189 Similar implantable defibrillator event rates in patients with unexplained syncope and left ventricular dysfunction whatever the result of electrophysiological testing

ObjectivesThe purpose of this study was to evaluate the ventricular arrhythmias (VA) frequency in patients with unexplained syncope, ischemic or non-ischemic cardiac disease and left ventricular dysfunction (LVEF) and negative electrophysiological study (EP), implanted with cardioverter-defibrillator (ICD).BackgroundAccording to the current guidelines, EP is performed to evaluate syncope in patients with significant altered LVEF, mainly to guide treatment by ICD. Limited data concerning incidence of ventricular events in patients with no inducible arrhythmias is available.MethodsWe evaluated 58 consecutive patients with unexplained syncope who underwent EP. All patients had a depressed LVEF (< 45%). Sustained VA was only inducible in 28 patients (VF n = 8, SMVT n = 20). All patients were treated with ICD. We compared primary endpoint of severe VA in patients with negative and positive EP.ResultsBaseline characteristic were similar in the both groups. In the population (97% men), mean age was 67 ± 10 years, 67% had ischemic cardiopathy; mean LVEF was 30 ± 7% in non inducible group, 32 ± 9% in inducible group (p=0.16). During the follow-up (25 ± 22 months), 22 severe VA occurred; Kaplan-Meier analysis of time to first appropriate ICD therapy for non-inducible and inducible VA showed overlapping curves (p = 0.9), with 11 (37%) and 11 (39%) events in each group. Sub-group analysis according to LVEF and etiology of cardiopathy did not show significant difference.ConclusionsIn patients with unexplained syncope, ischemic or non-ischemic cardiopathy and left ventricular dysfunction, severe VA occurs in the follow-up at same rate whatever the result of EP. This study suggests that these patients should be treated with ICD without doing electrophysiological testing