Welcome to Cardiology Today – Recorded November 03, 2025. This episode summarizes 5 key cardiology studies on topics like fetal tachycardia and digoxin. Key takeaway: Self-Powered Pacemakers: Heart’s Own Energy. Article Links: Article 1: Narrowed sinus rhythm electrograms in the zone of uniform slow conduction are helpful to identify VT isthmus location, shape, and orientation. (Heart rhythm) Article 2: Bioelectric energy harvesting from myocardial tissue in vivo: A new method for biological energy collection. (Heart rhythm) Article 3: Prolonged hospitalization after catheter ablation of ventricular tachycardia: Predictors and outcomes. (Heart rhythm) Article 4: Effect of leadless left ventricular endocardial and left bundle branch area pacing on biventricular repolarization metrics. (Heart rhythm) Article 5: The maternal exposure of digoxin and flecainide in relation to the safety and effectiveness in the treatment of non-hydropic fetal tachycardia. (Heart rhythm) Full episode page: https://podcast.explainheart.com/podcast/self-powered-pacemakers-hearts-own-energy-11-03-25/ Featured Articles Article 1: Narrowed sinus rhythm electrograms in the zone of uniform slow conduction are helpful to identify VT isthmus location, shape, and orientation. Journal: Heart rhythm PubMed Link: https://pubmed.ncbi.nlm.nih.gov/40578654 Summary: isthmus location, shape, and orientation. This study aimed to improve the identification of ventricular tachycardia (V.T.) isthmus characteristics using substrate mapping. Researchers conducted 31 canine postinfarction experiments, creating an infarct and border zone in the anterior left ventricle. The findings suggest that narrowed sinus rhythm electrograms in the zone of uniform slow conduction are valuable markers for precisely identifying the location, shape, and orientation of the V.T. isthmus. This advancement provides a more accurate method for delineating V.T. reentry circuits, which is critical for successful catheter ablation. Article 2: Bioelectric energy harvesting from myocardial tissue in vivo: A new method for biological energy collection. Journal: Heart rhythm PubMed Link: https://pubmed.ncbi.nlm.nih.gov/40499804 Summary: This study explored the innovative concept of bioelectric energy harvesting directly from myocardial tissue in vivo. Researchers developed an electrophysiological measurement system utilizing microneedle electrodes to collect energy from the heart. The investigation compared the available harvested energy with the energy consumption required for cardiac pacing. This research demonstrates the potential feasibility of an internal, self-powered energy source for cardiac devices, representing a significant step towards eliminating the need for traditional batteries in pacemakers. Article 3: Prolonged hospitalization after catheter ablation of ventricular tachycardia: Predictors and outcomes. Journal: Heart rhythm PubMed Link: https://pubmed.ncbi.nlm.nih.gov/40472946 Summary: This retrospective cohort study investigated predictors of prolonged hospitalization following catheter ablation of ventricular tachycardia (V.T.) in patients with structural heart disease. Researchers analyzed 318 patient cases between January 2022 and October 2024, defining prolonged hospitalization as a post-ablation length of stay greater than seven days. The study successfully identified key factors predicting extended hospitalization after V.T. ablation, along with their subsequent impact on patient outcomes. These findings are critical for improving patient selection, optimizing post-procedural care strategies, and potentially reducing adverse events. Article 4: Effect of leadless left ventricular endocardial and left bundle branch area pacing on biventricular repolarization metrics. Journal: Heart rhythm PubMed Link: https://pubmed.ncbi.nlm.nih.gov/40436356 Summary: This study aimed to evaluate the impact of leadless left ventricular (L.V.) endocardial pacing and leadless left bundle bran