Conduction System Pacing With Left Bundle Branch Pacing as Compared to Standard Right Ventricular Pacing

We hypothesize that in patients with high degree AV block with anticipated ventricular pacing >90%, and an EF >35% patients undergoing LBBP will demonstrate a significantly lower number of the primary composite endpoint of cardiovascular death, heart failure events, and change in LVESVi as compared to standard RV pacing. Echos will be performed at baseline, 12, 24, and 36 months. NTproBNPs are performed at baseline and follow-up. There will be a core echo lab, and blinded adjudication of ECGs and events.

Inclusion criteria

• Age ≥ 18 years
• Patients with an ejection fraction of >35%
• 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