Dobutamine Stress Echocardiography in Patients with Dilated Cardiomyopathy

Abstract

A clear distinction between two of the most common forms of dilated cardiomyopathy is very important due to their different prediction and therapeutic approaches. Dobutamine stress echocardiography appears to be a noninvasive selection method due to its clear differentiation potential. Major factors influence test interpretation, resulting in a wide interval of diagnostic accuracy for this test. Fraction flow reserve (FFR) is a novel invasive method for estimating coronary artery stenosis responsible for myocardium ischaemia. Decisions about lesion significance in coronary blood vessels have thus far been based on angiographic estimations, but this approach is being replaced by FFR measurements, which serve as a new gold standard and involve a noninvasive test. The goal of this study was to clearly differentiate two forms of dilated cardiomyopathies through analysis of the segmented mobility of the left ventricular wall. Fifty patients were analysed: 20 with ischaemic dilated cardiomyopathy, which was confirmed not only through coronary angiography but also functionally through FFR measurement, and 30 patients with nonischaemic dilated cardiomyopathy, which was confirmed by coronary angiography. A standard dobutamine stress echocardiography protocol was implemented. A positive dobutamine stress echocardiography test was defined as the presence of emerging incidents in segment contractility or worsening of existing incidents in at least one segment. Statistically relevant diff erences in the movement dynamics of a number of differently characterised segments during the observed time intervals (ANOVA p=0.000) was noted in both groups of patients, as was variation in the index value of the summarized mobility of the left chamber wall. In patients with ischaemic cardiomyopathies, regional contractility worsened at the maximum dose of dobutamine; in contrast, this feature slightly improved in nonischaemic cardiomyopathy patients. The results indicate that by analysing segmental motion, these two forms of dilated cardiomyopathies can be differentiated with high sensitivity (Sn=90%) and specificity (Sp=98%), which can be interpreted as concrete evidence of truly ischaemic lesions in coronary blood vessels.