regulation of heart contraction multicellular organismal signaling cardiac conduction 2010-09-29T08:46:05Z biological_process Transfer of an organized electrical impulse across the heart to coordinate the contraction of cardiac muscles. The process begins with generation of an action potential (in the sinoatrial node (SA) in humans) and ends with a change in the rate, frequency, or extent of the contraction of the heart muscles. GO:0061337 dph