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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
Copyright ©2012 by Pearson Education, Inc.All rights reserved.
EKG Plain and Simple, Third EditionKaren M. Ellis
Figure 2-11 Escape
Copyright ©2012 by Pearson Education, Inc.All rights reserved.
EKG Plain and Simple, Third EditionKaren M. Ellis
Figure 2-12 Usurpation
Copyright ©2012 by Pearson Education, Inc.All rights reserved.
EKG Plain and Simple, Third EditionKaren M. Ellis
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
Copyright ©2012 by Pearson Education, Inc.All rights reserved.
EKG Plain and Simple, Third EditionKaren M. Ellis
Figure 2-13 EKG Paper
Copyright ©2012 by Pearson Education, Inc.All rights reserved.
EKG Plain and Simple, Third EditionKaren M. Ellis
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
Copyright ©2012 by Pearson Education, Inc.All rights reserved.
EKG Plain and Simple, Third EditionKaren M. Ellis
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
Copyright ©2012 by Pearson Education, Inc.All rights reserved.
EKG Plain and Simple, Third EditionKaren M. Ellis
Figure 2-14 (A) Single- and (B) double-lead rhythm strips.
Copyright ©2012 by Pearson Education, Inc.All rights reserved.
EKG Plain and Simple, Third EditionKaren M. Ellis
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
Copyright ©2012 by Pearson Education, Inc.All rights reserved.
EKG Plain and Simple, Third EditionKaren M. Ellis
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
Copyright ©2012 by Pearson Education, Inc.All rights reserved.
EKG Plain and Simple, Third EditionKaren M. Ellis
Figure 2-15 12-Lead EKG
Copyright ©2012 by Pearson Education, Inc.All rights reserved.
EKG Plain and Simple, Third EditionKaren M. Ellis
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
Copyright ©2012 by Pearson Education, Inc.All rights reserved.
EKG Plain and Simple, Third EditionKaren M. Ellis
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
Copyright ©2012 by Pearson Education, Inc.All rights reserved.
EKG Plain and Simple, Third EditionKaren M. Ellis
Figure 2-16 Intervals
Copyright ©2012 by Pearson Education, Inc.All rights reserved.
EKG Plain and Simple, Third EditionKaren M. Ellis
Intervals Practice: Enlarged Intervals Practice: Enlarged Rhythm Strip 1Rhythm Strip 1
PR__________ QRS__________ QT__________
Copyright ©2012 by Pearson Education, Inc.All rights reserved.
EKG Plain and Simple, Third EditionKaren M. Ellis
Intervals Practice: Enlarged Intervals Practice: Enlarged Rhythm Strip 2Rhythm Strip 2
PR__________ QRS__________ QT__________
Copyright ©2012 by Pearson Education, Inc.All rights reserved.
EKG Plain and Simple, Third EditionKaren M. Ellis
Intervals Practice: Enlarged Intervals Practice: Enlarged Rhythm Strip 3Rhythm Strip 3
PR__________ QRS__________ QT__________