QRS-T angle predicts cardiac risk and correlates with global longitudinal strain in prevalent hemodialysis patients

Abstract

Background: Cardiovascular disease is the commonest cause of death in hemodialysis (HD) patients but accurate risk prediction is lacking. The spatial QRS - T angle is a promising electrophysiological marker for sudden cardiac death risk stratification. The aim of this study was to assess the prognostic value of spatial QRS-T angle derived from standard 12 lead electrocardiograms (ECG) and its association with echocardiographic parameters in HD patients. Methods: This prospective study of 178 prevalent HD patients (aged 67 ± 14 years, 72% men) collected ECG and echocardiographic data on an annual basis. Baseline echocardiograms at study entry were used for cross-sectional comparisons with ECGs. Study endpoints were all-cause mortality, cardiovascular mortality, and major adverse cardiac events (MACE). The QRS - T angle was calculated from standard 10-s ECG as the total cosine R to T (TCRT) using singular value decomposition and expressed in degrees. TCRT above 100∘ was defined as abnormal. Results: During a follow-up period of 36 ± 19 months, 74 patients died, including 17 cardiac deaths, and 54 suffered from MACE. In multivariate Cox regression analysis, QRS-T angle by TCRT at baseline was associated with increased cardiovascular mortality both as a continuous value and dichotomized below or above 100∘ (HR 1.016, p = 0.029, CI: 1.002-1.030 and HR 3.506, CI: 1.118-10.995, p = 0.031 respectively) and with MACE dichotomized at 100∘ (HR 1.902, CI: 1.046-3.459; p = 0.035). In multivariate regression analysis including baseline parameters, echocardiographic global longitudinal strain (GLS) was significantly correlated with TCRT (F 9.648, r2 = 0.192, standardized β = 0.331, unstandardized β = 3.567, t = 4.4429, CI: 1.976-5.157, p < 0.001). Conclusion: TCRT correlates with GLS and is independently associated with cardiac deaths and MACE in HD patients.