Abstract 17908: Prediction of Sudden Cardiac Death in Patients With Mild to Moderate Chronic Heart Failure: A Comparative Study of Early Repolarization and Heart Rate Recovery
Background: Identification of patients with chronic heart failure (CHF) at risk for sudden cardiac death (SCD) remains an important goal. Early repolarization pattern (ERP) on the 12-lead ECG has been associated with an increased risk of life-threatening ventricular arrhythmias in patients with chronic coronary artery disease. On the other hand, heart rate recovery (HRR) after exercise is related to autonomic function and reported to the prognostic marker in cardiovascular diseases. However, there is no information available on the comparison of the prognostic significance for SCD between ERP and HRR in patients with CHF.
Methods: We studied 92 consecutive outpatients (NYHA class: 2.0±0.6), with left ventricular ejection fraction less than 40% (30±7%), who were enrolled in our prospective cohort study. All patients underwent the standard 12-lead ECG and exercise test at enrollment. We assessed the presence of ERP, using the criteria of J-point elevation ≥0.1 mV in at least 2 inferior or lateral leads. HRR was defined as the difference in heart rate between at peak exercise and at one minute later after stopping exercise; a value <12 bpm was considered abnormal. The primary endpoint of this study was SCD.
Results: At enrollment, 10 and 47 patients had ERP and abnormal HRR, respectively. During the mean follow-up period of 6.7±3.5 yrs, 18 patients had SCD. Patients with SCD had significantly higher incidence of ERP than those without SCD (33% vs 5%, p=0.003). HRR was smaller in patients with than without SCD (11.7±7.1 vs 13.2±9.0 bpm), although the difference was not statistically significant. Kaplan-Meier analysis showed that SCD was observed significantly more frequently in patients with than without ERP (60% vs 14%, p=0.0003), while there was no difference in the SCD incidence between patients with and without abnormal HRR (21% vs 18%). A multivariate Cox analysis revealed that ERP was significantly and independently associated with SCD (hazard ratio 4.5 (95%CI 1.3-14.8), p = 0.013), although abnormal HRR showed no significant association with SCD.
Conclusion: ERP, but not HRR, would be associated with an increased risk of SD in patients with mild to moderate CHF.
- © 2013 by American Heart Association, Inc.