Unit 4 EKG Interpretation PDF

Preview

Summary

Unit 4 EKG Interpretation...

Description

Unit 4: EKG Interpretation Introduction   

What is an ECG? o Electrocardiogram Why is it important to be able to read ECG strips? What does arrhythmia or dysrhythmia mean in reference to the ECG?

Cardiac Monitoring 

   

Continuous cardiac monitoring via three-lead or five-lead systems o Three-lead o Five-lead  Clouds over grass  white (RA) over green (RL)  Smoke over fire  black (LA) over red (LL) Record and interpret 6-second strip every 4 hours Monitor ST segment and look for elevation/depression o Could indicate injury or ischemia Monitor for dysrhythmias Daily 12-lead ECG for cardiac patients

12-Lead EKG 

 

Leads o 3 standard limb leads o 3 augmented limb leads o 6 precordial leads Impulses toward electrode o Positive QRS Complex Impulses away from electrode o Negative QRS Complex

Electrical Current   

Limb Leads Augmented Leads Precordial Leads

EKG Graph Paper 

Graph paper o Used to standardize tracings o Vertical boxes measure voltage/amplitude o Horizontal boxes measure time o Width of each small box = 0.04 seconds o Width of each large box (5 small boxes) = 0.20 seconds o 5 large boxes (each consisting of 5 small boxes) = 1 second  15 large boxes = 3 seconds  30 large boxes = 6 seconds

Normal EKG Tracing 

 









P Waves o Conduction  First wave in the cardiac cycle  Represents atrial depolarization and spread of the impulse throughout the right and left atria o P waves occur regularly and appear similar in size, shape, and position o Normally, P Wave indicates the SA node discharged a beat o Should not exceed 3 boxes high (amplitude) PR Interval Q Waves o Conduction  The first negative, or downward, deflection following the P wave  ALWAYS a negative waveform o Physiological Q Waves  A normal Q wave is less than 25% of the height of the R wave  A normal Q wave duration does not exceed 0.04 seconds R Waves o Conduction  The first positive, or upward, deflection following the P wave  ALWAYS positive o The largest wave in the QRS Complex o Represents early ventricular depolarization o R Wave Progression S Wave o A negative waveform following the R wave  ALWAYS negative o R and S waves represent simultaneous depolarization of the left and right ventricles T Waves o Conduction  Represents ventricular repolarization o The beginning of the T wave is identified as the point where the slope of the ST segment appears to become abruptly or gradually steeper o Abnormal T waves  It may be difficult to clearly determine the onset and end of the T wave  Caused from electrical imbalances, myocardial ischemia, or injury U Waves o Conduction  Sometimes seen after the T wave  Represents ventricular repolarization of small segment of ventricles





o Unknown origin  May be normal  May indicate hypokalemia, cardiomyopathy, and digoxin toxicity o Abnormal U Waves  Seen in hypokalemia ST Segment o Conduction  The portion of the ECG tracing between the QRS Complex and the T wave  Represents the early part of repolarization of the right and left ventricles o Abnormal ST segment  The PR segment is used as the baseline from which to evaluate the degree of displacement of the ST Segment from the isoelectric line (elevation or depression)  Measure at the point 0.04 second (one small box) to the end of the QRS Complex  The ST segment is considered:  “elevated” if the segment deviates above baseline 1 mm  STEMI  “depressed” if the segment deviates below baseline 1 mm  NSTEMI QT Interval o QT Interval measures the total time taken for ventricular depolarization and repolarization o Beginning of QRS Complex and end of T Wave o 0.32-0.50 seconds  preferably...