Historical Development of the Monophasic Action Potential Recording Technique

In order to work as a pump, the cardiac muscle has to be able to contract and relax with a velocity which is adapted to the circulatory system of the actual species. The factors that limit cardiac rate are therefore a function of the time periods necessary for contraction and relaxation. The evolutionary process has created meaningful upper limits for the highest possible rate which the heart of any given species can reach during physiological conditions. The mechanism that puts a limit to the physiological increase of heart rate is the slow repolarization process of the myocardial muscle.