Effect of Stretch on Formation and Conduction of Electrical Impulses in the Isolated Sinoauricular Chamber of Frog's Heart

Abstract

The influence of stretch due to increased intraluminal pressure on the formation and conduction of electrical impulse was studied electrocardiographically in 12 isolated sinoauricular chambers of frog hearts perfused with frogs' Ringer. The impulse frequency was found to be directly proportional to the degree of intraluminal perfusion pressure up to a certain critical head of pressure (2–6 cm Ringer), beyond which the impulse frequency declined. At higher pressures the electrogram showed a diminished amplitude of the action potential and broadening and notching of sinus waves and auricular complexes. The duration and conduction velocity of electrical impulse was increased.