Reduced QT dispersion after early thrombolysis - protection of ventricular electrical stability

Journal of Clinical and Basic Cardiology 1999; 2 (1): 85-88

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Keywords: Elektrokardiographie,  Myokardinfarkt,  reperfusion,  Thrombolyse,  electrocardiography,  myocardial infarction,  reperfusion,  thrombolysis

Temporary QT prolongation during acute myocardial infarction predicts ventricular tachyarrhythmias. New data suggest that in acute myocardial infarction and in the pathogenesis of other ventricular arrhythmias the QT dispersion demonstrates ventricular inhomogeneity and ventricular instability better than QT prolongation. The aim of this study was to assess the effect of intravenous streptokinase on the QT, JT dispersions and their corrected values during therapy of acute myocardial infarction. Twenty patients, 10 patients with acute myocardial infarction treated with streptokinase (Group A), 10 acute myocardial infarction patients without streptokinase (Group B) and 10 healthy volunteers (Group C) were studied. Simultaneous 12 lead ECGs were recorded at the time of admission to hospital (day 1) in patients with acute myocardial infarction and prior to discharge (day 8 ± 2 ) in a standard setting. The QT intervals for each lead were measured manually on the enlarged ECGs (by a factor 3) using calipers by the same observer. Each QT interval was corrected for patient?s heart rate: QTc = QT/(SQRT RR) (msec). There were significantly greater mean QT, QTc, JT, JTc dispersions in Groups A and B in the early hours of infarction compared to Group C (p < 0.05). Patients with anterior myocardial infarction showed significantly greater QT, QTc and JT, JTc dispersions when compared to inferior myocardial infarction patients (p < 0.02 ). There were significantly greater reductions in QT, QTc, JT, JTc dispersions at day 8 ± 2 after streptokinase therapy compared to patients who were not treated with streptokinase (p < 0.05). Successful fibrinolytic therapy results in reduction in QT and JT dispersions. This can be taken into consideration in the risk stratification for malignant ventricular tachyarrhythmias and it is another evidence of the benefit of thrombolytic therapy in patients with acute myocardial infarction. J Clin Basic Cardiol 1999; 2: 85-8.