Exercise response in young women with mitral valve prolapse.

To detect for possible evidence of autonomic nervous system dysfunction, we assessed exercise response in 198 young women with echocardiographically documented MVP. The same test was used to determine whether patients with or without physical symptoms or with various auscultatory findings responded differently. Compared with 105 age- and sex-matched healthy subjects, the MVP patients showed significantly higher mean heart rate, systolic blood pressure, pulse pressure and rate-pressure (double) product, at both rest and exercise; significantly lower mean near-maximal physical working capacity (PWC170); significantly higher incidence of both arrhythmias and nonspecific ST and T wave changes; and a significantly longer mean corrected QT interval. None of these findings was associated with the presence of physical symptoms or with specific auscultatory or echocardiographic findings. These observations strongly suggest an autonomic nervous system imbalance in some young women with MVP, irrespective of whether physical symptoms are present.