![]() The SA node acts independently of the brain to generate electricity for the heart to beat. The heart has its own automatic pacemaker called the sinaoatrial, or SA node, located in the right atrium. ![]() The right ventricle then pumps blood through the pulmonary artery to the lungs where carbon dioxide is stripped off, oxygen is replaced, and the cycle begins again.The blood enters the right atrium though the vena cava, where it is collected and pumped to the right ventricle. Blood that returns to the heart is depleted of oxygen and carries carbon dioxide, the waste product of metabolism. ![]() This blood supplies organs and cells with oxygen and nutrients necessary for metabolism. Blood then flows into the left ventricle where it is pumped into the aorta and is distributed to the rest of the body.Oxygen-rich blood from the lungs enters the left atrium through the pulmonary veins.The right side of the heart collects blood from the body and pumps it to the lungs while the left side of the heart receives blood from the lungs and pumps it to the body.īlood flows through the body in the following way: The heart has four chambers - the right and left atrium and the right and left ventricle. What Does the Heart Look Like and How Does It Work? This kind of monitoring does not constitute a complete ECG.A heart monitor only measures the rate and rhythm of the heartbeat.By comparison, a heart monitor requires only three electrode leads – one each on the right arm, left arm, and left chest.The printed view of these recordings is the electrocardiogram.The signals received from each electrode are recorded.An electrode lead, or patch, is placed on each arm and leg and six are placed across the chest wall.Ten electrodes are needed to produce 12 electrical views of the heart.A standardized system has been developed for the electrode placement for a routine ECG.The electrocardiogram can measure the rate and rhythm of the heartbeat, as well as provide indirect evidence of blood flow to the heart muscle.The heart is a two stage electrical pump and the heart's electrical activity can be measured by electrodes placed on the skin.Numerous textbooks are devoted to the subject. While it is a relatively simple test to perform, the interpretation of the ECG tracing requires significant amounts of training. The electrocardiogram (ECG or EKG) is a diagnostic tool that is routinely used to assess the electrical and muscular functions of the heart. ![]() In some facilities and in certain circumstances, a third agent called thallium-201 might be used instead.Picture of the basic anatomy of the heart In most cases, the radiopharmaceutical used is called 99mTc sestamibi or 99mTc tetrafosmin. The camera or scanner rotates around the chest, and three-dimensional images of the heart are formed from the gamma rays passing through the body having been released from the radiopharmaceutical. While the patient is lying down on a scanner bed, a gamma camera or scanner is positioned in front of the heart. Differences in blood flow to different parts of the heart muscle can be shown more clearly when the blood flow is increased after exercise.īefore the images are taken, a radioactive medication (radiopharmaceutical) is injected into a vein, usually in the arm, which then passes through the blood stream and concentrates in the heart. The stress is in the form of exercise on a treadmill or exercise bike, or if this is not possible, by using medication to increase the blood flow to the heart. Images (or pictures) are taken of the heart while at rest and after the heart is stressed.
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