The standard human heart contains four chambers that work together to force blood through the vessels that travel throughout the body. A basic understanding of how these chambers function is important for EKG technicians because it allows medical professionals to provide high quality and comprehensive care to individuals who suffer from a wide variety of heart diseases. Demand for cardiac care has been increasing dramatically over the past several years because of a higher prevalence of heart disease secondary to diet and exercise related illnesses such as diabetes, high blood pressure, and obesity. These conditions can negatively affect the cardiac cells, nerve fibers, and blood vessels that are critical to survival. Individuals who take the time to understand how the heart works will develop a greater appreciation for the complexity of the circulatory system and will be better prepared to educate patients about the importance of heart health. The human heart is generally divided down the middle into two right chambers and two left chambers. Opposite sides of the heart are separated by a thick wall of tissue that prevents the mixing of deoxygenated blood that is received from the body and oxygenated blood that is received from the lungs. Each side of the heart consists of a smaller chamber known as an atrium and a larger chamber known as a ventricle. The atrium rests on top of the ventricle and is tasked with filling the ventricle with blood before it contracts and forces blood out of the heart. The separation of the two sides of the heart allows the right atrium and ventricle to pump deoxygenated blood to the lungs while the left atrium and ventricle pumps oxygenated blood to the body. In some cases, a defect may exist between the two sides of the heart that allows for the mixing of blood and a resultant decrease in the delivery of oxygen and nutrients to the body. In order to pump blood in the proper direction, it is critically important that the contraction of the ventricles occur after that of the atria. This coordinated contractile effort allows the atria to fill the ventricles with blood before the blood is pumped to the lungs and the rest of the body. A special collection of nerve tissue known as the sinoatrial (SA) node is responsible for creating the electrical signal that tells the cardiac cells to contract. The SA node is strategically located at the top of the right atrium so that a delay in conduction exists between the atria and the ventricles. The SA node is connected to a second collection of nerve tissue known as the atrioventricular (AV) node through a series of nerve fibers. The AV node is located near the convergence of the four chambers and is responsible for coordinating the conduction of the contractile signal along ventricular nerve branches. Cardiac contractile signals are created in the SA node at a rate of 60 – 100 times each minute depending on factors such as contractile efficiency and oxygen demands in the body. These signals are conducted through the atria and ventricles along nerve branches. As the electrical impulses travel through the heart, they are rapidly disseminated among all contractile cells in a given chamber through a series of intercellular communications known as gap junctions. These junctions ensure that all cells receive the signal to contract at the same time so that the maximum amount of force can be exerted on the blood contained in the chamber. Diseases that damage contractile cardiac cells and nerve fibers may interfere with the ability of the heart to conduct electrical signals and may compromise the ability of a chamber to exert the force required to maintain optimal contractile efficiency. This type of condition will result in abnormal tracings on the electrocardiogram that allow technicians and advanced medical personnel to perform an accurate ECG interpretation before developing a plan for long-term management. Individuals who are interested in learning more about how the heart works as well as employment options as an EKG technician are encouraged to visit www.ekgtechniciansalary.org where they will find extensive information on topics relevant to cardiac conduction and contraction along with facts relating to the technician education, training, and certification requirements in all 50 states. A career in the cardiovascular department is a rewarding opportunity for an individual to have a positive influence on the health and well-being of others while making a living. Those who enjoy interacting with others and contributing to the community will find that this career path is both personally and professionally satisfying.
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