Aortic Regurgitation (Chronic Regurgitation)

Essentials of Diagnosis

• Usually asymptomatic until middle age; presents with left-sided failure or chest pain.
  
• Wide pulse pressure with associated peripheral signs.
  
• Hyperactive, enlarged left ventricle.
  
• Diastolic murmur along left sternal border.
  
• ECG shows left ventricular hypertrophy; x-ray shows left ventricular dilation. Echo-Doppler confirms diagnosis and estimates severity.

General Considerations

Rheumatic aortic regurgitation has become less common than in the preantibiotic era, but nonrheumatic causes are frequent and are the major cause of isolated aortic regurgitation. These include congenitally bicuspid valves, infective endocarditis, and hypertension. Many patients have aortic regurgitation secondary to aortic root diseases such as cystic medial necrosis, Marfan's syndrome, aortic dissection, ankylosing spondylitis, Reiter's syndrome, and Syphilis.

Clinical Findings

A. Symptoms and Signs
The clinical presentation is determined by the rapidity with which regurgitation develops. In chronic regurgitation, the only sign for many years may be a soft aortic diastolic murmur. As the valve deformity increases, larger amounts regurgitate, diastolic blood pressure falls, and the left ventricle progressively enlarges. Most patients remain asymptomatic even at this point, and an often prolonged plateau phase, characterized by stable left ventricular dilation, occurs. Left ventricular failure is a late event and may be sudden in onset. Exertional dyspnea and fatigue are the most frequent symptoms, but paroxysmal nocturnal dyspnea and pulmonary edema may also occur. Angina pectoris or atypical chest pain may be present. Associated coronary artery disease and syncope are less common than in aortic stenosis.

Hemodynamically, because of compensatory left ventricular dilation, patients eject a large stroke volume which is adequate to maintain forward cardiac output until late in the course of the disease. Left ventricular diastolic pressure remains normal also but may abruptly rise when heart failure occurs. Abnormal left ventricular systolic function, as manifested by reduced ejection fraction and increasing end-systolic left ventricular volume, is a late sign.

The major physical findings relate to the wide arterial pulse pressure. The pulse has a rapid rise and fall (water-hammer pulse or Corrigan's pulse), with an elevated systolic and low diastolic pressure, owing to the large stroke volume and rapid diastolic runoff back into the left ventricle, respectively. The large stroke volume is also responsible for characteristic findings such as Quincke's pulses (subungual capillary pulsations), Duroziez's sign (diastolic murmur over a partially compressed peripheral artery, commonly the femoral), and Musset's sign (head bob with each pulse). The apical impulse is prominent, laterally displaced, and usually hyperdynamic and may be sustained. The murmur itself may be quite soft and localized; the aortic diastolic murmur is high-pitched and decrescendo. A mid or late diastolic low-pitched mitral murmur (Austin Flint murmur) may be heard in advanced aortic regurgitation, owing to obstruction of mitral flow produced by partial closure of the mitral valve by the regurgitant jet.