Association between resting painless ST-segment depression with sudden cardiac death in middle-aged population: A prospective cohort study.

BACKGOUND: Silent electrocardiographic ST change predicts future coronary heart disease (CHD) incidence and mortality, but the prognostic significance of painless ST-segment depression (STD) with respect to sudden cardiac death (SCD) in subjects without apparent CHD remain unclear. This study sought to test the association between non-ischemic resting STD and risk of SCD in the general population. METHODS: A total of 14,935 middle-aged subjects from the prospective, population-based Atherosclerosis Risk in Communities (ARIC) study were included in this analysis. Cox models were used to estimate the hazard ratios (HRs) adjusted for possible confounding factors. STD was defined as ST-segment depression of ≥0.05 mV in two or more contiguous leads. RESULTS: A total of 626 sudden cardiac death occurred during the mean follow-up of 20.4 years. Compared with those without STD, subjects with resting painless STD of at least 0.05 mV had a significantly increased risk of developing SCD (adjusted HR, 1.45; 95% CI, 1.20 to 1.76), and those with STD ≥ 0.1 mV had even higher risk of SCD (adjusted HR, 1.90; 95% CI, 1.25 to 2.88). Significant interactions were present between gender and STD (P = .03), and between race and STD (P = .01). STD was significantly predictive of SCD in males (adjusted HR, 1.57; 95% CI, 1.22-2.01) and in whites (adjusted HR, 1.65; 95% CI, 1.27-2.14). STD in lateral leads and global leads were strong predictors of SCD. CONCLUSIONS: Resting painless STD was an independent predictor of SCD in the middle-aged population without previously diagnosed CHD.

Early repolarization is associated with a significantly increased risk of ventricular arrhythmias and sudden cardiac death in patients with structural heart diseases.

BACKGROUND: Early repolarization pattern (ERP) has been proved to increase risk of arrhythmia death in the general population, but its prognostic significance in patients with structural heart disease (SHD) is controversial. OBJECTIVE: The purpose of this study was to conduct a meta-analysis of studies assessing the association between ERP and risk of ventricular arrhythmias (VTAs) and sudden cardiac death (SCD) in patients with SHD. METHODS: We performed a literature search using MEDLINE (January 1, 1966, to September 25, 2016) and EMBASE (January 1, 1980, to September 25, 2016) with no restrictions. Studies that reported odds ratio (OR) estimates with 95% confidence intervals (CIs) for the associations of interest were included. RESULTS: The search yielded 19 observational studies, involving 7268 patients that reported 1127 cases of VTAs or SCD. In the selected studies, the point estimates of the ORs were consistently greater than 1. Compared with those without ERP, patients with ERP experienced a significantly increased risk of developing VTAs or SCD (OR 4.76; 95% CI 3.62-6.26), ventricular fibrillation (OR 7.14; 95% CI 4.31-11.82), and SCD (OR 4.07; 95% CI 1.58-10.51). The results were consistent and statistically significant in all subgroups. ERP with J-point elevation in inferior leads, notching configuration, and horizontal or descending ST segment connote higher risk. CONCLUSION: ERP is associated with a significant increased risk of VTAs or SCD in patients with SHD. Future research should attempt to understand the exact mechanisms for the arrhythmia risk and to introduce ERP in the risk stratification in this patient group.