Diagnostic and prognostic values of the QRS‐T angle in patients with suspected acute decompensated heart failure

AIMS: The aim of this study was to investigate the diagnostic and prognostic utility of the QRS‐T angle, an electrocardiogram (ECG) marker quantifying depolarization–repolarization heterogeneity, in patients with suspected acute decompensated heart failure (ADHF). METHODS AND RESULTS: We prospectively enrolled unselected patients presenting to the emergency department with symptoms suggestive of ADHF. The QRS‐T angle was automatically derived from a standard 12‐lead ECG recorded at presentation. The primary diagnostic endpoint was a final adjudicated diagnosis of ADHF. The primary prognostic endpoint was all‐cause mortality during 2 years of follow‐up. Among the 1915 patients enrolled, those with higher QRS‐T angles were older, were more commonly male, and had a higher rate of co‐morbidities such as arterial hypertension, coronary artery disease, or chronic kidney disease. ADHF was the final adjudicated diagnosis in 1140 (60%) patients. The QRS‐T angle in patients with ADHF was significantly larger than in patients with non‐cardiac causes of dyspnoea {median 110° [inter‐quartile range (IQR) 46–156°] vs. median 33° [IQR 15–57°], P < 0.001}. The diagnostic accuracy of the QRS‐T angle as quantified by the area under the receiver operating characteristic curve (AUC) was 0.75 [95% confidence interval (CI) 0.73–0.77, P < 0.001], which was inferior to N‐terminal pro‐B‐type natriuretic peptide (AUC 0.93, 95% CI 0.92–0.94, P < 0.001), but similar to that of high‐sensitivity troponin T (AUC 0.78, 95% CI 0.76–0.80, P = 0.09). The AUC of the QRS‐T angle for discrimination between ADHF and non‐cardiac dyspnoea remained similarly high in subgroups of patients known to be diagnostically challenging, including patients older than 75 years [0.71 (95% CI 0.67–0.74)], renal failure [0.79 (95% CI 0.71–0.87)], and atrial fibrillation at presentation [0.68 (95% CI 0.60–0.76)]. Mortality rates according to QRS‐T angle tertiles were 4%, 6%, and 10% after 30 days (P < 0.001) and 24%, 31%, and 43% after 2 years (P < 0.001). After adjustment for clinical, laboratory, and ECG parameters, the QRS‐T angle remained an independent predictor for 2 year mortality with a 4% increase in mortality for every 20° increase in QRS‐T angle (P = 0.02). CONCLUSIONS: The QRS‐T angle is a readily available and inexpensive marker that can assist in the discrimination between ADHF and non‐cardiac causes of acute dyspnoea and may aid in the risk stratification of these patients.