Cardiac arrest: causes, management, and outcomes

Heart Disease

Relationship between cardiac arrest and coronary cardiac disease

The heart is an essential organ in the human body, it keeps the individual alive. Understanding how the heart operates and functions is essential to help protect your heart from heart disease. Cardiac arrest and coronary heart disease are significant heart related illness that has a high mortality rate. It is important for individuals with pre-existing heart disease to understand the symptoms of cardiac arrest and coronary heart disease, since these are both leading causes of fatality in the United States. Understanding how the heart works, the individuals risk for heart disease, and how to prevent or delay heart disease is essential. In this paper I will address the relationship between cardiac arrest and coronary heart disease. I will also explain how the heart functions and discuss some ways of preventing cardiac arrest and coronary heart disease.

Cardiac Arrest

Cardiac arrest is a condition where there is a sudden loss of heart function in an individual. Cardiac arrest can occur in someone with a history of heart disease or someone who have had no previous history with cardiac disease. Cardiac arrest happens to both males and females of all ages. The most popular cause of death relating to cardiac arrest is coronary disease. Cardiac arrest occurs in the human body when the cardiac vascular system ceases its functions, the brain cells that requires aerobic respiration to make ATP will stop functioning and die within four to six minutes (Martini & Nath, 2009).

A cardiac arrest is usually described as a sudden collapse for a patient who is non-responsive and has abnormal breathing. It is important to recognize the signs of cardiac arrest for survival. "Cardiac arrest requires prompt cardiopulmonary resuscitation (CPR), advance cardiac life support (ACLS) and optimal post-cardiac arrest care" (McDonough, 2009).

The cytoplasm of a damaged cardiac muscle cell differs from the cytoplasm of a normal cardiac muscle cell. When there is a decrease in oxygen, the cardiac muscle cells becomes highly dependent on anaerobic metabolism to meet the energy needs. In time the cytoplasm accumulates an abundance of enzymes associated with anaerobic energy production. The deterioration of the membrane of damaged cardiac muscle cells allows enzymes to enter the surrounding intercellular fluids. The presence of these enzymes in the circulation indicates that an infarction has occurred. There are diagnostic blood tests that can be performed to detect the existence of these enzymes in the cardiac circulation. The most common enzymes that may appear are: cardiac troponin T, cardiac troponin I, and the MB isomer of a special form of creatine phosphokinase that occurs only in cardiac muscle called CK-MB.

Coronary Artery Disease

Coronary artery disease is a condition where plaque builds up in the coronary arteries. Plaque buildup is caused by cholesterol deposits in the coronary arteries causing it become narrow and eventually blocked (CDC, 2010). The narrowing of the arteries over time is a condition known as atherosclerosis. The most common symptom of coronary artery disease is angina, which manifest itself with chest pain because of the lack of blood to the heart muscles (Dewey et. al., 2004). Coronary artery disease can weaken the heart muscles, leading to heart failure, where the heart cannot pump blood in a normal way. Other patients first symptom of coronary artery disease is a heart attack, patients can experience a high level of pain, burning or pressure in the chest. These symptoms get stronger with exertion, consumption of a large meal, emotion or exposure to cold air. The pain is usually described as a feeling of suffocation, or shortness of breath. The foundation of the pain is in the sternum; however the pain typically travels to the chest, shoulders, jaw, arms, and entire upper body including the jaw. When these symptoms are recognized early, the patient can get medical intervention which could save their lives. Unrecognized and untreated symptoms could be fatal. Coronary artery disease leads to heart attack. When there is blockage in the arteries, the blockage can rob the heart muscle of its blood supply causing the muscle to die. The death of this part of the heart muscle is known as a heart attack. In the United States coronary artery disease is the most common type of heart disease. (CDC, 2010).

