Right ventricular performance in dogs following pulmonary valvectomy

Maximal pulmonary regurgitation was produced in 7 dogs by pulmonary valvectomy. The hemodynamics, right ventricular volumes, and ventricle weights of the valvectomized dogs were compared with normals. Valvectomized dogs had normal systolic pressures in pulmonary artery and right ventricle and only moderate reduction in forward stroke volume/end-diastolic volume ratio ( FSV EDV) (mean = 0.31) (range 0.29 to 0.32) compared to normal dogs, which had a mean FSV EDV of 0.45 (range 0.42 to 0.46). Right ventricular weights were significantly increased in the valvectomized dogs. After surgical repair of tetralogy of Fallot, some children have FSV EDV considerably lower than 0.31; it is suggested that in these cases impairment of ventricular performance may be due to myocardial dysfunction rather than entirely due to pulmonary regurgitation.