Radial Strain Delay Based on Segmental Timing and Strain Amplitude Predicts Left Ventricular Reverse Remodeling and Survival After Cardiac Resynchronization Therapy

240 patients with symptomatic heart failure undergoing cardiac resynchronization therapy (NYHA class III/IV; QRS >120 milliseconds; ejection fraction, 23±7%). Divided into a derivation group (n=102) and a validation group (n=108).

Echocardiographic assessment of calculated radial strain delay (RSDc) >40%, based on both timing and amplitude of segmental strain, prior to CRT implantation

Patients with lower RSDc (e.g., RSDc ≤40%)

CRT response, defined as >15% reduction in left ventricular end-systolic volume at 6 monthssurrogate