The goal of this study is to test a new pacing method called anodal biphasic pacing (ABP) to determine if this pacing works as well-or better-than current pacing methods. This new method may improve how the heart works and reduce some of the problems caused by regular pacing.

Current implantable pacemakers use a monophasic cathodal waveform to stimulate the heart. Monophasic cathodal pacing (MCP) waveforms slow conduction, impair contractility, cause inflammation, increase risk of atrial fibrillation, heart failure, and mortality. Anodal biphasic pacing (ABP) is an alternative waveform that can stimulate the heart. ABP preconditions the heart and then initiates cardiac contraction. ABP may address the limitations of MCP.

This study is a single-center, prospective, investigator-initiated, non-randomized, study that will investigate ABP in patients with structurally normal hearts and those with non-ischemic cardiomyopathy who are undergoing interventional cardiac procedure, generator exchange of dual chamber Cardiac implantable electronic device (CIED), or de novo implant or generator exchange of CIED with cardiac resynchronization therapy.

Eligible participants, without heart disease and those with nonischemic cardiomyopathy, undergoing CIED implant or generator exchange or interventional cardiac procedure at Boston Medical Center will be screened and prospectively enrolled. Participants will be stratified by left ventricular ejection fraction (EF): those with severely reduced EF (≤35%), mid-range EF (> 35%-49%) and normal EF (EF≥ 50%).

Primary efficacy objectives:

1. To identify which patient populations have the greatest and most consistent hemodynamic benefit from ABP as compared with cathodal pacing.
2. To confirm that ABP does not negatively impact non-responders.
3. To define the ideal anodal biphasic waveform characteristics (amplitude and pulse width) that maximizes the positive effect in subjects who demonstrate hemodynamic improvement ABP
4. To assess differences in capture thresholds between anodal biphasic and cathodal pacing.

Secondary safety objectives:

1. To assess and characterize any ventricular arrhythmias associated with anodal biphasic in comparison to cathodal pacing.
2. To assess device safety
3. To assess procedure safety

Inclusion Criteria:

Cohort A

• Planned interventional cardiac procedure

Cohort B

• Planned generator exchange of dual chamber cardiac implantable electronic device (CIED)
• Functioning atrial lead

Cohort C

• Planned de novo implant or generator exchange of CIED with cardiac resynchronization therapy
• Functioning atrial lead

Exclusion Criteria:

• Permanent atrial fibrillation
• Third degree AV block without stable escape rhythm
• Ischemic heart disease or coronary disease > 40%
• Unable to receive heparin
• Are not fluent in English
• Unable to read in English
• Not able to provide informed consent
• Women who are pregnant