Percentage change in end-systolic volume index during low-dose dobutamine echocardiography was significantly associated with clinical events in idiopathic dilated cardiomyopathy (P=0.003).
Cohort (n=70)
Does the cardiac response to low-dose dobutamine assessed by echocardiography correlate with peak VO2 and predict clinical outcomes in patients with idiopathic dilated cardiomyopathy?
In patients with idiopathic dilated cardiomyopathy, the cardiac response to low-dose dobutamine assessed by echocardiography correlates with peak VO2 and predicts clinical outcomes.
p-value: p=0.003
AIMS: To evaluate myocardial contractile reserve using low-dose dobutamine echocardiography in patients with chronic heart failure secondary to idiopathic dilated cardiomyopathy stratified by peak exercise oxygen consumption (VO(2)). METHODS AND RESULTS: Sixty clinically stable patients (56+/-11 years; 45 males) with idiopathic cardiomyopathy and NYHA class I to III symptoms of heart failure were studied and followed-up for 13+/-3 months. All patients underwent cardiopulmonary exercise testing and low-dose dobutamine. The dobutamine infusion protocol consisted of an initial dose of 2.5 micro. kg(-1)per 3 min, increasing by 2.5 micro. kg(-1)per min every 3 min; the maximal dose was 10 micro. kg(-1)per min. The end-systolic volume index, left ventricular ejection fraction and cardiac output were measured at baseline and peak dobutamine dose and their change calculated as ((peak dose value-baseline value)/baseline value]x100. Ten normal subjects with normal left ventricular function and no coronary artery lesions served as a control group to compare low-dose dobutamine results. All analysed echocardiographic variables either at baseline or following dobutamine infusion were significantly lower in patients with chronic heart failure as a whole compared to the control group. When the patients were grouped according to Weber's classification, a statistically significant decrease in percentange changes in end-systolic volume index (rho=-0.77;P20 ml. kg(-1). min(-1)), 18.6+/-8% in class B (peak VO(2)between 16 and 20 ml. kg. min(-1)), and only 6.4+/-6% in class C (peak VO(2)between 10 and 16 ml. kg(-1). min(-1)) patient groups. At multivariate analysis, only the percentage change in end-systolic volume index was significantly associated with a peak VO(2)<15 ml. kg(-1). min(-1)(P=0.006). During the follow-up, 17 patients had events (15 readmissions for worsening heart failure and two deaths). At multivariate analysis, only the percentage change in end-systolic volume index was significantly associated with the occurrence of events (P=0.003). The area under the receiver operating characteristic curve for percentage change in end-systolic volume index was not significantly different from that for peak VO(2)(0. 86+/-0.04 vs 0.80+/-0.06;P:ns). CONCLUSION: This study indicates that in patients with chronic heart failure secondary to idiopathic cardiomyopathy, the cardiac response to low-dose dobutamine, as assessed by echocardiography, is correlated with peak VO(2), an objective and accurate measure of the severity of the disease and clinical outcome.
Domenico Scrutinio (Thu,) conducted a cohort in Idiopathic dilated cardiomyopathy with chronic heart failure (n=70). Low-dose dobutamine echocardiography vs. Normal subjects (control group) was evaluated on Occurrence of clinical events (readmissions for worsening heart failure and deaths) (p=0.003). Percentage change in end-systolic volume index during low-dose dobutamine echocardiography was significantly associated with clinical events in idiopathic dilated cardiomyopathy (P=0.003).