Influence of myocardial viability on responsiveness to cardiac resynchronization in ischemic dilated cardiomyopathy: a prospective observational cohort study.

Objective: To understand whether patients with post-ischemic dilated cardiomyopathy and myocardial viability (MV) could benefit from cardiac resynchronization therapy (CRT) in terms of clinical, echocardiographic and neuro- hormonal parameters compared to patients without MV.

Methods: One hundred and four consecutive patients were enrolled in a prospective observational cohort study. Using dobutamine stress echocardiography, 2 groups were identified: group A of 51 patients with MV and group B of 53 patients without MV. All patients were implanted with biventricular pacing devices combined with an internal cardioverter-defibrillator. Clinical, echocardiographic and neuro-hormonal parameters were evaluated at baseline and at six month follow-up. Analysis of variance for repeated measures on each variable suggestive of remodeling was performed. We considered responder every patient with: decrease of > 15% in left ventricular volumes and/or improvement in left ventricular ejection fraction of > 5% in addition to NYHA class improvement.

Results: All the variables improved in both groups (time effect). Comparing the two groups (group effect), the following variables were significantly better in group A: N-terminal pro-B-type natriuretic peptide (p=0.02), NYHA class (p=0.003), reverse remodeling (RR) (p=0.007), dP/dt (p=0.005), left ventricular ejection fraction (p=0.009), 3rd sound (p=0.01), and left ventricular end-systolic volume after the first week (p=0.035). RR occurred at the first week after CRT only in Group A and was maintained for all the time of this study. The maximum difference of the decrease of left ventricular volumes between the two groups occurred after the first week (p<0.001).

Conclusion: Patients with MV responded better than patients without MV with a significant improvement after the first week from CRT.