This document provides information on using EKGs to detect coronary ischemia during surgery. It reviews common EKG changes that indicate ischemia, injury, or infarction. It discusses evaluating patients' cardiac history and risk factors pre-operatively. During surgery, it recommends monitoring multiple leads, particularly leads II, III, and V5 to maximize detection of ischemia. While lead V5 is commonly used, evidence suggests combinations of precordial leads may be more sensitive. Continuous ST segment monitoring allows detection of subtle changes. EASI lead systems provide an alternative lead configuration that correlates well with standard 12-lead EKGs for identifying ischemia.

1. The Use of EKG to Detect
Coronary Ischemia: Pearls and
Pitfalls
NCANA District 3 & 4 Meeting
February 21, 2015
Karen Lucisano, CRNA, PhD

2. Lecture Objectives
• Review 12 Lead EKG changes which
may indicate myocardial ischemia, injury
or infarction
• Identify pre-existing EKG changes that
may affect the ability to detect coronary
ischemic changes
• Develop a plan to maximize the capability
of the EKG monitor to detect
intraoperative myocardial ischemia,
injury, or infarct

3. PRE-OPERATIVE
ASSESSMENT

4. Disease Prevalence
Are we likely to encounter this disease?
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6040a1.htm

5. Know the Big Picture
• Does my patient have known or
suspected coronary artery disease
– Determined by
• Patient history
• Chart Review
• 12 Lead EKG analysis
• If known what do we know about the
disease
– What vessels are affected
• LAD, LCX, RAD
– Has there been an infarct
• What is the current ejection fraction
– How well is the disease managed
• Meds
• Current symptoms
• Functional capacity

6. Know the Big Picture
• If suspected what are the risk factors
– Elevated cholesterol
– Hypertension‘
– Diabetes
– Overweight
– Smoking
– Sedentary lifestyle
– Unhealthy diet
– Stress
– Family history of coronary disease
– Age, gender
More risk factors=higher suspicion
http://www.nhlbi.nih.gov/health/health-topics/topics/hd

7. 7
EKG changes that indicate
low or no flow states

8. ISCHEMIA

9. 9
Causes of ST Segment
Depression

10. 10
Ischemic ST Depression

11. 11
Types of ST Depression &
Their Specificity for Ischemia

12. 12
T Wave Abnormalities

13. INJURY

14. Injury
Prinzmental’s Angina
Pericarditis
Ventricular Aneurysm
Early Repolarization
14
ST Segment Elevations
Causes

15. 15
Acute MI

16. 16
Prinzmetal’s Angina

17. 17
Pericarditis

18. 18
Ventricular Aneurysm

19. 19
Early Repolarization

20. INFARCTION

21. 21
Criteria for Acute MI Diagnosis
(in the absence of LVH & LBBB)
• ST elevation
– New ST elevation at the J point in two
contiguous leads with cut-points:
1. > 0.1 mV in all leads other than leads
V2-V3
2. V2-V3
a) Men: > 0.2 mV > 40; >0.25 < 40
b) Women: > 0.15mV
• ST depression and T wave
changes
• New horizontal or down sloping ST
depression > 0.5mV in two contiguous
leads and/or T inversion > 0.1 mV in two
contiguous leads with prominent R
waves or R/S ratio > 1
Thygesen,T., et al (2012). Third universal definition of myocardial
infarction. Journal of American College of Cardiology, 60(16), 1581-1598

22. 22
A Variety of QRS Mophologies

23. 23
Significant vs Non-Significant
Q waves

24. 24
Progression of an Infarct
Few
hours
2-3
days
Several
Weeks

25. 25
Myocardial vessels and their
distribution
anterior
inferior
II
III
aVF
V1---- V4
I
aVL

26. 26
Anatomy & Lead Correlation
High Lateral I & aVL
Low Lateral V5 & V6
Inferior
II, III & aVF Septal
V1 & V2
Anterior
V1-V4 or
V3 & V4

27. 27
Anterolateral Infarction

28. 28
Anterior Infarction

29. 29
Inferior Infarction

30. 30
Posterior Infarction

31. MI Detection and LBBB
• Any new onset of LBBB is suspicious
for MI
• ST segment abnormalities may reflect
altered ventricular depolarization
secondary to altered ventricular
repolarization.
– Represented by T wave depolarization and
ST segment deviation vector in the
opposite direction of Q wave vector
(discordant ST-segment elevation)
• Concordant ST-segment elevation
may indicate acute MI
– Sgarbossa’s Criteria may be used
maximize specificity
31
Sgarbossa E. B., Pinski S. L., Barbagelata A., Underwood D. A., Gates K. B., Topol E. J.,
Califf R.M., and Wagner G. S. (1996). Electrocardiographic diagnosis of evolving
acute myocardial infarction in the presence of left bundle-branch block. GUSTO-1
(Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded
Coronary Arteries) Investigators. N Engl J Med, 334(8), 481-487.

