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 Wo lff-Parkinson-White syndrome between 1968 and 1986 were reviewed to ev aluate the characteristics of atrial fibrillation. The patients were c lassified into two groups according to the presence (n = 166) or absen ce (n = 176) of documented episodes of atrial fibrillation preoperativ ely. The mean follow-up duration was 6 years (range 2 to 20). As compa red with reports based on smaller patient groups and shorter follow-up , the study revealed several new findings, 1) During follow-up, nine p atients in the atrial fibrillation group developed recurrent atrial fi brillation after a successful operation; five of these nine patients d id not have associated heart disease. 2) All three patients with a his tory 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 atrioventri cular (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 le ngth of AV reciprocating tachycardia that degenerated into atrial fibr illation (289 +/- 26 ms) was shorter than that for the AV reciprocatin g tachycardia without subsequent atrial fibrillation (316 +/- 51 ms, p < 0.005). 4) Sustained atrial fibrillation was induced in 30% of pati ents without a history of atrial fibrillation. 5) Atrial fibrillation occurred in four patients with an accessory pathway that conducted onl y in the retrograde direction. 6) The prevalence of multiple accessory pathway was equal in the group with (20 of 166) and without (29 of 17 6) atrial fibrillation. It is concluded that in most patients, convers ion of rapid reciprocating tachycardia is a likely mechanism of sponta neous atrial fibrillation. However, the probability that other mechani sms may contribute to the occurrence of atrial fibrillation in patient s with the Wolff-Parkinson-White syndrome is suggested by data from th ree patients with an accessory pathway that conducted only in the ante rograde direction and from five patients who had recurrent atrial fibr illation despite a successful surgical outcome. The data suggest that the surgical procedure does not result in late occurrence of atrial fi brillation.