Background: Immediate recurrence of atrial fibrillation (IRAF) occurs frequently after electrical cardioversion, its electrophysiological determinants and prognostic significance have, however, not been studied in detail. This study aimed to explore (1) the association of IRAF with clinical characteristics, pulmonary vein (PV) arrhythmogenicity as well as atrial electrophysiologic properties and (2) the prognostic significance of IRAF for outcome of PV isolation for atrial fibrillation (AF).
Methods and results: The subjects of this study were 41 consecutive patients (30 males, 11 females) who underwent PV isolation for drug-refractory AF. Following successful initial cardioversion, 19 patients (46%) had IRAF within 2 minutes. Coupling intervals of AF reinitiating beats arising from PVs were shorter (386 +/- 39 vs 490 +/- 136 ms, P = 0.008) and prematurity indices (0.38 +/- 0.06 vs 0.51 +/- 0.12, P = 0.01) smaller than those of premature beats not initiating AF. Patients with IRAF had more frequently AF duration <1 month, a longer P-wave duration, and a longer mid coronary sinus AF cycle length. Multivariate regression analysis revealed coronary sinus AF cycle length (beta= 0.186, P = 0.049), which was closely correlated with conduction time along the coronary sinus (R = 0.716, P = 0.003) to be independently associated with IRAF. While early AF recurrence rate (within the first 5 days) following the procedure was higher in the IRAF group (53 vs 18%, P = 0.02), outcome was not different between the two groups thereafter.
Conclusions: (1) IRAF is common in patients undergoing PV isolation for AF, (2) is initiated by premature atrial beats with short coupling intervals, and (3) seems to be associated with conduction disturbances along the coronary sinus. It reflects susceptibility of arrhythmia recurrence within the first 5 days after the procedure, but not thereafter.