Big Endothelin-1 (Big ET-1) is a protein that is mainly produced by vascular endothelial and smooth muscle cells and cardiomyocytes. Big ET-1 has been identified as a risk factor for a poor prognosis in patients with atrial fibrillation or coronary artery disease. This current study revealed that plasma Big ET-1 is a valuable tool for risk stratification in patients with LVNC.