Electrocardiography as a predictor of left main or three-vessel disease in patients with non-ST segment elevation acute coronary syndrome

IntroductionAcute coronary syndrome remains the leading cause of morbidity and mortality worldwide. It will continue to rise as the prevalence of patients with obesity and diabetes increases. Patients with non-ST segment elevation acute coronary syndrome had a bad prognosis in patients with left main ± three vessel diseases, so early identification of these patients by electrocardiography if ST segment elevation in lead aVR ⩾0.5 m and maximal QRS duration of ⩾90 ms is important for the selection of optimal treatment.Materials and methodsThe study was designed as a multicenter cross-sectional study that was conducted on 150 patients presenting with non-ST segment elevation acute coronary syndromes, 80 patients had non-ST segment elevation myocardial infarction and 70 patients had unstable angina in the period between January 2009 till January 2010. All patients had full history, clinical examination, laboratory investigations including lipid profile, blood glucose, cardiac Troponin T and renal function, also electrocardiography and coronary angiography was done to prove the diagnosis. ECG was analyzed to assess the degree of ST segment elevation in aVR, ST segment depression in other leads and the maximal QRS was analyzed. Coronary angiography was done to all patients with detection of the presence of left main 50% stenosis at least with or without other three significant coronary vessels showing 70% stenosis or more to be included in 67 patients in group I. Group II include 83 patients with normal coronaries or significant stenosis in one or two vessels.ResultsLeft main coronary stenosis with or without three significant coronary vessel stenosis occurs in 67 patients (44.7%) in group I vs. 83 patients (55.3%) in group II (i.e. without left main disease or three vessel disease). The mean age of the patients 59 ± 9 years which was not significant in both the groups (P > 0.05). The following also were not significant gender, smoking, dyslipidemia, renal impairment, hypertension and positive family history. Diabetes was considered significant in 44 patients (65.7%) in group I in comparison to 34 patients (41%) in group II (P < 0.003). Positive Troponin T was also significant in group I in 47 patients (70.1%) vs. 33 patients (39.8%) in group II. ST segment elevation ⩾0.5 mm in lead AVR is significant in group I in 52 patients (77.6%) vs. 29 patients (34.9%) in group II (P < 0.001). ST segment depression ⩾0.5 mm in leads other than aVR is significant in group I in 56 patients (83.6%) vs. 41 patients (49.4%) in group II (P < 0.001). The presence of QRS duration > 90 ms in the admission ECG was significant in group I in 45 patients (67.2%) vs. 16 patients (19.3%) in group II (P < 0.001).ConclusionST-segment elevation in lead aVR ⩾0.5 mm and QRS duration ⩾90 ms are good electrocardiographic predictors of left main or three vessel disease in patients with non-ST segment elevation acute coronary syndrome.