Acute aortic regurgitation is distinct from chronic aortic regurgitation. The top three causes are endocarditis, aortic dissection, and blunt trauma. Analogous to the situation with acute mitral regurgitation (see separate posting), there has not been time for compensatory dilation of the ventricle, so back pressures rise. The left ventricular pressure rises significantly, and patients present with heart failure.
Because the compensatory ventricular dilation and increase in stroke volume has not yet occurred, none of the peripheral signs of aortic insufficiency are seen. No water hammer pulse, no Duroziez sign (to-and-fro murmur over the femoral artery with femoral artery compression) and no exaggerated pulsations seen distally. And in fact, the long murmur of aortic regurgitation is shortened and softened and heard mainly in early diastole (Stout, Circulation, 2009). It is heard best with the patient sitting and leaning forward. Augmentation maneuvers include bilateral compression of the arms, with handgrip as a less specific alternative. Don’t be discouraged though, a search for this sign may pay off in key situations. The International Registry of Acute Aortic Dissections has shown that the diastolic murmur of aortic regurgitation is present in as many as 44% of patients.(Hagen JAMA 2000)
The treatment is surgical, though afterload reduction is an important temporizing measure.
Take home points:
Acute aortic regurgitation presents with congestive heart failure
The murmur is shorter and more subtle than the chronic form
Peripheral signs of aortic regurgitation typically are not seen