Effects of increased residual volume, increased output resistance and autonomic drugs on ventricular suction in the turtle.

Immersed, isolated turtle ventricles were allowed to beat when filling only by suction. Obstruction of ejection at various volumes showed an inverse relationship between residual volume and volume aspirated. Diastolie aspiration occurred even with residual volumes of at least 0.55 ml. Ventricles, filling by suction only, maintained continuous output of up to 3 ml./min. working against pressures of 16 to 22 cm. H2O. In these circumstances ejection was diminished or abolished by acetylcholine and usually increased by epinephrine. This work amplifies and further quantitates recent work showing ventricular diastolie suction in a variety of species.