Electrocardiogram(ECG) Prepared by Joycelyn Parazo-Reyes, RN MAN Electrocardiogram An electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a noninvasive transthoracic graphic produced by an electrocardiograph, which records the electrical activity of the heart over time is a test that checks for problems with the electrical activity of your heart. graph produced by an electrocardiograph records the electrical activity of the heart over time provides various waves and normal vectors of repolarization and repolarization of the myocardia does not directly assess the contractility of the heart, but gives a rough indication of increased or decreased contractility Its name is made of different parts: electro, because it is related to electrical activity cardio, Greek for heart gram, a Greek root meaning "to write" Depolarization It is the electrical activation of heart muscle cells is cause by an electrical process Contraction of the atrial muscle cells and pumping of blood from the atria to the ventricles immediately follow atrial activation or depolarization . Repolarization Electrical reverse process Immediately after depolarization of ventricular muscle cells. repolarization occurs . The two upper chambers are called atria. A natural electrical system causes the heart muscle to contract and pump blood through the heart to the lungs and the rest of the body. and the two lower chambers are called ventricles. Anatomy and Physiology The heart is a muscular pump made up of four chambers . . with many normal variations. This rate is set by a small collection of specialized heart cells called the sinoatrial (SA) or sinus node . Each beat of your heart is triggered by an electrical impulse generated from special cells in the upper right chamber of your heart The heart normally beats between 60 and 100 times per minute. “ It has "automaticity. Located in the right atrium. the sinus node is the heart's "natural pacemaker. ." meaning it discharges all by itself without control from the brain. and (2) an electrical impulse travels through the atria to reach another area of the heart called the atrioventricular (AV) node. which lies in the wall between the 2 ventricles. Two events occur with each discharge: (1) both atria contract. . From the AV node. causing them to contract and pump blood. an electrical wave travels to both ventricles. The AV node serves as a relay point to further propagate the electrical impulse. . 12 to 0. Intervals shorter or longer than this range indicate possible problems. . This delay is perfectly timed to account for the physical passage of the blood from the atrium to the ventricle.20 seconds. The normal delay between the contraction of the atria and of the ventricles is 0. . Ventricular contractions (both right and left) show as a series of 3 waves. Atrial contractions (both right and left) show up as the P wave. Q-R-S. known as the QRS complex. The ECG records the electrical activity that results when the heart muscle cells in the atria and ventricles contract. This reflects the electrical activity produced when the ventricles are recharging for the next contraction (repolarizing). The third and last common wave in an ECG is the T wave. . QRS. When viewed from multiple anatomic- electric perspectives (that is. . these waves can show a wide range of abnormalities of both the electrical conduction system and the muscle tissue of the heart's 4 pumping chambers. The electrical activity results in P. leads). and T waves that have a myriad of sizes and shapes. . or angina. Find the cause of unexplained chest pain. Indication of ECG 1. Check the heart's electrical activity. inflammation of the sac surrounding the heart (pericarditis). 2. which could be caused by a heart attack. irregular heartbeats (palpitations). such as shortness of breath. Find the cause of symptoms of heart disease. dizziness. 4. Find out if the walls of the heart chambers are too thick (hypertrophied). or rapid. .3. fainting. Check how well mechanical devices that are implanted in the heart. Check how well medicines are working and whether they are causing side effects that affect the heart.5. 6. such as pacemakers. . are working to control a normal heartbeat. high cholesterol. Check the health of the heart when other diseases or conditions are present.7. or a family history of early heart disease. such as high blood pressure. diabetes. cigarette smoking. . How ECG works! Sympathetic electrical impulses in the heart originate in the Sinoatrial node and travel through the heart muscle where they impart electrical initiation of systole or contraction of the heart . The electrical waves can be measured at selectively placed electrodes (electrical contacts) on the skin. Electrodes are placed on different sides of the heart measure the activity of different parts of the heart muscle Each heartbeat produces a set of P- QRS-T waves . An electrocardiogram — also called an ECG or EKG — records these electrical signals as they travel through your heart. . . . 12 lead ECG ECG leads : combination of electrodes that form an imaginary line in the body along which electrical signals are measured A typical ECG runs at a paper speed of 25 millimeters per second. translating to 0. • Each small block of ECG paper is is square millimeters.04 seconds or 40 milliseconds . • A large block has 5 small squares across. hence there are 5 large blocks per second . V2. and aVF. V5. V4. . and V6 The other points of view represent combinations of the pads placed on the arms and legs. III . These are called I. aVR. V3. These are called V1. II. 12 lead ECG Six of these points of view are the locations of the 6 pads placed across your chest. aVL. II. aVF • derived from limb leads but from different vectors • negative electrodes are a modification of Wilson's central terminal . aVL. a) Limb Leads I. III • first three leads forming the basis of Einthoven's triangle b) Augmented Limb Leads aVR. V2. V5. V6 • no augmentation required due to close proximity to the heart . c) Precordial Leads V1. V4. V3. . . . . . . . . beginning precedes ventricular contraction . ventricles begin to depolarize QRS complex : depolarization of ventricular myocardia . P wave : depolarization of the atrial myocardia . beginning precedes the onset of atrial contraction PR interval : atria contracts and begins to relax. length of time required for ventricular depolarization and repolarization T wave : repolarization of the ventricular myocardia . beginning precedes ventricular relaxation . QT interval : beginning of the QRS complex to the end of T wave . ECG is Interpreted by the following: Doctor such as an internist. or surgeon Trained nurses. paramedics . electrophysiologist. cardiologist. family medicine doctor. anesthesiologist. ECG Strips . The first deflection of the cardiac cycle 2. Represents depolarization of the atria 3. P wave 1. and ends when it returns to baseline . Begins as the waveform begins to leave the baseline. AV node. bundle branches. and Purkinje fibers . PR interval 1. Represents the time required for the electrical impulse to leave the SA node and travel through the atria. Measured from the beginning of the QRS as the first wave leaves the baseline to the J point . QRS complex 1. Represents ventricular depolarization 2. J point a) The junction between the QRS and the ST segment b) Where the last wave of the complex begins to flatten out at. or below the baseline c) Elevation or depression of the ST segment can make finding the J point difficult . above. Represents ventricular recovery or repolarization QT interval 1. Measures ventricular depolarization and repolarizatio . Represents the end of ventricular conduction T wave 1. ST segment 1. Represents the recovery period of the Purkinje fibers . U wave 1. ECG Machine . keys etc 5. avoid unnecessary movement . Instruct client to remain calm and still during the procedure. Procedure 1. Position Client on Supine procedure 3. coins. Ask client to remove metal. Explain the procedure to the client and attempt to allay anxiety 2. Inform the client that the procedure is painless and non-invasive 4. Place electrodes on the skin and attach to the monitor cable (chest. Prepare the skin on the chest for electrode attachment Cleanse the skin with alcohol Shave the area when necessary to improve skin electrode connection Place KY jelly for other electrode connection 7. Provide Privacy . arms and lower extremities 8.6. . Once finish. diagnosis. provide skin care 12. date and time . Observe the monitor for any changes in rate and rhythm 11.9. Document the results and evaluate client response on the procedure Documentation Name. age. Turn on the monitor and set the machine 10.