Long-term outcome of pre-specified ECG patterns in acute coronary syndrome

Abstract

Background: Long-term outcome of real-life acute coronary syndrome (ACS) patients with selected ECG patterns is not well known.

Purpose: To survey the 10-year outcome of pre-specified ECG patterns in ACS patients admitted to a university hospital.

Methods: A total of 1184 consecutive acute coronary syndrome patients in 2002-2003 were included and followed up for 10 years. The patients were classified into nine pre-specified ECG categories: 1) ST elevation; 2) pathological Q waves without ST elevation; 3) left bundle branch block (LBBB); 4) right bundle branch block (RBBB) 5) left ventricular hypertrophy (LVH) without ST elevation except in leads aVR and/or V₁; 6) global ischemia ECG (ST depression ≥0.5 mm in 6 leads, maximally in leads V_4-5 with inverted T waves and ST elevation ≥0.5 mm in lead aVR); 7) other ST depression and/or T wave inversion; 8) other findings and 9) normal ECG.

Results: Any abnormality in the ECG, especially Q waves, LBBB, LVH and global ischemia, had negative effect on outcome. In age- and gender adjusted Cox regression analysis, pathological Q waves (HR 2.28, 95%CI 1.20-4.32, p = .012), LBBB (HR 3.25, 95%CI 1.65-6.40, p = .001), LVH (HR 2.53, 95%CI 1.29-4.97, p = .007), global ischemia (HR 2.22, 95%CI 1.14-4.31, p = .019) and the combined group of other findings (HR 3.01, 95%CI 1.56-6.09, p = .001) were independently associated with worse outcome.

Conclusions: During long-term follow-up of ACS patients, LBBB, ECG-LVH, global ischemia, and Q waves were associated with worse outcome than a normal ECG, RBBB, ST elevation or ST depression with or without associated T-wave inversion. LBBB was associated with the highest mortality rates.

Keywords: Acute coronary syndrome; ECG; Left bundle branch block; Long-term mortality; Prognosis.