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.

The purpose of the MADIT-RIT trial is to compare the time to first inappropriate therapy using high rate cutoff and/or long delay in primary prevention patients receiving an ICD or CRT-D device compared to standard programming.

Inclusion Criteria:

• Primary prevention patient with ischemic or non-ischemic heart disease who meets current guidelines for dual-chamber ICD or CRT-D device therapy
• Patient in sinus rhythm
• Patient on stable optimal pharmacologic therapy for the cardiac condition or who has developed a recent ICD indication that necessitates ICD therapy concurrent with the optimization of pharmacologic therapy
• Patient ≥ 21 years of age, or legal representative, willing and capable of giving informed consent

Exclusion Criteria:

• Patient with an implanted pacemaker or CRT-P
• Patient with existing ICD or CRT-D device components
• Patient with a history of VT or VF
• Patient with permanent or chronic AF, or cardioversion for AF, within the past three calendar months before enrollment
• Patient with coronary artery bypass graft surgery or percutaneous coronary intervention within the past three calendar months prior to enrollment
• Patient with enzyme-positive myocardial infarction within the past three calendar months prior to enrollment
• Patient with angiographic evidence of coronary disease who are candidates for coronary revascularization and are likely to undergo coronary artery bypass graft surgery or percutaneous coronary intervention in the foreseeable future
• Patient with second or third degree heart block
• Patient in NYHA Class IV
• Patient who is pregnant or plans to become pregnant during the course of the trial
• Patient with irreversible brain damage from preexisting cerebral disease
• Patient with presence of any disease, other than the patient's cardiac disease, associated with a reduced likelihood of survival for the duration of the trial, e.g., cancer, uremia, liver failure, etc.
• Patient with chronic renal disease with BUN ≥ 50mg/dl or creatinine ≥ 2.5 mg/dl
• Patient participating in any other clinical trial
• Patient unwilling or unable to cooperate with the protocol
• Patient who lives at such a distance from the clinic that travel for follow-up visits would be unusually difficult
• Patient who does not anticipate being a resident of the area for the scheduled duration of the trial
• Patient unwilling to sign the consent for participation
• Patient whose physician does not allow participation