Non-invasive assessment of reperfusion of the infarct-related artery during coronary thrombolysis and its relation with left ventricular function

Abstract

We monitored ST segment continuously for at least 3 h after the beginning of lytic treatment in 103 patients undergoing early coronary thrombolysis for acute myocardial infarction in order to ascertain whether this technique, which has been shown to be useful to assess recanalization of the infarct-related artery, is also able to identify the improvement in left ventricular function associated with successful reperfusion. Global left ventricular function (assessed in the 30° right anterior oblique projection with the area/length method) and infarct zone wall motion (studied with the centerline method) were evaluated at least 4 weeks after the event. Reperfusion was thought to be achieved when ST segment elevation dropped>50% relative to the most abnormal peak documented at any time in the study. Eighty patients (78%) met the criterium for successful reperfusion (group 1), and 23 (22%) did not (group 2). Both groups had similar clinical and angiographic characteristics. All indexes of global left ventricular function were significantly better in group 1 than in group 2 patients (end-diastolic volume: 176 ± 51 vs. 209 ± 76 ml, end-systolic volume: 66 ± 40 vs. 97 ± 55 ml, ejection fraction: 65 ± 13 vs. 57 ± 11%, respectively, all P < 0.02). Also the severity (−1.6 ± 1.3 vs. − 2.6 ± 1.01 S.D./chord, respectively, P < 0.001) and the extension of hypokinesia in the infarct zone (number of chords with>2 S.D.: 13 ± 16 vs. 28 ± 17, respectively, P < 0.0001) were less in group 1 than in group 2 patients. Furthermore, in reperfused patients, both global left ventricular function and regional wall motion were better in those admitted < 60 min from onset of pain. In conclusion, patients with rapid (> 50%) decrease of ST segment elevation have smaller infarct size and better global left ventricular function than patients without electrocardiographic signs of reperfusion as assessed by continuous ST segment monitoring. This suggests that this non-invasive technique is a powerful tool able to identify patients most benefiting from thrombolytic therapy.