Understanding Cardiac Arrest: Causes, Symptoms, Treatment, and Prevention

Last updated:
May 30, 2023

Cardiac arrest is a life-threatening medical emergency that occurs when the heart suddenly stops beating or beats irregularly, disrupting the flow of oxygenated blood to vital organs. It is a condition that requires immediate attention and intervention to prevent irreversible damage or loss of life. Cardiac arrest can strike anyone, regardless of age or health status, and its critical nature demands prompt action for the best chance of survival. This article provides an overview of cardiac arrest, emphasizing its urgency and highlighting the importance of immediate response and effective treatment.


What Is Cardiac Arrest?

Cardiac arrest is an abrupt loss of heart function due to a disruption in the normal electrical impulses that control the heart rate and rhythm. It is a medical emergency and can be fatal if not treated immediately. Cardiac arrest is not the same as a heart attack, although a heart attack can lead to cardiac arrest.

When cardiac arrest occurs, the heart stops beating effectively and stops pumping blood to the brain and other organs. As a result, the brain and other organs can be damaged or destroyed without oxygen-rich blood. If cardiac arrest is treated quickly and effectively, it can restore normal heart rhythm and blood flow. However, if treatment is delayed or ineffective, the patient may suffer permanent brain damage or death.


How Does Cardiac Arrest Differ From Other Heart-Related Conditions Like a Heart Attack?

Cardiac arrest occurs when the heart's electrical system malfunctions, leading to an abnormal heart rhythm. In cardiac arrest, the heart is unable to pump blood effectively, leading to a rapid loss of consciousness and the absence of a pulse and normal breathing.

On the other hand, a heart attack, medically known as a myocardial infarction, is caused by a blockage in the blood vessels supplying the heart muscle. This blockage typically occurs due to the buildup of fatty deposits called plaque in the coronary arteries. When a coronary artery becomes completely blocked, blood flow to a section of the heart muscle is compromised, leading to the death of that portion of the muscle.

While both cardiac arrest and heart attack are serious medical emergencies, their causes and mechanisms differ. Cardiac arrest primarily involves a malfunction of the heart's electrical system, disrupting its ability to pump blood effectively. In contrast, a heart attack is caused by a blockage in the blood vessels supplying the heart muscle, resulting in the death of a portion of the muscle due to inadequate blood flow.


What Causes Cardiac Arrest?

Cardiac arrest can have various causes, and understanding them is crucial for recognizing risk factors and taking preventive measures. Here are the common causes and triggers of cardiac arrest:


Coronary Artery Disease (CAD)

Coronary artery disease (CAD) is a leading cause, characterized by the buildup of plaque in the coronary arteries that supply blood to the heart. When the plaque ruptures or a blood clot forms, it can block the artery, leading to a heart attack or triggering a lethal arrhythmia. Heart failure, a condition where the heart cannot pump blood effectively, can also contribute to cardiac arrest due to weakened heart muscle.



Disturbances in the heart's electrical system can lead to abnormal heart rhythms (arrhythmias) that can cause cardiac arrest. The two main types of Arrhythmias are:

  • Ventricular fibrillation (VF) is a life-threatening arrhythmia in which the heart's electrical signals become chaotic, causing the ventricles (lower chambers) to quiver instead of pumping blood effectively.
  • Ventricular tachycardia (VT) is a rapid and abnormal heartbeat originating from the ventricles, and can also trigger cardiac arrest.


Structural Heart Abnormalities

Structural heart abnormalities refer to physical defects or abnormalities in the structures of the heart. These conditions involve the heart's valves, chambers, walls, or blood vessels. Structural heart abnormalities can be present at birth (congenital) or develop later in life (acquired). Here are some common examples:


  • Cardiomyopathy: Cardiomyopathy is a group of diseases that affect the heart muscle, causing it to become enlarged, thickened, or weakened. There are different types of cardiomyopathy, including hypertrophic cardiomyopathy, dilated cardiomyopathy, and restrictive cardiomyopathy.
  • Heart Valve Abnormalities: This refers to abnormalities or malfunctions of the heart valves, which control the flow of blood within the heart. Conditions like aortic stenosis, mitral valve prolapse, and regurgitation fall under this category.
  • Congenital Heart Defects: These are heart abnormalities that develop during fetal development and are present at birth. Examples include atrial septal defect (ASD), ventricular septal defect (VSD), patent ductus arteriosus (PDA), and tetralogy of Fallot. These defects can affect the heart's structure, blood flow, and oxygenation.


