| Objective: To study the myocardial viability by means of dobutamine stress echocardiography(DSE) ,to predict the probability of the functional recovery of myocardium after percutaneous coronary intervention(PCI),to probe the safety and accuracy of DSE and its clinical prospect by compared with the follow up six months consequences and to get the outcome about the actual recovery of the fragmental myocardium and the cardiac function as a whole after PCI. Methods: Thirty-six patients were performed DSE 2 to 7 days before PCI determined by coronary artery angiography(CAG). Medicines such as β-blocker and calcium antagonist that may affect the myocardial contractibility had been withheld for at least twenty-four hours before DSE . To calculate the body surface area(BSA), the height and the body weight of every patient were measured. Dobutamine was injected through peripheral vein with micro syringe pump continuously and the dose was increased every five minutes . Two dimensional echocardiography ,twelve leads Electrocardiogram, blood pressure and heart rate(HR) were recorded five minutes before and after DSE andthree minutes after each stage of the experiment. All patients were monitored by Electrocardiogram simultaneously. The rest echocardiogram was recorded six months after PCI. The images of LAX,SAX,AP4 and AP2 echocardiography were collected in real time and were compiled side by side ,all the images were stored with MO optical disk and Sony videotape for later analysis. Cardiac Function was measured with Simpson method. The left ventricular wall movement was analyzed at one week or more intervals by only one experienced ultrasound expert and the third time analysis should be carried out if there were significant differences, the average value of the two close consequences was adopted. The accuracy, sensitivity and specificity of the prediction to the myocardial viability were evaluated with DSE according to the actual recovery of the myocardial contractibility about six months after PCI. Results: Thirty-two patients were accomplished the whole process of study, among the 512 left ventricular wall fragments, 15(2.92%) of them could not be demonstrated clearly and were excluded from the study, the number of normal and abnormal fragments of left ventricular wall movement detected by echocardiography at rest before PCI was 399(77.92%) and 98(19.14%). The sensitivity, specificity and accuracy ofthe prediction to the myocardial viability by DSE is 84.44%, 90.57% and 87.76% respectively, the ratio of positive and negative prediction is 88.37% and 87.27%. The improvement of cardiac function is significant in either myocardial infarct group or non-myocardial infarct group. The systolic blood pressure(SBP) and HR increased gradually, on the contrast, the diastolic blood pressure(DBP) decreased slightly when the dose of dobutamine was less than 20μg·kg-1·min-1 while with a tendency of increase as it was more than 20μg·kg-1·min-1, but all the level of DBP was lower than that of the rest stage. Both blood pressure and HR recovered remarkably after 5 minutes of DSE.Conclusions: The detection of myocardial viability by means of DSE is safe and practicable with high level of sensitivity and specificity. Combining low dose (2.5-10μg·kg-1·min-1) with high dose (20-40μg·kg-1·min-1) of DSE can increase the positive ratio of the detection of the hibernation myocardial cell. The contractibility of viable myocardial fragments and the cardiac function as a whole can be improved by PCI. DSE has an important value in the therapeutic decision-making of coronary heart disease and could be utilized widely. |
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