Heart Sounds: Third Heart Sound

	Aortic Regurgitation

Description	Valve incompetence allows backflow from aorta to ventricle. Caused by rheumatic heart disease, endocarditis, aortic diseases (Marfan’s syndrome, medial necrosis), syphilis, ankylosing spondylitis, dissection, cardiac trauma.

Type and Detection	Heard with diaphragm, patient sitting and leaning forward; Austin-Flint murmur heard with bell; ejection click heard in 2nd intercostal space

Findings on Examination	Early diastolic, high pitch, blowing, often with diamond-shaped midsystolic murmur, sounds often not prominent; duration varies with blood pressure; low-pitched rumbling murmur at apex common (Austin-Flint); early ejection click sometimes present. In left ventricular hypertrophy, prominent prolonged apical impulse down and to left Pulse pressure wide; water-hammeror biferiens pulse common in carotid, brachial, and femoral arteries.

Heart Sound Components	S₁ soft; S₂ split may have tambour- like quality; M₁ and A₂ often intensified; S₃-S₄ gallop is common.