Effect of Right Ventricular Lead Position on Defibrillation Threshold

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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Effect of Right Ventricular Lead Position on Defibrillation Threshold

Conditions
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Ventricular Tachycardia, Ventricular Fibrillation

Intervention / Treatment
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* Procedure: Implantable Cardioverter Defibrillator (ICD)


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Apex First<br>Patients born in odd-numbered years will receive an implantable cardioverter defibrillator (ICD). Defibrillation threshold determined with the right ventricular lead placed first in the apex and then in the septum. Final lead position will be determined at the discretion of the implanting physician. | Procedure: Implantable Cardioverter Defibrillator (ICD)<br>* Patients will receive an Implantable Cardioverter Defibrillator (ICD), with the leads implanted in either the apex or the septum as the first location. After defibrillation threshold is determined, the leads position will be changed to the second location and DFT will be determined again.<br>|
| Other: Septum First<br>Patients born in even-numbered years will receive an implantable cardioverter defibrillator (ICD). Defibrillation threshold determined with the right ventricular lead placed first in the septum and then in the apex. Final lead position will be determined at the discretion of the implanting physician | Procedure: Implantable Cardioverter Defibrillator (ICD)<br>* Patients will receive an Implantable Cardioverter Defibrillator (ICD), with the leads implanted in either the apex or the septum as the first location. After defibrillation threshold is determined, the leads position will be changed to the second location and DFT will be determined again.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Defibrillator threshold | Defibrillator threshold (DFT) will be determined at the time of implantation for each patient at the apex and the septum. A difference of >4 joules will be considered clinically significant. | At the time of each surgery through study completion, or up to 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of patients with improved defibrillation threshold at the septum versus the apex | The percentage of patients that have an improved safety profile from septal implantation versus apical implantation will be calculated. Improved safety profile is defined as a defibrillation threshold increase of >4 joules. | At the time of each surgery through study completion, or up to 12 months |