What're the treatments for cardiac arrest?
Sudden cardiac death (also called sudden arrest) is death resulting from an abrupt loss of heart function (cardiac arrest). Sudden cardiac death is an instant unexpected death which occurs within one hour of an abrupt change in a person's stable clinical state. The mechanism is generally a ventricular tachyarrhythmia. The underlying pathology is usually coronary heart disease in middle-aged and elderly persons, but can also be one of the familial well-defined cardiomyopathies such as hypertrophic cardiomyopathy, dilated cardiomyopathy, arrhythmogenic right ventricular dysplasia or long QT syndrome. In
children and young athletes the two main causes of sudden death are long QT syndrome and hypertrophic cardiomyopathy. Loss of consciousness and family history of sudden cardiac death should encourage the physician to examine the patient's relatives.
Sudden cardiac arrest cases are usually due to abnormal heart rhythms called arrhythmias, the vast majority of which are ventricular fibrillation. Ventricular fibrillation is a condition in which the heart's electrical impulses suddenly become chaotic, causing the heart to cease pumping blood effectively. Victims of SCA collapse and quickly lose consciousness, often without warning. Unless a normal heart rhythm is restored, death will follow within a matter of minutes.
The cause of sudden cardiac arrest is not well understood. Many victims have no history of heart disease, or if heart disease is present, it has not functionally impaired them. Unlike a heart attack, which is the death of muscle tissue from loss of blood supply, many victims of SCA have no prior symptoms. SCA can strike anyone, at any time, anywhere.
SCD is the death of a person due to the sudden loss of function of the heart. This type of death is rarely expected because it usually occurs very shortly after the first symptoms start showing. Sudden cardiac arrest (SCA) is a condition in which the heart stops beating suddenly and unexpectedly due to a malfunction in the heart's electrical system. The malfunction that causes SCA is a life-threatening abnormal rhythm, or arrhythmia. The most common arrhythmia is ventricular fibrillation (VF).
When in VF, the heart's rhythm is so chaotic (called "fibrillating") that the heart merely quivers, and is unable to pump blood to the body and brain. These graphics show a heart with a normal rhythm and a heart experiencing ventricular fibrillation (VF). Once a heart has entered VF, sudden cardiac arrest occurs. A victim in SCA first loses his or her pulse, then consciousness, and finally the ability to breathe. But all of this happens quickly-in a matter of seconds. Without immediate treatment from a defibrillator, 90-95 percent of SCA victims will die.
The only way to effectively treat sudden cardiac arrest (SCA) is with an electrical shock delivered by a defibrillator. Voltage stored by the defibrillator pushes electrical current through the heart by means of the electrodes or paddles placed on the chest. This brief pulse of current halts the chaotic activity of the heart, giving it a chance to start beating again with a normal rhythm. Delivering a shock that returns the heart to a normal rhythm is called defibrillation. Survival rates for SCA are highest when defibrillation occurs within the first few minutes. The person has the best chance of survival if the defibrillation shock is given within the first three minutes of collapsing.
The victim may or may not have diagnosed heart disease. The time and mode of death are unexpected. It occurs within minutes after symptoms appear. The most common underlying reason for patients to die suddenly from cardiac arrest is coronary heart disease (fatty buildups in the arteries that supply blood to the heart muscle).When the heart suddenly stops beating effectively and breathing ceases, a person is said to have experienced sudden cardiac death.
SCD is not the same as actual death. In actual death, the brain also dies. The important difference is that sudden cardiac death is potentially reversible. If it is reversed quickly enough, the brain will not die. Sudden cardiac death is also not the same as a heart attack. A heart attack (myocardial infarction) is the result of a blockage in an artery which feeds the heart, so the heart becomes starved for oxygen. The part that has been starved is damaged beyond repair, but the heart can still beat effectively. |
