High resolution imaging of the human cardiac conduction system using reflectance confocal microscopy.

Rhythmical contraction of the heart is controlled by the cardiac conduction system (CCS) that consists of the three main parts: the sino-atrial node, the atrioventricular node and the His-Purkinje system. A heartbeat signal, originated from CCS, spreads through its branches to the different parts of the heart, initiating depolarization of the ventricles. However, this highly important system could not be distinguished visually from the surrounding heart tissues: myocardium (MC) and connective tissue (CT).