challenging cardiac arrhythmias: a case-based...
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Challenging Cardiac Arrhythmias:A Case-based Approach
Mary G Carey, PhD, RN, CNS, FAHAAssociate Director, Clinical Nursing Research Center, Strong Memorial Hospital
Associate Professor, School of NursingVermont sponsored New England Assembly of Nurse Anesthetists Fall Workshop
October 26, 2013© 2013 Mary G. Carey, PhD, RN, CNS, FAHA
Recommendations vary regarding initial competency
It is unknown what is neccessray to maintain competency
Major interpretation errors are common (4% to 33%) but adverse patient outcomes resulting from these errors are rare (<1%).
Computer analyses of ECGs are useful adjuncts but should not replace a qualified clinician in making patient decisions.
Evidence-Based Knowledge
The best way to avoid errors in interpreting ECGs, is to analyze an ECG systematically, step by step.
• Rate?• Regularity?• P waves?• PR interval?• QRS duration?
Calculate heart rate Regular or irregular Normal or absent
Narrow or wideFixed or variable
Interpretation?
The ECG PaperHorizontally (measure of time)
One small box - 0.04 seconds One large box - 0.20 seconds
Vertically (amplitude) One little box 1mm One large box 5 mm or 0.5 mV
Calculating Heart Rate
Option 1 Count the # of R waves in a 6 second rhythm
strip, then multiply by 10. Best used with irregular rhythms
Interpretation? 9 x 10 = 90 bpm
3 sec
3 sec
Option 2 Find a R wave that lands on a bold line. Count the # of large boxes to the next R wave. Best used with regular rhythms
R wave
Calculating Heart Rate
Marriott's Practical ElectrocardiographyGS Wagner & HJL Marriott
0.12-0.20 (3-5 boxes)
<0.12seconds (3 boxes)
Is the PR interval fixed or variable?
Fixed
Does every P wave cause a
QRS complex?
1st degree
Are some QRS complexes dropped?
2nd degree,Type II
Variable
Is the PR interval lengthening?
2nd degree, Type I
Is the PR interval random?
3rd degree
Flow Chart for Heart Blocks
Rhythm
60 bpm• Rate?• Regularity? Regular
Normal
Narrow
• P waves?• PR interval? Fixed but too long • QRS duration?
Interpretation? 1st Degree AV Block
Rhythm
50 with 6 sec strip30 with R toR• Rate?
• Regularity? Irregularnl, but 4th no QRS
Narrow
• P waves?• PR interval? Lengthens• QRS duration?
Interpretation? 2nd Degree AV Block, Type I
Wenckebach
Rhythm
40 bpm• Rate?• Regularity? Regular
Normal, some blocked
Narrow
• P waves?• PR interval? Fixed• QRS duration?
Interpretation? 2nd Degree AV Block, Type II
Rhythm
40 bpm• Rate?• Regularity? Regular
No relation to QRS
Wide
• P waves?• PR interval? None • QRS duration?
Interpretation? 3rd Degree AV Blockwith a Idioventricular Escape Rhythm
95 bpm• Rate?• Regularity? Irregular
Intermittent
Narrow & wide
• P waves?• PR interval? Fixed, nl or absent
• QRS duration?
Interpretation? Bigeminy with a ventricular couplet
24 year old trauma patient (lead I)
Bradycardia with early repolarization and premature junctional contractions (PJCs)
• Rate?
• Regularity?
• P waves?
• PR interval?
• QRS duration?
37-54 bpm
Regular, irregular
Normal, inverted
NarrowFixed
Tri- athlete
72 yo male, routine resting 12-lead ECG
Sinus rhythm at 80 bpm with a left bundle branch block (LBBB)
Fragmented QRS complexes (fQRS)
• Improved sensitivity and negative predictive value (Das, et al. 2006)
• Associated with adverse cardiac events (Pietrasiket al. 2007)
• Regional fQRS patterns predict regional infarction in the absence of Q waves (Mahenthiran, et al. 2007)
Characteristics of the 12-lead HolterECG in Professional Firefighters
National Institutes of Health Grants R21 NR011077
Mary G. Carey RN, CNS, PhDAssociate ProfessorThe State University of New YorkUniversity at Buffalo September 29, 2010
Single Lead Monitoring Lead II
Interpretation? Sinus Rhythm with baseline wander and artifact
60 bpm• Rate?• Regularity? Regular
Normal
Narrow
• P waves?• PR interval? Fixed• QRS duration?
Injury is regional, not global
Interpretation? Sinus Rhythm at 60 bpm an acute anterior lateral wall infarction
Challenging Cardiac Arrhythmias:A Case-based Approach
Mary G Carey, PhD, RN, CNS, FAHAAssociate Director, Clinical Nursing Research Center, Strong Memorial Hospital
Associate Professor, School of NursingVermont sponsored New England Assembly of Nurse Anesthetists Fall Workshop
October 26, 2013© 2013 Mary G. Carey, PhD, RN, CNS, FAHA