CARDIAC ACTION POTENTIAL

Purkinje fibers (a.k.a. Purkyne tissues or subendocardial branches) are specialized cardiac fibers which regulate the heartbeat. Located in the inner ventricular and septal walls of the heart, Purkinje fibers are end-organ extensions of the autonomic nervous system; electrical activation of atrial Purkinje fibers originates from the sinoatrial node (SA node) while ventricular Purkinje fibers are activated from the atrioventricular node (AV node). The spread of electrical activity (ie, depolarization) through the entire heart can be visualized on an electrocardiogram (ECG).

Stimulation of ventricular Purkinje fibers per se causes contraction of ventricular cardiac muscle cells due to generation of ion-dependent action potentials.

AVIVA scientists record action potentials in isolated Purkinje fibers, and can evaluate the effect of agents and ion channel agonists and antagonists on action potential duration (“APD”) or monophasic APD to gauge cardiac safety.