Circulation: Arrhythmia And Electrophysiology On The Beat

Dr Paul Wang:   Welcome to the monthly podcast, On The Beat for Circulation: Arrhythmia and Electrophysiology. I'm Dr Paul Wang, editor-in-chief, with some of the key highlights from this month's issue.                                 In our first paper, Ruairidh Martin and associates used ultra-high-density mapping to access the ventricular tachycardia circuit dependent upon re-entry, with scar regions in 36 tachycardias in 31 patients. The author has found that 11 of the ventricular tachycardia circuits and isthmuses were single-loop, and 25 were double-loop. Three had two entrances, five had two exits, and fifteen had dead-end activation. Isthmuses were defined by barriers which included anatomical obstacles, lines of block, and slow conduction in 27 out of 36 isthmuses. The barrier to conduction in isthmus appeared to be partially functional in 75% of circuits. Isthmus voltage is often higher in ventricular tachycardia than in sinus or paced rhythms. The authors found that conduction velocity in the VT i