Perform an EKG Examination

Perform an EKG examination I. Theoretical Concepts The system consists of: a. SA node: located at the junction between the superior vena cava and the right atrium. Cells in the SA node automatically and regularly emit impulses with a frequency of 60100x/minute. b. AV node: located between the coronary sinuses on the posterior wall of the right atrium. The cells in the AV node emit lower impulses than the SA node, namely 40-60x/minute. c. Bundle of His: The AV node then becomes the bundle of His which penetrates the tissue separating the atrial myocardium and ventricular myocardium, then travels to the ventricular septum which then branches into the right bundle (Right Bundle Branch) and the left bundle (Left Bundle Branch). RBB and LBB then go to the endocardium of the right and left ventricles, these bundles branch into Purkinje fibers II. ECG SUPPORT There are 2 types of ECG pad leads: 1. Bipolar leads These leads only record the potential difference of 2 electrodes, these leads are marked with Roman numerals I, II and III. a. Viewpoint I Recording the potential difference between the right hand (RA) and the left hand (LA), where the right hand is negatively charged (-) and the left hand is positively charged (+). b. Viewpoint II Recording the potential difference between the right hand (RA) and the left leg (LF), where the right hand is negatively charged (-) and the left leg is positively charged (+) c. Viewpoint III Recording the potential difference between the left hand (LA) and the left leg (LF), where the left hand is negatively charged (-) and the left leg is positively charged (+). 2. Unipolar Lead This unipolar lead is divided into 2 leads, namely: a. Extremity unipolar leads 1) aVR interface Recording the electrical potential on the right hand (RA) where the right hand is positively charged (+), the left hand and left foot form indifference electrodes. 2) aVL lead Recording the electrical potential on the left hand (LA), where the left hand is positively charged (+), the right hand and left foot form indifference electrodes 3) aVF lead Recording the electrical potential on the left leg (LF), where the left leg is positively charged (+), the right hand and left hand form indifference electrodes. b. Precordial unipolar leads Recording the heart's electrical potential with the help of exploratory electrodes placed in several places on the chest wall. Indifference electrodes are obtained by combining the three limb electrodes Location of Stake: V1 : IV intercostal space right sternal line V2 : IV intercostal space left sternal line V3 : Midway between V2 and V4 V4 : V intercostal space, left midclavicular line V5 : Parallel to V4, anterior axillary line V6 : Parallel to V5 mid axillary line III. ECG curve The ECG curve describes the electrical processes that occur in the atria and ventricles. This electrical process consists of: - Atrial depolarization - Atrial repolarization: small intensity and coincides with ventricular depolarization which has a much greater intensity. - Ventricular depolarization - Ventricular repolarization 1. P waves The P wave is a picture of the normal P wave atrial depolarization process: -Width less than 0.12 seconds -High is less than 0.3 milliVolts -Always positive in lead II -Always negative in lead aVR 2. QRS waves This is a picture of the normal QRS wave ventricular depolarization process: -Width 0.06 – 0.12 seconds -Height depends on lead a. The Q wave is the first negative deflection of the QRS wave. Normal Q waves: width less than 0.04 seconds, height/depth less than 1/3 the height of R b. The R wave is the first positive deflection of the QRS wave. Waves are generally positive in leads I, II, V5 and V6. In aVR leads, V1 and V2 are usually only small or absent. c. The S wave is the negative deflection after the R waveIn leads aVR and V1 the S waves appear deep, from V2 to V6 they will appear to progressively disappear or decrease in depth 3. T waves Is a picture of the process of ventricular repolarization. Generally positive T waves in leads I, II, V3-V6 and inverted in aVR. 4. U Wave Is a wave that occurs after the T wave and before the next P wave. The cause of U waves is still unknown but is thought to be due to slow repolarization of the interventricular conduction system. 5. PR interval The PR interval is measured from the P wave surface to the QRS wave surface. Normal values range from 0.12-0.20 seconds. 6. ST segment The ST segment is measured from the end of the S wave to the beginning of the T wave. This segment is normally isoelectric, but in the precordial leads it can vary from 0.5 to+ 2mm. The rising ST segment is calledST elevationand the one that goes down is calledST depression. VI. ECG indications An electrocardiogram does not directly assess cardiac contractility. However, an ECG can provide a comprehensive indication of the rise and fall of contractility. Analysis of a number of depolarization and repolarization normal waves and vectors yields important diagnostic information. -It is the gold standard for the diagnosis of cardiac arrhythmias -The ECG guides the level of therapy and risk for patients with suspected acute myocardial infarctio -ECG helps find electrolyte disturbances (e.g. hyperkalemia and hypokalemia) -ECG allows discovery of conduction abnormalities (e.g. right and left bundle branch blocks) -ECG is used as a screening tool for ischemic heart disease during cardiac stress testing -ECG is sometimes useful to detect non-cardiac disease (e.g. pulmonary embolism or hypothermia) VII. ECG Recording Procedure 1. Tool Preparation a. ECG machine equipped with: - Cable for power source - Cable for earth (ground) - Electrode cables: extremities, chest - Extremity electrode plate/rubber binding - Chest electrode suction balloon b. Jelly c. Tissue paper d. Alcohol swab e. Marker (for serial ECG recording) f. ECG paper 2. Patient Preparation a. Explanation: purpose of the examination, things to pay attention to when recording b. The chest wall should be open 3. How it Works a. Turn on the EKG machine b. Lay the patient quietly on a large bed, hands and feet do not touch each other c. Clean the chest, wrists and feet with alcohol cotton (if necessary shave the chest and wrists) d. The four extremity electrodes are given jelly e. Attach the four extremity electrodes to both wrists and feet f. The chest is given jelly according to the location for electrodes V1-V6 g. Attach the chest electrode by pressing the sucker h. Make 3 calibrations i. Record each 3-4 beat lead j. After completing recording all leads, recalibrate k. Jelly is cleaned from the patient's body l. Tell the patient that the recording is complete m. Turn off the EKG machine n. Note: Patient name; age; time, date, month and year of recording; name of each lead; recorder name o. Clean and tidy the tools 4. Attention a. Before working, check that the machine speed is 25mm/sec with a voltage of 1mVolt. If necessary, the calibration is reduced to ½ mVolt or enlarged to 2mVolt b. Avoid electrical and mechanical interference during recording c. When recording the nurse must face the patient