Cardiac Arrest

Cardiac arrest is a medical emergency in which the heart suddenly stops pumping blood effectively, causing a person to collapse, stop breathing normally and lose consciousness. Immediate emergency help, cardiopulmonary resuscitation and use of an automated external defibrillator can be lifesaving while specialist care identifies and treats the cause.

Overview

Cardiac arrest is a sudden failure of the heart’s pumping function. When it happens, blood flow to the brain and other vital organs stops or becomes severely reduced. A person usually collapses, becomes unresponsive and is not breathing normally. This is an emergency that requires immediate action.

Cardiac arrest is different from a heart attack. A heart attack occurs when blood flow to part of the heart muscle is blocked, often causing chest pain or pressure. Cardiac arrest is an electrical or pumping failure that causes the heart to stop circulating blood. However, a heart attack can lead to cardiac arrest, so both conditions are closely connected.

The first minutes are critical. Calling emergency services, starting cardiopulmonary resuscitation, known as CPR, and using an automated external defibrillator, or AED, when available can help maintain circulation and may restore a normal heart rhythm. Hospital care then focuses on stabilizing the person, protecting the brain and organs, and identifying the underlying cause.

Symptoms

The most typical symptom of cardiac arrest is sudden collapse. The person does not respond when spoken to or gently shaken, and they may have no normal breathing. Some people have gasping, snoring or irregular breaths; this is not normal breathing and should be treated as a sign of cardiac arrest.

Cardiac arrest can happen without warning. In some cases, symptoms occur shortly before collapse, especially if the cause is a heart attack or a worsening heart rhythm problem. These warning symptoms may include chest discomfort, shortness of breath, palpitations, dizziness, fainting, nausea, unusual sweating or sudden extreme weakness.

• Sudden loss of consciousness
• No response to voice or touch
• No normal breathing, or only gasping breaths
• No signs of circulation such as purposeful movement
• Possible bluish or pale skin color

Any suspected cardiac arrest should be treated as an emergency, even if the person looks as though they are only fainting or sleeping. It is safer to call emergency services and begin CPR if the person is unresponsive and not breathing normally.

Causes & Risk Factors

Cardiac arrest most often results from a dangerous heart rhythm, such as a very fast, chaotic rhythm that prevents the heart from pumping effectively. This rhythm disturbance may be triggered by coronary artery disease, a heart attack, heart failure, valve disease, inflammation of the heart muscle or structural abnormalities of the heart.

Other causes are not primarily cardiac but can still stop the heart. These include severe oxygen deprivation, drowning, major blood loss, trauma, electric shock, severe allergic reaction, severe infection, drug toxicity, overdose and major disturbances in blood minerals such as potassium or magnesium. In children and younger adults, breathing problems, inherited heart rhythm disorders or congenital heart disease may be important causes.

Risk factors include older age, previous heart attack, known coronary artery disease, heart failure, cardiomyopathy, certain inherited heart conditions, uncontrolled high blood pressure, diabetes, smoking, substance misuse and a family history of sudden unexplained death. A history of fainting during exercise, unexplained seizures or sudden collapse in relatives should be discussed with a doctor.

Although some risk factors cannot be changed, many can be managed. Regular medical care for heart disease, blood pressure, cholesterol, diabetes and rhythm problems can reduce overall cardiovascular risk. People with known heart conditions should follow their specialist’s advice and attend follow-up appointments.

Diagnosis

During the emergency itself, cardiac arrest is diagnosed clinically: the person is unresponsive and not breathing normally. Emergency teams check for signs of circulation, begin resuscitation and attach a monitor or defibrillator to identify the heart rhythm. Treatment is started immediately and is not delayed for detailed tests.

After the person is stabilized, doctors investigate the cause. Tests may include an electrocardiogram, blood tests, chest imaging and echocardiography to assess heart structure and pumping function. Depending on the situation, coronary angiography may be used to look for blocked heart arteries, and advanced imaging may help evaluate the heart, lungs, brain or blood vessels.

Specialists may also review medications, toxic exposures, electrolyte levels, oxygen levels and signs of infection or trauma. If an inherited condition is suspected, the assessment may include family history, rhythm monitoring, exercise testing or genetic counseling. The goal is to identify a treatable cause and estimate the risk of recurrence.

Treatment Options

Immediate treatment begins before hospital arrival. The key steps are to call emergency services, start CPR and use an AED if one is available. CPR helps circulate oxygenated blood to the brain and organs, while an AED can analyze the heart rhythm and deliver a shock when appropriate. Bystanders should follow emergency dispatcher instructions and the AED’s voice prompts.

