Heart arrhythmia muscle cell firing off an impulse on its own. All of the cells in the heart have the ability to initiate an action potential; however, only some of these cells are designed to routinely trigger heart beats. These cells are found in the conduction system of the heart and include the SA node, AV node, Bundle of His and Purkinje fibers. The sinoatrial node is a single specialized location in the atrium that has a higher automaticity (a faster pacemaker) than the rest of the heart and, therefore, is usually responsible for setting the heart rate and initiating each heart
Cardiac neural crest cells the young mice were tagged with enhanced green fluorescent protein (EGFP) and then traced. Tagged CNCCs were concentrated in the cardiac outflow tract, and some were found in the ventricular myocardium. These cells were also shown to be differentiating into cardiomyocytes as the heart grew. Although less were found, these EGFP-labelled CNCCs were still present in the adult heart. When a heart attack was induced, the CNCCs aggregated in the ischemic border zone area (an area of damaged tissue that can still be saved) and helped contribute to the regeneration of the tissue to some extent via differentiation into cardiomyocytes