Abstract 4861: Prolonged QRS Duration is a Strong Predictor of Adverse Outcomes in Patients With Non-ST-Segment Elevation Acute Coronary Syndrome

Background: Although ECG assessment of myocardial ischemia is usually based on ST-segment changes, prolonged QRS duration (QRSd) has been shown to be more sensitive than ST-segment change for the detection of ischemia. However, the implication of QRSd in non-ST-segment elevation acute coronary syndromes (NSTE-ACS) is not known. Methods: We studied 501 patients with NSTE-ACS who underwent coronary angiography during hospitalization. Patients with bundle branch block, left ventricular hypertrophy, and paced rhythm were excluded. Maximal QRSd and ST-segment deviation were measured on admission 12-lead ECG. Patients were divided into the 4 groups according to QRSd: ≤80 ms (n=153, G-A); 81–90 ms (n=214, G-B); 91–100 ms (n=86, G-C); and ≥101 ms (n=48, G-D). Troponin T (TnT), brain natriuretic peptide (BNP), and high-sensitivity C-reactive protein (hsCRP) were measured on admission. Results: There were no differences in sex or coronary risk factors except for diabetes mellitus in the 4 groups. In G-A, G-B, G-C, and G-D, age was 64±12, 67±11, 68±11, and 69±11 years; the rates of diabetes mellitus were 23%, 33%, 49%, and 50%; Killip class ≥2 was 3%, 6%, 11%, and 31%; positive TnT was 16%, 36%, 44%, and 56%; the levels of BNP were 105±259, 158±235, 306±355, and 391±390 pg/ml; hsCRP was 0.180±0.233, 0.400±0.748, 0.417±0.530, and 0.716±1.230 mg/dl; the degrees of summed ST-segment depression in all leads except aVR were 1.8±2.8, 2.8±3.6, 5.4±5.1, and 8.7±6.0 mm; ST-segment elevation in lead aVR was 0.1±0.2, 0.1±0.3, 0.5±0.6, and 0.8±0.6 mm; the frequencies of left main or 3-vessel disease (LM/3VD) were 1%, 5%, 49%, and 88%; and major adverse events (death, [re]infarction, or urgent revascularization) at 30 days were 5%, 13%, 24%, and 67%, respectively (all p<0.01). Multivariate analysis showed that QRSd was the strongest predictor of 30-day adverse events (OR 2.40, 95%CI 1.54 –3.24, p<0.001), followed by the degree of ST-segment elevation in lead aVR (OR 1.97, 95%CI 1.20 –5.82, p=0.039) and positive TnT (OR 1.60, 95%CI 1.10 –3.17, p=0.048). Conclusions: In patients with NSTE-ACS, prolonged QRSd on admission ECG is strongly associated with LM/3VD and predicts adverse outcomes, even after adjusting for ST-segment changes, biomarker profiles and traditional risk factors.