Heart Attack

A myocardial infarction is commonly known as a heart attack. A heart attack is where part of the circulation becomes blocked which leads to a lack of oxygen in the cardiac muscle cells, causing them to die. The death of the cardiac muscle cells creates an infarct which is the buildup of nonfunctional cells. Coronary artery disease is the most common cause of heart attack. Blockage in the heart is a severe problem, the severity of the disease is determined based on the location of the blockage. If the blockage is located near the start of one of the coronary arteries, the disease can spread throughout the heart causing the heart to stop beating. If the blockage is a small blockage, affecting one of the smaller arterial branches the individual could survive the heart attack with the right intervention and care. This type of disease is not curable, although the individual can survive this trauma; much care is needed to assist with the complications from this medical condition. As a result of this complication other medical problems can arise; such as a scar tissue can be formed in the damaged area which could lead to irregular heartbeat, other heart vessels can become constricted causing additional circulatory problems (Martini & Nath, 2009). Individuals who have suffered a heart attack require proper post intervention care to ensure stability of the heart after heart attack.

Myocardial infarctions are usually caused by blockages in the heart, such as those in coronary artery disease (CAD). The formation of plaque in the heart is also a great risk factor, this condition is called coronary thrombosis. When a vessel is already affected and narrowed by plaque formation, a sudden spasm in the smooth muscles of the vascular wall could cause blockage in the heart. Although pain is not always associated with heart attack an individual with this type of blockage will experience pain, which will persist even when they are resting. In some types of heart attack the individual feels an enormous amount of pain in the chest and arm, while in some other types of heart attack there is no pain (silent heart attack). When there is pain present the individual takes it as a sign and gets treatment, whereas in the silent heart attack there are no obvious symptoms and this could be deadly. Roughly about 25% of heart attacks go unnoticed and untreated (Martini & Nath, 2009).

Reality of Heart Disease

Getting regular checkups and knowing your risk for heart disease is extremely important. Understanding the symptoms of a heart attack could help save your life. Approximately 25% of myocardial infarction patients die before receiving medical intervention and 65% of myocardial infarction deaths among individuals under the age of 50 years, happen within an hour of the first infarction (Martini & Nath, 2009). The fundamental goals of treatment are to limit the size of the infarction, avoid additional complications by preventing irregular contractions, improve circulation with vasodilators, provide relief from the pain, decrease cardiac workload and hopefully eliminate the cause of the circulatory blockage. Patients must be treated with anticoagulants to help prevent the formation of new thrombi and clots. If anticoagulants are given within the first six hours after a myocardial infarction it can reduce the extent of damage. Patients who have suffered a myocardial infarction should be treated with daily usage of an anticoagulant such as Coumadin or Aspirin, in some cases patients are treated with both depending on their condition. This is recommended to prevent further blockage, since research suggests about 20% of patients circulatory blockage will reappear (Martini & Nath, 2009).

Approximately 1.3 million myocardial infarctions occur in the United Sates annually and about 50 die within a year of the incident (CDC, 2010). The mortality rate for women and heart attack is higher than that of men although more men suffer from heart attacks. Health care professionals believe the mortality rate for women under 70 is higher because heart disease in women is not diagnosed as early as men and is usually not treated as aggressively as in men. In the last several years there has been a great movement about brining awareness of heart disease for women.

Anatomy of the Heart

Understanding the anatomy of the heart is essential for preventing heart attacks and protecting yourself from heart disease. The heart is the pump of the cardio vascular system; it pumps the blood that is necessary for circulation in the body. The organs in the human body needs blood to stay alive and functional, therefore survival depends on the functionality of the heart. The arteries in the heart transport the blood from the heart to the rest of the body and then the blood returns to the heart through the veins. Essential parts of the heart are capillaries, arterioles and venous, which aids the functions of the heart. The capillaries have thin layers of walls, which functions mainly in the exchange of gas, it dissolves gas, aids in getting nutrients and discharge of waste products between the blood and its surrounding tissues (Martini & Nath, 2009). The heart is located in the chest, near the anterior chest wall directly posterior to the sternum. The arteries and veins of the heart are connected to the base of the heart. The base of the heart is at the level of the third costal cartilage, posterior to the sternum and centered about 1.2 cm to the left. The heart is divided into four parts, not equal mainly because the right side dominates the heart. The four chambers of the heart are responsible for pumping the blood from the heart to the lungs and the rest of the body. The two right and left atria have highly expandable walls that are relatively thin. The chambers of the heart must be filled with blood to avoid the atrium from deflating. The auride is the expandable extension of the atrium. The boundaries between the left and right ventricles are the interventricular sulus and posterior interventricular sulus.

