title: Transient Increase in ST-segment Changes at Time of Reperfusion in Acute Myocardial Infarction Treated by Coronary Angioplasty.
abstract: PURPOSE: The clinical significance of early ST-segment re-elevation, a so called Òreperfusion peakÓ in patients with acute myocardial infarction (AMI) treated with thrombolysis is unclear. We examined the incidence and significance of early ST-segment re-elevation immediately upon reperfusion in patients undergoing percutaneous transluminal coronary 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 onset of chest pain, were included. Twenty-four patients were treated with primary PTCA and eight with rescue PTCA. Computerized on-line vectorcardiography was used for continuous ischemia monitoring. A reperfusion peak was defined as an increase in ST-vector magnitude (ST-VM) of > 50 µV, starting within two minutes after the re-opening of the infarct-related coronary artery and followed by an immediate decrease in the ST segment. RESULTS: Primary success was achieved in all treated patients. Twenty of the patients (63%) developed a reperfusion peak. ST-VM before coronary angiography was significantly larger (p = 0.004) and peak enzyme levels were higher (p = 0.014) in patients who developed a reperfusion peak. Thrombolytic treatment prior to rescue angioplasty, time to reperfusion, target vessel, presence of collaterals or medication on admission did not differ significantly between the groups. CONCLUSION: The occurrence of a reperfusion peak during the minutes after the onset of reperfusion is a common finding in patients with AMI treated at an early stage with angioplasty. There is a relationship with the occurrence of a reperfusion peak and the extent of the initial ST deviation (presumably reflecting the myocardium at risk) and peak enzyme levels. The importance of a reperfusion peak for clinical outcome and prognosis is so far not known.
authors.affiliation: Department of Medicine, University Hospital, SE-901 65, Umea, Sweden. Johan.Nilsson@medicin.umu.se
authors.initials: JB
authors.lastname: Nilsson
authors.initials: A
authors.lastname: Eriksson
authors.initials: U
authors.lastname: Naslund