Devices proposed for use in the protocol no longer used by physician

The purpose of this study is to determine how the position of the right ventricular (RV) coil of an implantable cardioverter defibrillator (apex versus septum) affects the defibrillation threshold; specifically, can defibrillator threshold be improved by implantation site selection.

The investigators propose a prospective, pseudo-randomized study of patients who are electing to undergo implantation of an implantable cardioverter defibrillator (ICD).

There are two locations in the heart in which ICDs are normally implanted: the apex and the septum. The purpose of this study is to determine whether the ICD performs better in one location or the other, as measured by defibrillation threshold. In this study, both locations will be tested in each patient. The final location will be determined by the implanting physician as the location that is best for the patient.

Inclusion Criteria:

• Patient indicates for single-chamber (VR), dual-chamber (DR) or resynchronization CRT-D) implantable defibrillator
• Left-sided implant
• Single coil or dual coil (single coil for testing)
• Age ≥ 18 years of age
• Ability to consent
• Medically stable, in the opinion of the implanting physician, to undergo defibrillation safety margin testing
• Procedure performed under conscious sedation
• English-speaking

Exclusion Criteria:

• Patient unable to understand and consent to the procedure on his or her own
• Pregnant or breastfeeding patients
• New York Heart Association (NYHA) Class IV
• Patients with pre-existing RV leads
• Pacemaker dependent
• Patient medically unstable to undergo defibrillation testing (e.g., high risk for deep sedation; patients that develop respiratory compromise or hemodynamic instability from the sedation)
• Patients that require general anesthesia instead of conscious sedation
• Patients <18 years of age
• Non-English-speaking

Because this is a pilot study with limited data collection, data will not need to be shared.