Cardiac arrest is a sudden and often unexpected loss of heart function, breathing, and consciousness. This condition occurs when the heart’s electrical system malfunctions, causing the heart to stop pumping blood effectively to the brain, lungs, and other vital organs. Cardiac arrest is a medical emergency that requires immediate intervention to prevent death or serious brain damage.

Key Characteristics of Cardiac Arrest:

Loss of Pulse: During cardiac arrest, the heart stops beating or beats so weakly that it fails to pump blood through the body, resulting in a lack of detectable pulse.
Absence of Breathing: Breathing may stop entirely, or patients may exhibit irregular gasping, known as agonal respiration, which is ineffective for sustaining life.
Unresponsiveness: The lack of blood flow to the brain causes a sudden loss of consciousness, and the person becomes unresponsive to external stimuli.

Causes of Cardiac Arrest

Cardiac arrest can result from a variety of conditions that disrupt the heart’s electrical system, including:

Arrhythmias: Irregular heart rhythms, such as ventricular fibrillation or ventricular tachycardia, are the most common causes. These arrhythmias cause the heart to quiver rather than pump blood effectively.
Heart Attack (Myocardial Infarction): A heart attack can trigger cardiac arrest by damaging the heart muscle, leading to electrical disturbances.
Heart Conditions: Diseases like cardiomyopathy (enlarged heart), coronary artery disease, heart failure, or congenital heart defects increase the risk of cardiac arrest.
Respiratory Arrest: Conditions that stop breathing, such as severe asthma, choking, or respiratory diseases, can also lead to cardiac arrest due to a lack of oxygen.
Electrical Imbalances: High or low levels of potassium, calcium, or magnesium in the blood can disrupt the heart’s electrical activity.
Trauma: Severe injuries, such as those from a major car accident or electrocution, can damage the heart and lead to cardiac arrest.
Drug Overdose: Overdosing on certain drugs, such as opioids or stimulants, can cause respiratory or cardiac arrest.

Symptoms of Cardiac Arrest

Cardiac arrest often occurs without warning, but some people may experience symptoms in the minutes or days leading up to it:

Sudden collapse
No pulse
No breathing
Loss of consciousness

In some cases, warning signs may include chest pain, shortness of breath, fatigue, or dizziness before an arrest occurs.

Immediate Response: Chain of Survival

Cardiac arrest is highly time-sensitive, and rapid intervention is critical for survival. The “chain of survival” outlines five critical steps:

Immediate Recognition and Activation: Recognize cardiac arrest quickly and call emergency services.
Early Cardiopulmonary Resuscitation (CPR): CPR should be started immediately to maintain blood flow to the brain and organs.
Rapid Defibrillation: Using an Automated External Defibrillator (AED) can restore a normal heart rhythm in cases of ventricular fibrillation.
Advanced Life Support: Paramedics provide medications and advanced resuscitation techniques on arrival.
Post-Cardiac Arrest Care: In a hospital, treatment focuses on stabilizing the heart, protecting brain function, and addressing the underlying cause of the cardiac arrest.

Difference between Cardiac Arrest and Heart Attack

A heart attack is caused by a blockage in the blood flow to the heart muscle, which can damage the heart but does not always cause the heart to stop. However, a heart attack can lead to cardiac arrest if the damage triggers an irregular heartbeat. In contrast, cardiac arrest is the sudden cessation of heart function due to electrical malfunction.

Importance of Immediate Action

Cardiac arrest can lead to irreversible brain damage within 4–6 minutes due to lack of oxygenated blood. Immediate CPR and defibrillation are vital to prevent this damage and increase the chance of survival.