Drug Overdose

Certain drugs, especially those that affect the heart's electrical activity, can increase the risk of cardiac arrest. For example, some illegal drugs, such as cocaine or amphetamines, can cause severe arrhythmias or lead to a heart attack. Additionally, certain prescription medications, when taken inappropriately or in excessive amounts, can also disrupt the heart's electrical system and contribute to cardiac arrest.


Electrical Shock

Electrical injuries or severe electric shocks can cause cardiac arrest. The high voltage electrical current passing through the body can interfere with the heart's electrical signals, leading to arrhythmias or directly stopping the heart.


Respiratory Failure

Respiratory failure can cause cardiac arrest due to reduced oxygen supply to the heart, disruption of the heart's electrical system, and increased workload on the heart. These factors can lead to impaired cardiac function and, in severe cases, result in cardiac arrest.



Severe trauma, such as a blunt force injury to the chest or a significant impact to the heart, can disrupt the heart's electrical system and trigger cardiac arrest. This can occur in situations like motor vehicle accidents, physical assaults, or sports-related injuries.


Among adults, how prevalent is sudden cardiac arrest?

The prevalence of cardiac arrest among adults can vary depending on various factors, including the population studied and geographic location. However, it is estimated that the annual incidence of cardiac arrest is around 55 to 100 cases per 100,000 people in the general adult population.

In the United States, for example, Sudden Cardiac Arrest (SCA) is a leading cause of death, accounting for approximately 325,000 adult deaths each year. It is estimated that one in every 1,000 adults is affected by Sudden Cardiac Arrest annually. Similar patterns are observed in other developed countries.

What Are The Symptoms Experienced During Cardiac Arrest?

During cardiac arrest, the common symptoms and signs include:

  • Sudden Loss of Consciousness
  • Shortness of Breath
  • Lack of Pulse
  • Chest Pain or Discomfort
  • Dizziness or Lightheadedness
  • Palpitations or Rapid Heartbeat
  • Fatigue or Weakness


These three signs—sudden loss of consciousness, absence of breathing, and lack of a pulse—are the primary and most prominent indicators of cardiac arrest. It is essential to recognize that cardiac arrest is a medical emergency that requires immediate action.


On observing The Signs Of Cardiac Arrest, How Quickly Should One call for emergency help?

Upon observing the signs and symptoms of cardiac arrest, it is crucial to call for emergency help immediately. Time is of the essence in the event of a cardiac arrest, and prompt action can significantly increase the chances of survival.

In most countries, including the United States, the emergency number to call is 911. This number should be dialed immediately upon recognizing the signs of cardiac arrest.

Calling for emergency help initiates the activation of the emergency medical services (EMS), who can provide further instructions over the phone and dispatch medical professionals to the location as quickly as possible. The dispatcher may also provide guidance on performing cardiopulmonary resuscitation (CPR) until help arrives.


How is a Cardiac Arrest Treated?

When encountering a person in cardiac arrest, immediate actions should be taken to increase the chances of survival. The immediate initiation of CPR and early defibrillation (if an AED is available) can significantly increase the chances of survival. Every minute that passes without intervention decreases the likelihood of a successful outcome.


Cardiopulmonary resuscitation (CPR)

Early CPR help circulate oxygen-rich blood to the brain and other vital organs. This is crucial in maintaining organ function and increasing the chances of a successful resuscitation outcome. Even if you are not formally trained in CPR, performing chest compressions alone is still valuable and can make a significant difference in a cardiac arrest situation.


At what rate should chest compressions be performed during a cardiac arrest?

You should deliver chest compressions to an unresponsive patient in cardiac arrest by pushing hard and fast, at a rate of approximately 100-120 compressions per minute.



Early defibrillation is crucial in restoring a normal heart rhythm during cardiac arrest. It stops life-threatening abnormal rhythms and improves the chances of survival. Time is of the essence, as the success of defibrillation decreases with each passing minute. AEDs in public spaces and the expertise of medical professionals ensure prompt intervention and increase the likelihood of a positive outcome.


Over the past decade, how has the survival rate from cardiac arrest changed?

Over the past decade, there has been a gradual improvement in the survival rates from cardiac arrest. This positive trend can be attributed to several factors, including increased public awareness of cardiac arrest and the importance of early intervention, improved access to automated external defibrillators (AEDs) in public spaces, advancements in resuscitation techniques, and enhanced coordination between emergency medical services (EMS) and hospitals.