32. Normal Variant for Altered
Ventricular Depolarization
• Normal Variant for LBBB
32Retrieved from http://lifeinthefastlane.com/ecg-
library/basics/sgarbossa/2/25/2014

33. Sgarbossa’s Criteria
Score > 3 has a specificity of 90% for
diagnosing MI
33

34. A comparison
Normal variant
Discordant
Abnormal variants
Concordance
ST depression
Excessive ST elevation

35. MI detection and RBBB
• Any new ST elevation or Q waves
may indicate ischemia or infarction
35

36. INTRAOPERATIVE
MONITORING PLAN

37. EKG Leads Most Sensitive and Specific to
Intra-operative
Myocardial Ischemia in the Adult Patient
• Shantella Bennett, SRNA, BSN; Justin Flesher, SRNA, BSN;
• Kaleisha Flythe, SRNA, BSN
• Quawanna Hunt, SRNA, BSN; Robert Littlejohn, SRNA, BSN;
• Lora Overacre, SRNA, BSN
Carolinas Medical Center Nurse Anesthesia Program/University of North
Carolina at Charlotte
An Evidenced Based Systematic Review of the
Literature
Based Upon the Available
Evidence

38. Schematic of the Systematic
Review of the Literature
Coronary
Artery
Ischemia
EKG
Monitoring Specificity Sensitivity
Intra-
Operative
& & & &
TotalArticles=751
Medline
viaEBSCO
HOST
N=87
CINAHL
N=0
PubMED
N=19
Webof
Science
N=1
Science
Direct
N=644
KeyWords
Databases
Searched
ArticlesIncludedafterTitleReviewN=87
ArticlesIncludedafterabstractreviewN=18
Prospective
Study
N=5
Quasi-
Experimental
Design
N=2
Meta-
Analysis
N=1
Typesof
Research
Studies
TotalarticlesremainingafterfullarticlereviewN=8

39. London et al.,1988
Design:
– Quasi-Experimental
Methods:
– N=105
– Patients with diagnosed or suspected coronary artery disease.
All patients underwent non-cardiac surgery and were monitored
with a 12-lead EKG
– Ischemia defined as ≥ 0.1 mV depression, measured 60msec
after J-point; duration ≥ 1 minute
– Passive induction of ischemia during cardiac surgery with
general anesthesia.
Findings:
– V5 was most sensitive single lead to ST segment changes
(75%).
– Most sensitive combination of two leads was in V4 and V5
(90%)
– Leads II, V4, and V5 were the most sensitive (96%) of ST
segment changes.
– ** 5 lead (II, V2-V5) detected 100% of ST changes
London, M. J., et al. (1988). “Intraoperative myocardial ischemia: localization by continuous 12-lead
electrocardiography.” Anesthesiology 69(2): 232-241.

40. Results Level of Evidence
Evidence
Hierarchies/Strength of
Evidence
# Leads Most
Sensitive
for
Ischemia
(IA) Meta-analysis
Strongly recommended; good
evidence
1 V4,V5,III
(IIB) Experimental Design
Recommended; at least fair
evidence
1 V5 only
(IIIA) Well-Designed, Quasi-Experiment
design;
Strongly recommended; good
evidence
3 V2,V3,III;
V4,V5,II;
V3,V6,III
(IIIB) Well-Designed, quasi-experimental
design;
Recommended at least fair evidence
2 V5,II; V2,V3,V4
(IVB ) Well-designed, non-experimental
design, Recommend; at least fair
evidence
1 V4,V5,II

41. Most Sensitive Leads
0
1
2
3
4
5
6
II III V2 V3 V4 V5 V6
NumberofStudies
Lead
Most Sensitive Leads for Ischemia Detection

