What Is Sudden Cardiac Arrest?


Globally, sudden cardiac arrest (SCA), or out-of-hospital cardiac arrest 

(OHCA), continues to be a significant health burden,1 It generates close to 20% of all deaths in developed nations. This is a huge problem that has a worldwide scope.2

SCA occurs when the heart instantly and suddenly stops beating for numerous reasons.  More people die from SCAs than from lung cancer, AIDS, or other types of cancer every two minutes.   SCAs are extremely deadly because the blood supply to the brain and, more critically, to the organs instantly stops.  An SCA results in death if it is not tackled within minutes3

Causes of sudden cardiac arrest

Cardiac arrest is brought on by arrhythmias, which are abnormal heartbeats. Children who have experienced respiratory arrest from choking or drowning may also have cardiac arrest.

There are situations when a cardiac arrest's cause is unknown.

A cardiac arrest can occasionally be brought on by an action or activity. People who have cardiac issues or other risk factors are more likely to have triggering events.

Primary triggers of cardiac arrest

The two factors most frequently associated with cardiac arrest are strenuous exercise for individuals, particularly people assigned males at birt who do not routinely exercise, and alcohol abuse. Up to 3 in 20 cardiac arrests are related to drinking, while around 2 in 20 cardiac arrests are related to physical activity.4

Signs and symptoms of sudden cardiac arrest

In the hour before their cardiac arrest, the majority of persons had one or more symptoms. Even a few weeks before a cardiac arrest, some symptoms may start to manifest. However, many individuals who experience cardiac arrest have no prior symptoms.

The following are potential indicators of a heart attack, a significant contributor to cardiac arrest.

  • Inability to breathe (more common in women than in males) 
  • Excessive tiredness (atypical fatigue)
  • backache
  • flu-like signals
  • Vomiting, nausea, and stomach discomfort
  • Angina (more prevalent in males than in women)-related chest discomfort 
  • frequent fainting or dizziness, especially while engaging in vigorous exercise, sitting, or laying on your back
  • Feelings of your heart racing, fluttering, or skipping a beat are known as heart palpitations.5

Management and treatment for sudden cardiac arrest

A cardiac arrest is deadly, If medical care is not received right away. Outside of hospitals, cardiac arrests are most common. This implies that the injured person's emergency treatment depends on family, friends, or members of the local community.

Emergency medical care

Below is a list of things you can do to assist someone undergoing cardiac arrest.

  • Check to see whether the subject wakes up after being knocked unconscious by screaming and tapping on their body. Check for a pulse and respiration. Call 9-1-1 for assistance if the person is not breathing properly and is not responding
  • begin CPR
  • Find an AED. Give the patient a shock to restart their heart according to the AED's voice instructions.
  • When an opioid overdose may have been the cause of cardiac arrest, naloxone should be administered as emergency care. First responders have naloxone on standby
  • Keep doing CPR until emergency personnel arrives and take over. In addition to doing CPR, emergency personnel may administer additional shocks using an AED to correct the patient's irregular heartbeat. Additionally, they could provide medications via an intravenous (IV) line

Hospitalization following a cardiac arrest

You will be admitted to a hospital for continuous care and treatment if you survive a cardiac arrest. Healthcare professionals constantly watch your heart while you're in the hospital. The goal of hospital care is to protect vital organs, particularly the brain.

Targeted Temperature Management (TTM);All patients who are unable to follow instructions when their heartbeat recovers require TTM. TTM aids in brain protection by reducing body temperature through the use of cooling blankets, cooling helmets, ice packs, or other techniques.

Oxygen Therapy; In order for your organs to continue working while you recuperate, oxygen treatment can help you receive enough oxygen into your lungs.

Extracorporeal Membrane Oxygenation (ECMO); Blood is pumped through an artificial lung as part of an extracorporeal membrane oxygenation (ECMO) procedure to supply oxygen and remove carbon dioxide before returning the blood to your body.

Your medical team will try to determine the reason for your cardiac arrest while you are in the hospital. Medications and surgical cardiac procedures like valve replacement and coronary intervention (also known as coronary angioplasty) may be used as therapies if you are diagnosed with cardiovascular disease.6

Diagnosis of sudden cardiac arrest

When you experience a cardiac arrest, emergency personnel will inquire of any witnesses as to what they witnessed. The doctor at the emergency department will examine you physically and look up both your personal and family medical histories. In order to evaluate your condition, the doctor will also request tests. A treatment plan to lower your risk of mortality or complications can be created with the aid of test findings and your doctor.

