Sex differences in implantable cardiac defibrillator therapy according to arrhythmia detection times

Abstract

ObjectiveIn implantable cardiac defibrillators (ICDs), long-detection times safely reduce unnecessary and inappropriate therapies. We aimed to evaluate ICD treatment of ventricular arrhythmias in women, compared with men, also taking into account ICD detection.MethodsThe Advance III trial randomised patients implanted with an ICD for primary or secondary prevention in two arms—long and nominal ventricular arrhythmias detection times before therapy delivering (number of intervals needed to detect (NID) 30/40 and 18/24, respectively). The main endpoint of this post hoc analysis was the incidence of ICD therapies evaluated through Kaplan-Meier method and univariate Cox regression models.ResultsOverall, 1902 patients (304 women, 65±11 years) were randomised. Women showed a lower risk of ICD therapy (HR 0.63, 95% CI 0.43 to 0.93, p=0.022); this difference was observed only in the long-detection arm (HR 0.37, p=0.013) and not in the short detection arm (HR 0.82, p=0.414). No significant sex differences were observed concerning inappropriate therapies and mortality rate. Long-detection settings significantly reduced overall ICD therapies and appropriate ICD therapies, both in women (overall 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).ConclusionsIn patients with ICDs, the strategy of setting a long-detection time to treat ventricular arrhythmias (NID 30/40) reduces overall delivered therapies, both in women and men, when compared with nominal setting (NID 18/24). The reduction was significantly higher in women. Overall, women were less likely to experience ICD therapies than men; this result was only observed in the long-detection arm.Clinical trial registrationNCT00617175.

Safety and Efficacy of an Implantable Cardioverter Defibrillator (ICD) in the Detection and Prevention of Cardiac Arrhythmia - A Systematic Review

“…Quality analysis of this systematic review was conducted using the CASP standard checklist. From the analysis, two studies [ 8 , 19 ] were of the best quality, scoring eleven. The lowest score was eight, identified in four studies [ 1 , 17 , 18 , 20 ].…”

“…The study characteristics were identified and extracted on a pre-designed Excel worksheet. Table 4 shows the study characteristics extracted [ 1 , 8 , 16 - 21 ].…”

“…The studies' analysis identified that most of the patients and the users of ICDs were males [ 1 , 8 , 16 - 21 ]. Women were observed to have lower ICD therapies compared to men [ 8 ].…”

“…Preventing sudden cardiac deaths, whether primary or secondary, has used ICDs as the standard therapy for patients with a high risk of ventricular tachyarrhythmia (VT/ VF) [ 8 ]. Studies conducted identified that increasing the time for detecting VT/ VF and having cutoff rates set high helped reduce ICD therapies deemed unnecessary.…”

Heartbeat: focus on heart disease in women

“…Three original research papers in this issue of Heart address sex differences in cardiac arrhythmias. In patients with an implanted cardiac defibrillator (ICD) a long-detection time for arrhythmia detection delivered fewer ICD therapies in women compared with men, suggesting that more arrhythmias self-terminated within 40 beats (compared with 24 beats with shorter detection times), with no sex difference in overall survival benefit of ICDs 5. In patients with atrial fibrillation (AF), the risk of ischaemic stroke varied with age in women compared with men, being lower in women under age 66 yearsn, not different in women age 66–75 years, and higher only in those over age 75 years, suggesting that the conventional scores for estimated stroke risk in AF patients might need to be modified 6.…”