Asystole is a total absence of heart rhythm. When the heart is in asystole, it has stopped beating, or electrical activity is occurring on such a low level that it cannot be detected with an electrocardiograph. Most people who develop asystole die, although a small number are revived, depending on what causes their hearts to stop beating and how quickly medical treatment is provided. Asystole is one of the criteria which can be used to pronounce someone dead.
The heart can become asystolic for a number of different reasons. Damage or disease in the heart can cause it to stop beating because the cells in the heart become damaged, for example, as can drug overdoses, oxygen deprivation, and a spike in potassium levels. It is not uncommon for the heart rhythm to be irregular before the heart stops beating altogether.
On a cardiac monitor, an asystolic rhythm looks like a flat line, as opposed to the jagged lines associated with electrical activity in the heart. For this reason, asystolic arrest is sometimes referred to as “flatlining” in colloquial English. Fans of medical dramas may have heard this term used on television.
There are some treatments which can be used in an attempt to get the heart beating again. Medications like epinephrine, vasopressin, and atropine may be injected, and chest compressions are used to force some blood through the circulatory system. In some cases, internal cardiac massage may be utilized, and doctors can try pacing, in which the heart is shocked with small electrical impulses in a pattern to try and restore regular rhythm.
The main concern with asystole is that the longer the heart doesn't beat, the more the brain becomes deprived of oxygen. Even with chest compressions or cardiac massage, not enough blood reaches the brain. A cessation of heart activity for more than 15 minutes is generally considered a sign that the patient is truly dead, because even if the heart can be restarted at that point, the brain will be too badly damaged. Nevertheless, every measure is taken to revive the patient up to the point of no return.
For the few patients who recover from asystole, it is common to experience bruising and pain in the chest, and sometimes ribs are broken with chest compressions. Usually follow-up care is needed to provide support while the patient recovers and to address the underlying condition which caused the heart to stop in the first place.
