Trans-cardiac gradient of secretoneurin in patients with Takotsubo syndrome.

INTRODUCTION Secretoneurin (SN) is a novel biomarker that provides prognostic information in patients with cardiovascular disease. In experimental models, SN production is increased in the failing myocardium. Currently, no information is available on SN production in human myocardium. Accordingly, we wanted to determine the trans-cardiac gradient of SN in patients with Takotsubo syndrome (TTS), and to correlate circulating SN concentrations with indices of cardiac structure and function. METHODS We included 15 women diagnosed with TTS according to established criteria. Plasma SN concentrations were measured in blood samples obtained simultaneously from the aortic root and the coronary sinus. Coronary physiology was assessed by invasive measurements, and we used cardiac magnetic resonance imaging (cMRI) to determine left ventricular ejection fraction (LVEF) and cardiac mass. RESULTS Median age was 65 years and median LVEF was 45%. Median SN concentration was 39 (25th-75th percentile 31-44) pmol/L in the coronary sinus and 37 (30-41) pmol/L in the aortic root (p=0.02 for difference). SN concentrations in the aortic root showed the highest correlations with N-terminal B-type natriuretic peptide (rho=0.47) and estimated glomerular filtration rate (rho=-0.41). In contrast, we found weak correlations between SN concentrations and index of myocardial resistance (rho=0.12), LVEF (rho=0.08), and cardiac mass (rho= -0.09). CONCLUSION We demonstrate a positive trans-cardiac gradient of SN in patients with TTS, which supports the hypothesis that SN is produced and released in the human myocardium in situations of myocardial dysfunction and stress.