The heart works continuously; it does not take a break. The cardiac muscles require a continuous supply of blood to continue its functions normally. The myocardium needs a separate flow of blood supply; it does not get its blood supply from the continuous flow of blood that goes through the four chambers of the heart. When the body is working harder than normal it demands a higher supply of oxygen, which significantly increases the blood flow to the myocardium. The coronary circulation of blood is made up of an extensive network of coronary blood vessels.

A normal heart beat originates from the cardiac muscle cells which are known as the specialized muscle cells and the contractile cells. The specialized muscle cells controls and regulates the heart beat and the contractile cells make the contractions that move the blood. The pacemaker is starting point of the heartbeat, which is generated from the SA node. An electrical impulse is generated from the pacemaker, then sent through the heart by the conducting system and distributed so that the stimulated contractile cells will push the blood at the right time, in the right direction. This function of the heart can be monitored by doctors using an electrocardiogram (EEG or EKG). A machine can be connected to the human skin which can read the electrical movements of the conducting system in the heart. This procedure can help medical professionals assess the condition of the heart.

The SA node creates impulses at regular intervals, which creates regular heartbeat, one after another for the entire life of the individual. There is a brief pause between each heartbeat. The cardiac cycle is the duration between the beginning of one heartbeat and the start of the following heartbeat. Although a heartbeat last a very short time, only about 370 msec, this is a very complex and important part of the bodily function. The cardiac cycle consists of periods of alternating cycles of contractions followed by relaxations repeated constantly. The chambers of the wall contracts and forces the blood into the nearby chambers or arterial trunk during the systole contraction. After the systole period the muscles of the heart relaxes which is known as the diastole period, which enables the chambers of the heart to refill with blood and become prepared for the next cardiac cycle. The pressure in the heart chambers rises during the systole to facilitate the contraction and movement of blood, then it falls during the diastole when the heart muscles relaxes and waits for the next cycle. Blood moves from a chamber with more pressure to a chamber with less pressure. The pressure within the individual chambers pushes the blood out of the chamber into another adjacent chamber with less pressure. Interconnections between arteries are called arterial anastomoses. Because the arteries are interconnected in this way, the blood supply to the cardiac muscle remains relatively constant despite pressure fluctuations in the left and right coronary arteries as the heart beats. This is the same principle that governs the functionality of blood between atria and ventricles, ventricles and arterial trunks and between the atria and major veins.

The coronary arteries are located at the aortic sinuses, which is the bottom of each aorta. The blood pressure in the coronary arteries is at its highest peak during the system circuit. With each contraction of the ventricles blood rushes into the aorta. The rush of blood into the aorta creates elevated pressures in the aorta, which causes the walls of the aorta to stretch to accommodate the influx of blood. When the ventricles relaxes during the cardiac cycle, the flow of blood into the aorta ceases which causes a decline in pressure and the aorta wall recoils which is called the elastic rebound. During the elastic rebound blood is pushed in both directions, forward into the systemic circuit and backward through the aortic sinuses which go into the coronary arteries. This process of increase of blood pressure and elastic rebound keeps the steady flow of blood to the cardiac muscle tissues, ensuring the cardiac muscles have the necessary blood supply to continue its normal functions. Myocardial blood flow is different, it consists of peaks during the period where the heart muscles are relaxed and then it ceases when the heart muscles contracts.

Preventing Heart Attacks

There are many ways to protect ourselves from going into cardiac arrest. Understanding the human body and how the cardio vascular system functions will help to prevent coronary cardiac disease. Coronary Artery Disease is the most frequent cause of heart attack in the United States. As individuals we should become familiarize with the anatomical, functional and pathological aspects of coronary cardiac disease. Individuals with a pre-existing cardiac disease or those that are at risk for cardiac disease should become educated with the subject to prevent cardiac arrest. There is a relationship between growth from childhood to adulthood and cardiovascular risk factors. Some of the factors influencing cardiovascular risks are; blood pressure, plasma glucose, insulin and apoliprotein B, hypertension, obesity, and diabetes (Goodwin & Sharp, 1992). Individuals with any one of these risk factors should be concerned, individuals with more than one of these risk factors are more at risk for heart disease.