technical aspects of the ekg

EKGEKGPlain Plain and SimpleSimple

CHAPTER

Third Edition

Copyright ©2012 by Pearson Education, Inc.All rights reserved.

EKG Plain and Simple, Third EditionKaren M. Ellis

Technical Aspects of the EKG

4



The EKG MachineThe EKG Machine

• Electrically speaking, the heart is a transmitter and the EKG machine is the receiver



Figure 4-1 Man Attached to EKG Machine



Control FeaturesControl Features

• Chart speed: Regulates speed of EKG printout. Normal speed is 25 mm/second

• Gain: Regulates the amplitude of the EKG waves and complexes. Normal setting is 1

• Document any change in settings



Electrical SafetyElectrical Safety

• Macroshock: High-voltage shock that allows 110 volts to travel through skin– Caused by: Inadequate grounding of electrical

equipment (frayed/broken wires or cords, electrical outlet damage, or other)

– Results in: Burns, neurologic damage, fatality




• Microshock: Smaller shock that travels up a conduit into the heart (pacemaker, etc.)– Caused by: Frayed grounding wire or other– Results in: Burns, neurologic damage, fatality




• ALWAYS CHECK FOR FRAYED WIRES OR COMPONENTS BEFORE DOING AN EKG

• NEVER USE A FAULTY MACHINE



ArtifactArtifact

• Unwanted jitter or interference on the EKG tracing

• Four kinds– Somatic tremors– Baseline sway– 60-cycle interference– Broken recording



Figure 4-2 Somatic Tremors Artifact



Figure 4-3 Baseline Sway



Figure 4-4 60-Cycle Interference



Figure 4-5 Broken Recording



TroubleshootingTroubleshooting

• Involves determining and alleviating the cause of artifact and recording errors

• Find the common limb of the affected leads and direct corrective efforts there

• May involve replacing electrode patches or reattaching loose or detached wires

• If artifact is on cardiac monitor in hospital, can change lead selector switch to monitor rhythm in another (clearer) lead



Artifact Troubleshooting Artifact Troubleshooting Practice 1Practice 1



Artifact Masquerading as Artifact Masquerading as AsystoleAsystole

• The rhythm looks like asystole (flat-line), but is artifact. Several monitor wires and patches were loose or disconnected. The patient was fine



Figure 4-7 Artifact Masquerading as Asystole (Flat-Line)



True AsystoleTrue Asystole

• The next slide is true asystole. This patient has no pulse and is not breathing. It looks the same as the previous strip, doesn’t it?



Figure 4-8 True Asystole



Toothbrush TachycardiaToothbrush Tachycardia

• The next slide is from a man who was brushing his teeth. The arm movements jiggled the EKG wires and created what appeared to be a dangerous rhythm



Figure 4-9 “Toothbrush Tachycardia” masquerading as a rhythm



True Lethal RhythmTrue Lethal Rhythm

• The next slide is a true rhythm. Looks a lot like the previous strip, doesn’t it?



Figure 4-10 Ventricular Tachycardia, a potentially lethal rhythm



CPR ArtifactCPR Artifact

• Seen during CPR• Can resemble ventricular rhythms• May cause health care personnel to think

there is a rhythm when there is not

technical aspects of the ekg

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