NONINVASIVE ASSESSMENT OF REPERFUSION OF THE INFARCT-RELATED ARTERY DURING CORONARY THROMBOLYSIS AND ITS RELATION WITH LEFT-VENTRICULAR FUNCTION

We monitored ST segment continuously for at least 3 h after the beginn ing of lytic treatment in 103 patients undergoing early coronary throm bolysis for acute myocardial infarction in order to ascertain whether this technique, which has been shown to be useful to assess recanaliza tion of the infarct-related artery, is also able to identify the impro vement in left ventricular function associated with successful reperfu sion. Global left ventricular function (assessed in the 30 degrees rig ht anterior oblique projection with the area/length method) and infarc t zone wall motion (studied with the centerline method) were evaluated at least 4 weeks after the event. Reperfusion was thought to be achie ved when ST segment elevation dropped > 50% relative to the most abnor mal peak documented at any time in the study. Eighty patients (78%) me t the criterium for successful reperfusion (group 1), and 23 (22%) did not (group 2). Both groups had similar clinical and angiographic char acteristics. All indexes of global left ventricular function were sign ificantly better in group 1 than in group 2 patients (end-diastolic vo lume: 176 +/- 51 vs. 209 +/- 76 ml, end-systolic volume: 66 +/- 40 vs. 97 +/- 55 ml, ejection fraction: 65 +/- 13 vs. 57 +/- 11%, respective ly, 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 i n 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 ventri cular 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 bette r global left ventricular function than patients without electrocardio graphic signs of reperfusion as assessed by continuous ST segment moni toring. This suggests that this non-invasive technique is a powerful t ool able to identify patients most benefiting from thrombolytic therap y.