A systolic murmur may be heard in patients with acute mitral regurgitation or ventricular septal rupture. The associated parasternal thrill indicates ventricular septal defect, whereas murmur of mitral regurgitation may be limited to early systole. The systolic murmur, which becomes louder on Valsalva and prompt standing, suggests hypertrophic obstructive cardiomyopathy (idiopathic hypertropic subaortic stenosis)