Abstract 114: Relationship Between Duration of QRS Complex and Long Term Mortality in U.S. Veterans With Atherothrombotic Risk Factors

Abstract

Background: The 12-lead electrocardiogram (ECG) remains a cost-effective diagnostic tool in risk stratification for cardiovascular disease. Little is known of the prognostic value of QRS duration but recent reports suggest that a prolonged QRS duration may be associated with adverse outcomes. We investigated the relationship between QRS duration and long term mortality in Veterans with atherothrombotic risk factors. Methods: We retrospectively collected data from a Veterans Affairs (VA) medical center for consecutive patients (October 2001 to January 2005) to determine the long term mortality rates associated with different intervals of QRS duration in patients who presented for coronary angiography. Results: Of the 1193 charts reviewed, 1186 had a QRS duration reading recorded. For these 1186 patients the mean follow-up period was 103±52 months. Mean age was 63.2±10.8 years with 98% male. Mean body mass index was 30.0±5.9. The prevalence of comorbidities was: hypertension (88%), hyperlipidemia (79%), obstructive coronary artery disease (73%), left ventricular hypertrophy (50.4%), diabetes mellitus (45%), peripheral vascular disease (17%), and cerebrovascular accident (8%). Mean left ventricular ejection fraction (LVEF) was 47±13%, and mean PR interval was 172.5±30.5 milliseconds (ms). Most patients were on beta-blocker (82%). Among patients with bundle branch blocks (BBB), left BBB was present in 4.6% and right BBB was present in 6.9%. Mean QRS duration was 102.2±23.6 ms. As the QRS duration increased by intervals of 10-milliseconds, the mortality rate (%) increased [QRS ≤100 (40.7%), 101 to 110 (51.3%), 111 to 120 (66.3%), >120 (71.2%), p<0.001]. Among patients with QRS duration >120, mortality was higher in those >150 vs. 121 to 150 (79.7% vs 65.7, p=0.045). While QRS duration was a significant univariate predictor of morality, QRS duration is not significant when adjusted for 10 covariates listed above (odds ratio = 1.00 [95% Cl = 0.98 to 1.01], p = 0.72). Conclusion: Long term mortality was higher as QRS duration increased. QRS duration had utility in predicting mortality within this cohort of US Veterans with atherothrombotic risk factors.