Observational study of heart rhythm during pacemaker implants in heart failure or slow heart rate

Participants in this study will either have heart failure (HF) and are scheduled to undergo pace maker (PM) implantation, cardiac resynchronization therapy pacemaker (CRT-P), cardiac resynchronization therapy defibrillator (CRT-D) implantation, His bundle pacing (HIBP) or left bundle area pacing (LBAP) (including HIBP/LBAP for patients with HF, for patients who have failed CRT implant or patients who are CRT non-responders), or have atrioventricular (AV) block or bradycardia and are scheduled to undergo dual chamber pacemaker implantation. In this study additional heart rhythm measurements will be collected during the implant procedure to better understand how His bundle and/or parahisian pacing (HISP) effects electrical conduction in the hearts of patients with HF or AV block.

The hypothesis is that His bundle or parahisian pacing (HISP) and left bundle area pacing (LBAP) may normalize atrioventricular (AV) conduction with a narrow combination of the Q wave, R wave and S wave (QRS complex) in functional bundle branch block or conduction delay in patients with heart failure (HF).