| Objectives. The aims of this study were 1) to design a computer program used for wall motion analysis in stress echocardiography, 2) to evaluate the hemo-dynamic response to step-wise infiision of dobutamine in normal subjects, and 3) to assess the value of quantitative dobutamine stress echocardiography (DSE) for detecting coronary artery disease (CAD).Methods. 1) Based on an IBM microcomputer and an image processor,a program was written with the language of Turbo Pascal 5.0. The program had the abilities to display in a continuous loop side-by-side images of the left ventricle, and to quantitatively assess the segmental systolic wall thickening(WTh) and fractional area change(FAC). Forty normal subjects and 40 patients with previous myocardial infarction were analyzed to evaluate the reproducibility of the measurements and the reliability to locate the infarct sites. 2) In the normal subjects, two-dimentional echocardiogram with standard views and pulsed Doppler spectrum of ascending aorta were recorded during step-wise infusion of dobutamine (dosage, 5-30 μg /kg/min). The correlations between the dosage and heart rate(HR), blood pressure(BP), rate-pressure product (RPP), stroke volume (SV), ejection fraction(EF), and cardiac output(CO) were analyzed. 3) Eighty-two patients with suspected CAD and myocardial infarction underwent quantitative DSE with the above mentioned protocoL A positive result was defined as detecting a new wall motion abnormality (WMA) induced by dobutamine. The sensitivity, specificity, and accuracy of DSE for diagnosing CAD were establised by comparing with coronary angiography.Results. 1) The WThs and FACs measured with the computer program had good reproducibility and the infract sites were located correctly by the WTh and FAC analysis. 2) During DSE, the WThs, HR, RPP increased with the increase of dobutamine dosage. At high dosage, the SV and EF increases were limited, but the CO increase persisted after the termination of dobutamine infusion.
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