Abstract 

INTRODUCTION: Chest pain in unstable angina is associated with EKG changes in T-wave and ST-segment, which may help diagnose the disease. Based on certain references EKG changes prolonged for more than 12 hours may be suggestive of non-Q myocardial infarction. This study was conducted to assess the mean duration of EKG changes in patients with unstable angina.

methods: This cross-sectional study was conducted on 34 patients in 2001. The subjects were randomly selected among patients hospitalized in the critical care unit of Isfahan Nour Hospital. New ST-segment T-wave changes and ruling out of acute myocardial infarction by enzymatic tests (Total CPK, CPK-MB, LDH) constituted criteria of inclusion in the study. Subjects with Wolf-Parkinson-White syndrome (WFW), salivary diseases, those taking anti-arrhythmic, anti-angina, or digital medications, patients with left bundle branch block, and those who had recently undergone surgery (all of which may cause T-wave and ST-segment changes) were excluded from the study. The patients were followed up for three months after discharges.

results: EKG changes persisted for 28.65±7 days. Changes of ST-segment and T-wave lasted for 14.7±24 and 30.1±38 days, respectively. The minimum and maximum durations of EKG changes in patients were 1 day and 90 days, respectively. Eight patients underwent angiography; seven displayed abnormal findings. Statistical analysis did not show a significant relationship between the duration of EKG changes and severity of coronary involvement or incidence of future complications.

Discussion: EKG changes in patients with unstable angina who have recently developed these changes may persist for an average duration of one month and may complicate diagnosis. Hence greater importance should be attached to clinical symptoms and further laboratory diagnostic methods should be used.

Keywords . Myocardial infarction . ST-segment . T-wave . EKG changes