The purpose of this study is to show that Adaptive CRT is at least as good at optimizing a patient's cardiac resynchronization therapy (CRT) as the current method of using an echocardiogram.

The intent of this study is to demonstrate the safety and effectiveness of the ST Monitoring Feature in the Fortify® ST ICD system (or other Implantable Cardioverter Defibrillator (ICD) systems with the ST Monitoring Feature).

The purpose of the BLOCk-CTI study is to evaluate the safety and effectiveness of the Blazer® Open-Irrigated Ablation Catheter for the treatment of sustained or recurrent type 1 atrial flutter.

The objective of this study is to confirm the long-term safety and reliability of the Linox Lead System as used with BIOTRONIK ICDs.

This study will assess the impact of higher rate cutoffs and longer delays than standard programming on inappropriate therapy in primary prevention ICD and CRT-D patients.

MADIT-CRT PAR is an FDA mandated follow-up registry for patients that participated in the MADIT-CRT IDE study examining long-term mortality.

The main purpose of the System Longevity Study is to evaluate long-term performance of Medtronic market-released cardiac therapy products by analyzing product survival probabilities. This study is part of the Product Performance Platform (PPP).

The purpose of this clinical trial is to compare monthly versus quarterly review of Cardiac Compass® Trends with OptiVol for initiation of clinical action.

The purpose of this multicenter post-approval study is to evaluate the acute and chronic performance of the QuickFlex® µ 1258T left ventricular lead.

This study will evaluate the efficacy and safety of Azimilide on the incidence of cardiovascular hospitalizations, cardiovascular emergency department visits or cardiovascular death in patients with Implantable Cardioverter Defibrillators (ICDs)