QRS-T angle: is it a specific parameter associated with sudden cardiac death in type 2 diabetes? Results from the SURDIAGENE and the Mini-Finland prospective cohorts.

AIMS/HYPOTHESIS: Type 2 diabetes is associated with a high risk of sudden cardiac death (SCD), but the risk of dying from another cause (non-SCD) is proportionally even higher. The aim of the study was to identify easily available ECG-derived features associated with SCD, while considering the competing risk of dying from non-SCD causes. METHODS: In the SURDIAGENE (Survie, Diabete de type 2 et Genetique) French prospective cohort of individuals with type 2 diabetes, 15 baseline ECG parameters were interpreted among 1362 participants (mean age 65 years; HbA1c 62±17 mmol/mol [7.8±1.5%]; 58% male). Competing risk models assessed the prognostic value of clinical and ECG parameters for SCD after adjusting for age, sex, history of myocardial infarction, N-terminal pro b-type natriuretic peptide (NT-proBNP), HbA1c and eGFR. The prospective Mini-Finland cohort study was used to externally validate our findings. RESULTS: During median follow-up of 7.4 years, 494 deaths occurred including 94 SCDs. After adjustment, frontal QRS-T angle ≥90° (sub-distribution HR [sHR] 1.68 [95% CI 1.04, 2.69], p=0.032) and NT-proBNP level (sHR 1.26 [95% CI 1.06, 1.50] per 1 log, p=0.009) were significantly associated with a higher risk of SCD. Nevertheless, frontal QRS-T angle was the only marker not to be associated with causes of death other than SCD (sHR 1.08 [95% CI 0.84, 1.39], p=0.553 ). These findings were replicated in the Mini-Finland study subset of participants with diabetes (sHR 2.22 [95% CI 1.05, 4.71], p=0.04 for SCD and no association for other causes of death). CONCLUSIONS/INTERPRETATION: QRS-T angle was specifically associated with SCD risk and not with other causes of death, opening an avenue for refining SCD risk stratification in individuals with type 2 diabetes.

Poor R-wave progression as a predictor of sudden cardiac death in the general population and subjects with coronary artery disease.

BACKGROUND: Poor R-wave progression (PRWP) is a common clinical finding on the standard 12-lead electrocardiogram (ECG), but its prognostic significance is unclear. OBJECTIVE: The purpose of this study was to examine the prognosis associated with PRWP in terms of sudden cardiac death (SCD), cardiac death, and all-cause mortality in general population subjects with and without coronary artery disease (CAD). METHODS: Data and 12-lead ECGs were collected from a Finnish general population health examination survey conducted during 1978-1980 with follow-up until 2011. The study population consisted of 6854 subjects. Main end points were SCD, cardiac death, and all-cause mortality. PRWP was defined as R-wave amplitude ≤ 0.3 mV in lead V3 and R-wave amplitude in lead V2 ≤ R-wave amplitude in lead V3. RESULTS: PRWP occurred in 213 subjects (3.1%). During the follow-up period of 24.3 ± 10.4 years, 3723 subjects (54.3%) died. PRWP was associated with older age, higher prevalence of heart failure and CAD, and ß-blocker medication. In multivariate analyses, PRWP was associated with SCD (hazard ratio [HR] 2.13; 95% confidence interval [CI] 1.34-3.39), cardiac death (HR 1.75; 95% CI 1.35-2.15), and all-cause mortality (HR 1.29; 95% CI 1.08-1.54). In the subgroup with CAD, PRWP had a stronger association with cardiac mortality (HR 1.71; 95% CI 1.19-2.46) than in the subgroup without CAD, while the association with SCD was significant only in the subgroup with CAD (HR 2.62; 95% CI 1.38-4.98). CONCLUSION: PRWP was associated with adverse prognosis in the general population and with SCD in subjects with CAD.