The Hodgkin-Huxley (H-H) theory of the action potential, formulated 50 years ago, remains one of the great success stories in biology, and ranks among the most significant conceptual breakthroughs ...

A premature ventricular contraction occurs when a focus in the ventricle generates an action potential before the next scheduled sinoatrial nodal action potential. Premature, occurring earlier ...

Atrial fibrillation occurs when action potentials fire very rapidly within the pulmonary veins or atrium in a chaotic manner. The result is a very fast atrial rate — about 400 to 600 beats per ...