心房肌复极的电整复性与阵发性心房颤动发生机制的实验研究

Objective Electrical restitution was believed to be a determinant responsible for the stability of heart rhythm. Although numerous studies focused on the role of action potential duration restitution (APDR) in the initiation and maintenance of ventricular fibrillation (VF), the relationship between atrial APDR and atrial fibrillation (AF) has not been fully understood. This study aims to investigate the characteristics of APDR of left atrium (LA) and right atrium (RA) in canines and the relevance to induction of AF. Methods Monophasic action potential (MAP) was recorded from LA and RA in 14 canines using the MAP recording-pacing combination catheter. APDR, plotted as action potential duration (APD) on the preceding diastolic interval (DI), was assessed by use of programmed stimulation with a single extrastimulus (S_1S_2) at LA and RA. Episodes of AF were recorded and analyzed. Results APD_(90) was significantly shorter in the LA than that in the RA [( 157.4 ± 43.5 ) ms vs. ( 170. 9 ± 37. 9)ms, P < 0. 05]. The mean slope of the APDR curve by S_1S_2 in the LA was significantly greater than that in the RA ( 1.3 ±0. 4 vs. 0. 9 ± 0. 3, P < 0. 05 ). The incidence of induced AF was significantly higher in the LA than in the RA (11/18 vs. 7/18, P < 0. 05). Conclusions The APDR and MAP characteristics are not uniform between atriums, which may be one of the important mechanisms responsible for the initiation of AF. Heterogeneity of APDR between LA and RA might create critical gradients or a dispersion of repolarization and subatrate for re-entrant arrhythmias and vulnerability to AF.

Restitution of atrial repolarization and atrial fibrillation in canine atrium