Contractile function in canine right ventricle

Regional right ventricular (RV) motion was examined in six acutely instrumented dogs by implanting radiopaque markers in three regions of the free wall: the apex, the midventricle, and the outflow tract. These markers were filmed at the paced heart rate of 180 beats/min with a high-speed biplane X-ray system, and their motion was analyzed with a digital computer. Local deformation was separated into percent length changes in the two mutually perpendicular principal directions. The major component exhibited shortening along a path from apex to conus. (apex - 13.6%, midventricle -13.1%, conus -8.7%); the minor component exhibited small amounts of lengthening and some shortening (apex +4.7%, midventricle +1.8%, conus -0.5%). From these two measurements we calculated the peak RV free wall thickening (apex 13.6%, midventricle 14.1%, conus 10.9%). The experimental technique developed for this study was found to be suitable for the repeated analysis of intact ventricular performance in chronic animal studies. Th...