Testing could involve:

  • a blood test like full blood count, kidney function test, liver function test, test for cholesterol and triglycerides, blood clotting test, etc
  • cardiac event monitoring, stress testing, and imaging tests are examples of heart tests.
  • genetic analysis. The risk of cardiac arrest is increased by several gene alterations. Depending on your family history and if you have survived a cardiac arrest, your doctor can recommend genetic testing for you and your blood relations.
  • catheterization of the heart7

Risk factors

Anyone can experience a sudden cardiac arrest (SCA), but specific risk factors can make it more likely to occur. These include a family history of SCA, high blood pressure, smoking, obesity, high cholesterol, age, sex, and a history of heart disease.4


Brain damage, heart failure, and post-cardiac arrest syndrome are just a few of the serious and lasting aftereffects of abrupt cardiac arrest. Blood clots, liver damage, and renal failure are further serious side effects. The likelihood of these consequences can be considerably decreased, though, with timely CPR and defibrillation. Those who are prone to sudden cardiac arrest should collaborate with their healthcare professionals to create preventative and treatment strategies.


How can I prevent sudden cardiac arrest?

By keeping a healthy weight, exercising frequently, quitting smoking, controlling stress, and addressing any underlying medical disorders, such as high blood pressure, high cholesterol, or diabetes, you can lower your chance of suffering a sudden cardiac arrest.

How is sudden cardiac arrest different from a heart attack?

Heart attacks and cardiac arrest are frequently misunderstood. An electrical malfunction of the heart that stops the beating is the cause of cardiac arrest. It is frequently deadly if nothing is done right away, while a heart attack is brought on by artery blockages. The heart normally continues to beat even when the decrease in blood supply affects the cardiac muscle.

How common is sudden cardiac arrest

Worldwide, sudden cardiac arrest is one of the main causes of mortality. An estimated 350,000 Americans suffer from sudden cardiac arrest each year, according to estimates.

When should I see a doctor?

If you suffer symptoms like chest pain or discomfort, shortness of breath, palpitations, dizziness, fainting, or unexplained lethargy, you should consult a doctor. You should also visit a doctor for routine checkups and to handle any current medical concerns.


Unexpected sudden cardiac arrest (SCA) is a medical emergency that has to be treated right away. The abrupt loss of consciousness, lack of breathing, and absence of a pulse or heartbeat are symptoms. Early intervention, including CPR and defibrillation, can greatly enhance results. The use of drugs, medical treatments, and lifestyle changes may be beneficial for those at high risk of SCA.


  1. Zimmerman DS, Tan HL. Epidemiology and risk factors of sudden cardiac arrest. Current Opinion in Critical Care [Internet]. 2021 Dec [cited 2023 Apr 25];27(6):613. Available from: https://journals.lww.com/co-criticalcare/Abstract/2021/12000/Epidemiology_and_risk_factors_of_sudden_cardiac.11.aspx
  2. Josephson ME. Sudden cardiac arrest. Indian Heart Journal [Internet]. 2014 Jan [cited 2023 Apr 25];66:S2–3. Available from: https://linkinghub.elsevier.com/retrieve/pii/S0019483214000078
  3. Nicole Olmstead. Sudden cardiac arrest awareness month [Internet]. You’re the Cure. 2015 [cited 2023 Apr 25]. Available from: https://www.yourethecure.org/sudden-cardiac-arrest-awareness-month
  4. Cardiac arrest - causes and risk factors | nhlbi, nih [Internet]. 2022 [cited 2023 Apr 27]. Available from: https://www.nhlbi.nih.gov/health/cardiac-arrest/causes
  5. Cardiac arrest - symptoms | nhlbi, nih [Internet]. 2022 [cited 2023 Apr 27]. Available from: https://www.nhlbi.nih.gov/health/cardiac-arrest/symptoms
  6. Cardiac arrest - treatment | nhlbi, nih [Internet]. 2022 [cited 2023 Apr 27]. Available from: https://www.nhlbi.nih.gov/health/cardiac-arrest/
  7. Cardiac arrest - diagnosis | nhlbi, nih [Internet]. 2022 [cited 2023 Apr 27]. Available from: https://www.nhlbi.nih.gov/health/cardiac-arrest/diagnosis
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Jacinta Chinwendu Ogbaegbe

Bachelor in medical laboratory science, Clinical/Medical Laboratory Science/Research and Allied Professions, Imo State University

Jacinta Chinwendu, a dedicated medical laboratory scientist and mother of one is driven by a deep passion for health and wellness. With over five years of experience in the health sector, she has honed her expertise and understanding of medical science. Currently, as a health writer at Klarity Health, Jacinta utilizes her knowledge to educate and empower others about important health topics. Her commitment to promoting well-being and sharing valuable insights has made her an influential figure in the field of health education.

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