Asystole (also known as flatline) is a state of no cardiac electrical activity, hence no contractions of the myocardium and no cardiac output or blood flow. Asystole is one of the conditions required for a medical practitioner to certify death.
When a patient displays asystole, the treatment of choice is an injection of epinephrine and atropine (vasopressin may also be used) and chest compressions. In asystole, the heart will generally not respond to defibrillation because it is already depolarized. However, some emergency physicians advocate a trial of defibrillation in case the rhythm is actually fine ventricular fibrillation otherwise indistinguishable from asystole, although little evidence exists to support the practice. Asystole is usually a confirmation of death as opposed to a heart rhythm to be treated, although a small minority of patients are successfully resuscitated if the underlying cause is identified and treated immediately. Generally, after a minute and a half to five or so minutes, the heart will not respond to defibrillation or injections of epinephrine and atropine (if ventricular fibrillation or asystole is still present) and the patient is then declared dead or brain-dead. However, the latest American Heart Association guidelines for cardiac resuscitation have replaced atropine in the treatment of most cases of asystole with a vasopressor only, citing a lack of evidence of effectiveness. The victim will then be put on cardiopulmonary bypass and dialysis if the heart, lungs, liver, and kidneys are to be transplanted because of the need to keep blood circulating and filtered in order to prevent organ-damaging events like thrombosis, embolism, necrosis, DIC, or cardiopulmonary or renal failure.