TRANSIENT INCREASE IN ST-SEGMENT CHANGES AT TIME OF REPERFUSION IN ACUTE MYOCARDIAL-INFARCTION TREATED BY CORONARY ANGIOPLASTY

Purpose. The clinical significance of early ST-segment re-elevation, a so called ''reperfusion peak'' in patients with acute myocardial infa rction (AMI) treated with thrombolysis is unclear. We examined the inc idence and significance of early ST-segment re-elevation immediately u pon reperfusion in patients undergoing percutaneous transluminal coron ary angioplasty (PTCA) where the time of reperfusion can be precisely established. Methods. Thirty-two patients (6 women, 26 men, age 61.5 /- 10.2 years) with an AMI, admitted less than four hours after the on set of chest pain, were included. Twenty-four patients were treated wi th primary PTCA and eight with rescue PTCA. Computerized on-line vecto rcardiography was used for continuous ischemia monitoring. A reperfusi on peak was defined as an increase in ST-vector magnitude (ST-VM) of > 50 mu V, starting within two minutes after the re-opening of the infa rct-related coronary artery and followed by an immediate decrease in t he ST segment. Results. Primary success was achieved in all treated pa tients. Twenty of the patients (63%) developed a reperfusion peak. ST- VM before coronary angiography was significantly larger (p = 0.004) an d peak enzyme levels were higher (p = 0.014) in patients who developed a reperfusion peak. Thrombolytic treatment prior to rescue angioplast y, time to reperfusion, target vessel, presence of collaterals or medi cation on admission did not differ significantly between the groups. C onclusion. The occurrence of a reperfusion peak during the minutes aft er the onset of reperfusion is a common finding in patients with AMI t reated at an early stage with angioplasty. There is a relationship wit h the occurrence of a reperfusion peak and the extent of the initial S T deviation (presumably reflecting the myocardium at risk) and peak en zyme levels. The importance of a reperfusion peak for clinical outcome and prognosis is so far not known.