[Dobutamine stress echocardiography in distinguishing ischemic from nonischemic dilated cardiomyopathy]

The aim of this study was to evaluate the diagnostic accuracy of dobutamine stress echocardiography for detection of coronary artery disease in patients with dilated cardiomyopathy. Detection of regional wall motion abnormalities at rest does not reliably distinguish ischemic from nonischemic cardiomyopathy.

To distinguish between ischemic and nonischemic dilated cardiomyopathy (DCM), we studied 50 patients with left ventricular dysfunction (20 ischemic and 30 nonischemic, detected by coronary angiography) using dobutamine stress echocardiography. Echocardiographic images were obtained at baseline, low and paek dose of dobutamine. Rest and stress left ventricular wall motion scores were derived from analysis of regional wall motion.

Dobutamine infusion was terminated after achievement of the target heart rate or maximal protocol dose in 16 (80%) patients with ischemic heart disease and in 23 (73.3%) patients with nonischemic heart disease. At rest, there were more normal segments (p<0.001) and a trend toward more akinetic segments (p, not significant) per ischemic than per nonischemic DCM patients. However, either at rest or with low-dose dobutamine, individual data largely overlapped. At peak dose, in ischemic DCM, regional contraction worsened in many normal or dyssinergic regions at rest (in some cases after inprovement with low-dose dobutamine); in contrast, in nonischemic DCM, further mild impovement was observed in a variable number of left ventricular areas. Thus, with peak-dose dobutamine, more akinetic and less normal segments were present per ishemic than per nonischemic DCM patient (both, p<0.001). A value of six or more akinetic segments was 90% sensitive and 98% specific for ischemic DCM.

Our data show that analysis of regional contraction by dobutamine stress echocardiography can distinguish between.