Since the unexpected death of pop star Michael Jackson on 25th June 2009, many people have asked me what a cardiac arrest is and others have been frightened by the mere suggestion that the heart can stop working just like that. News reports said Michael was rushed to the hospital after suffering from a cardiac arrest, but died soon after arrival in spite of the fact that he was staying in a home only a six-minute drive from the UCLA Medical Center, where paramedics brought him for treatment. A cardiac arrest is the sudden loss of cardiac function, when the heart abruptly stops beating. A person whose heart has stopped will lose consciousness and stop normal breathing, and their blood pressure will be absent. Unless attempts are made to resuscitate them immediately, a cardiac arrest leads to death within a few minutes. This is often referred to by doctors as "sudden death". The commonest cause of a cardiac arrest is a condition known as entricular fibrillation. This occurs when the normal, regular, electrical activity of the heart muscle contraction is replaced by chaotic electrical activity such that the heart stops beating and pumping blood to the brain and other parts of the body. Permanent brain damage and death can occur unless the flow of blood to the brain is restored within five minutes. The most common cause of a ventricular fibrillation is a heart attack but less common cause of cardiac arrest include respiratory arrest (loss of breathing function), choking, trauma, electrocution and drowning. It is important for us to note that a cardiac arrest is not the same as a heart attack. In a heart attack (acute myocardial infarction), a blood vessel becomes completely blocked by a blood clot, leading to death of some heart muscle and there is enough irritability of the muscle to cause ventricular fibrillation. In sudden cardiac arrest, the heart simply stops beating, and the ventricles, the two blood-pumping chambers at the bottom of the heart, go into fibrillation which is a useless fluttering such that the bottom chambers of the heart, the ventricles, beats at an extremely rapid rate say 400 to 600 times a minute. When this happens, no blood gets pumped to the rest of the body, and without the necessary oxygen in the blood vessels going to the brain, and so on, the brain then begins to die. The usual estimate is that the chance of survival goes down 10 per cent for every minute that the heart stops beating. That means that Michael Jackson probably could not have been saved. Some drugs can cause cardiac arrest and that is why the doctor who attended to him was quizzed by the police. One report said Michael had received an injection of morphine before the crisis and others mentioned the possible use of the prescription narcotic Demerol. An overdose of sedative drugs like tranquilizers can cause a cardiac arrest and you ought to be very careful what drugs you put into your body. When there is a blockage of an artery, it affects the rhythm of the heart and when this is not corrected right away one loses cardiac function and everything stops quite quickly. It is estimated that between 200,000 and 300,000 Americans die each year from a cardiac arrest and is the most common cause of death in the United States. The heart is an electrical pump. It requires an electrical spark through pathways in the heart so that all the muscle cells contract at once and produce a heart beat which will pump blood through the heart valves and into all the organs of the body so that they can function normally. When the electrical system is irritated and fails to produce electrical activity then the heart ceases to beat and the heart muscle is not able to supply blood to the body, particularly the brain, and the body dies. The commonest cause of death in such cases as mentioned earlier is a ventricular fibrillation where due to the loss of a coordinated electrical signal, the bottom chambers of the heart stop beating and instead behaves like worms moving in jiggles. The heart is a muscle itself, and like any muscle, it needs blood supply to provide oxygen for it to work. It is supplied by coronary arteries which lie on the surface of the heart. In some people some coronary arteries dive into the heart muscle itself and they may be blocked when the heart muscle that surrounds the abnormally placed artery squeezes aggressively, as happens during exercise. This shuts off the blood supply to part of the heart as happened in the case of Mark Vivien Foe, the Cameroonian football star who died on the field during a Confederation’s cup game. When this happens there is an immediate loss of consciousness, and the affected person cannot be aroused. The person will fall or slump over and no pulse will be felt neither will there be any sign of breathing. This condition can only be treated with electrical shocks to the heart from a device known as a defibrillator to restore the heart rhythm. For this shock to be effective, it must happen within less than four to six minutes to minimise brain damage from lack of blood and oxygen supply. That is the reason why in most advanced countries defibrillators are made available in many public places allowing almost anybody to treat sudden death. The frightening aspect is that in 30 per cent to 50 per cent of cardiac arrests this is actually the first manifestation of an underlying heart disease. The person may NOT have chest pain, shortness of breath or anything as a warning sign. Those at greatest risk of a cardiac arrest are males over the age of 40 years of age who smoke, have high blood pressure and diabetes. In most advanced countries those deemed “high risk” have tiny defibrillators implanted in their chests. When the device detects a ventricular fibrillation, a shock is automatically delivered to the heart, restoring the heart beat and averting sudden death. The next time you are tempted to hit your chest and say “Do you know who I am” remember you are hitting an organ (the heart) which can decide to stop just like that irrespective of who you are! That alone should make you humble. Source: Daily Graphic/Ghana