Clinical Research Directory

Inclusion Criteria: 1. Aged between 18 and 70 years old; 2. Diagnosis of chronic cardiac insufficiency according to current guidelines, and received guideline-directed medical therapy (GDMT) for at least 3 months; 3. Have indications for CRT/LBBP or ICD implantation, and expected atrial pacing ratio \> 20%, including: Sinus rhythm, QRS duration \> 120ms, LBBB, LVEF ≤ 35% with symptomatic heart failure; Sinus rhythm, QRS duration ≥ 150ms, non-LBBB, LVEF ≤ 35% with symptomatic heart failure; Sinus rhythm, QRS duration \> 120ms, LBBB, LVEF 36%-50% with symptomatic heart failure; Symptomatic heart failure with LVEF ≤ 50% and expected ventricular pacing ratio \> 20%; Symptomatic heart failure with LVEF ≤ 50% requiring ICD implantation for primary or secondary sudden death prevention, with atrial pacing indication due to sinus bradycardia or expected atrial pacing ratio \> 20%; 4. Patients with pacing-induced cardiomyopathy requiring upgrade therapy, in sinus rhythm, and requiring reimplantation of atrial lead; 5. Signed written informed consent form approved by the ethics committee. Exclusion Criteria: 1. Expected survival time less than 12 months; 2. Status after mechanical tricuspid valve replacement, or congenital heart disease (including dextrocardia, transposition of great arteries, single left persistent superior vena cava); 3. Previous history of atrial fibrillation; 4. Previous cardiac surgery, or requiring surgical treatment for severe structural heart disease within 1 year; 5. Pregnancy, planned pregnancy, or heart transplantation; 6. Patient refusal to participate in the study.