LEft Bundle branchArea Pacing to Avoid Pacing-induced CARdiomyopathy

This study is testing a newer type of pacemaker lead placement called left bundle branch area pacing (LBBAP) — which mimics the heart's natural electrical system more closely — versus traditional right ventricular pacing in people who need a pacemaker. The goal is to see whether LBBAP prevents the heart muscle weakening that can happen over time with conventional pacing. **You may be eligible if...** - You have an advanced heart block (a condition where electrical signals from the upper to lower heart are blocked — either frequent 2nd degree or complete 3rd degree) or atrial fibrillation with a very slow heart rate - Your heart's pumping function is preserved or only mildly reduced (left ventricular ejection fraction above 45%) **You may NOT be eligible if...** - Your heart's pumping function is already significantly reduced (ejection fraction 45% or below) - You have symptoms of heart failure - You had a heart attack, unstable chest pain, or coronary intervention within the past 3 months - You have a life expectancy of less than 6 months - You have been hospitalized for heart failure in the past - You have significant pulmonary artery high blood pressure or moderate-to-severe valve disease - You are pregnant or have had a prior heart transplant Talk to your doctor to see if this trial is right for you.