As mitral stenosis worsens, the cardiac output can be reduced, with a compensatory increase in the sympathetic nervous activity. An accelerated sympathetic nervous activity is responsible for various pathophysiological changes, including atrial thrombus formation, pulmonary congestion and myocardial ischemia. In this study, the sympathetic nervous activity was evaluated in patients with rheumatic mitral valvular stenosis, both before and after a percutaneous mitral balloon valvuloplasty (PMV).

A PMV was successfully performed in 19 patients with mitral stenosis. The hemodynamic data were obtained by Swan-Ganz catheterization, and the variability in the heart rate evaluated by time domain measure via 24-hour ECG monitoring. An exercise test was performed according to Chung's exercise protocol, with the plasma norepinephrine level obtained before, during and after exercise.

After the PMV, the right ventricle systolic, mean pulmonary arterial, pulmonary capillary wedge and left atrial pressures were significantly decreased. However, there were no significant changes in the right atrial, right ventricle end-diastolic and left ventricle end-diastolic pressures. After the PMV, the plasma norepinephrine level, an indicator of the sympathetic activity, was significantly decreased. On the other hand, the variability in heart rate, indicator of parasympathetic activity, was significantly decreased.

In patients with mitral valvular stenosis, the sympathetic activity is accelerated, while the parasympathetic activity is decreased. This situation can be immediately reversed after a successful PMV.