Series Of Studies Of Clinical Cardiac Electrophysiology

Purpose: To detect the accuracy and practicality of viable myocardium, we compared intracoronary electrocardiogram with emission computed tomography .To observe the IC-ECG's advantage of the accuracy, compared it with the emission computed tomography, and obtained new index of the electrocardiolopy.Methods: From Oct. 2000 to Sep. 2001,30 patients who suffered myocardial infarction and underwent PCI operation accepted 99mTc-MIBI myocardial tomography with low dose dobutamine(3p.g/kg/min) and sublingual nitroglycerin(p.5mg) before PCI operation. All patients were studied by rest imaging three weeks after operation, and observed the accuracy and safety of using dobutamine and nitroglycerin together for detecting the viable myocardium. We recorded synchronous IC^ECG and ECG of all patients during PCI operation and observed the changes of ST segment. All patients were departed into two groups according to the changes of ST segment of IC-ECG. Group A included the patients whose ST segment elevated more than 0.2 my, and group B included the patients whose ST segment elevated less than ,0.2 mV during the operation.Result: There were 117 segments of hypoperfusion in rest imaging before operation. There was improvement in the myocardium perfusion of hypoperfusive cases after using drug imaging and PCI operation. Theresults showed that 41 segments had improvement, 23 segments had normal uptake, and 53 segments had no changes after drugs. During three follow-up weeks after operation, 48 segments had improvement, 28 segments had normal uptake. 41 segments had no improvement in 53 segments that had no changes formerly. There were improvement of 12 segments within inefficient 53 segments after operation. According to the criterion of PCI after 3 weeks, the sensitivity was 84.2%, and the specificity was 77.4% of 99mTc-MIBI myocardial tomography after injected low dose dobutamine and sublingual nitroglycerin. There were 6 patients had viable myocardium (31.6%) in group A, and 1 patient had viable myocardium (9.1%) in group B(P<0.01). There were!2 patients had partly viable myocardium (63.2%) in group A, and 3 patients had partly viable myocardium (27.3%) in group B(P<0.01). There were 1 patient had no viable myocardium (5.3%) in group A, and 7 patients had no viable myocardium (63.6%) in group B(P<0.01).Conclusion: The sensitivity was 84.2%, and the specificity was 77.4 % of 99mTc-MIBI myocardial tomography after injected low dose dobutamine and sublingual nitroglycerin. Using dobutamine and nitroglycerin together had safety with low side effect of detecting viable myocardium. The sensitivity was 81.8%, and the specificity was 87.5% of IC-ECG. IC-ECG had prompt accurate and economic advantage for detecting viable myocardium comparing with emission computed tomography. It maybe have much application in clinic. IC-ECG identified early viable myocardium from the electrocardiolopy, and had prediction for the prognosis of the patients underwent PCI.