Specific statistics regarding survival rates from cardiac arrest can vary depending on the region, population studied, and the quality of emergency medical care. However, there have been instances of significant improvements in survival rates observed in certain communities and healthcare systems. For example, some regions have reported notable increases in bystander CPR rates and AED utilization, resulting in improved survival outcomes.


What Is The Recovery Process After Cardiac Arrest?

The recovery process after cardiac arrest involves post-resuscitation care, neurological assessment, cardiac evaluation, rehabilitation and recovery, addressing underlying conditions, and long-term management for secondary prevention. It aims to stabilize the patient, evaluate any potential brain damage, assess the heart's condition, promote physical and cognitive recovery through rehabilitation, and prevent future cardiac events through lifestyle modifications and ongoing medical care.


How to Prevent Cardiac Arrest?

Preventing cardiac arrest involves adopting a comprehensive approach that focuses on maintaining heart health and reducing risk factors. Here are some preventive measures individuals can take:


  • Engage in Regular Exercise: Aim for at least 150 minutes of moderate-intensity aerobic exercise or 75 minutes of vigorous exercise per week.
  • Follow a Heart-Healthy Diet: Emphasize a diet rich in fruits, vegetables, whole grains, lean proteins, and healthy fats while limiting saturated fats, trans fats, salt, and added sugars.
  • Maintain a Healthy Weight: Achieve and maintain a body weight within a healthy range to reduce the risk of heart disease.
  • Limit Alcohol Consumption: Moderation is key. Men should limit alcohol to two drinks per day, while women should limit it to one drink per day.
  • Avoid Tobacco Products: Quit smoking and avoid exposure to secondhand smoke.
  • Manage Underlying Medical Conditions: Monitor blood pressure regularly, maintain healthy cholesterol levels, and keep blood sugar levels under control through proper management. If you have known heart conditions, work with your healthcare team to manage and treat them effectively.
  • Schedule Routine Check-ups: Regularly visit your healthcare provider for comprehensive health assessments.
  • Adhere to Medications: Take prescribed medications as directed, including those for managing blood pressure, cholesterol, diabetes, and other underlying conditions.
  • Know Your Family History: Understand if there are any genetic predispositions to heart disease, such as familial cardiac conditions.

It's important to remember that preventive measures may vary depending on individual circumstances and risk factors. Consult with healthcare professionals for personalized advice and recommendations based on your specific health profile. Regularly assessing and addressing cardiovascular risk factors can significantly reduce the likelihood of cardiac arrest and promote overall heart health.

Key Takeaway

  • Cardiac arrest is a sudden loss of heart function, leading to a cessation of blood flow and oxygen supply to vital organs.
  • Cardiac arrest often manifests as a sudden loss of consciousness, absence of breathing, and lack of a pulse. Other symptoms may include chest discomfort, dizziness, and palpitations prior to the arrest.
  • Cardiac arrest can be caused by various factors, including heart disease (coronary artery disease, heart failure), arrhythmias (ventricular fibrillation, ventricular tachycardia), drug overdose, electrocution, and trauma.
  • Immediate actions should be taken when encountering a person in cardiac arrest, including calling for emergency help, starting CPR, and using automated external defibrillators (AEDs) if available.
  • CPR plays a crucial role in maintaining blood circulation and providing oxygen to vital organs. It involves delivering chest compressions at a rate of 100-120 per minute to an unresponsive adult patient in cardiac arrest.
  • Early defibrillation, either through an AED or by trained medical professionals, is vital in restoring a normal heart rhythm. It helps stop life-threatening abnormal rhythms like ventricular fibrillation and increases the chances of survival.
  • Sudden cardiac arrest is a significant health issue, and its prevalence varies among populations. It can occur in both adults and children.
  • The recovery process after cardiac arrest involves post-resuscitation care, neurological assessment, cardiac evaluation, rehabilitation and recovery, addressing underlying conditions, and long-term management for secondary prevention.
  • Adopting preventive measures can reduce the risk of cardiac arrest. This includes maintaining a healthy lifestyle, managing underlying medical conditions, avoiding tobacco and excessive alcohol consumption, regular check-ups, adhering to prescribed medications, and being aware of family history.
  • Recognizing symptoms, providing immediate treatment (CPR and defibrillation), and adopting preventive measures are crucial for improving outcomes and reducing the incidence of cardiac arrest.

a group training in cpr/bls
CPR AED and First Aid Certification. Get certified Now with the latest AHA guidelines.
Takes less than 20 minutes. Or take a Practce test
Compare & Start Now
Test your knowledge by taking a Practice Test