Cardiac arrest is a sudden and serious medical emergency in which the heart abruptly stops pumping blood, resulting in the loss of consciousness, breathing, and pulse. Without immediate intervention, it can lead to death within minutes.
The condition affects hundreds of thousands of people annually, with survival largely depending on how quickly CPR and defibrillation are administered. This article will explore the types, causes, symptoms, treatments, and prevention strategies related to cardiac arrest.
What Is Cardiac Arrest?
Cardiac arrest happens when the heart’s electrical system malfunctions, causing the heart to stop beating effectively. Unlike a heart attack—where blood flow to the heart is blocked—cardiac arrest results in an immediate cessation of blood circulation to the brain and body.
When this occurs, a person loses consciousness within seconds, and breathing either becomes abnormal (gasping) or stops completely. Without rapid intervention, such as cardiopulmonary resuscitation (CPR) or defibrillation, death is almost certain.
According to the American Heart Association, over 430,000 deaths occur each year in the U.S. due to cardiac arrest.
Types of Cardiac Arrest
Cardiac arrest can manifest in different forms, each with varying levels of severity and outcomes:
- Cardiac Arrest: The heart stops pumping blood, halting circulation.
- Sudden Cardiac Arrest (SCA): Occurs unexpectedly in someone who may or may not have known heart disease.
- Sudden Cardiac Death (SCD): When cardiac arrest leads to death.
- Aborted Sudden Cardiac Death: When immediate intervention (such as CPR or defibrillation) successfully revives the person, preventing death.
Warning Signs and Symptoms
Cardiac arrest typically occurs without warning. However, some people may experience symptoms moments before or during the episode:
- Sudden collapse
- No pulse or heartbeat
- Unresponsiveness (even when shaken or shouted at)
- Gasping, abnormal breathing, or complete respiratory arrest
- Sudden loss of consciousness
- Occasionally, prior signs like chest discomfort, palpitations, dizziness, or fainting
If someone shows these symptoms, it’s critical to act fast and initiate CPR immediately while calling emergency services.
What Causes Cardiac Arrest?
Cardiac arrest is usually triggered by an electrical disturbance in the heart, known as arrhythmia. The most common arrhythmia in out-of-hospital cardiac arrests is ventricular fibrillation (VF)—a rapid, erratic heartbeat that prevents the heart from pumping effectively.
Common Causes Include:
- Coronary Artery Disease (CAD): The most frequent cause, resulting in heart attack and disrupted rhythm.
- Cardiomyopathy: A thickened or enlarged heart muscle.
- Congenital Heart Disease: Structural abnormalities from birth.
- Heart Attack (Myocardial Infarction): Often precedes or triggers cardiac arrest.
- Myocarditis: Inflammation of the heart muscle, often from viral infections.
- Electrical Abnormalities: Such as Long QT syndrome or Brugada syndrome.
- Heart Tamponade: Accumulation of fluid in the sac surrounding the heart.
- Severe Electrolyte Imbalances: Such as hyperkalemia or hypokalemia.
Non-Cardiac Triggers Include:
- Pulmonary Embolism: Blood clot in the lungs
- Drowning or Near-Drowning Incidents
- Blunt Chest Trauma (Commotio Cordis)
- Drug Overdose (especially opioids and stimulants)
- Severe Bleeding (hemorrhagic shock)
- Asphyxiation or Obstructed Airways
How Cardiac Arrest Is Diagnosed
During a cardiac arrest, diagnosis is typically clinical—based on the sudden collapse, unresponsiveness, lack of pulse, and absence of breathing. Once resuscitated, further tests are performed to determine the root cause.
Diagnostic Tools Include:
- Electrocardiogram (ECG/EKG): Detects arrhythmias or evidence of heart attack.
- Blood Tests: Check for electrolyte levels, oxygen saturation, pH, and drug toxicity.
- Chest X-ray / CTA: Identify lung conditions like pulmonary embolism or pneumothorax.
- Echocardiogram: Assesses structural problems or fluid around the heart.
- Cardiac Catheterization: Reveals blockages in the coronary arteries.
- Electrophysiology Studies (EPS): Evaluates the heart’s electrical pathways.
Accurately identifying the cause is critical to guide treatment and prevent future episodes.
Emergency Treatment Options
Cardiac arrest is fatal without urgent medical action. Immediate CPR and defibrillation can restore circulation and save lives.
How to Perform Hands-Only CPR:
- Call 911 Immediately: If available, ask someone to bring an AED (automated external defibrillator).
- Begin Chest Compressions:
- Place the person on a flat surface.
- Interlock hands and push hard and fast on the center of the chest.
- Maintain a pace of 100–120 compressions per minute.
- Push down at least 2 inches deep.
- Continue CPR Until Help Arrives: Do not stop unless the person shows signs of life or medical personnel take over.
The Role of AEDs in Resuscitation
An AED is a portable device designed to detect abnormal heart rhythms and deliver an electric shock (defibrillation) to restore a normal heartbeat.
How to Use an AED:
- Turn it on: It will give voice-guided instructions.
- Expose the Chest: Attach pads as indicated.
- Deliver the Shock: Follow prompts and make sure no one is touching the person during shock delivery.
- Resume CPR if Advised: Continue chest compressions until emergency responders arrive.
AEDs are increasingly found in public places like airports, malls, and schools and are safe for use by non-professionals.
Hospital and Long-Term Treatments
Once the person is revived and in the hospital, doctors may use a combination of treatments depending on the cause of cardiac arrest:
- Medications: Anti-arrhythmics, vasopressors, or beta-blockers.
- Cardiac Catheterization: To treat heart attacks or blocked arteries.
- Pacemaker or ICD (Implantable Cardioverter Defibrillator): Prevents future arrests by correcting abnormal rhythms.
- Surgical Interventions: Such as valve repair or coronary bypass surgery.
- Targeted Temperature Management (TTM): Cooling the body to protect the brain post-resuscitation.
Preventing Cardiac Arrest
While not all cases of cardiac arrest are preventable, managing heart health significantly reduces risk.
Tips to Lower Your Risk:
- Follow a Heart-Healthy Diet: Emphasize vegetables, fruits, whole grains, lean proteins, and healthy fats.
- Exercise Regularly: At least 150 minutes per week of moderate-intensity activity.
- Avoid Tobacco and Illicit Drugs: Smoking and substance use increase cardiovascular risk.
- Limit Alcohol Consumption: Excess drinking can trigger arrhythmias.
- Manage Chronic Conditions: Keep cholesterol, blood pressure, and diabetes in check.
- Screening and Monitoring: Especially important for those with a family history of cardiac disease or sudden death.
People with inherited heart conditions may require specialized monitoring, medication, or devices like ICDs as a preventive measure.
Complications After Survival
Even after successful resuscitation, cardiac arrest survivors may face complications due to the lack of oxygen during the event.
Potential Long-Term Effects:
- Brain Damage: From oxygen deprivation (hypoxic-ischemic encephalopathy).
- Memory Loss and Cognitive Impairment
- Kidney Injury: Due to poor circulation during the arrest.
- Heart Failure: Resulting from weakened or damaged heart muscle.
- Mental Health Challenges: Anxiety, depression, and PTSD are common.
Rehabilitation programs involving neurology, cardiology, physical therapy, and mental health support can aid in long-term recovery.
Why Every Second Counts
Statistics show that each minute without CPR reduces a person's survival chance by 7–10%. If CPR is initiated within the first 1–2 minutes, survival rates can double or triple. That’s why public awareness and access to AEDs are vital components of community health.
By recognizing the signs of cardiac arrest and acting quickly, you could save a life—even if you’re not a healthcare professional.
