OBSERVATIONS SUGGESTING A HIGH-INCIDENCE OF EXERCISE-INDUCED SEVERE MITRAL REGURGITATION IN PATIENTS WITH MILD RHEUMATIC MITRAL-VALVE DISEASE AT REST

Objectives. The aim of this study was to determine the hemo dynamic ef fects of upright bicycle ergometry in symptomatic patients with mild, mixed mitral stenosis and regurgitation. Background. Patients with see mingly mild rheumatic mitral valve disease often complain of exertiona l dyspnea or fatigue. These symptoms are usually ascribed to flea-depe ndent increases in the gradient across the stenotic mitral valve. Alth ough catheterization studies in these patients may demonstrate an incr ease in mitral valve gradient proportional to an increase in cardiac o utput, this approach does not specifically address the underlying mech anism of any observed increases in mitral gradient or left atrial (i.e ., pulmonary capillary wedge) pressure. Exercise echocardiography is u niquely suited to the dynamic assessment of exercise-induced hemodynam ic changes. Methods. Fourteen symptomatic patients with exertional dys pnea and mild mitral stenosis and regurgitation at rest performed symp tom-limited upright bicycle ergometry with quantitative two-dimensiona l, Doppler and color Doppler echocardiographic analysis. Results. Aver age pulmonary artery systolic pressure in the 13 patients with adequat e spectral signals of tricuspid regurgitation increased from 36 +/- 5 mm Hg (mean +/- SD) at rest to 63 +/- 14 mm Hg at peak exercise (p < 0 .001). The mean transmitral pressure gradient in ail patients increase d from 4.5 +/- 1.4 mm Hg at rest to 12.7 +/- 2.7 mm Hg at peak exercis e (p < 0.001). Five patients developed severe mitral regurgitation dur ing exercise. Conclusions. Patients with exertional dyspnea and mild m itral stenosis and regurgitation at rest demonstrate a marked increase in pulmonary artery systolic pressure and mean transmitral pressure g radient during dynamic exercise. In a subset of these patients, marked worsening of mitral regurgitation appears to be the underlying mechan ism of this hemodynamic deterioration. Because of the small sample siz e, this novel observation must be considered preliminary with respect to the true prevalence of exercise-related development of severe mitra l regurgitation. If additional studies confirm the importance of this phenomenon, it has important implications for the management of patien ts with rheumatic mitral valve disease.