Impact of cardiac resynchronization therapy on functional mitral regurgitation.

Abstract

Introduction: Cardiac resynchronization therapy (CRT) is an essential treatment for heart failure (HF) with ventricular dyssynchrony, designed to enhance contractile function and symptoms. Its criteria are based on trials such as COMPANION and CARE-HF, which endorse its use in symptomatic patients (NYHA III–IV) with LVEF < 35%, QRS > 120 ms, and sinus rhythm.

Case Presentation: A 67-year-old woman with progressive dyspnea (NYHA II/III) lasting 3 months, accompanied by heart failure signs such as elevated NT-proBNP levels (1979 pg/mL), crackling rales, and a grade III/VI holosystolic murmur at the mitral focus. Echocardiography showed severe mitral regurgitation and global hypokinesia with segmental dyssynchrony. The estimated left ventricular ejection fraction (LVEF) was 35%. Diastolic dysfunction was also noted, with high filling pressures indicated by a pulmonary artery systolic pressure (PSAP) of 45 mmHg. The ECG demonstrated sinus rhythm, a PR interval of 162 ms, and left bundle branch block with a QRS duration of 160 ms. Right heart catheterization confirmed moderate pulmonary hypertension and elevated wedge pressures at 27 mmHg. Coronary angiography ruled out coronary artery disease.

Therapeutic Management: Despite severe mitral regurgitation, it was concluded that the best initial approach was to start with optimal medical therapy and CRT, delaying mitral valve replacement.

Conclusion: This case demonstrates a timely and appropriate indication for CRT in a patient with advanced HF, LVEF < 35%, and a wide QRS on BCRI, fully meeting the criteria. CRT was selected to address the mechanical dyssynchrony underlying systolic dysfunction and functional mitral regurgitation, to reverse ventricular remodeling, and avoid primary surgical intervention.