Ключевые слова: assistance, cardiac conduction system, cardiac massage, cardiac resuscitation, chest, chest wall, cpr, death, doctor, emergency services, first aid, healthcare and medicine, healthcare worker, heart attack, human cardiopulmonary system, human hand, human heart, illness, instructor, life, lifeguard, massaging, medical equipment, medical exam, medical occupation, medical procedure, paramedic, patient, physical pressure, practicing, pushing, rescue, shock, showing, skill, teaching, training, urgency,