Abstract
Quantitative observations on the pulmonary arterial pressure pattern were made by approaching mathematically using the method of FOURIER analysis and the first derivatives. Concept that the pulmonary arterial system was a transfer element of the control system made it possible to make analysis of its stability by utilizing the results of FOURIER analysis. Right heart catheterization was performed of thirty-two patients with mitral stenosis, atrial septal defect and chronic pulmonary emphysema. The Bode diagram revealed that the high energy distribution in the higher frequency was seen in cases with chronic pulmonary emphysema than in mitral stenosis or atrial septal defect. Gain margin and phase margin were smaller in chronic pulmonary emphysema than in the other two groups. Pulmonary vascular compliance was nearly inversely proportional to gain margin and phase margin. Positive relationships were found between PA dp/dt and gain margin and phase margin. Positive relationship were also found between PA dp/dt and RV dp/dt. The stability of the pulmonary arterial system was chiefly determined by the distensibility of the pulmonary artery. And this distensibility effects the systolic ejection and possibly the contractility of the heart muscle.
