[Left ventricular volumetric and contractility behavior during stress echocardiography with dobutamine]

Aim of this study was to assess the behaviour of left ventricular volumes during dobutamine echocardiography in patients with coronary artery disease (CAD) compared to subjects with normal coronary angiograms. We have measured the end-diastolic and end-systolic volumes and a non invasive index of myocardial contractility (the ratio between systolic blood pressure and end-systolic volume index, SBP/ESVI) in 67 patients undergoing dobutamine echocardiography and quantitative coronary angiography. Patients were divided into 3 groups: Control group (n = 10) without CAD; Group I (n = 30) with CAD but normal resting wall motion; Group II (n = 27) with CAD and resting wall motion abnormalities. Volumetric response to dobutamine was deemed abnormal when percent changes of left ventricular volumes from baseline to peak infusion were below 2 standard deviations of the mean values obtained in the control group. The normal or pathological volumetric response was compared with the extent of significant ( > 70% lumen stenosis) coronary artery disease. In the control group, dobutamine produced a significant decrease in both end-diastolic and end-systolic volumes, with percent changes from rest to peak of 24 +/- 5% and 29 +/- 5% respectively, and an average increase of 70 +/- 20% in the SBP/ESVI ratio. Among the 22 Group I patients who showed dobutamine-induced asynergies, volumetric response in those with multivessel disease was normal in 5/14 (36%) and abnormal in 7/8 (87%, p < 0.05), whereas among the remaining 8 patients who had no dobutamine-induced asynergies, an abnormal volumetric response was always associated with multivessel disease (n = 3/3, 100%). In Group II, the prevalence of abnormal volumetric responses in the presence (n = 15) or absence (n = 12) of dobutamine-induced new or worsening asynergies was respectively 92% and 87% in patients with multivessel disease, whereas in those with single vessel disease the prevalence was lower, although not significantly (8 and 13%, p = 0.08 vs multivessel CAD). Predictive accuracy of an abnormal volumetric response for identifying multi-vessel coronary artery disease in Groups I and II was not significantly different (77 and 85%, respectively, NS). Our preliminary data indicate that the evaluation of left ventricular volumes during dobutamine echocardiography yields additional information on myocardial intropic reserve, useful for diagnostic and functional assessment of patients with coronary artery disease. Moreover, this study emphasizes the importance of defining the "normal" left ventricular performance during DE to be able to regard an abnormal volumetric behaviour as a reliable marker of impaired inotropic reserve.