Cardiac Arrest

Overview

The beating of the heart muscles is controlled by a series of electrical impulses. A healthy heart has a clear, regular beating rhythm. It contracts and relaxes alternately in order to pump blood, producing a clearly identifiable ‘lub-dub’ sound. When this intricate system of electrical signals is disturbed, an abnormal heart rhythm is the result. Disorganised electrical impulses can cause the heart to beat faster or slower than normal and in an erratic manner. Such irregular heart rhythm is known as cardiac arrhythmia and it can have serious, even life-threatening consequences.

What Is Cardiac Arrest?

When the heart suddenly stops beating and pumping blood, the patient is said to be suffering from a cardiac arrest. This is also known as sudden cardiac death. On account of the sudden loss of heart function, the patient is unable to continue breathing and loses consciousness. This is a medical emergency and in the absence of immediate treatment, the patient will die.

It is possible for the patient to survive and make a full recovery in the instance of a prompt emergency treatment. If possible a defibrillator should be applied but this equipment is not easily accessible in public places. Hence, the best solution is to call an ambulance as soon as possible and administer CPR in order to keep circulation going until the ambulance arrives.

What Causes Cardiac Arrest?

Cardiac arrest often occurs suddenly and unexpectedly. However, there are certain risk factors that can alert one to the possibility of suffering cardiac arrest. One of the main causes for this condition is a form of cardiac arrhythmia known as ventricular fibrillation. The term ‘fibrillation’ refers to the sudden and rapid series of quivering movements of heart muscles in the region of the ventricles.

The right and left ventricles are the lower chambers of the heart and their main role is to pump blood out of the heart and towards other organs and tissues. When the heart experiences an episode of ventricular fibrillation, the muscles of the ventricles jerk rapidly in an uncontrolled fashion instead of performing a coordinated contraction that effectively pumps blood out. This fibrillation or quivering movement is ineffective for actually pumping blood to nearby and distant parts of the body. The resultant loss of critical blood supply to organs, including the heart itself, can be fatal within a very short span of time. In fact, a few minutes can make the difference between life and death.

There can be a number of causes for ventricular fibrillation. Often, it is caused by a heart attack, also known as myocardial infarction. Cardiac arrest could also occur when the heart has become abnormally enlarged. As a result of this enlargement, the heart muscles may be unable to adhere to their normal beating rhythm, resulting in sudden cardiac death.

Sometimes, however, the condition responsible for cardiac arrest remains unidentified. The list below enumerates some known causes :

• Ventricular fibrillation.
• Severe blood loss.
• Cardiomegaly or an abnormally enlarged heart.
• Coronary artery disease.
• Cardiomyopathy.
• Cardiac tamponade.
• Connective tissue disorders such as Marfan syndrome.
• Problems with the electrical impulses governing cardiac contractions. This includes disorders such as Brugada syndrome.
• Hypoxia or oxygen deprivation.
• Hypovolemia or abnormally low blood volume as a result of fluid loss.
• Hypoglycemia or abnormally low blood sugar.
• Hypothermia or an abnormal drop in core body temperature.
• Abnormally high or low serum potassium, since this can directly affect heart rhythm.
• Congenital heart defects.
• Lactic acidosis.
• Heart attack.
• Scarring as a result of a prior heart attack.
• Pulmonary embolism.
• Tension pneumothorax.
• Certain medications including paracetamols, antidepressants and beta-blockers.

What Are Some Possible Complications?

When the heart suddenly stops functioning, the most critical and immediate risk is that of death. A recovery is possible if emergency treatment is made available at this point. Otherwise, death can occur within minutes.

Some studies have found that even post-recovery, victims of cardiac arrest are at an increased risk of developing mental health problems. In fact, it is estimated that nearly 1 in every 4 survivors of cardiac arrest will develop psychological problems such as post-traumatic stress disorder or depression.

How Is The Condition Recognised?

There may not be enough time for formal diagnosis or tests. However, the condition can be identified by observing its symptoms. When a person suffers from cardiac arrest, the heart is unable to reach enough blood to various vital organs such as the brain and lungs. As a result, the patient stops breathing, has no pulse, becomes unconsciousness and is unresponsive to stimuli. If all of these indications are observed, it is likely that the person has suffered a cardiac arrest.

What Should Be Done To Help?

As soon as you notice that someone near you has suffered a cardiac arrest, you should immediately call an ambulance for emergency support. The first few minutes after the heart stops beating are the most critical. It is during this time that emergency action should be taken in order to ensure the patient’s survival.

The best way to address a case of cardiac arrest is by administering cardiopulmonary resuscitation, better known as CPR. However, this maneuver should preferably be performed by a trained individual. CPR is a manual method of delivering artificial respiratory support through a combination of chest compressions and mouth-to-mouth resuscitation. This procedure helps to maintain circulation and oxygenation to some extent until the heart muscles can be revived. Hence, CPR is only a temporary measure.

The patient should then receive defibrillation. This involves administering an electric shock to the heart muscles in order to revive them, allowing the natural pacemaker in the heart to re-establish its normal rhythm. The sooner that this can be done, the higher will be the likelihood of survival and recovery.

Treatment and Prevention

Cardiac arrest can be reversed successfully if timely medical assistance is available. It is important to perform proper CPR treatment on the patient while the ambulance arrives. This regulates the flow of blood and oxygen to and from the heart. The next procedure performed on the patient is AED or Ambulatory External Defibrillator. It is a portable electronic device that detects abnormal heartbeats, such as in case of arrhythmia, and regulates it by sending external electric impulses. The additive effect of CPR and AED is what rescues a patient from the sudden cardiac arrest.  Once the patient’s heartbeat is normalized, he/she is admitted to the hospital in order to prevent the occurrence of more cardiac arrests.

In order to prevent such life-threatening cardiac issues, one must strictly follow a heart-healthy diet and lifestyle. This includes less consumption of trans-fat, sugar, and red-meat based foods and gradually shifting to a healthier diet, rich in antioxidants. Alcohol and smoking should be completely refrained from. Have a physically active lifestyle and maintain a healthy BMI. These preventive measures should be followed more strictly if one has a family history of cardiac issues.

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