Inclusion Criteria:  Age ≥ 18 years Patients with an ejection fraction of ≥50%  Patients with an indication for ventricular pacing and high-degree atrioventricular block where the degree of anticipated RV pacing is >90% including:  Third degree AV block Symptomatic or asymptomatic second-degree AV block First degree AV block ≥ 280ms with a narrow QRS, or ≥ 240ms with an intraventricular delay (QRS duration ≥120ms) Echocardiogram within the last 3 months, with ability to have DICOM images  Exclusion Criteria:  Indication for an implantable cardioverter defibrillator Presence of a mechanical tricuspid valve Any prior attempt at implantation of an ICD, CRT, HBP, or LBBP Lack of capacity to consent Other serious medical condition with life expectancy of <2 years Pregnancy Patients in whom the conduction system abnormality is expected to be transient or recover over time Patients with permanent atrial fibrillation