What Should You Know About Cardiac Arrest?

We often hear the terms heart attack and cardiac arrest as fatal conditions. Although most individuals use the term 'heart attack' to define cardiac arrest, these two are not the same.

A cardiac arrest, also known as cardiopulmonary arrest/cardiorespiratory arrest, is defined as cessation of adequate heart function and respiration, resulting in death without reversal. It occurs when there is a sudden loss of heart function due to impaired functioning of the heart's electric system, which is responsible for controlling the rate and rhythm of the heartbeat. It can occur in individuals who may or may not have been diagnosed with previous heart disease.

In contrast, a heart attack occurs due to obstruction of blood flow to the heart, which can sometimes trigger abnormal electrical disturbances, leading to cardiac arrest.

Signs and symptoms of cardiac arrest

A cardiac arrest presents with immediate and drastic changes and some signs and symptoms that may occur before the cardiac arrest. These include:

Immediate signs

• Sudden collapse
• Unconsciousness
• Loss of pulse and breathing

Signs which may occur just before a cardiac arrest can include:

• Shortness of breath
• Fatigue, weakness and dizziness
• Chest discomfort
• Pounding/fluttering heartbeat

Although these are some signs and symptoms associated with a cardiac arrest, in most cases cardiac arrests occur without any warning signs.

Causes of cardiac arrest

Generally, cardiac arrests are most commonly caused by abnormal heart rhythms, also known as arrhythmias, which occur due to an impaired electrical system of the heart. As a result, the heart beats abnormally fast, slow, or irregularly. In most cases, these arrhythmias are harmless, but some types can cause sudden cardiac arrests.

Heart conditions cause electric problems, which lead to sudden cardiac arrests

Sudden cardiac arrests can occur in individuals with no known heart condition. However, cardiac arrhythmias leading to cardiac arrests can develop in individuals with pre-existing heart disease, which may not have been diagnosed. These heart diseases include:

• Ventricular fibrillation: It causes the lower chambers of the heart to beat abnormally fast and irregularly.
• Coronary artery disease: The heart’s arteries are blocked, leading to obstruction of blood flow to the heart.
• Scarred heart tissue: It occurs because of a prior heart attack or other causes. Scarring of heart tissue makes individuals more prone to abnormal heart rhythms triggering a cardiac arrest.
• Cardiomyopathy: The heart muscle is thickened and enlarged as a result of heart valve disease, high blood pressure or several other causes. An abnormal heart muscle makes you more prone to sudden cardiac arrests.
• Valvular heart disease: Abnormalities in the heart valves such as narrowing and leaking can lead to thickening of the heart muscle, increasing the risk of abnormal heart rhythms and a sudden cardiac arrest.
• Electrical abnormalities in the heart: Sometimes, the heart’s electric system by itself is problematic in some individuals, instead of heart muscle or valve disease. These are called primary heart rhythm abnormalities.

Risk factors of cardiac arrest

Several factors are associated with an increased risk of cardiac arrest and these include:

• Family history of heart diseases/cardiac arrest
• Increasing age
• Previous heart attack
• High cholesterol and blood pressure
• Alcohol, smoking and drug abuse
• Obesity
• Inactive lifestyle
• Diabetes

Treatment of cardiac arrest

Sudden cardiac arrest requires immediate treatment and medical attention to increase supply of oxygen-rich blood to the organs for survival. This includes:

Immediate care

• Cardiopulmonary resuscitation (CPR): It is the first line treatment that needs to be provided. It involves compression of the chest by another person, to increase blood flow to the organs. CPR serves as vital treatment until more advanced emergency care is available.
• Defibrillation: Once emergency care is available, a machine called a defibrillator is used to deliver electric shock to the heart through the chest wall, to help regain heartbeat and heart function.

Long-term treatment

Once the patient has recovered, the doctor performs some tests to determine the cause of the cardiac arrest and provide appropriate treatment based on the cause to reduce the risk of another cardiac arrest in future. Patients may receive medications or undergo surgical procedures based on their condition.

Prevention of cardiac arrests

The risk of cardiac arrests can be reduced by following a heart healthy lifestyle, getting regular-checkups and screenings for heart diseases.

Lifestyle measures include:

• Heart-healthy diet
• Regular exercise
• Weight control
• Quitting smoking and reducing alcohol intake

It is important to stay aware of all the signs and symptoms, appropriate lifestyle measures, and screening tests for early detection of risk factors and prevention of cardiac arrests.

Dr Gobu P

MD. (Gen. Med), DM (Cardiology), FIMSA, FESC

Senior Consultant & Interventional Cardiologist -
Institute of Cardiac Sciences