejection fraction (HFpEF): LVEF of 50% or greater.
  • Common Causes: Hypertension (most common), aging, obesity, diabetes mellitus, atrial fibrillation, and CAD. Amyloid deposits are found in over 10% of HFpEF patients.
  • Heart failure with mildly reduced ejection fraction (HFmEF): LVEF between 40% and 50%. This category includes "up to 25% of all patients with heart failure" and often receives similar treatment to HFrEF.

II. Screening and Diagnosis

A. Screening for Asymptomatic Patients at Risk:

  • Pooled Cohort Equation to Prevent Heart Failure risk score: Can identify asymptomatic patients at increased risk, though the inclusion of race as a variable "is likely a flawed approach and limits the utility."
  • Natriuretic Peptide Biomarker-based Screening: Useful in patients at risk (e.g., hypertension, diabetes, vascular disease). Elevated B-type natriuretic peptide (BNP) or N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels may prompt team-based care to prevent LV dysfunction. However, "there is no agreed-on standard for such screening and no certainty as to its cost-effectiveness."

B. Clinical Evaluation and Diagnosis:

  • Comprehensive History and Physical Examination: Focus on risk factors and assessment of fluid and perfusion status.
  • Initial Diagnostic Testing:ECG: Evaluates for myocardial infarction, tachyarrhythmia, or LV hypertrophy.
  • Chest Radiography: May show cardiomegaly, vascular congestion, Kerley B lines, or pleural effusion; can also rule out pulmonary causes of dyspnea.
  • Natriuretic Peptides (BNP/NT-proBNP): Crucial for differentiating cardiac from pulmonary causes of dyspnea. "BNP levels are elevated in patients with increased filling pressures and heart failure (typically >400 pg/mL)," while low in pulmonary disease (typically <100 pg/mL). High sensitivity and negative predictive value for HF. Note: BNP levels can be influenced by kidney failure, age, sepsis, ARNI therapy, female sex, and are typically reduced in elevated BMI.
  • Laboratory Assessment: Complete blood count, serum electrolytes, kidney and liver function tests, glucose, lipid levels, and thyroid-stimulating hormone (TSH).
  • Echocardiography: "The primary diagnostic modality for evaluation of heart failure." Provides information on chamber size, thickness, systolic/diastolic function, valvular pathology, and clues to underlying causes (e.g., regional wall motion abnormalities for CAD, myocardial changes for amyloidosis).
  • Cardiac Magnetic Resonance (CMR) Imaging: Used for myocarditis and infiltrative processes (e.g., hemochromatosis, sarcoidosis, amyloidosis). Not routinely recommended; used only "in the search for a specific diagnosis."
  • H2FPEF Risk Score: Assesses the likelihood of HFpEF to discriminate cardiac versus noncardiac dyspnea. Variables include obesity, atrial fibrillation, age >60, multiple antihypertensive drugs, and specific echocardiographic findings (E/e′ ratio >9, estimated pulmonary artery systolic pressure >35 mm Hg).
  • Evaluation for Ischemia: CAD is the "leading cause of heart failure in the United States (>50% of patients)." Stress testing or coronary angiography may be considered based on symptoms, risk factors, and ECG/echocardiogram findings.
  • Diagnosis Confirmation: HFrEF and HFpEF are diagnosed by appropriate LVEF combined with increased left ventricular filling pressures, documented by elevated natriuretic peptides, echocardiographic criteria, or invasive hemodynamic assessment.

C. Classification of Heart Failure Severity:

  • New York Heart Association (NYHA) Functional Classification: Categorizes symptom severity (Class I: no limitations to Class IV: unable to perform any physical activity without symptoms). Patients can move between classes.
  • American College of Cardiology (ACC)/American Heart Association (AHA) Stages of Heart Failure:Stage A: At Risk for HF: Risk factors present, but no symptoms, structural heart disease, or cardiac biomarkers.
  • Stage B: Pre-HF: No symptoms, but evidence of structural heart disease, reduced ventricular function, increased filling pressures, or elevated biomarkers.
  • Stage C: Symptomatic HF: Structural heart disease with current or previous HF symptoms.
  • Stage D: Advanced HF: Marked HF symptoms that interfere with daily life and recurrent hospitalizations despite optimized guideline-directed medical therapy (GDMT). Patients can only progress in these stages.

