[Syncope in patients with Wolff-Parkinson-White syndrome: clinical data, electrophysiologic substrate and prognostic...

Syncope in Wolff-Parkinson-White (WPW) patients might be considered a premonitory event heralding the future development of sudden death. Therefore, we reviewed the clinical and electrophysiologic data of 91 WPW patients referred for invasive evaluation of known arrhythmias, in order to assess the incidence and clinical relevance of syncope. Thirty-four patients (37%, Group I) reported the occurrence of 1 or more syncopal episodes, while 57 patients (63%, Group II) had no syncope. These 2 groups did not differ significantly with regard to age, sex, incidence and characteristics of arrhythmias, clinical history and frequency of arrhythmic events, presence of associated cardiac diseases. Eleven patients in Group I and 9 in Group II were resuscitated from a cardiac arrest. The sensitivity (40%), the specificity (64%) as well as the positive predictive value (32%) and the negative predictive value (71%) of syncope vs a cardiac arrest were not significant. There were no statistical differences in the effective refractory period of the right atrium, atrioventricular node, accessory pathway and right ventricle between the 2 groups. Furthermore, no differences were noted in the cycle length of tachycardia (327 +/- 60 ms in Group I and 335 +/- 46 ms in Group II) and in the minimum RR interval during atrial fibrillation (248 +/- 49 ms and 244 +/- 43 ms, in Group I and II, respectively) as well as in the number of patients who had a minimum RR interval during atrial fibrillation less than or equal to 250 ms (15 patients--65%--in Group I and 21 patients--62%--in Group II).(ABSTRACT TRUNCATED AT 250 WORDS)