Abstract 2146: Significant Electrocardiographic Predictors of Cardiovascular Mortality in Patients with Left Bundle Branch Block
Although QRS prolongation has been reported to be a significant predictor of mortality in patients with left bundle branch block (LBBB), the prognostic value of other ECG criteria in patients with LBBB in a large general medical population is unclear. Analyses were performed on the first ECG recorded among 42,301 male veterans since 1987. Subgroup analysis was performed on those with LBBB. Using computerized algorithms, several ECG interpretations defined by standardized computer criteria in MUSE® ECG system were extracted. Cardiovascular (CV) mortality was the main outcome with a mean follow-up of 6 years. LBBB was present in 556 (1.3%) patients with a mean age of 57 years. After adjusting for age and heart rate in a Cox model, the only significant predictors of CV mortality in patients with LBBB were: left atrial abnormality (HR 2.7, p<0.001), QRS duration>150 ms (HR 1.8, p<0.001), atrial fibrillation (HR 1.9, p=0.01) and left axis deviation (HR 1.5, p=0.02). For practical clinical utility, a simple score derived from the summation of the most significant predictors was made and adjusted for age and heart rate. More ECG abnormalities were associated with higher risk of CV death. Survival curves demonstrated a stepwise increase in mortality when there were more ECG abnormalities or higher summation scores. Left atrial abnormality,QRS duration, atrial fibrillation and left axis deviation were significant independent predictors of CV death in patients with LBBB. A simple technique of summing the number of ECG abnormalities is a powerful predictor of CV death and can be easily calculated and used in daily clinical practice.