Intermediate- to high-risk pulmonary embolism with normal B-type natriuretic peptide.

We report a case of acute pulmonary embolism, severe right ventricular dysfunction on echocardiogram, and normal (83.2 pg/mL) B-type natriuretic peptide (BNP). Initial BNP testing was performed 1 hour after symptom onset, which was not enough time for its elevation. B-type natriuretic peptide determination 24 hours later increased to 664.9 pg/mL. Previously, similar cases have been reported in acute cardiogenic pulmonary edema, autoimmune right ventricular myocarditis, and end-stage heart failure patients. The half-life of BNP is 23 minutes, and therefore, approximately 2 hours is required to reflect changes in the setting of acute left ventricular dysfunction. So, it is possible that this observation could be used in right ventricular dysfunction secondary to acute pulmonary embolism. This case identifies another clinical condition characterized by acute severe right ventricular dysfunction with normal BNP and highlights the relevance between the time interval of symptom onset and drawing the first sample for BNP measurement. To the best of our knowledge, such association has not been previously described. Because emergency medicine physicians are the initial responders to acute left and right ventricular dysfunction patients, they should be aware of this 2-hour lag period before the onset of BNP elevation to avoid underdiagnosing ventricular dysfunction.