Author + information
Background: In terms of pathomechanism of J wave syndrome, delayed depolarization theory is based on heterogenous regional conduction velocity in ventricular myocardium. If polymorphic ventricular tachycardia is induced without regional conduction velocity heterogeneity, it may support the early repolarization theory. We evaluated the transmural conduction time at multiple transmural pathway in canine early repolarization syndrome models.
Methods: The Study followed the “Principles of laboratory animal care”. Transmural pseudo-ECG and endocardial/epicardial action potentials were recorded from coronary-perfused canine left ventricular wedge preparations (n = 14). The Ito agonist NS5806 (7-10 μM) and Ca2+ channel blocker verapamil (3 μM) were used to pharmacologically mimic ER syndrome genotypes. Transmural conduction times were measured before and after the provocative agents infusion at the 5 fixed epicardial unipolar electrodes. Transmural conduction time was defined as the time from endocardial pacing to onset of signal at the unipolar electrode.
Results: Polymorphic VTs (pVT) developed in 10 of 14 preparations. There was no delayed phase 0 upstroke in transmembrane action potential in any preparation even with induced pVT. In all preparation, transmural conduction time increased significantly after Ito agonist NS5806 (7-10 μM) and Ca2+ channel blocker verapamil (3 μM) perfusion. However, dispersion of transmural conduction time did not show heterogeneity (7.1 +/- 3.51 vs. 7.7 +/- 4.55, p = 0.240).
Conclusions: In early repolarization syndrome model, polymorphic ventricular tachycardia can be induced without regional conduction velocity heterogeneity. It may support the early repolarization theory.
Poster Hall, Hall C
Sunday, March 19, 2017, 9:45 a.m.-10:30 a.m.
Session Title: Arrhythmias and Clinical EP: Basic 5
Abstract Category: 4. Arrhythmias and Clinical EP: Basic
Presentation Number: 1281-114
- 2017 American College of Cardiology Foundation