Cardiac Resynchronization Therapy for Non-ischemic Cardiomyopathy—Immediate Changes in QRS Duration, with Left Bundle Branch Block Pattern on Electrocardiogram

BACKGROUND: We evaluated mean QRS duration improvement immediately after cardiac resynchronization therapy (CRT) in patients with non-ischemic cardiomyopathy (NICM), with a left bundle branch block (LBBB) pattern on electrocardiogram (ECG), owing to obligatory right ventricular pacing or as a new finding; and to what extent. METHODS AND RESULTS: We tabulated ECGs of 18 subjects, 24 hours before and after receiving CRT, for both groups. The percentage decreases of QRS duration in all groups were statistically similar (p<0.05). There was a significant negative correlation (p<0.05) between age and the percentage of the QRS decrease. CONCLUSIONS: The study showed a greater reduction in QRS duration with CRT for younger subjects.