New observations on atrial fibrillation before and after surgical treatment in patients with the Wolff-Parkinson-White syndrome

The records of 342 patients who received surgical treatment for the Wolff-Parkinson-White syndrome between 1968 and 1986 were reviewed to evaluate the characteristics of atrial fibrillation. The patients were classified into two groups according to the presence (n = 166) or absence (n = 176) of documented episodes of atrial fibrillation preoperatively. The mean follow-up duration was 6 years (range 2 to 20). As compared with reports based on smaller patient groups and shorter follow-up, the study revealed several new findings. 1) During follow-up, nine patients in the atrial fibrillation group developed recurrent atrial fibrillation after a successful operation; five of these nine patients did not have associated heart disease. 2) All three patients with a history of atrial fibrillation and an accessory pathway conducting in the anterograde direction only had a successful surgical procedure and no postoperative atrial fibrillation. 3) The cycle length of atrioventricular (AV) reciprocating tachycardia was significantly shorter in the atrial fibrillation group (304 ± 42 ms, mean ± SD) than in the no-atrial fibrillation group (321 ± 54 ms, p < 0.005), and the cycle length of AV reciprocating tachycardia that degenerated into atrial fibrillation (289 ± 26 ms) was shorter than that for the AV reciprocating tachycardia without subsequent atrial fibrillation (316 ± 51 ms, p < 0.005). 4) Sustained atrial fibrillation was induced in 30% of patients without a history of atrial fibrillation. 5) Atrial fibrillation occurred in four patients with an accessory pathway that conducted only in the retrograde direction. 6) The prevalence of multiple accessory pathways was equal in the group with (20 of 166) and without (29 of 176) atrial fibrillation. It is concluded that in most patients, conversion of rapid reciprocating tachycardia is a likely mechanism of spontaneous atrial fibrillation. However, the probability that other mechanisms may contribute to the occurrence of atrial fibrillation in patients with the Wolff-Parkinson-White syndrome is suggested by data from three patients with an accessory pathway that conducted only in the anterograde direction and from five patients who had recurrent atrial fibrillation despite a successful surgical outcome. The data suggest that the surgical procedure does not result in late occurrence of atrial fibrillation.