Modification of ventricular loading conditions demonstrated that the normal right ventricular contraction pattern is a consequence of loading conditions rather than intrinsic myocardial properties.
Observational
Does the modification of loading conditions alter the pressure-volume relation and contraction pattern of the right and left ventricles?
The contraction pattern of the right ventricle is primarily determined by its loading conditions rather than intrinsic myocardial properties.
Ventricular pressure-volume diagrams were obtained from the right ventricle in patients before and after relief of right ventricular pressure load, in patients with volume loaded right ventricles, and from the left ventricle in patients after the Mustard procedure for transposition of the great arteries. The patterns of ejection during pressure development and decline were similar in patients after relief of pressure load and in those with isolated volume load. A right ventricular pressure load, however, reduced ejection during the two "isovolumic" periods, and the overall shape of the pressure-volume loop resembled that of the normal left ventricle. Pressure-volume diagrams obtained from the left ventricle after the Mustard procedure were indistinguishable from the normal right ventricle, which accords with the hypothesis that the normal right ventricular contraction pattern is a consequence of loading conditions rather than a reflection of an intrinsic property of the myocardium.
Redington et al. (1990) conducted an observational in Right ventricular pressure/volume load and transposition of the great arteries. Modification of loading conditions was evaluated on Ventricular pressure-volume diagrams and contraction patterns. Modification of ventricular loading conditions demonstrated that the normal right ventricular contraction pattern is a consequence of loading conditions rather than intrinsic myocardial properties.