Early changes in ventricular repolarization after thrombolytic therapy in patients with acute myocardial infarction as indicators for prediction of epicardial coronary artery reperfusion.

OBJECTIVES: To investigate the relationship between early T-wave inversion after thrombolytic therapy and the likelihood of successful epicardial coronary reperfusion. SUBJECTS AND METHODS: Thrombolytic therapy was given to 195 patients with ST segment elevation due to acute anterior myocardial infarction (AMI). Coronary angiography was performed. Receiver operating characteristic (ROC) curve (grade of sensitivity versus false positive) was calculated using likelihood ratio method to identify the ideal cut-off values of the ventricular repolarization variables. RESULTS: Predictive indices showed 80% sensitivity, 83% specificity, 81% accuracy, 88% positive predictive value and 71% negative predictive value for early T-wave inversion after thrombolytic therapy. A good concordant agreement was noted between the data of coronary angiography and early T-wave inversion in the infarct-related ECG leads after thrombolysis (kappa coefficient kappa= 0.876). Stepwise multivariate analysis revealed that early T-wave inversion after thrombolytic therapy of AMI was significantly associated with a history of preinfarction angina, residual infarct-related coronary artery stenosis >50%, short time to thrombolytic therapy <90 min, and evening time for occurrence of thrombolysis (p < 0.05). The ROC curve data analysis showed that early T-wave inversion amplitude after AMI had 87% sensitivity and 84% specificity for predicting successful reperfusion, with an ideal cut-off value of 7.2 mm, while time of T-wave inversion had 80% sensitivity and 79% specificity, with an ideal cut-off value of 120 min. CONCLUSION: The data indicate that early inversion of T wave after AMI is a statistically significant independent variable in predicting successful epicardial coronary thrombolysis status.

Predictive accuracy of tissue Doppler imaging for assessment of noninfarct myocardial region in patients with acute myocardial infarction.

OBJECTIVES: To investigate the value of pulsed tissue Doppler imaging (TDI) in order to predict significant coronary artery stenosis supplying the noninfarct region in patients after acute anterior myocardial infarction. SUBJECTS AND METHODS: Transthoracic echocardiography and coronary angiography were performed on 220 patients with acute anterior myocardial infarction. The TDI-derived variables of the mitral valve annulus in the noninfarct region, systolic velocity (Sm), early diastolic velocity (Em) and late diastolic velocity (Am), were estimated in centimeters per second, and the Em/Am ratio was calculated. RESULTS: Predictive indices revealed that the impaired TDI-derived variables, Sm, Em, Am and the Em/Am ratio, were an indicator for predicting significant coronary stenosis in the noninfarct region. Multivariate analysis revealed that the impaired Sm and Em velocities were significantly associated with age of the patients, coronary collaterals and infarct-related artery stenosis (p < 0.05). Receiver-operating characteristic curve data of TDI-derived variables for prediction of significant coronary stenosis revealed that the cut-off values of Sm, Em, Am and Em/Am ratio were 7.2 cm/s, 6.4 cm/s, 12.1 cm/s and 0.56, respectively. The kappa coefficient value indicated that there was an agreement between coronary angiography and the TDI-derived variables Sm, Em, Am and Em/Am ratio in noninfarct regions (kappa = 0.770, 0.731, 0.693 and 0.679, respectively). There was a significant correlation between the severity of coronary artery stenosis (independent variable) and impaired Sm and Em/Am ratio (dependent variables), y = 11.5 - 0.05x, r = -0.902, (p < 0.05), and y = - 0.14x + 1.87, r = -0.754, (p < 0.05), respectively. CONCLUSION: TDI can be used to identify patients with significant stenosis of the coronary arteries supplying the noninfarct region and consequently may be helpful in considering patients for coronary angiography in the early postinfarction period.