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Background: The Multicenter Automatic Defibrillator Implantation Trial-Reduce Inappropriate therapy (MADIT-RIT) trial showed a significant reduction in inappropriate implantable cardioverter defibrillator (ICD) therapy in patients programmed to high-rate cut-off (Arm B) or delayed ventricular tachycardia therapy (Arm C), compared with conventional programming (Arm A). There is limited data on the effect of cardiac resynchronization therapy with a cardioverter defibrillator (CRT-D) on the effect of ICD programming. We aimed to elucidate the effect of CRT-D on ICD programming to reduce inappropriate ICD therapy in patients implanted with CRT-D or an ICD, enrolled in MADIT-RIT.Methods and Results: The primary end point of this study was the first inappropriate ICD therapy. Secondary end points were inappropriate anti-tachycardia pacing and inappropriate ICD shock. The study enrolled 742 (49%) patients with an ICD and 757 (51%) patients with a CRT-D. Patients implanted with a CRT-D had 62% lower risk of inappropriate ICD therapy than those with an ICD only (hazard ratio [HR] =0.38, 95% confidence interval: 0.25-0.57; P<0.001). High-rate cut-off or delayed ventricular tachycardia therapy programming significantly reduced the risk of inappropriate ICD therapy compared with conventional ICD programming in ICD (HR=0.14 [B versus A]; HR=0.21 [C versus A]) and CRT-D patients (HR=0.15 [B versus A]; HR=0.23 [C versus A]; P<0.001 for all). There was a significant reduction in inappropriate anti-tachycardia pacings in both group and a significant reduction in inappropriate ICD shock in CRT-D patients.Conclusions: Patients implanted with a CRT-D have lower risk of inappropriate ICD therapy than those with an ICD. Innovative ICD programming significantly reduces the risk of inappropriate ICD therapy in both ICD and CRT-D patients.Clinical Trial Registration: http://clinicaltrials.gov; Unique identifier: NCT00947310. [ABSTRACT FROM AUTHOR]

Inappropriate Therapy in Single Versus Dual Chamber Background The majority of implantable cardioverter defibrillators (ICDs) are dual-chamber devices, but studies on the frequency of inappropriate therapy in dual- versus single-chamber devices have shown conflicting results. The aim of this study is to determine whether implantation of dual-chamber ICD devices decrease the incidence of inappropriate therapy without an unacceptable increase in complications. Methods In the ICD arm of the MADIT-CRT study (N = 704), comparisons of single- versus dual-chamber ICD devices were investigated on the endpoints of inappropriate therapy (antitachycardia pacing [ATP] and shocks) and device- and procedure-related complications by use of multivariate Cox proportional hazard regression analysis (hazard ratio dual:single chamber) adjusting for relevant covariates. Results The frequency of inappropriate therapies in single- and dual-chamber recipients was 41/294 (14%) and 50/410 (12%), respectively. There was no significant difference in overall inappropriate therapy (hazard ratio [HR] = 0.95 [CI: 0.63-1.45], P = 0.95) or inappropriate ATP (HR = 0.98 [CI: 0.61-1.58], P = 0.94), between single- and dual-chamber devices, using single-chamber as a reference (Dual:Single). However, there was a trend toward a decrease in inappropriate shocks (HR = 0.60 [CI: 0.34-1.08], P = 0.09) in the dual-chamber group. The same was evident when only analyzing inappropriate therapy for atrial tachyarrhythmias (HR = 0.88 [CI: 0.56-1.38], P = 0.58). There was no significant difference between the groups in device- or procedure-related complications (HR = 1.54 [CI: 0.82-2.90], P = 0.18). Conclusion No significant difference was found in inappropriate therapy or complications in patients treated with single- versus dual-chamber ICD devices. [ABSTRACT FROM AUTHOR]