Cardiac resynchronization therapy and pulmonary artery banding in advanced heart failure infants with left ventricular dilated cardiomyopathy and left bundle branch block

Importance Infantile dilated cardiomyopathy (DCM) associated with left bundle branch block (LBBB) is a rare but life‐threatening condition, especially when severe heart failure is present. Identifying effective solutions to improve the prognosis is crucial. Objective This study aims to evaluate the short‐term clinical outcomes and cardiac functional changes in infants with LBBB‐associated DCM treated with a combined approach of electrical and mechanical cardiac resynchronization. Methods We conducted a retrospective analysis of five infants who underwent epicardial cardiac resynchronization therapy (CRT) combined with pulmonary artery banding between 2023 and 2024. The primary endpoint was improvement in clinical functional class and cardiac function, assessed by left ventricular ejection fraction (LVEF) and N‐terminal pro‐B‐type natriuretic peptide levels. Secondary endpoints included indicators of cardiac reverse remodeling, evaluated by LV end‐diastolic dimension (LVEDd), its z‐score, cardiac resynchronization, and QRS duration. Results The five enrolled infants had a median age of 6 months (range, 3–12 months). All received guideline‐directed medical therapy and were followed for a median of 11 months (range, 6–24 months). All patients achieved normalization of functional class. The median LVEF increased from 26% to 65%, with improvements observed within 1 month. The median LVEDd decreased from 46 to 28 mm, and the corresponding z‐score decreased from 11.2 (range, 7.6–13.2) to 0.7 (range, –1.1 to 2.3). The median QRS duration narrowed from 138 to 115 ms. Mechanical dyssynchrony was virtually resolved in all patients by the last follow‐up. Interpretation The combined resynchronization strategy appears to be highly effective for treating infants with LBBB‐associated DCM. Further studies are needed to differentiate the specific roles of electrical and mechanical synchronization in improving outcomes.