Abstract 11174: Development and Validation of a Prognostic Index for Risk Stratification of Patients with Early Repolarization
Background: An early repolarization (ER) pattern on the electrocardiogram (ECG) is associated with increased risk for cardiac and all-cause mortality in the general population. We sought to develop and validate a prognostic index (PI) of all-cause mortality to risk stratify patients with ER.
Methods: We identified 852 consecutive patients (mean age 49±12 years, 99% male) with ER, defined as J-point elevation ≥0.1mV in either inferior or lateral leads, from the VA electronic ECG database. Relevant clinical characteristics and all-cause mortality were obtained through chart review. All ECGs were analyzed by a cardiologist blinded to the clinical data. The initial cohort was randomly split into a derivation set and a validation set (2/3 and 1/3 of patients, respectively). The regression coefficients of each independent factor using Cox regression analysis were used to derive a PI, which was then applied to the validation set to assess its validity.
Results: During a mean follow up of 7.4±5.6 years, 170 (20%) patients died. In Cox regression analysis, older age (hazard ratio [HR]=1.04, 95% confidence interval [CI] 1.02-1.05), lower body mass index (HR=0.91, 95% CI 0.87-0.95), non-African American race (HR=0.49, 95% CI 0.32-0.76), current use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (HR=1.84, 95% CI 1.20-2.84) or sulfonyureas (HR=2.50, 95% CI 1.38-4.54), prolonged QT (HR=1.02, 95% CI 1.01-1.03) and increased ER amplitude (HR=1.45, 95% CI 1.06-1.99) independently predicted all-cause mortality. The PI, derived from these variables combined, reliably predicted all-cause mortality (p<0.0001). In the derivation set, mortality was 10.3%, 22.2% and 29.9% in the low, intermediate and high risk groups, respectively (log-rank p<0.0001). In the validation set, mortality was 8.3%, 22.9% and 38.6% in the low, intermediate and high risk groups, respectively (log-rank p<0.0001). The area under the receiver operating characteristic curve for the PI was 0.73 in the derivation set and 0.75 in the validation set.
Conclusion: A PI derived from simple clinical and ECG characteristics is a powerful predictor of all-cause mortality in male patients with ER and may be used clinically for risk stratification in this patient population.
- © 2011 by American Heart Association, Inc.