42. Conclusions
• Contrary to the well-known standard of practice, which advises
practitioners to monitor lead II and V5 for coronary ischemia, this
study found a surprisingly large amount of conflicting data
suggesting a wide range of leads.
• The majority of the research studies recommended monitoring
multiple leads with the most common leads equally suggesting V4 &
V5.
• The majority of evidence is at a IIIA and IIIB evidence grading
level.
• Another common finding amongst the studies encouraged the use of
precordial leads over limb leads if multiple lead monitoring could
not be accommodated.
• Based on the evidence found in this systematic review of the
literature, we recommend the use of leads II, III, and V5 when 3 leads
are monitored. If monitoring 2 leads, we suggest leads III and V5
• All agreed that the greater the number of leads the greater the
sensitivity was for detecting ischemia

43. What Leads to Monitor
• Basesd upon known location of disease
– RAD
• II, III, avF
– LAD
• V1-V4
– LCX
• I, avL, V5, V6
– If we don’t know
• Based upon evidence
• II, III, V5
• Automated ST analysis allows continual
and trending of ST deviations in all
available leads
• Dependent upon proper identification of 3
points
– Iso
– J point
– J+

44. ST Set Points Adjustments

45. Continuous ST segment
analysis

46. V Lead
• Where should it be placed??

47. What Leads to Monitor
• Do we need to choose?
• Maybe not!

48. Alternative Lead Configuration
Options
Interpolated 6 lead EKG
System
Requires Special Cable (VaVb)EASI Lead System
Requires no special cable
10 Lead System
(Mason-Likar)
Requires 10 lead cable

49. Leads configuration yield
Available Leads

50. EASI Lead Configuration

51. What does the manufacturer
say?

52. EASI
What does the evidence say???
Single database search
• Web of Science
• Keywords
– EASI & Ischemia
• 8 studies
• 1999-2008
• Nursing, medicine, prehospital medicine
• EASI compared to conventional 12 Lead
EKG
• ALL studies found acceptable level of
correlation

53. References
EASI & Ischemia
• 1. Drew, B.J., et al., Accuracy of the EASI 12-lead
electrocardiogram compared to the standard 12-lead electrocardiogram
for diagnosing multiple cardiac abnormalities. Journal of
Electrocardiology, 1999. 32: p. 38-47.
• 2. Feldman, C.L., et al., Comparison of the five-electrode-derived
EASI electrocardiogram to the mason likar electrocardiogram in the
prehospital setting. American Journal of Cardiology, 2005. 96(3): p. 453-
456.
• 3. Lancia, L., et al., A comparison between EASI system 12-lead
ECGs and standard 12-lead ECGs for improved clinical nursing
practice. Journal of Clinical Nursing, 2008. 17(3): p. 370-377.
• 4. Nelwan, S.P., et al., Simultaneous comparison of 3 derived 12-
lead electrocardiograms with standard electrocardiogram at rest and
during percutaneous coronary occlusion. Journal of Electrocardiology,
2008. 41(3): p. 230-237.
• 5. Sejersten, M., et al., Comparison of EASI-derived 12-lead
electrocardiograms versus paramedic-acquired 12-lead
electrocardiograms using Mason-Likar limb lead configuration in
patients with chest pain. Journal of Electrocardiology, 2006. 39(1): p.
13-21.
• 6. Sejersten, M., et al., Detection of acute ischemia from the EASI-
derived 12-lead electrocardiogram and from the 12-lead
electrocardiogram acquired in clinical practice. Journal of
Electrocardiology, 2007. 40(2): p. 120-126.
• 7. Wehr, G., et al., A vector-based 5 electrode 12-lead ECG (EASI
(R)) is equivalent to the conventional 12-lead ECG for diagnosis of
myocardial ischemia. Journal of the American College of Cardiology,
2002. 39(5): p. 122A-122A.
• 8. Welinder, A., et al., Diagnostic conclusions from the EASI-
derived 12-lead electrocardiogram as compared with the standard 12-
lead electrocardiogram in children. American Heart Journal, 2006.
151(5): p. 1059-1064.

54. EASI Mode

55. 12 lead EKG capture

56. References
• Dubin, D. Rapid interpretations of EKG’s 5th
edition. Cover Publishing Co.; 1998.
• Scheidt, S. and J.A. Erlebacher. Basic
electrocardiography. Novartis Pharmaceuticals
Corporation, New Jersey;1986.
• Kernicki J and Weiler K. Electrocardiograph for
Nurses: Physiologic Correlates. New York: Wiley;
1981.
• Foster D. Twelve-Lead Electrocardiography-Theory
& Interpretation (2nd edition). London: Springer -
Verlag; 2007.
• Sgarbossa E. B., Pinski S. L., Barbagelata A., