Abstract
IntroductionIn implantable cardiac defibrillators (ICD) a long detection time safely reduces unnecessary and inappropriate device interventions.HypothesisThis post-hoc analysis of the Advance III trial aimed to evaluate the incidence of ICD therapies in women compared with men and to test the hypothesis that prolonged windows for detection of ventricular arrhythmias could provide sex-specific effects on the time to first ICD therapy.MethodsThe Advance III trial randomized ICD patients to a long ventricular arrhythmias detection setting (30/40 intervals) or to the nominal setting (18/24 intervals). Kaplan-Meier method and univariate Cox regression models were utilized. Of 1902 randomized patients, 304 were women.ResultsThere were no sex differences in age (mean 65±11 years), sudden death prevention (25% with secondary prevention indications) and other major comorbidities. Women presented a higher incidence of biventricular ICD (51% vs 39% respectively), less frequent ischemic etiology (36% vs 64% respectively) and had smaller ventricles (60 vs 64 mm respectively). When comparing long vs nominal detection windows, long detection settings significantly reduced overall ICD therapies and appropriate ICD therapies, both in women (overall Hazard Ratio (HR)=0.31, p=0.007; appropriate HR=0.33, p=0.033) and in men (overall HR=0.69, p=0.006; appropriate HR=0.73, p=0.048). When comparing women vs. men, women showed a lower risk of ICD therapy (HR0.63, 95%CI0.43-0.93, p=0.022); this difference was observed only in the long detection arm (HR0.37, p=0.013), as shown in the figure, but not in the short detection arm (HR0.82, p=0.414). No significant sex differences were observed concerning inappropriate therapies and mortality rate.ConclusionIn our trial women were less likely to experience ICD therapies than men; this result was only observed in the long detection arm. A long detection strategy seems to be particularly effective in women.