End-diastolic and end-systolic ventricular volume clamper for isolated canine heart.
We devised a servo-controlled pump system which can clamp both end-diastolic and end-systolic volumes of the left ventricle of an excised, supported canine heart at desirable values in the face of changing patterns of ejection and filling. The system consists of a Bellofram cylinder and a powerful electromagnetic shaker which is driven by a position servo circuit. A water-filled balloon placed in the ventricle was connected to the water housing of the cylinder. As the ECG triggered the system, a fixed amount of water reciprocated between the heart and the cylinder in a programmed manner. The onset, duration, and speed of ejection and those of filling can be programmed separately. The performance of this pump system was tested in experiments on 15 cross-circulated hearts and proved satisfactory for precise analysis of the instantaneous pressure-volume relation in the ventricle.
D000818:Animals; D001794:Blood Pressure; D001810:Blood Volume; D004285:Dogs; D006334:Heart Function Tests / Q000295:instrumentation*; D016276:Ventricular Function