III. Management of Heart Failure

A. General Principles:

  • Multidisciplinary Team Management: Essential for optimal treatment due to the complexity and high comorbidity burden (e.g., hypertension, diabetes, CKD, COPD, dementia, malignancy, depression). Involves primary care, cardiology, and other specialists.
  • Patient Education and Adherence: Repeated patient education, nonjudgmental assessment of adherence, and addressing obstacles are crucial for medication, diet, activity, and weight monitoring. Avoiding over-the-counter NSAIDs is advised.
  • Primary Care Prevention: Focus on modifying risk factors like hypertension (goal <130/80 mm Hg) and diabetes (metformin, SGLT2 inhibitors). Weight loss and smoking cessation also prevent CAD, a major HF cause. Routine vaccinations (pneumonia, influenza) are important.
  • Lifestyle Modification: Sodium restriction (1.5-2 g/day) and fluid restriction (1.5-2 L/day) are commonly advised. "Exercise training is recommended for all patients," improving functional capacity and quality of life.
  • Sleep-Disordered Breathing: Common and underdiagnosed. Guideline-directed medical therapy for HF is the initial treatment. Persistent sleep-disordered breathing despite HF therapy should be treated with CPAP for obstructive sleep apnea. Adaptive...
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3 months ago
53 minutes

GI Joe Medical Boards
Cardiology - Diagnostics

Diagnostic Testing in Cardiology

I. Foundational Principles of Diagnostic Testing

The document begins by establishing the "diagnostic cornerstone" of CVD as the "clinical history and physical examination." This initial assessment is critical for ensuring a "focused and appropriate diagnostic evaluation." Subsequent cardiovascular testing serves both "diagnostic and prognostic information," and its application should be judicious, considering:

  • Symptoms: The patient's reported symptoms.
  • Pretest likelihood of disease: The probability of disease before testing.
  • Impact on patient management: Whether test results will change treatment strategies.
  • Shared decision-making: Collaboration between clinician and patient.

II. Diagnostic Testing for Atherosclerotic Coronary Artery Disease (CAD)

Diagnostic tests for CAD are broadly categorized into those providing functional evidence (ischemia, blood flow, wall motion abnormalities) and anatomic information (atherosclerotic burden).

A. Functional Studies (Detection of Ischemia and Blood Flow)

These studies reveal the presence, extent, and severity of ischemia.

  • Exercise ECG:
  • Utility: "Reasonable initial diagnostic test in patients suspected of having CAD." Less accurate than stress testing with imaging.
  • Advantages: Provides data on "exercise capacity, blood pressure and heart rate response, and provoked symptoms."
  • Limitations: "Not useful when baseline ECG is abnormal (LVH, LBBB, paced rhythm, preexcitation, >1-mm ST-segment depression)."
  • Prognostic Value: "Exercise capacity is a powerful predictor of outcomes," with individuals unable to achieve 5 metabolic equivalents (METs) or the first stage of a Bruce protocol having "higher all-cause mortality." Heart rate recovery (drop of <12/min in the first minute post-exercise) is also associated with higher mortality.
  • Stress Echocardiography:
  • Utility: "Effective diagnostic test option for patients suspected of having CAD." Recommended when baseline ECG is abnormal or specific myocardial area information is needed.
  • Advantages: Combines "exercise data acquired along with wall motion images to assess for ischemia," allows evaluation of "valve function and pulmonary pressures," "relatively portable and less costly than nuclear protocols," and "entire study is completed in <1 h."
  • Limitations: "Image quality is suboptimal in some patients," "image interpretation is difficult when baseline wall motion abnormalities are present," and diagnostic accuracy decreases with single-vessel disease or delayed image acquisition.
  • SPECT Myocardial Perfusion Imaging (MPI) / Nuclear Stress Testing:
  • Utility: "Effective diagnostic test option for patients suspected of having CAD." Recommended with abnormal baseline ECG or need for specific myocardial area information.
  • Advantages: Gating and attenuation correction improve specificity. Late reperfusion imaging can assess myocardial viability with thallium.
  • Limitations: "Attenuation artifacts can be caused by breast tissue or diaphragm interference." LBBB may cause false-positive septal abnormalities. Involves "Radiation exposure."
  • Viability Testing: Regions with fixed defects can be infarct or hibernating myocardium; viability assessment (e.g., thallium or dobutamine echo) helps differentiate.
  • Cardiac PET/CT:
  • Utility: "Provides best perfusion images in patients with perfusion, function, and viability."
  • Advantages: "Study duration is shorter and radiation dose is lower than SPECT stress only," "absolute myocardial blood flow can be measured," and "can be combined with CAC scoring."
  • Limitations: "Not widely available," "more expensive than SPECT," and involves "Radiation exposure."
  • Cardiac Magnetic Resonance (CMR) Imaging:
  • Utility: Assesses "wall motion abnormalities during dobutamine infusion" and "perfusion abnormalities during adenosine infusion." Identifies "anomalous coronary artery origin."
  • Advantages: "Provides excellent spatial resolution," "accurate test for myocardial ischemia or viability," and provides data on "infarction and viability using gadolinium contrast."
  • Limitations: "Some patients experience claustrophobia," "may be contraindicated in patients with an older pacemaker, ICD, or other implanted device," certain gadolinium agents are contraindicated in CKD, "sinus rhythm and a slower heart rate are needed for improved image quality," and "limited availability and expertise."

