[Dynamics of the heart rate in active orthostasis of patients with hemodynamically effective mitral valve stenosis].

Heart rate dynamics in response to active orthostasis of 10 min duration were examined in 48 patients with mitral stenosis and compared with the mean and diastolic pulmonary artery pressure. Classification of the characteristics of the heart rate was done according Drischel and co-workers (1963) using amplitude and time values. In contrast to healthy subjects, in patients with mitral stenosis the best regulatory behavior was observed in type B with lower pulmonary artery pressure, the least favorable regulatory dynamics being predominant in type A with higher pulmonary artery pressure. From a functional diagnostic point of view, regulatory efficiency can be graded on the following descending scale: (1) the best regulatory behavior in type B; (2) a decrease in the amplitude values in type B; (3) transition of the dynamics to type A; and (4) prolongation of the time values in type A. The pathophysiological mechanisms are changes in the sensitivity of dilatation receptors in the intrathoracic low-pressure system and of the carotid baroreceptors.