Circulatory Changes in Mitral Stenosis at Rest and on Exercise

Abstract

There is some increase in the pulmonary artery pressure in many patients with mitral stenosis and this pressure may rise considerably on exercise as was first shown by Hickam and Cargill (1948). have described a method of calculating the area of the mitral orifice in life and Gorlin et al. (1951 a and b) have attempted to evaluate the factors causing this pulmonary hypertension at rest and on exercise. Although in these cases, the stenosed mitral valve must be the primary cause, other changes that may occur in the pulmonary vasculature or in the pulmonary blood volume may also be of importance. Lagerlof et al. (1949) and Borden et al. (1949) using the Hamilton method, injecting dye directly into the pulmonary artery, showed no increase in the pulmonary blood volume in patients with mitral stenosis at rest. Kopelman and Lee (1951) verified these findings with dye injected into an antecubital vein and also showed no significant increase in the intrathoracic blood volume in mitral stenosis even when in congestive cardiac failure. This was in contrast with patients in left ventricular failure who showed a well marked increase in intrathoracic blood volume.The Hamilton dye method has been used in a further study of patients with mitral stenosis to determine the changes in cardiac output and intrathoracic blood volume that occur during mild exercise.MATERIAL AND METHODS Sixteen patients with mitral stenosis were investigated. Some of these had auscultatory signs of aortic valve involvement but mitral stenosis was considered to be the predominant lesion. None had clinical signs of congestive cardiac failure at the time of the investigation. Previous experience has shown that the presence of a giant left atrium or of tricuspid regurgitation prevents a reliable result with the method used, and no patient investigated had either of these conditions. Nine subjects without evidence of cardiovascular disease were similarly investigated.The Hamilton dye method consists of the injection of a known amount of dye (Evans Blue T 1824) into an antecubital vein and the collection of rapidly timed arterial samples. From these a time-concentration curve can be constructed and the cardiac output and mean circulation time calculated as described by Hamilton et al. (1932). By the application of Stewart's formula (1921) the volume of blood between injection and sampling points can be determined and this has been referred to as the " intrathoracic blood volume."In a series of five duplicate tests at rest, the coefficient of variation for the intrathoracic blood volume was found to be 6-5 per cent: although the number is small, changes in the intrathoracic blood volume of more than 13 per cent are probably significant. Similarly changes in the cardiac output of the same order are probably significant, the summation of errors in the technique being 6 per cent (Hamilton et al., 1948;Kopelman and Lee, 1951). It has been found that the cardiac output obtained by this method corresponds *

The Precordial Isotope Dilution Curve in Mitral Stenosis and Correlations with the Clinical, Heart‐catheterization and Roentgenologic Findings

“…The negative correlation observed between the cardiac index and the pulmonary circulation times is in accordance with the results obtained by the precordial technique in patients with mitral disease (12). A similar observation in patients with mitral stenosis has been made by the arterial sampling method (27). In the latter study, also, a negative correlation between the cardia.c index and cardiothoracic ratio was observed.…”

Interpretation of Changes in “Central” Blood Volume and Slope Volume During Exercise in Man*

“…patients wvith heart disease have been based upon the assumption that changes in CBV indicate changes in the volume of blood inside the thorax (19)(20)(21)(22). Since an extensive redistribution of systemic venous and arterial blood flow and blood volume occurs in patients with heart disease, such conclusions are invalid.…”

The Pulmonary Blood Volume in Mitral Stenosis 1

“…Despite the three values in the range between 450 and 600 dscm-5, which obviously grossly deviate, the data were found to fit quite well an exponential curve of the general form log y = -. 3 the theoretical variables and the actual measured values was 0.9982. This relationship is quite similar to that noted previously between cardiac output and pulmonary resistance in patients with mitral stenosis (22), as well as in other situations where pulmonary resistance is raised (23,24).…”