Topics: Cardiovascular System, Pericardium, Epicardium, Myocardium, Endocardium, Cardiac Muscle Tissue, Intercalated discs, Atrioventricular valves, Superior vena cava, Inferior vena cava, Coronary sinus, Foramen ovale, Pectinate muscles, atrium, Right Ventricle, Right atrioventricular valve, Trabeculae carneae, Pulmonary Circuit, Conus arteriosus, pulmonary valve, Coronary Arteries, Coronary circulation, Coronary Artery, Arterial Anastomoses, cardiac vein, Heart Disease, Coronary Artery Disease, Angina pectoris, Myocardial infarction, heart attack, Cardiac Cycle, Conducting System, electrocardiogram, Automaticity, Conducting Cells, Sinoatrial Node, heart node, Atrioventricular Node, Abnormal Pacemaker Function, Purkinje Fibers, Contractile Cells, Refractory Period, Cardiac Contractions, Cardiodynamics, Cardiovascular regulation, Atrial Reflex, Bainbridge reflex, Cardiac Cycle, heart rate