Limitations in calculating left ventricular volume by two dimensional geometry--an exised canine heart study.
The left ventricle was removed from 76 dogs and was cast in silicone, in vitro, under three fixing pressure levels to simulate various end-diastolic pressures. This cast was designated as a silicone cast. The waxen cast was constructed by adding attachments which protrude inside the LV cavity, such as the papillary muscles and trabeculae carneae to the silicone cast. The cast volumes were compared with the volume calculated by the area-length method, including ellipsoid and paraboloid models, and by Chapman's method in which silhouettes of the silicone casts projected on 4 planes were used. Under a lower fixing pressure, the volume of papillary muscles and trabeculae carneae accounted for about 35% of the LV volume which was independent of either size of heart or weight of the dog. This ratio was reduced at higher fixing pressure levels. The relationship between the cast volume and the volume calculated by the silhouette method was linearly proportional. However, the deviation increased with higher fixing pressure levels and with larger ventricular volumes in all calculation methods, indicating the shape of the left ventricle cannot be represented by any ideal symmetrical spherical model. The calculated volume agreed with its corresponding cast volume with an error of less than 10% if either the fixing pressure level was below 5 mmHg, or the volume was less than 50 ml.
Minezaki
K K
KK
Department of Physiology 2, School of Medicine, Tokai University, Kanagawa, Japan.
Wang
L M
LM
Yamada
Y
Y
Shinozaki
Y
Y
Okino
H
H
D000818:Animals; D004285:Dogs; D006321:Heart / Q000033:anatomy & histology*; D006352:Heart Ventricles / Q000033:anatomy & histology; D008433:Mathematics; D008953:Models, Anatomic