The aim of this study was to explain the discordance observed between disabling exercise intolerance and compensated left ventricular volume overload in patients with mitral regurgitation due to valve prolapse with chorda[ rupture. A symptom-limited upright bicycle ergometry (increasing workload by 25 W every 3 min) with quantitative two-dimensional and color Doppler echocardiography was performed in 15 patients (average age 52 ± 14 years) with valve prolapse associated with mitral regurgitation. Left ventricular volumes on a beat by beat basis at rest and at peak of upright exercise were compared to data obtained from 5 matched normal control subjects (mean age 43 ± 17 years). A subdivision into two groups was made in patients with mitral regurgitation on the basis of limiting symptoms. Group 1 consisted of 8 patients without a history of exertional dyspnea (NYHA functional class I). The remaining 7 patients (Group 2) were symptomatic for exertional dyspnea (NYHA functional class II). A flail mitral leaflet was found in 14 patients (the posterior leaflet was involved in 12 and the anterior leaflet in 2), one patient had severe prolapse of the two leaflets. The exercise time was not different in the two groups (11 ± 2 and 11 ± 3 min, respectively). Heart rate increased during exercise to 144 ± 11 b/min in Group 1 (88%) and to 151 ± 16 b/min in Group 2 (90%). Systolic blood pressure was higher at peak exercise in Group 1 (197 ± 10 mmHg) in comparison to Group 2 (174 ± 10 mmHg; p <0.01). A highly significant decrease in end-systolic volume index and an increase in ejection fraction were observed in both mitral regurgitation groups. However, the end-systolic volume index was significantly greater in Group 2 at rest (36 ± 7 vs 26 ± 6 ml/m2; p <0.01) and at peak exercise (28 ± 6 vs 19 ± 3 ml/m2; p <0.006). The absolute value of ejection fraction at peak exercise was lower in Group 2 patients (65 ± 5 vs 72 ± 5%; p <0.01). In these patients the regurgitant jet at color flow Doppler increased more than in asymptomatic patients during exercise (16 vs 9%) and a greater size of maximum jet area was found (20 ± 8 vs 12 ± 3 cm2; p <0.02). In normal subjects the exercise time was 19 ± 3 min. Heart rate and systolic blood pressure increased to 165 ± 13 b/min and 175 ± 16 mmHg at peak exercise respectively. The end-systolic volume index decreased significantly from 16 ± 3 to 11 ± 2 ml/m2 (p = 0.001) and ejection fraction increased from 59 ± 2 to 69 ± 2% (p = 0.001). In conclusion, in patients with mitral regurgitation due to valve prolapse and chordal rupture, left ventricular systolic function improves at peak exercise as a result of end-systolic volume index reduction. Symptomatic patients have significantly larger end-systolic volume index at rest and at peak exercise and lower ejection fraction at peak exercise. In comparison with asymptomatic patients, the increase in mitral regurgitation may possibly contribute to exercise intolerance and dyspnea despite normal systolic function.
|Number of pages||5|
|Publication status||Published - 1997|
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine
- Radiology Nuclear Medicine and imaging