Turning the tide in heart failure: A case report of one-year improvement in a CRT-P super-responder with HFrEF and LBBB

Background: Cardiac resynchronization therapy (CRT) is an established treatment for heart failure with reduced ejection fraction (HFrEF) and electrical dyssynchrony, especially in patients with left bundle branch block (LBBB). In symptomatic patients with LVEF ≤35%, sinus rhythm and LBBB with a QRS duration ≥130 ms despite optimal treatment, CRT is suggested according to the 2021 ESC Guidelines to enhance symptoms, quality of life, and survival. In older patients who are not candidates for a defibrillator, cardiac resynchronization therapy pacemaker (CRT-P) is generally used. Response rates are generally 55% to 70% in large trials, with optimal outcomes in patients with LBBB and QRS duration ≥150 ms. Case Presentations: A 76-year-old woman physician with hypertension and dyslipidaemia, despite optimal treatment, presented with NYHA class III. ECG revealed complete LBBB in sinus rhythm. Echocardiography demonstrated an LVEF of 28%, left ventricular dilation, and significant functional mitral regurgitation. Coronary angiography was negative for obstructive coronary artery disease. CRT-P was implanted. At 6 months, the patient was still a non-responder with persistent systolic dysfunction, adverse remodelling, diastolic dysfunction and residual regurgitation. Echocardiography-guided device optimization adjusting AV delay by transmitral Doppler to preserve atrial contribution, VV delay by LVOT VTI and strain analysis to improve synchronization and reduce regurgitation. At One-year follow-up, the patient showed significant improvement in NYHA class I–II and improved exercise tolerance. Echocardiography showed significant reverse remodelling, and LVEF was improved to 67%. Device interrogation revealed ongoing thresholds and >99% biventricular pacing. Conclusions: This case illustrates a CRT-P super-responder outcome, the role of guideline-directed selection, close follow-up, and tailored optimization to maximize both clinical and structural benefits.