CARDIAC ARREST - RISK FACTORS AND CAUSES
Risk factors and causes
Cardiac arrest occurs without warning but it will occur rarely in a normal heart unless factors such as drug use and trauma are present. Cardiac arrest happens when there is an existing heart disease like coronary heart disease or a damaged heart due to a previous heart attack. Up to 90% of adults surrendered to cardiac arrest are due to atherosclerosis in two or more coronary arteries according to the American Heart Association. Compared to the general population the rate of sudden cardiac death is six time higher than the heart attack survivors. The most common cause of cardiac arrest is ventricular tachycardia can get worse to become ventricular fibrillation which leads ultimately to sudden cardiac death.
Ventricular fibrillation results in a heart rate of 350 beats per minute or higher and this rate of heart beat cannot be maintained by the heart for more than a few minutes with out treatment. If this condition is not treated within six to eight minutes, permanent damage of brain will occur which may result in the death of the patient. Among younger people sudden cardiac death is much less common due to the coronary artery disease and there are other conditions which will result in sudden cardiac death in younger population as the following:
(1) Because of the enlargement, thickening or stiffening of the heart the ability to pump blood is weakened and the condition is known as Hypertrophic cardiomyopathy. Some individuals with this condition do not experience any symptoms but others suffer from dyspnea (short breath), fainting or angina (chest pain) which can gradually worsen. Sudden cardiac death may occur to any person despite of the presence or absence of the symptoms or even unaware of the condition. According to American Heart Association, sudden cardiac death occurs in 36% of young athletes are due to hypertrophic cardiomyopathy.
(2) Another condition is dilated cardiomyopathy in which the individuals have an increased chance of getting serious arrhythmias or ventricular fibrillation which can lead to cardiac arrest.
(3) Ventricles will start receiving abnormal signals due to the abnormal electrical pathways between the heart and its chambers resulting in a rapid and irregular heartbeat and this condition is Wolff-Parkinson-White syndrome.
(4) Another disorder is Long QT syndrome in which the heart and its electrical system which can lead to rapid heartbeat due to stress, fear or anger results in fainting or cardiac arrest. This condition can also caused by certain medications. Generally this condition is under-recognized and under-diagnosed.
(5) Sudden ventricular fibrillation can also be caused by a genetic defect known as Brugada syndrome which is related to SCN5A gene mutation.
Other rare conditions are congenital heart disease or heart defects, embolism, Kawasaki disease, severe aortic stenosis, coronary artery spasm, bradycardia and cardiac tamponade. Events such as choking, electrocution and physical trauma can also be the reasons for cardiac arrest. Cardiac arrest is believed to be hereditary mainly among males. According to a recommendation of an international panel of cardiologists in 2003, the people have to see a physician in case of any death of a close relative due to sudden cardiac arrest.