Essay Example on Define the electrocardiogram ECG

Left arm or under the left clavicle Same as for aVR aVF Average potential of right arm or under the right clavicle and left arm or under the left clavicle Left leg or lowest rib left midclavicular line Same as for aVR V1 Average potential of right arm left arm and left leg Fourth intercostal space ICS right sternal border Same as for aVR V2 Same as for V1 Fourth ICS left sternal border Same as for aVR V3 Same as for V1 Midway between V2 and V4 Same as for aVR V4 Same as for V1 Fifth ICS left midclavicular line Same as for aVR V5 Same as for V1 Horizontal to V4 left anterior axillary line Same as for aVR V6 Same as for V1 Horizontal to V4 left midaxillary line Same as for aVR Examine the normal ECG pattern of one cardiac cycle The normal ECG pattern of one cardiac cycle is the P wave the QRS complex a T wave and sometimes a U wave Explain the cardiac events represented by each part of a normal pattern as seen on the ECG The ECG shows the P wave representing atrial depolarization the QRS complex representing ventricular depolarization a T wave representing ventricular repolarization Define depolarization and repolarization Depolarization occurs when negatively charged cells develop a positive charge Repolarization occurs when these cells return to their negative charge Explain the appearance and the cause of a U wave A U wave resembles the T wave but is smaller and is caused by a slowed or delayed repolarization of the purkinje fibers It can be mistaken for a P wave 

An irregular U wave can be caused by low potassium or other electrolyte imbalances Identify the time interval represented by each small square on the horizontal axis of ECG paper by each large block Each small box represents 0 04 seconds each large box represents 0 20 seconds Identify the voltage represented by each small square on the vertical axis of ECG paper by each large block Each small block represents 0 1mv each large box represents 0 5mv List the normal times of the P R interval QRS duration and QT interval The P R interval lasts 0 12 to 0 20 seconds the QRS duration lasts from 0 04 to 0 12 seconds and the QT interval lasts 0 36 0 44 seconds Age gender and other factors largely affect the time of the QT interval Explain the importance of checking the configuration and location of P waves QRS complexes ST segments and T waves The configuration and location of the P wave can display if the impulse is consistently coming from the SA node or if a ectopic focus is being detected The configuration of the QRS complexes can signify cell death dysrhythmia or a supraventricular impulse The ST segments can signify myocardial infarction pericarditis hyperkalemia or hypokalemia or ventricular hypertrophy T waves can signify myocardial infarction and ventricular hypertrophy