Severe mitral regurgitation with a normal-sized left atrium

The syndrome of severe mitral regurgitation with a normal-sized left atrium may or may not be associated with pulmonary hypertension and prominent left atrial V waves. To explain these pressure alterations by a single pressure-volume relationship is probably not adequate. It would appear that, whatever the clinical circumstances, normal pulmonary vascular pressures cannot exclude the diagnosis of mitral regurgitation.