Value of nitroglycerin test in the diagnosis of heart failure in emergency department patients with undifferentiated dyspnea.

BACKGROUND: Rapid diagnosis of heart failure (HF) in acutely dyspneic patients can be challenging for emergency department (ED) physicians. HYPOTHESIS: Cardiac output (CO) change with sublingual nitroglycerin (NTG) could be helpful in the diagnosis of HF in patients with acute undifferentiated dyspnea. MATERIALS AND METHODS: A prospective study of patients >18 years admitted to the ED for acute dyspnea. Using thoracic bioimpedance, we measured CO change at baseline and after sublingual administration of 0.6 mg of NTG. HF was defined on the basis of clinical examination, pro-brain natriuretic peptide levels, and echocardiographic findings. Diagnostic performance of delta CO was calculated by sensitivity, specificity, likelihood ratio and receiver operating characteristic (ROC) curve. RESULTS: This study included 184 patients with mean age of 64 years. Baseline CO was comparable between the HF group and the non-HF group. At its best cutoff (29%), delta CO showed good accuracy in the diagnosis of HF with a sensitivity, specificity, positive and negative likelihood ratios of 80%, 44%, 57%, and 66% respectively. Area under ROC curve was 0.701 [95% CI 0.636-0.760]. The decrease of CO with sublingual NTG was significantly higher in patients with HFpEF compared with those with HFrEF. Multivariate analysis, showed that delta CO was an independent factor associated with HF diagnosis [OR 0.19 (95% CI 0.11-0.29); p < .001]. CONCLUSIONS: Our study showed that CO change with sublingual nitroglycerin is a simple tool that may be helpful for the diagnosis of HF in ED patients with undifferentiated dyspnea.

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

AIM OF THE STUDY: 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. METHODS: 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. RESULTS: 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%). CONCLUSIONS: 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.