Exercise echocardiography in combined mild mitral valve stenosis and regurgitation

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 hemodynamic effects of upright bicycle ergometry in symptomatic patients with mild, mixed mitral stenosis and regurgitation.

BACKGROUND

Patients with seemingly mild rheumatic mitral valve disease often complain of exertional dyspnea or fatigue. These symptoms are usually ascribed to flow-dependent increases in the gradient across the stenotic mitral valve. Although catheterization studies in these patients may demonstrate an increase in mitral valve gradient proportional to an increase in cardiac output, this approach does not specifically address the underlying mechanism of any observed increases in mitral gradient or left atrial (i.e., pulmonary capillary wedge) pressure. Exercise echocardiography is uniquely suited to the dynamic assessment of exercise-induced hemodynamic changes.

METHODS

Fourteen symptomatic patients with exertional dyspnea and mild mitral stenosis and regurgitation at rest performed symptom-limited upright bicycle ergometry with quantitative two-dimensional, Doppler and color Doppler echocardiographic analysis.

RESULTS

Average pulmonary artery systolic pressure in the 13 patients with adequate 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 all patients increased from 4.5 +/- 1.4 mm Hg at rest to 12.7 +/- 2.7 mm Hg at peak exercise (p < 0.001). Five patients developed severe mitral regurgitation during exercise.

CONCLUSIONS

Patients with exertional dyspnea and mild mitral stenosis and regurgitation at rest demonstrate a marked increase in pulmonary artery systolic pressure and mean transmitral pressure gradient during dynamic exercise. In a subset of these patients, marked worsening of mitral regurgitation appears to be the underlying mechanism of this hemodynamic deterioration. Because of the small sample size, this novel observation must be considered preliminary with respect to the true prevalence of exercise-related development of severe mitral regurgitation. If additional studies confirm the importance of this phenomenon, it has important implications for the management of patients with rheumatic mitral valve disease.

Rapid echocardiographic assessment of left and right heart hemodynamics in critically ill obstetric patients

OBJECTIVE

Our purpose was to compare noninvasive two-dimensional and Doppler echocardiography and right heart catheterization with a pulmonary artery catheter in the estimation of stroke volume, cardiac output, cardiac index, left ventricular filling pressure, pulmonary artery systolic pressure, and right atrial pressure in a heterogeneous group of critically ill obstetric patients.

STUDY DESIGN

Eleven critically ill obstetric patients requiring invasive monitoring for clinical management were prospectively studied. Simultaneous Doppler and pulmonary artery catheter readings of stroke volume, cardiac output, cardiac index, left ventricular filling pressure, pulmonary artery systolic pressure, and right atrial pressure were acquired. Mean +/- SD or median and range, as appropriate, of each parameter were compared, and data for all parameters were subjected to regression analysis. A two-tailed p value < 0.05 was regarded as significant.

RESULTS

There was no significant difference between the two techniques in the estimation of cardiac index, intracardiac pressures, or pulmonary artery systolic pressure. There was a good correlation between the two methods for stroke volume (R2 = 0.98), cardiac output (R2 = 0.98), cardiac index (R2 = 0.96), left ventricular filling pressure (R2 = 0.79), pulmonary artery systolic pressure (R2 = 0.85), and right atrial pressure (R2 = 0.86).

CONCLUSION

Two-dimensional and Doppler echocardiography allow rapid, reliable, noninvasive assessment of hemodynamic parameters in critically ill obstetric patients and may give the clinician valuable information that may influence therapeutic and clinical management.