Davidsons Principles and practice of medicine_22Edition page no 623-624 Aoic regurgitation Aetiology and pathophysiology This condition is due to disease of the aoic valve cusps or dilatation of the aoic root (Box 18.109). The LV dilates and hyperophies to compensate for the regurgitation. The stroke volume of the LV may eventually be doubled or trebled, and the major aeries are then conspicuously pulsatile. As the disease progresses, left ventricular diastolic pressure rises and breathlessness develops. Clinical features Until the onset of breathlessness, the only symptom may be an awareness of the hea beat . paicularly when lying on the left side, which results from the increased stroke volume. Paroxysmal nocturnal dyspnoea is sometimes the first symptom, and peripheral oedema or angina may occur. The characteristic murmur is best heard to the left of the sternum during held expiration. a thrill is rare. A systolic murmur due to the increased stroke volume is common and does not necessarily indicate stenosis. The regurgitant jet causes fluttering of the mitral valve and, if severe, causes paial closure of the anterior mitral leaflet, leading to functional mitral stenosis and a soft mid-diastolic (Austin Flint) murmur. In acute severe regurgitation (e.g. perforation of aoic cusp in endocarditis), there may be no time for compensatory left ventricular hyperophy and dilatation to develop and the features of hea failure may predominate. In this situation, the classical signs of aoic regurgitation may be masked by tachycardia and an abrupt rise in left ventricular end-diastolic pressure; thus, the pulse pressure may be near normal and the diastolic murmur may be sho or even absent. Investigations Regurgitation is detected by Doppler echocardiography . In severe acute aoic regurgitation, the rapid rise in left ventricular diastolic pressure may cause premature mitral valve closure. Cardiac catheterisation and aoography can help in assessing the severity of regurgitation, and dilatation of the aoa and the presence of coexisting coronary aery disease. MRI is useful in assessing the degree and extent of aoic dilatation. Management Treatment may be required for underlying conditions, such as endocarditis or syphilis. Aoic valve replacement is indicated if aoic regurgitation causes symptoms, and this may need to be combined with aoic root replacement and coronary bypass surgery. Those with chronic aoic regurgitation can remain asymptomatic for many years because compensatory ventricular dilatation and hyperophy occur, but should be advised to repo the development of any symptoms of breathlessness or angina. Asymptomatic patients should also be followed up annually with echocardiography for evidence of increasing ventricular size. If this occurs or if the end-systolic dimension increases to 55 mm or more, then aoic valve replacement should be undeaken. Systolic BP should be controlled with vasodilating drugs, such as nifedipine or ACE inhibitors. There is conflicting evidence regarding the need for aoic valve replacement in asymptomatic patients with severe aoic regurgitation. When aoic root dilatation is the cause of aoic regurgitation (e.g. Marfan's syndrome), aoic root replacement is usually necessary. <img alt="" src=" />