Korelasi kadar ST2 terlarut (sST2) dengan miokardial longitudinal strain speckle tracking dua dimensi untuk menilai disfungsi ventrikel kiri subklinis pada subjek stenosis aorta berat = Asscociation of the biomarkers soluble ST2 and subclinical left ventricular systolic dysfunction assessed by myocardial global longitudinal strain in patients severe aortic stenosis