In hospital, care may include advanced resuscitation, airway and breathing support, intravenous medicines, correction of electrolyte or metabolic problems, and treatment of reversible causes. If a blocked heart artery is suspected, cardiac catheterization and procedures to restore blood flow may be considered. If breathing failure, infection, trauma or drug toxicity is involved, the relevant specialist teams manage those conditions.

Longer-term treatment depends on the cause and the person’s overall health. Options may include heart rhythm monitoring, medicines, treatment for coronary artery disease, surgery or catheter-based procedures, an implantable cardioverter-defibrillator for selected patients, cardiac rehabilitation and lifestyle management. The right approach is decided by a cardiologist or multidisciplinary specialist team after detailed assessment.

Recovery care may also involve neurological assessment, physical therapy, psychological support and education for family members. Acibadem International’s multidisciplinary specialists and JCI-accredited hospitals diagnose and treat cardiac arrest causes for international patients, with care planned according to each patient’s clinical needs.

Living With / Prognosis

Life after cardiac arrest varies widely and depends on the cause, how quickly CPR and defibrillation were started, how long the brain lacked normal blood flow and the person’s overall health. Some people recover well, while others need rehabilitation for physical, memory, concentration or emotional changes. Follow-up care is important even when recovery seems rapid.

Survivors commonly need a structured plan to reduce the chance of another event. This may include regular cardiology visits, rhythm monitoring, treatment of heart disease, medication review and advice about physical activity. Cardiac rehabilitation can help people rebuild strength safely and understand how to manage risk factors.

Emotional recovery is also important. Survivors and families may feel anxious, uncertain or fearful after a sudden emergency. Clear information, counseling when needed and training family members in CPR and AED use can help restore confidence. Any new fainting, chest discomfort, palpitations or breathlessness should be discussed promptly with a doctor.

When to See a Doctor

Cardiac arrest itself requires emergency medical help immediately. If a person collapses, is unresponsive and is not breathing normally, emergency services should be called at once. CPR should be started and an AED used if available. Waiting to see whether the person improves can be dangerous.

A doctor should also be consulted urgently for symptoms that may indicate a serious heart problem, especially chest pain or pressure, unexplained shortness of breath, repeated fainting, palpitations with dizziness, or fainting during exercise. People with known heart disease should seek medical advice if symptoms change or become more frequent.

Families should seek specialist assessment if there is a history of sudden unexplained death, especially at a young age, or if several relatives have fainting episodes, seizures of unclear cause or inherited heart disease. Early evaluation can identify conditions that may be treatable or require monitoring.

Frequently asked questions

What is cardiac arrest?

Cardiac arrest is a sudden loss of effective heart pumping, which stops normal blood flow to the brain and body. The person usually collapses, becomes unresponsive and is not breathing normally. It is a medical emergency that needs immediate CPR, emergency services and, when available, an AED.

Is cardiac arrest the same as a heart attack?

No. A heart attack is usually caused by a blocked artery reducing blood flow to the heart muscle. Cardiac arrest is when the heart suddenly stops pumping effectively, often because of a dangerous rhythm. A heart attack can trigger cardiac arrest, so both conditions can occur together.

What should a bystander do if cardiac arrest is suspected?

Call emergency services immediately, or ask someone else to call. Start CPR if the person is unresponsive and not breathing normally, and use an AED as soon as one is available. Follow the emergency dispatcher’s instructions and the AED voice prompts.

Can cardiac arrest happen in healthy people?

Yes, although it is more common in people with known or silent heart disease. In younger or apparently healthy people, inherited rhythm disorders, heart muscle conditions, congenital heart disease or intense triggers may be involved. Any unexplained fainting, especially during exercise, should be evaluated by a doctor.

How is the cause of cardiac arrest found?

After emergency stabilization, doctors use tests such as electrocardiography, blood tests, heart imaging and sometimes coronary angiography. They also review medical history, medicines, family history and possible non-heart causes such as oxygen deprivation or electrolyte problems. The investigation guides prevention and long-term treatment.

What treatments may prevent another cardiac arrest?

Prevention depends on the underlying cause. Treatment may involve medicines, management of coronary artery disease, rhythm procedures, an implantable defibrillator in selected patients, rehabilitation and lifestyle changes. A cardiologist decides the safest plan after a full assessment.

When should someone seek medical advice after surviving cardiac arrest?

Follow-up with a cardiologist is essential after discharge, even if the person feels well. Urgent medical advice is needed for chest discomfort, fainting, palpitations, shortness of breath or new neurological symptoms. Ongoing care helps monitor recovery and reduce future risk.

References

• American Heart Association
• European Society of Cardiology
• Resuscitation Council UK
• Mayo Clinic
• National Heart, Lung, and Blood Institute

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.