Rate Adaptation of Action Potential Duration in the Human Right Atrium with Paroxysmal Lone Atrial Fibrillation

摘要

Objective: To study rate adaptation of action potential duration (APD) in right atrium in paroxysmal lone atrial fibrillation (PAF). Methods: Monophasic action potential (MAP) at 90%, 50% of repolarization (APD90, APD50) and APD90-50 were measured in 11 patients with PAF during 9 atrial pacing cycle lengths (CLs), which included 600,550,500, 460,420, 380, 340, 300 and 280ms. There were AF episode for one month before MAP was recorded in all patients. 11 patients with AVNRT but without history of AF served as a control group. Results: APD90s and APD90-50s at longer CLs (600, 550, 500ms) in the PAF group were significantly shorter than those in the controls (P<0.05). But APD90s at shorter CLs (340,300,280ms) were longer than those with control group (P<0.05). However, there was no significantly difference at rapid pacing between two groups. Conclusions: The changes of rate adaptation of APD in right atrium with PAF have been in existence before "electrical remodeling", which is partly responsible for the initiation and maintenance of AF.Key words: Lone atrial fibrillation, Action potential duration, Rate adaptation, electrical remodeling