Evidence of reverse remodeling after long-term biventricular stimulation for resynchronization in patients with wide QRS selected on the basis of echocardiographic electromechanical delays.

BACKGROUND: There is increasing evidence that cardiac resynchronization therapy (CRT) may trigger an inverse remodeling process leading to decreased left ventricular (LV) volumes in patients with heart failure and wide QRS. However, it is still important to simplify patient selection and achieve a widely applicable parameter to better stratify patients who are candidates for CRT.

METHODS: Eighteen patients (13 males, 5 females, mean age 67.5 +/- 7.2 years) with advanced heart failure due to ischemic (n = 12) or idiopathic dilated cardiomyopathy (n = 6) and complete left bundle branch block received biventricular pacing. The patients were considered eligible in the presence of echocardiographic evidence of intra- and interventricular asynchrony, defined on the basis of LV electromechanical delay. Investigations were performed before pacemaker implantation (at baseline), the day after, and 3 and 6 months later.

RESULTS: Two patients died before the first outpatient examination. There were 15 (83%) responders to reverse remodeling among the remainder. In the overall population, there was a significant and progressive improvement in LV sphericity indexes, ejection fraction, mitral regurgitation area and LV volumes (p < 0.001). The improvement in the interventricular mechanical delay after CRT was significantly correlated with the decrease in LV end-systolic volume (r2 = 0.2558, p = 0.04).

CONCLUSIONS: CRT reduces LV volumes in patients with advanced heart failure, complete left bundle branch block and detailed documentation of ventricular asynchrony prior to therapeutic pacing. Broadly applicable Doppler echocardiographic measures may increase the specificity of the long-term response to CRT in terms of LV performance.