Copyright ©2012 by Pearson Education, Inc. All rights reserved. EKG Plain and Simple, Third Edition...

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

EKG Plain and Simple, Third EditionKaren M. Ellis

Escape and UsurpationEscape and Usurpation

• Escape: Predominant pacemaker slows, lower pacemaker takes over at slower rate. An escape beat is a beat that comes in after a pause

• Usurpation: Irritable lower pacemaker takes control and becomes new pacemaker at a faster rate, suppressing or inhibiting the previous pacemaker



Figure 2-11 Escape



Figure 2-12 Usurpation



EKG PaperEKG Paper

• Graph paper that EKGs are printed on• Divided into small blocks 1 millimeter in

height and width• Counting horizontally measures time

(intervals)• Counting vertically measures amplitude



Figure 2-13 EKG Paper



EKG Paper DelineationsEKG Paper Delineations

• One small block is 0.04 seconds• Five small blocks = one big block• One big block = 0.20 seconds• 25 small blocks = 1 second• Five big blocks = 1 second• 1500 small blocks = 1 minute• 300 big blocks = 1 minute



12-Lead EKGs and Rhythm Strips12-Lead EKGs and Rhythm Strips

• 12-Lead EKG: Printout of the heart’s electrical activity viewed from 12 different angles as seen in 12 different leads

• A lead is an electrocardiographic picture of the heart’s electrical activity

• Rhythm Strip: Printout of only one or two leads at a time



Figure 2-14 (A) Single- and (B) double-lead rhythm strips.



Benefit of Double-Lead StripsBenefit of Double-Lead Strips

• Both leads show the same rhythm, just viewed from two different angles

• Therefore both leads have the same rhythm, intervals, and heart rate



Benefit of Double-Lead StripsBenefit of Double-Lead Strips

• Two leads provide twice the chance of identifying the rhythm. For example, P waves may not be visible in one lead, but are very clear in the other

• Having two leads shows how the same rhythm can look different in different leads



Figure 2-15 12-Lead EKG



IntervalsIntervals

• Measurement of time between the P-QRS-T waves and complexes

• Measurements allow determination of heart’s efficiency at conducting its impulses down the pathway



IntervalsIntervals

• PR: Measured from beginning of P to beginning of QRS

• QRS: Measured from beginning of QRS to its end

• QT: Measured from beginning of QRS to end of T wave



Figure 2-16 Intervals



Intervals Practice: Enlarged Intervals Practice: Enlarged Rhythm Strip 1Rhythm Strip 1

PR__________ QRS__________ QT__________




PR__________ QRS__________ QT__________

Copyright ©2012 by Pearson Education, Inc. All rights reserved. EKG Plain and Simple, Third Edition...

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