A randomized controlled study on the effects of left bundle branch region pacing (LBBAP) under different programmed modes on left atrial volume and atrial high-frequency events in patients with sick sinus syndrome

INTERVENTION: Fixed Optimized AV Interval Group:Disable minimization of ventricular pacing function, fixed pacing AV interval at 150ms, sensing AV interval at 120ms;Minimized Ventricular Pacing Group:Enable minimization of ventricular pacing function (MVP/VIP, etc.), set pacing AV interval at 200ms, sensing AV interval at 150ms; CONDITION: Sick Sinus Syndrome PRIMARY OUTCOME: Change in left atrial volume (LAV) at 12 months (?LAV = LAV12m ? LAV0m);Safety outcomes (including device‐related discomfort/symptoms, device and lead‐related abnormalities, arrhythmias and rhythm events, major clinical events); SECONDARY OUTCOME: Incidence of atrial high‐rate episodes (AHRE), including atrial fibrillation, atrial flutter, and atrial tachycardia;Atrial fibrillation burden; INCLUSION CRITERIA: 1. Sick sinus syndrome with successful LBBAP implantation; 2. Paced QRS duration < 130 ms; 3. DDD pacing mode; 4. Age 18–80 years; 5. Willing to participate in the clinical trial and signed written informed consent.