The circulatory physiology of Helix pomatia. II. The isolated heart.

This work was undertaken to study the mechanical factors affecting the function of the isolated heart of Helix pomatia in order to help understand the variations in heart activity observed in intact animals. Biedermann (1884), working upon the isolated heart of Helix, observed that the frequency of beat increased with distension of the heart. Biering (1929) found that in the isolated Helix heart the frequency and output varied directly with the venous pressure. Schwartzkopff (1954) confirmed this and also found that the frequency and output varied inversely with the arterial pressure and peripheral resistance. Civil & Thompson (1972) found that the isolated heart of Helix would only pump fluid effectively when surrounded by a sealed chamber of fixed volume (artificial pericardium). They found that the heart output increased as the venous pressure rose and that reducing the volume of fluid in the artificial pericardium so that the heart increased in volume resulted in an increase in heart output.