Cardiac performance was analyzed in intact Amyda japonica heart, perfusing with turtle Ringer-Locke´s solution, in various levels of arterial and venous blood pressure.
Ringer-Locke´s solutions containing with low calcium or high calcium were perfused and cardiac performances were analyzed.
The results obtained were as follows:
1. The ventricular stroke work increased with the increment of venous blood pressure or venous filling pressure, and also with that of the arterial blood pressure. Moreover, the higher the arterial blood pressure, the steeper the increment of ventricular stroke work was visible. (Fig 1.3)
2. The higher the arterial blood pressure, the lower the cardiac output, was demonstrated, for arterial blood pressure is the resistance to the ventricular blood flow. In specific arterial blood pressure, venous blood pressure was proportional to the cardiac output. (Fig 2.4)
3. In the heart perfused with Ringer-Locke´s solutions containing 0, 0.1, 0.3, 0.5 mg/ml CaCl2 ventricular stroke work was the highest in 0.1 mg/ml solution which is the nearest concentration to the plasma. Perfusing with calcium free solution, heart maintained beat more than an hour, but ventricular stroke work decreased less than 1/3 of normal.
Perfusing with 0.3 and 0.5 mg /ml CaCl2 solutions, ventricular stroke work tended decrease a little, which was not statistically significant. The nature of the cardiac performance to the various arterial and venous pressures was similar to that of the normal heart. (Fig. 5)
4. The cardiac output was the highest in 0.1 mg/ml solution, and the lowest in talcum free solution. Amyda japonica heart was relatively sensitive to hypocalcemia (up to 0.02 mg/ml) and hypercalcemia (0.5 mg/ml). (Fig. 6)
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