Abstract 3311: Causes of Syncope in Wolff-Parkinson-White Syndrome and Results of the Treatment
Background: Syncope in Wolff-Parkinson-White syndrome (WPW) may reveal an arrhythmic event, but also can be without relationships with WPW. At the time of the curative treatment by catheter ablation of accessory pathway (AP), to establish rapidly the diagnosis is important. The purpose of the study was to evaluate the causes of syncope by noninvasive techniques in WPW.
Methods: 52 patients (pts), 29 men, 23 women aged from 11 to 72 years, (mean 31±16) with WPW were admitted for unexplained dizziness and/or syncope; they had no other heart disease and had no documented arrhythmias. Two noninvasive studies were performed without hospitalization:
electrophysiological study (EPS) by transesophageal route which consisted of atrial pacing up to 2 nd d AV block, programmed atrial stimulation using 1 and 2 extrastimuli in control state and after isoproterenol
Head-up tilt test.
EPS: paroxysmal junctional tachycardia (PJT) was induced in 23 pts (44 %). Atrial fibrillation >1 min (AF) and/or antidromic tachycardia was induced in 21 pts (40 %); among pts with inducible tachycardias, 9 had both tachycardias, PJT and AF. A potentially dangerous form (rapid conduction in accessory pathway (AP) > 240 /min in control state or > 300 b/min after isoproterenol and AF or antidromic tachycardia induction) was noted in 21 pts (40 %).
Tilt test was positive in 19 pts, 9 with abnormal EPS and 10 with negative EPS.
At the term of the studies, syncope was related to a rapid tachyarrhythmia in 21 pts and to a PJT followed by a vagal reaction in 15 pts. Syncope was not related to WPW in 15 pts, but to a vasovagal phenomenon in 10 of them. The follow-up (5±2 years) indicated that pts with inducible arrhythmias were treated by AP catheter ablation and became free of syncope; those with vasovagal hypertonia were not treated; they remained free of arrhythmias during the follow-up, but 3 had still dizziness. In 3 other pts with negative studies, AP catheter ablation did not suppress syncope.
Conclusion: Syncope in WPW syndrome frequently is directly related to the preexcitation and the AP ablation suppress the symptoms. However, in 29 % of the patients, syncope was unrelated to WPW, was generally of benign significance and was not suppressed by AP ablation.