Pointers of associated mitral valve obstruction in severe aortic regurgitation

Pointers of associated mitral valve obstruction in severe aortic regurgitation

Mid diastolic Austin Flint murmur in severe AR may be mistaken for associated mitral stenosis. Pointers of associated mitral valve obstruction in severe aortic regurgitation are:

1. Long duration of symptoms. Long duration of symptoms, even decades, can occur in mitral stenosis. But if the symptoms are due to severe aortic regurgitation, they will rapidly deteriorate and present for evaluation.
2. Paroxysmal nocturnal dyspnoea.  Paroxysmal nocturnal dyspnoea (PND) is more likely to occur with associated mitral stenosis, though left ventricular decompensation in severe aortic regurgitation can sometimes cause PND.
3. Hemoptysis. Hemoptysis can occur in mitral stenosis by various mechanisms. One of the important mechanism being rupture of bronchial varices. These are non existent in severe aortic regurgitation.
4. Atrial fibrillation: Atrial fibrillation is due to long standing atrial dilatation and overload in mitral stenosis. In aortic regurgitation, by the time atria starts dilating, patient would be in a decompensated state.
5. Loud first heart sound: Loud first heart sound is due to the stiff mitral valve, closing slightly later as the left atrial pressure is high. This does not occur in isolated aortic regurgitation.
6. Opening snap: Opening snap is the typical opening sound of a stenosed mitral valve, which is characteristic of mitral stenosis and not seen in isolated aortic regurgitation.

Orthopnoea can occur in severe mitral stenosis as well as decompensated aortic regurgitation.

When combination of lesions are present, it is often difficult to assess the severity of each clinically. This even extends to echocardiography sometimes. Aortic regurgitation shortens pressure half time in mitral stenosis, which would mean overestimation of severity of mitral stenosis [1].

Reference

1. F A Flachskampf, A E Weyman, L Gillam, C M Liu, V M Abascal, J D Thomas. Aortic Regurgitation Shortens Doppler Pressure Half-Time in Mitral Stenosis: Clinical Evidence, in Vitro Simulation and Theoretic Analysis. J Am Coll Cardiol. 1990 Aug;16(2):396-404.