Cardiac arrest
A condition where the heart suddenly stops beating effectively.
Cardiac arrest, sometimes called sudden cardiac arrest (SCA), happens when the heart either stops beating entirely or beats in a way that cannot generate a pulse. Without effective pumping, blood cannot circulate properly, and the brain and other organs receive less blood flow. A lack of oxygen to the brain can cause a person to lose consciousness, and brain cells begin to die within minutes. This can lead to coma or a persistent vegetative state. The condition is usually recognized by the absence of a central pulse and by breathing that is abnormal or absent.
The collapse of blood flow in cardiac arrest is often caused by arrhythmias—irregular heart rhythms. Ventricular fibrillation and ventricular tachycardia are the most common types recorded. However, because many cardiac arrests happen outside a hospital or when a person’s heart activity is not being monitored, it is often difficult to determine the exact mechanism in each case.
Structural heart disease, particularly coronary artery disease, is a frequent underlying condition in people who experience cardiac arrest. The main risk factors are age and cardiovascular disease. Other heart-related conditions include heart failure and inherited arrhythmias. Additional factors that can contribute to cardiac arrest include major blood loss, lack of oxygen, electrolyte disturbances (such as very low potassium), electrical injury, and intense physical exercise.
Diagnosis is made when a pulse cannot be found in an unresponsive patient. Treatment aims to quickly restore spontaneous circulation using interventions like CPR, defibrillation, or cardiac pacing. Two CPR protocols exist: basic life support (BLS) and advanced cardiac life support (ACLS). If spontaneous circulation returns, the event is considered sudden cardiac arrest. If the person does not survive, it is called sudden cardiac death. For those whose pulse is restored, care focuses on preventing brain injury and preserving neurological function. This may involve airway management and mechanical ventilation, maintaining blood pressure and organ perfusion through fluids and vasopressors, correcting electrolyte imbalances, monitoring the heart with an EKG, managing reversible causes, and controlling temperature. Targeted temperature management may improve outcomes. In post-resuscitation care, an implantable cardiac defibrillator might be considered to red
- field
- Medicine
- known_for
- Sudden cessation of heart function leading to hemodynamic collapse
- annual_incidents_in_US
- Approximately 535,000
- out_of_hospital_percentage
- 61%
- in_hospital_percentage
- 39%
Lore & Background
Cardiac arrest often occurs due to arrhythmias, with ventricular fibrillation and ventricular tachycardia being most commonly recorded. Structural heart disease, such as coronary artery disease, is a common underlying condition. Risk factors include age, cardiovascular disease, cigarette smoking, high blood pressure, high cholesterol, and diabetes. Approximately 50% of cardiac arrests occur in 10% of the population perceived to be at greatest risk due to aggregate harm of multiple risk factors.
Reader's Guide
Cardiac arrest is a critical medical emergency diagnosed by the inability to find a pulse in an unresponsive patient. Treatment aims to rapidly achieve return of spontaneous circulation using interventions such as CPR, defibrillation, or cardiac pacing. Post-resuscitation care may include measures to protect the brain, such as airway management, temperature management, and correction of electrolyte imbalances. The condition becomes more common with age and affects males more often than females. In the United States, black people are twice as likely to die from cardiac arrest as white people. The underlying causes can be cardiac, such as coronary artery disease, or non-cardiac, such as respiratory arrest or trauma. The most common mechanism is an arrhythmia that prevents the heart from generating adequate cardiac output.
Did You Know?
- Cardiac arrest is not preceded by any warning symptoms in approximately 50 percent of people.
- Among those whose pulses are re-established, targeted temperature management may improve outcomes.
- Current cigarette smokers with coronary artery disease have a two to threefold increase in the risk of sudden death between ages 30 and 59.
- Coronary artery disease underlies 68 percent of sudden cardiac deaths in the United States.
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