New heart pacing technique aims to boost therapy for heart failure

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * \- 1 Sinus rhythm * 2 Left ventricular ejection fraction (LVEF) ≤ 35%, QRS duration ≥ 150 ms; or 130 ms \< QRS duration \< 150 ms with left bundle branch block (LBBB) morphology * 3 LVEF ≤ 40% with expected ventricular pacing \> 20% * 4 New York Heart Association (NYHA) class II, III, or ambulatory IV symptoms * 5 After at least 3 months of guideline-directed medical therapy (GDMT) optimization * 6 Age ≥ 18 years * 7 Signed informed consent form, good compliance, and ability to complete study follow-up Exclusion Criteria: * Prior implantation of CRT/ICD/pacemaker: Previous implantation of any cardiac implantable electronic device (CIED), except for patients in Group C requiring device replacement/upgrade * Non-compliance with GDMT requirements: Failure to receive or inability to tolerate optimized medical therapy * Inappropriate QRS duration: QRS \< 130 ms (Groups A and C) * Excessive improvement in LVEF: Recent (within 3 months) LVEF \> 40% with clear evidence of normalized cardiac function * Severe valvular heart disease: Severe aortic stenosis/regurgitation, mitral stenosis requiring surgical or interventional treatment * Recent cardiovascular events: Acute myocardial infarction, stroke/transient ischemic attack (TIA) within 3 months before enrollment; coronary revascularization (PCI or CABG) within 6 months before enrollment * Unstable angina pectoris: Canadian Cardiovascular Society (CCS) class III-IV * Severe arrhythmias: History of sustained ventricular tachycardia or ventricular fibrillation (without ICD protection) * Types of cardiomyopathy: Hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy (ARVC), and other specific etiologies not suitable for CRT * Severe renal insufficiency: Estimated glomerular filtration rate (eGFR) \< 30 mL/min/1.73m² or uncontrolled renal failure * Severe liver dysfunction: Child-Pugh class C * Active infection: Including sepsis, infective endocarditis, etc. * Malignant tumor: Advanced malignant tumor with expected survival \< 12 months * Pregnancy or lactation: Positive pregnancy test in women of childbearing age or planned pregnancy * Cognitive impairment: Inability to provide informed consent or follow the study protocol * Mental illness: Severe mental disorders affecting treatment compliance * Geographical restrictions: Inability to maintain contact or return to the medical center regularly during follow-up * Venous access disorders: Inability to implant CRT via venous route (e.g., bilateral subclavian vein occlusion) * Contralateral device: Implanted contralateral CIED leading to risk of lead crossing or interference * Participation in other interventional clinical trials, or other conditions deemed unsuitable for enrollment by the investigator