CSP Versus BiVP for Heart Failure Patients with RVP Upgraded to Cardiac Resynchronization Therapy

This study is comparing two types of cardiac resynchronization therapy (CRT) — a pacemaker upgrade that helps both sides of the heart beat in sync — in people with heart failure whose heart function has worsened from long-term right-sided pacing. The two approaches are conduction system pacing (CSP) and traditional biventricular pacing (BiVP). **You may be eligible if...** - You have symptomatic heart failure (reduced heart pumping function, LVEF below 50%) after having a right ventricular pacemaker for at least 3 months - You are in NYHA class II–IV (symptoms ranging from mild to severe) - Your pacemaker is pacing the right ventricle more than 40% of the time - Your NT-proBNP blood test is elevated (above 125 pg/mL in normal heart rhythm, or above 250 pg/mL if you have atrial fibrillation) - You are between 18 and 80 years old **You may NOT be eligible if...** - You have had a heart attack within the past 3 months - You have frequent or difficult-to-control abnormal heart rhythms - You have a mechanical tricuspid heart valve - You are pregnant or planning pregnancy - Your life expectancy is less than 12 months - You have complex congenital heart disease or a previous heart transplant Talk to your doctor to see if this trial is right for you.