B. Anatomic Information (Atherosclerotic Burden)

These studies visualize the coronary arteries.

  • Coronary Angiography (Invasive):
  • Utility: "Provides anatomic diagnosis of the presence and severity of CAD."
  • Advantages: Allows "evaluation of coronary anatomy with functional assessment of coronary stenosis (FFR, IFR)" and "Percutaneous revascularization can be performed after diagnostic study."
  • Limitations: "Invasive," with risks associated with "vascular access and radiocontrast exposure (kidney dysfunction, allergy, bleeding)," and "Radiation exposure."
  • FFR/IFR: "Measures the hemodynamic significance of a lesion and helps determine the need for intervention."
  • Coronary CT Angiography (CTA):
  • Utility: "Useful for patients with intermediate risk for CAD, particularly in patients aged <65 y." Also used for "acute chest pain in the emergency department" in select cases.
  • Advantages: "Identifies anomalous coronary arteries," and "coronary artery vessel lumen and atherosclerotic lesions can be visualized in detail."
  • Limitations: Requires high-resolution CT, "does not provide detailed images of distal vessel anatomy," "Catheterization will be needed if intervention is planned," and involves "Radiation and radiocontrast exposure."
  • PROMISE trial: Showed low composite cardiovascular event rates and similar outcomes at 2 years for initial CTA vs. functional testing in intermediate pretest probability patients.
  • Coronary Artery Calcium (CAC) Scoring:
  • Utility: "May inform preventive treatment decisions for patients with intermediate or borderline 10-y risk for cardiovascular events."
  • Advantages: "CAC scores are predictive of cardiovascular risk in selected patients."
  • Limitations: "Does not provide data on coronary luminal narrowing," and involves "Radiation exposure."
  • Interpretation: Scores categorized as 0 (no disease), 1-99 (mild), 100-400 (moderate), >400 (severe). Absence of CAC is associated with low cardiovascular event risk.

C. Cardiac Stress Testing General Considerations:

  • Pretest Probability: Stress testing is most effective in patients with an "intermediate pretest probability of CAD (10% to 90%)."
  • Exercise Preference: "Stress testing to evaluate for CAD should always be performed with exercise unless exercise is contraindicated or the patient is unable."
  • Medication Management: Cardiac medications may be withheld before testing to achieve adequate h...
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3 months ago
31 minutes

GI Joe Medical Boards
Cardiology - Coronary Artery Disease

Coronary Artery Disease (CAD)

This briefing summarizes key information regarding Coronary Artery Disease, covering stable angina pectoris, acute coronary syndromes (ACS), and management in specific patient populations.

I. Stable Angina Pectoris

Definition and Diagnosis: Stable angina pectoris is characterized as "reproducible angina (discomfort or pressure of the chest, neck, or arms) of at least 2 months' duration that is precipitated by a stable level of exertion or emotional stress and is relieved with rest." In contrast, unstable angina is defined by "new-onset angina or angina occurring at a relatively low level of exertion, occurring at rest, or accelerating in frequency or severity," carrying an increased short-term risk for acute myocardial infarction (MI).

The evaluation of angina involves a focused history to elicit details on:

  • Anginal Characteristics: Quality, location, radiation, duration, aggravating factors (exertion, anxiety, meals), relieving factors, and associated symptoms (shortness of breath, nausea, diaphoresis).
  • Atypical Presentation: Certain groups, including "women and patients with diabetes mellitus, may present only with atypical symptoms, including exertional dyspnea, nausea, or exaggerated fatigue."
  • Physical Examination: Focuses on the cardiovascular system and ruling out conditions mimicking angina (e.g., heart failure, pulmonary hypertension, valvular heart disease, hypertrophic cardiomyopathy).
  • Diagnostic Testing: The initial step is to determine pretest probability of CAD. Stress testing is used for diagnosis and prognosis. If abnormal, further evaluation is warranted.

General Approach to Treatment: Treatment for stable angina involves a multi-pronged approach, encompassing:

