Cardiac arrest happens when the heart suddenly stops beating. This can be caused by a heart attack in which the heart’s demand for oxygen is not met and heart muscle begins to die. With cardiac arrest, normal circulation of blood stops, because of a failure of the heart to contract. Cardiac arrest is a medical emergency. The most common cause of cardiac arrest is Coronary Artery Disease. Less common causes include major blood loss, lack of oxygen, very low potassium, heat failure and intense physical exercise.
Causes of cardiac arrest
- Coronary Artery Disease – Coronary Artery Disease (CAD), also known as ischemic heart disease, is responsible for 62 to 70 percent of all SCD ( sudden cardiac death). CAD is a much less frequent cause of SCD in people under age 40. Cases have shown that the most common finding at postmortem examination of sudden cardiac death is chronic high-grade stenosis of at least one segment of a major coronary artery, the article that supply the heart muscle with its blood supply.
- Structural Heart Disease – Structural heart diseases are not related to CAD account for 10 percent of all SCDs. Left ventricular hypertrophy is thought to be a leading cause of structural heart disease in the adult population. This is the most commonly result of longstanding high blood pressure which has caused secondary damage to the wall of the main pumping chamber of the heart, the left ventricle. In the year 1999 United States has found that this accounted to over 30 percent of structural heart disease for those under 30 years. a study of military recruits age 18-35 found that this accounted for over 40 percent of SCDs. Congestive heart failure increases the risk of SCD.
- Non-cardiac arrest – Sudden cardiac arrest due to non-cardiac causes accounts for the remaining 15 – 25 percent. The most common non-cardiac causes are trauma, major bleeding, overdose, drowning etc. cardiac arrest can also be caused by poisoning or lighting.
Signs and Symptoms
Cardiac arrest is not preceded by any warning symptoms in approximately 50 percent of people. For those who do experience symptoms, they will be non-specific, such as new or worsening chest pain, fatigue, shortness of breath, weakness and vomiting. When cardiac arrest occurs, the most obvious sign of its occurrence will be the lack of a palpable pulse in the victim. The main criterion for diagnosing a cardiac arrest, as opposed to respiratory arrest, which shares many of the same features, is lack of circulation, however there are a number of ways of determining this. Near-death experience are reported by 10 to 20 percent who survive cardiac arrest.
Certain strategies to prevent cardiac arrest are with the prime causes of cardiac arrest being ischemic heart disease, efforts to promote a healthy diet, exercise, and smoking cessation are important. For people at risk of heat disease, measures such as blood pressure control, cholesterol lowering are used. An implantable cardioverter defibrillator is a battery-powered device that monitors electrical activity in the heart and when an asystole is detected is able to deliver an electrical shock to terminate the abnormal rhythm. ICDs are used to prevent sudden cardiac arrest. Numerous studies have been conducted on the use of ICDs for the secondary prevention of SCD. These studies have shown improved survival with ICDs compared to the use of anti-arrhythmic drugs. Primary prevention of SCD with ICD therapy for high-risk patient population had similarly shown improved survival rates in a number of large number of studies. Th high-risk patient populations in these studies were defined as those severe ischemic cardiomyopathy.