Acute electrocardiographic changes associated with successful coronary thrombolysis in acute myocardial infarction.

In this study ECG changes were analyzed to assess the acute effects of antegrade blood flow on the ECG in patients with AMI. The study population consisted of 22 patients with MI in whom the totally occluded left anterior descending artery (LAD) or right coronary artery (RCA) was recanalized by intracoronary urokinase infusion (recanalized group) and 14 patients in whom the occluded coronary artery was not successfully recanalized (control group). No significant difference was found in the sum of ST segment elevation (V2-V4 leads for the LAD-occluded group, II, III and aVF leads for the RCA-occluded group) before urokinase infusion. In the recanalized group sigma ST abruptly increased in 5 min after recanalization in 13 of 16 LAD-occluded patients from 1.49 +/- 0.89 mV to 2.44 +/- 1.67 mV (p less than 0.005), and in 4 of 6 RCA-occluded patients from 0.66 +/- 0.12 mV to 1.42 +/- 0.52 mV (p less than 0.01). However increased sigma ST in the recanalized group was reduced to the control value existing before recanalization within 30 min after recanalization and continued to decline more rapidly than in the control group. These transient ST segment elevations were not correlated with long-term angiographic determinants of left ventricular function. We conclude that ST segment shows abrupt augmentation after successful thrombolysis and that continuous ST segment monitoring is useful for assessing thrombolysis in AMI.