Sudden and Unexpected Cardiac Arrest in Apparently Healthy Young Adults.
Cardiac arrest occurs when an individual’s heart suddenly stops pumping blood into the body. About 4 to 14 per 100,000 apparently healthy young adults aged 18 to 40 suffer sudden cardiac arrest worldwide each year.
UNDERSTANDING: Based on autopsy (post-mortem) studies 55% to 69% of young adults who die of cardiac arrest have a heart rhythm problem which is the result of electrical impulse abnormality. When heart beats, it contracts and ejects blood into the arteries to circulate in the entire body. Each heart beat is initiated by a self-generating electrical impulse in a small tiny area within the heart called the Sinus Node. From here the electrical impulse spreads into the heart muscle and causes the heart to contract. An abnormality in the generation of the electrical impulse or its conduction through the heart muscle could occasionally make the heart rhythm very disorganized and chaotic to such a degree that heart is unable to contract and pump blood into the arteries essentially causing heart to stop. This is called cardiac arrest. In a very simplified language this is a kind of electrical short circuiting in the heart. Out of the few electrical abnormalities that could cause cardiac arrest and are genetically present in some individuals, the one that is most common is called “Long QT Syndrome”. In this condition, after passage of each electrical impulse the recovery period that makes the heart ready for another impulse, is prolonged. If a new impulse is generated while the heart has not fully recovered from the previous impulse, it can rarely throw the heart into an electrically chaotic and disorganized rhythm called “Ventricular Fibrillation” which causes heart to stop resulting in cardiac arrest and sudden death.
Besides the electrical rhythm abnormalities of genetic origin, sometimes illicit drug overdose, genetic defect causing heart to become weak and dilated called “Dilated Cardiomyopathy” and blockage in the arteries supplying blood the heart muscle also can lead to sudden cardiac arrest and death.
How to handle this critical situation:
1. Call 911
2. Start CPR (Cardio Pulmonary Resuscitation). It is very important to learn how to do CPR and provide basic life support until ambulance arrives.
3. If the chaotic heart rhythm is such that it can be treated with electrical shock, called “Defibrillation”, it should be immediately given and repeated according to a treatment algorithm along with IV injections of a drug called Epinephrine. The ambulance crew is well trained in handling this situation. They are able to provide the treatment immediately and while the patient is being transported to a hospital.
4. If the patient survives, he or she should receive an implantable cardiverter-defibrillator (ICD). This small device is surgically placed under the skin and by wires connected with the heart. It can continuously monitor the heart, and whenever the heart goes into a chaotic rhythm (cardiac arrest) situation, it recognizes the condition and automatically shocks the heart to restore normal regular rhythm.
PROGNOSIS:
Among all apparently healthy young individuals about 60% die before reaching the hospital. 9% to 16% are lucky enough to survive and are discharged from the hospital alive. However survival rate increases to about 35% for those who have a witnessed cardiac arrest and receive prompt CPR and electrical shock by a defibrillator.