  1. Risk Factor Modification: "Regular physical activity, weight loss, tobacco cessation, and dietary changes." Blood pressure control (goal <130/80 mm Hg) and diabetes management are also emphasized.
  • Cardioprotective Medications:Aspirin: Low-dose (75-162 mg/d) is recommended for secondary prevention due to similar efficacy and lower bleeding risk compared to high-dose. Clopidogrel is an alternative for aspirin-intolerant patients.
  • Lipid-lowering Therapy (Statins): High-intensity statin therapy (atorvastatin 40-80 mg/d or rosuvastatin 20-40 mg/d) is a cornerstone of secondary prevention, significantly reducing MI, death, and stroke. Nonstatin medications (ezetimibe, PCSK9 inhibitors) may be added for statin intolerance or inadequate LDL reduction. Icosapent ethyl provides further risk reduction in high-risk patients with hypertriglyceridemia.
  • ACE Inhibitors/ARBs: Indicated in stable angina with concomitant diabetes, chronic kidney disease, LV dysfunction (EF ≤40%), heart failure, or history of MI. ARBs are alternatives for ACE inhibitor intolerance, but combination therapy is not recommended.
  • Antianginal Medications:β-Blockers: First-line therapy, reducing heart rate, contractility, and blood pressure, thereby decreasing myocardial oxygen demand. Titration to a resting heart rate of 55-60/min is aimed for. Caution is advised with non-dihydropyridine calcium channel blockers due to additive negative effects.
  • Calcium Channel Blockers: Useful as first-line, when symptoms persist despite β-blockers, or when β-blockers are not tolerated. Short-acting dihydropyridines should be avoided. Non-dihydropyridines are contraindicated in LV dysfunction.
  • Nitrates: Improve myocardial oxygen delivery and reduce oxygen demand. Short-acting sublingual nitrates are for acute relief. Long-acting nitrates require a nitrate-free interval (8-12 hours) to prevent tolerance. Concurrent use with phosphodiesterase-5 inhibitors is contraindicated due to hypotension risk.
  • Ranolazine: Reduces wall tension and myocardial oxygen consumption. Has a modest QT-prolonging effect and interactions with CYP3A4 inhibitors.

Coronary Revascularization: Revascularization aims to "lessen angina and improve quality of life" in stable syndromes. In high-risk cases (left main CAD, large ischemic burden, heart failure), it's indicated for "prevention of future events and improved survival."

  • Percutaneous Coronary Intervention (PCI): Catheter-based techniques to relieve coronary obstruction. Drug-eluting stents are preferred. PCI "has not been shown to be superior to guideline-directed medical therapy in reducing the risk for death or MI in patients with stable angina but no anatomic or physiologic criteria for revascularization."
  • Coronary Artery Bypass Grafting (CABG): A reasonable option for multivessel CAD, resulting in "decreased recurrence of angina, lower rates of MI, and fewer repeat revascularization procedures compared with PCI or medical therapy alone," especially with arterial conduits. CABG is associated with improved survival in patients with left main or three-vessel CAD and is indicated in those with multivessel disease and diabetes. It also improves 10-year survival in patients with severe LV dysfunction.

After Revascularization:

  • Antiplatelet Therapy: Indefinitely after revascularization. Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor is crucial to reduce stent thrombosis and ischemic events. Duration depends on individual risk factors (minimum 1 month for bare metal stents, at least 6 months for drug-eluting stents in stable angina).
  • Routine Periodic Testing: "Routine periodic anatomic or ischemic testing without a change in clinical or functional status is not recommended for risk stratification or to guide therapeutic decision making in patients with chronic coronary disease, including for secondary prevention after a coronary revascularization procedure."

II. Acute Coronary Syndromes (ACS)

General Considerations: ACS results from "acute or subacute plaque rupture or erosion and coronary blood flow impairment, manifesting as acute-onset chest pain or an angina equivalent." It's characterized by serum biomarkers of myocardial injury (elevated troponin T or I).

  • STEMI vs. NSTE-ACS: Differentiated by ECG findings.
  • ST-elevation MI (STEMI): "ST-segment elevation of at least 1 mm in two or more contiguous limb or chest leads" (specific criteria for V2/V3). New bundle branch block may be a STEMI equivalent. STEMI signifies the need for "rapid initiation of reperfusion therapy."
  • Non–ST-elevation acute coronary syndrome (NSTE-ACS): Categorized by cardiac injury biomarkers. Non–ST-elevation MI is biomarker-positive without STEMI criteria. Unstable angina is biomarker-negative.
  • Mimics of STEMI: Acute pericarditis, acute aortic syndromes, severe hypercalcemia, LV hypertrophy, and supraventricular tachycardias can present with similar ECG findings or symptoms. Careful history, physical exam, and biomarker patterns are crucial for differentiation.

Reperfusion (for STEMI): "Prompt reperfusion with primary PCI (PPCI) or thrombolytic therapy is indicated in all patients with STEMI who do not have limited life expectancy from other nonreversible disease." Shorter reperfusion times correlate with improved outcomes.

  • Primary Percutaneous Coronary Intervention (PPCI): Preferred method when available within 90 minutes (first medical contact to PPCI) or 120 minutes (transfer to P...
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3 months ago
46 minutes

GI Joe Medical Boards
I'm Dr. Joseph Kumka, Gastroenterology Fellow, educator, and host of evidence-based, board-oriented medical podcasts. Whether you're a resident gearing up for the boards, a fellow diving deep into subspecialty topics, or a practicing clinician hungry for high-yield updates—you’re in the right place.