Study On The Significance Of T Wave And The Influence Of Coronary Revascularization After Acute Myocardial Infarction

[Objective] To explore the determinant of persistent negative T wave and early or late T wave normalization after acute myocardial infarction.[Methods] We studied 283 patients with first acute myocardial infarction. All the patients' ECG showed that ≥2 relative leads had negative T waves 24 to 36 hours after the onset. At the first weekend of the onset, dobutamine stress echocardiography was done to the patients with no such restrictions as (1)hypertrophic cardiomyopathy, (2)unstable angina or within the first week of AMI, (3)severe ventricular arrhythmia or supraventricular arrhythmia, (4)patients were too sensitive to dobutamine to tolerant the test, (5)moderate or severe hypertension and (6)uncontrolled moderate to severe heart failure. And then a revascularization procedure was carried out on patients with ischemic response in the stress echocardiography. ECG was recorded at the hospital discharge, and at the fourth month. T waves inverting ≥0.01mv in more than 2 relative leads of ECG is called negative T wave. T wave normalization is that negative T wave become reared, or T wave is at the electric potential line at the hospital discharge or at the fourth month, whereas persistent negative T waves is that T waves of the relative leads are still negative at the fourth month. Patients were divided into 3 groups according to the ECG changes. The 1^st group was early T wave normalization group, the 2^nd group was late T wave normalization group, and the 3^rd group was persistent negative T wave group.[Results] There were 198 patients with T wave normalization, including 42 patients in Group 1 and 156 patients in Group 2. During the dobutamine stress echocardiography , there were 29(68.4%) patients with persistent myocardial construction in Group 1, whereas 20(13.0%) patients in Group 2, and 2(2.6%) patients in Group 3; there were 6(14.3%) patients with myocardial ischemic response( including biphasic response and ischemic in adjacent area) in Group 1, whereas 111(71.0%) patients in Group 2 and 46(53.8%) patients in Group 3. The patients who had ischemic response were selected to have coronary intervention. Among all the patients selected to have undergone coronary intervention, there were 4(10.5%) patients to perform selective coronary revascularization in Group 1, whereas 88 (79.6%) patients t in Group 2, and 9 (19.0%) patients in Group 3. The three groups had significant statistic difference (P<0.05) .[ Conclusion ] Early T wave normalization is associated with myocardial stunning, and small dose of dobutamine can induce function improvement of myocardial stunning. Late T wave normalization is mainly observed in the patients with ischemic response who had undergone coronary revascularization. Persistent negative T wave is associated with the extension of the myocardial infarction, non-revascularization or persistent, serious myocardial injury.