Relation of early improvement in coronary flow reserve to late recovery of left ventricular function after beta-blocker therapy in patients with idiopathic dilated cardiomyopathy.

BACKGROUND

Beta-blocker therapy reverses left ventricular (LV) remodeling in patients with idiopathic dilated cardiomyopathy (IDC). Improvement in coronary circulation by beta-blocker could play a role in these circumstances. This study investigated the relationship between change in coronary flow reserve (CFR), as a marker of coronary circulation, and subsequent improvement in LV ejection fraction (LVEF) at follow-up during carvedilol therapy in patients with IDC.

METHODS

Eighteen patients with IDC underwent CFR measurements by transthoracic Doppler echocardiography at baseline and after 1 month of treatment with carvedilol. A follow-up echocardiographic assessment of LVEF was done at 12 +/- 6 months of treatment. The patients were classified by the degree of improvement in LVEF in the follow-up study, as group A (LVEF change > or = 10%) and group B (LVEF change < 10%).

RESULTS

Although there was no significant difference in CFR between the 2 groups at baseline, CFR was significantly higher in group A than in group B at 1 month of therapy (3.7 +/- 0.5 vs 2.5 +/- 0.9; P < .01). Coronary flow reserve change after 1 month was significantly greater in group A than in group B (1.3 +/- 0.6 vs 0.4 +/- 0.5; P < .01). Logistic regression analysis revealed that CFR change predicted a significant improvement in LVEF at follow-up (P < .05). Furthermore, a significant correlation was found between the change in CFR after 1 month and that in LVEF on follow-up (r = 0.65, P < .01).

CONCLUSIONS

This study demonstrated that early change in CFR is associated with subsequent improvement in LVEF, suggesting the potential predictive value of coronary circulation for subsequent LV reverse remodeling after beta-blocker therapy in patients with IDC.