Managed Ventricular Pacing ("MVP") Trial

MVP Trial (Managed Ventricular Pacing ("MVP") Versus Backup Ventricular Pacing at a Rate of 40 Beats Per Minute ("VVI 40") Pacing Trial)

The purpose of the study is to compare two device settings (sets of instructions) used by the ICD. The Implantable Cardiac Defibrillator ("ICD") can be set to use one wire (top or bottom of the heart) or two wires (top and bottom). The study will compare how much time either ICD wire is used by the ICD and the status of congestive heart failure.

Recent research supports the hypothesis that reducing the amount of pacing in the lower right chamber of the heart may prevent the progression of congestive heart failure (CHF) in some implantable cardioverter defibrillator (ICD) patients. CHF refers to symptoms (shortness of breath, fatigue, fluid overload) caused by decreased pumping action of the heart muscle. The ICD can be set to use one wire (top or bottom of the heart) or two wires (top and bottom). Both settings allow the heart to beat more naturally using its own electrical signals. Two device settings will be compared. Managed ventricular pacing (MVP) will allow the ICD to use both wires only as necessary. This setting allows the ICD to send electrical signals to the top and bottom chambers of the heart if needed. The other setting, ventricular pacing (VVI) will allow the ICD to operate the bottom chamber of the heart if it is needed.

Inclusion Criteria:

• Conventional indication for ICD therapy according to current evidence-based guidelines and in accordance with the corresponding United States Centers for Medicare and Medicaid Services National Coverage Determination for the use of ICDs.
• Prior myocardial infarction ("MI") and an left ventricular ejection fraction ("LVEF") of less than 30%
• Ischemic Dilated Cardiomyopathy (IDCM), New York Heart Association ("NYHA") Class II or II heart failure, and LVEF less than or equal to 35%
• Non-Ischemic Dilated Cardiomyopathy (NIDCM) greater than 3 months, NYHA Class II or II heart failure, and LVEF less than or equal to 35%
• First ICD implant
• Successful implant with a study device with approved labeling

Exclusion Criteria:

• Failure to meet any of the inclusion criteria
• Class I pacing indication
• Chronic atrial fibrillation ("AF") without any documented sinus mechanism for at least 6 months
• Inability or unwillingness to give informed consent
• Life expectancy less than 12 months or a heart transplant anticipated within 6 months
• Inability to successfully comply with study participation and follow up requirements
• Patient involved in another clinical trial that may confound the results of the study