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

This trial is comparing two types of cardiac pacemaker/resynchronization therapy for people with heart failure and an abnormal electrical pattern in the heart (wide QRS complex). It is comparing a newer approach called "conduction system pacing" to the established method called "biventricular pacing," looking at which one better prevents death, hospitalization, or the need for a heart transplant. **You may be eligible if...** - You are 18 or older - You have heart failure with a weakened left ventricle (ejection fraction ≤ 35%) - You have a specific abnormal electrical pattern on your ECG (left bundle branch block with QRS ≥ 130 ms, or non-LBBB with QRS ≥ 150 ms) - Or you need a pacemaker for a slow heart rate (AV block) AND have a weak heart - You have agreed to participate and signed informed consent **You may NOT be eligible if...** - You had a heart attack or heart procedure in the past 3 months - You are pregnant - You are currently in another interventional clinical trial Talk to your doctor to see if this trial is right for you.