Clinical Manifestation Of Aortic Regurgitation
Aortic regurgitation results when the aortic valve cusps are not able to close the aortic orifice completely during diastole. This may be caused by abnormalities of the valve or dilatation of the aortic root. Aortic valve cusps are inflamed in acute rheumatic carditis giving rise to mild aortic regurgitation. Moderate to severe aortic regurgitation may also result. Generally, aortic valve and the mitral valve are affected simultaneously in rheumatism.
Mild and moderate cases may remain asymptomatic. Chronic severe AR is associated with symptoms like palpitation, exertional dypsnea and chest pain. The symptoms are gradually progressive and when the compensatory mechanisms become inadequate, congestive heart failure ensues. Angina also may occur in chronic severe AR. Acute severe AR presents as a medical emergency because it results in congestive heart failure.
Mild cases may have only an early diastolic murmur as evidence of AR. This murmur is high pitched and is best heard along the left sterna border. It increases in intensity during expiration. The murmur is best appreciated when the patient leans forward and holds the breath in expiration. The murmur of AR resulting from aortic root dilatation may be best heard along the right sterna border.
In moderate and severe cases, the peripheral signs are present. These are high volume, collapsing pulse, wide pulse pressure (high systolic and low diastolic), prominent carotid pulsation and prominent capillary pulsation demonstrable in the nail bed as well as in the retina. Pistol shot sound can be heard over the femoral arteries. Auscultation over the arteries while applying pressure reveal systolic murmur above the point of compression and diastolic murmur below that (Duroziez murmurs). The systolic blood pressure recorded in the lower limb is 40 mm or above that recorded in the upper limb (Hill’s sign).
In More Severe Cases
Precordium is hyperactive. Apex beat is characteristically shifted down and out and it is forcible. Significant AR is associated with left ventricular third heart sound. A mid-diastolic, or presystolic murmur or a combination of both may be heard well over the apex beat. The murmur is produced because of the premature closure of the mitral valve caused by the regurgitant stream of blood. There may be an ejection systolic murmur heard along the left sterna border as well as over the aortic area, and this murmur is conducted to the carotids. This is caused by the increased flow across the aortic valve in sytole. The aortic component of the second sound is usually soft in severe AR.
In cases with pulmonary arterial hypertension, the pulmonary second sound is loud. Acute severe AR is conspicuous by the absence of peripheral signs and left ventricular enlargement. Electrocardiogram shows left ventricular hypertrophy. Chest radiograph shows left ventricular enlargement. The aorta in most of the cases appears dilated and on fluoroscopy it is hyperdynamic. Echocardiography helps in assessing the aetiology and severity of AR. Cardiac catheterization and angiography are used for accurate assessment of the hemodynamic abnormality.
© 2014 Funom Theophilus Makama