Conduction System Pacing vs Biventricular Pacing in Systolic Dysfunction and Wide QRS: Mortality, Heart Failure Hospitalization or Cardiac Transplant

Conduction System Pacing vs Biventricular Resynchronization Therapy in Systolic Dysfunction and Wide QRS: Mortality, Heart Failure Hospitalization or Cardiac Transplant

Conduction system pacing vs biventricular resynchronization therapy in systolic dysfunction and wide QRS: mortality, heart failure hospitalization or cardiac transplant (CONSYST-CRT II trial).

Superiority trial that aims to study the composite endpoint consisting of all-cause mortality, cardiac transplant or heart failure hospitalization at 12-month follow-up.

To date, studies have shown that conduction system pacing could get similar clinical and echocardiographic responses to those obtained with biventricular therapy.

This study will randomize 320 patients to a strategy of biventricular pacing versus conduction system pacing.

CONSYST-CRT II study will analyze a clinical endpoint as primary endpoint and the following parameters in both groups: left ventricular ejection fraction, ventricular volumes, echocardiographic response (>=15% decrease in left ventricular end-systolic volume), NYHA functional class, heart failure hospitalization, all-cause mortality, cardiac transplant, QRS shortening, echocardiographic dyssynchrony (atrioventricular, interventricular, intraventricular) and global longitudinal strain.

As a secondary endpoint, baseline predictors of response to conduction system pacing and biventricular pacing according to cardiac magnetic ressonance and electrocardiographic imaging will be studied.

Clinical, electrocardiographic, echocardiographic follow-up will be performed during 12 months.

Inclusion Criteria:

• Patient must indicate acceptance to participate in the study by signing an informed consent document.
• Patient must be ≥ 18 years of age.
• Left bundle branch block, QRS ≥130 and LVEF <=35%. No indication of stimulation for AV block.
• Non-left bundle branch block, QRS ≥150 and LVEF <=35%.
• Resynchronization therapy indication for ventricular dysfunction (LVEF <40%) and indication of cardiac pacing for AV block.
• LVEF <=35% in NYHA class III or IV, atrial fibrillation and intrinsic QRS >=130 ms, provided a strategy to ensure biventricular capture is in place.

Exclusion Criteria:

• Myocardial infarction, unstable angina or cardiac revascularization during the previous 3 months.
• Pregnancy.
• Participating currently in a clinical investigation that includes an active treatment.