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 remod- eling 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 signifi- cantly 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.