Evaluation of cardiac sympathetic nerve activity and left ventricular remodelling in patients with dilated cardiomyopathy on the treatment containing carvedilol

Aims It has been reported that carvedilol improves cardiac sympathetic nerve activity (CSNA) in patients with dilated cardiomyopathy (DCM). However, the influence of carvedilol on cardiac I-123-meta-iodobenzylguanidine (MIBG) scintigraphic findings and left ventricular (LV) remodelling has not been determined in DCM patients. Methods and results In 30 patients with DCM and 10 normal controls, the delayed heart/mediastinum count (H/M) ratio, delayed total defect score (TDS), and washout rate (WR) were determined by I-123-MIBG scintigraphy. In addition, the left ventricular end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), and LV ejection fraction (LVEF) were calculated by echocardiography. In the DCM patients, the regional defect score index (RDSI), regional washout rate index (RWRI), and wall motion score index (WMSI) were also determined to evaluate regional adrenergic dysfunction and wall motion. Examinations were repeated in all DCM patients after standard treatment containing carvedilol at a dose of 10-20 mg/day (mean dose: 16 +/- 4 mg/day) for a mean of 12 +/- 1 months. Both the I-123-MIBG scintigraphic and echocardiographic parameters were significantly worse in the DCM patients than the normal control subjects. After treatment, all of these parameters improved significantly in the DCM patients. There was a significant correlation between the changes of I-123-MIBG findings and changes of the LVEDV and LVESV after treatment. Moreover, there was a significant correlation between changes of the WMSI and those of the RDSI or RWRI in DCM patients. Conclusion Both I-123-MIBG scintigraphic parameters and echocardiographic parameters were improved in the DCM patients. There was a significant correlation between the changes of I-123-MIBG scintigraphic and echocardiographic findings after treatment. These findings implicate that long-term, including carvedilol, therapy can improve both CSNA and LV remodelling in patients with DCM.