Abstract
A method for quantitative detection of tricuspid regurgitation is proposed. In cases without tricuspid insufficiency or intracardiac shunt, l/slope (tsFV) of the earpiece dye-dilution curve after injection of dye into the femoral vein (FV curve) was significantly correlated with that (tsPA) of the curve after injection into the pulmonary artery (PA curve) within each range of right heart blood volume (RBV) calculated as a product of cardiac output and mean transit time difference between FV curve and PA curve. The relationship among the 3 parameters was expressed as a statistically significant regression equation; log(tsFV)=0.9858 log(tsPA)+0.2980 log(RBV)-0.6418 (p<0.005, sd of predicted tsFV=±0.591). The assumption was made that tricuspid regurgitation causes prolongation of tsFV without any changes in tsPA or RBV, being based on the concepts of the indicator dispersion and of the path-length distribution. The ratio of tricuspid regurgitation to cardiac output was claculated from (observed tsFV-predicted tsFV)/predicted tsFV, in which predicted tsFV is the value calculated from tsPA and RBV using the equation shown above.
In 2 patients who manifested clinical tricuspid insufficiency, large amount of tricuspid regurgitant fraction was determined by this method. It is suggested that the present method utilizing double injections-single sampling dye-dilution technique is useful for clinical quantitation of tricuspid regurgitation.
