Value of systolic time intervals in the diagnosis of heart failure in emergency department patients with undifferentiated dyspnea.

Abstract

The diagnosis of heart failure in the emergency department (ED) is challenging. The aim of this study was to evaluate systolic time intervals (STIs) using phonoelectrocardiography for the diagnosis of heart failure (HF) in ED patients with undifferentiated dyspnea. A total of 855 patients with dyspnea and suspected HF were prospectively enrolled. They underwent echocardiographic measurements of left ventricular ejection fraction (LVEF), B-type natriuretic peptide (BNP) testing and computerised phonoelectrocardiography to assess STIs including electromechanical activation time (EMAT), left ventricular ejection time (LVET) and EMAT/LVET ratio. Diagnosis accuracy of STIs was calculated including sensitivity, specificity, likelihood ratio and receiver operating characteristic (ROC) curve. Patients with HF (n=530) had significantly higher EMAT and lower LVET compared with non-HF patients. ROC curve c-statistic was 0.74, 0.72 and 0.78 for EMAT, LVET and EMAT/LVET respectively. Sensitivity and specificity of EMAT/LVET at a cut-off=40% were 72% and 88% respectively. EMAT/LVET had the highest correlation with LVEF (r=0.48). In patients with intermediate BNP (n=107), positive likelihood ratio increased from 1.8 with BNP alone to 3.6 with BNP combined to EMAT/LVET. Patients without HF had STIs values not significantly different from those with preserved LVEF (≥45%). Given their immediate availability, phonoelectrocardiography STIs' parameters and particularly EMAT/LVET ratio could have an important role in the diagnosis approach of HF in patients with undifferentiated dyspnea in the ED.