Effects of thrombolysis on vectorcardiographic indices of ventricular repolarization: correlation with ST-segment resolution

Abstract To investigate the effects of thrombolysis on vectorcardiographic (VCG) descriptors of ventricular repolarization in association with ST-segment resolution, 70 consecutively recruited patients with acute myocardial infarction underwent digital 12-lead electrocardiograms (ECGs) before and at 3 hours after thrombolysis. The alterations in the VCG descriptors spatial T amplitude and spatial QRS-T angle from the pre- to the post-thrombolysis ECG, as well as the ST-segment resolution, were calculated. Angiography revealed patency of the infarct-related coronary artery after thrombolysis in 52 (74%) patients (group A) and occlusion in 18 (26%) (group B). The spatial T amplitude was highly significantly reduced after thrombolysis in group A ( P P = .016). The spatial QRS-T angle was also significantly, although only marginally, reduced after thrombolysis in group A ( P = .019), whereas it was not changed after thrombolysis in group B ( P = .868). An ST-segment resolution of 60% and a 25% reduction in the spatial T amplitude after thrombolysis were able to identify patency of the infarct-related coronary artery with sensitivities of 90% and 77% and specificities of 94% and 74%, respectively. Both VCG descriptors were significantly affected by thrombolysis in patients with acute myocardial infarction, but constituted only moderate markers of thrombolysis efficacy, as evidenced by the presence of patency in the infarct-related coronary artery, compared with the ST-segment resolution.