A Cardiac Arrest, also known as cardiopulmonary arrest or circulatory arrest is a sudden, unexpected loss of heart function, where the heart suddenly stops pumping blood to the body, usually because of a problem with the electrical signals in the heart. When this happens, the brain is deprived of oxygen due to which a person may become unconscious.
Although it is widely confused with a heart attack, both the conditions are quite different. A heart attack occurs when the blood supply to a part of the heart is blocked. But occasionally, a heart attack can trigger an electrical malfunction which leads to sudden cardiac arrest. In simple words, cardiac arrest is an electrical problem during which a person becomes unconscious, while a heart attack is a circulation problem and the person will be conscious.
When a cardiac arrest occurs, the brain and other vital organs are deprived of oxygen, due to which a person becomes unconscious. The pulse that can be usually observed in the wrist and the neck stops. If this condition persists without immediate medical treatment, it may lead to permanent brain damage and even death.
Causes of Cardiac Arrest
Sudden Cardiac Arrest is most often caused due to an abnormality in the heart rhythm called an Arrhythmia, which occurs due to an abnormality in the heart’s electrical activity. The sinus node, which is the heart’s electrical stimulator located in the upper right chamber generates electrical impulses that coordinates the heart rate and the pumping of blood. In this condition, the heart’s muscles undergo rapid, irregular contractions and the heart fibrillates. This fibrillation can be either Atrial Fibrillation or Ventricular Fibrillation, which are irregular electrical signals in the upper and lower chambers of the heart respectively.
Arrhythmia can be triggered in a person due to some other heart-related causes such as:
- Heart Attack: This happens when there is a loss of blood flow to a part of the heart. It usually occurs due to coronary heart disease and can trigger ventricular fibrillation.
- Coronary Artery Disease: This is the most common cause of cardiac arrest. In this condition, there is build-up of plaque inside the coronary arteries, due to which they become constricted, adversely affecting the supply of oxygen-rich blood to the heart.
- Valvular Heart Disease: The blood supply to the heart can be affected if the valves of the heart are damaged. A diseased valve can either restrict the flow of blood to the heart or allow the blood to leak backwards, both of which put extra strain on the heart and increases the risk of cardiac arrest.
- Cardiomyopathy: It is a disease of the heart muscle due to which the heart is unable to pump an adequate amount of blood. It can lead to heart tissue damage and possibly arrhythmia.
- Congenital Heart Disease: It is a common type of birth defect in which there is a problem with the structure of the heart. The defect can involve the walls or the valves of the heart or the arteries and veins.
- Disorders in the heart’s electrical system: Disorders like Long QT syndrome and Brugada syndrome can result in abnormal heart rhythms.
- Marfan Syndrome: It is an inherited disorder which affects the connective tissue and can cause parts of the heart to stretch and become weak.
Some of the other causes may include:
- Drug overdose
- Advanced stages of cancer
- Oxygen deprivation
- Major infection
- Excessive or insufficient levels of potassium
- Severe haemorrhage
Risk Factors of Cardiac Arrest
The common risk factors include:
- Family history of heart disease
- High blood pressure
- Sedentary lifestyle
- High cholesterol
Diagnosing Cardiac Arrest
In the event of a sudden cardiac arrest, it is important to seek immediate medical attention in order to identify the underlying cause and help prevent future occurrences. A cardiac specialist may recommend the following tests:
- Electrocardiogram (ECG): In this method, the heart doctor attaches sensors that can detect the electrical activity of your heart to your chest. This can reveal any abnormalities in the heart rhythm or electrical patterns.
- Chest X-Ray: An X-ray allows the cardiologist to check the size of the heart and detect any signs of disease in the heart.
- Blood Tests: Your heart surgeon may test a sample of your blood to measure the levels of potassium and magnesium.
- Angiogram: In this procedure, a liquid dye is injected into the arteries of the heart through a long, thin tube called a catheter, which causes the arteries to become visible on X-ray and helps identify the areas of blockage.
- Ejection Fraction Testing: A heart specialist can determine the heart’s pumping capacity by measuring the percentage of blood that is pumped out of the ventricle with each heartbeat, known as ejection fraction.
- Nuclear Scan: Tiny amounts of radioactive material such as thallium are injected into the bloodstream and its movement through the heart and lungs is detected using special cameras.
Treatment For Cardiac Arrest
- Cardiopulmonary resuscitation (CPR): It is a critical emergency procedure to treating sudden cardiac arrest. It helps maintain the flow of oxygen-rich blood to the vital organs of the body till a more advanced medical help arrives. If a person becomes unconscious due to cardiac arrest, start chest compressions by placing one hand in the centre of the person’s chest and covering the first hand with the other hand. Push down hard and fast using your upper body weight whilst keeping your elbows straight, and repeat the procedure about 100-120 times per minute. In the meantime, call emergency services. CPR alone is insufficient to restart the heart; its main purpose is to restore the partial flow of oxygenated blood to the heart and the brain.
- Defibrillation: This involves delivering an electric shock to the heart which stops the heart and the chaotic rhythm for an instant. This can allow the normal heart beat to resume.
- Medication: This is a long-term recovery procedure resorted to after a person recovers. Anti-arrhythmic drugs may be used for long-term treatment of arrhythmia. Medications called beta-blockers may also be used.
- Surgery: Different surgeries can be performed by a cardiac surgeon to remove blockages in the heart and/or repair damaged blood vessels and valves. Coronary angioplasty helps unblock the coronary arteries. Coronary bypass surgery involves sewing veins and arteries bypassing the narrow section in order to restore the blood flow to the heart. Corrective heart surgery may be performed to rectify a congenital heart deformity or a defective valve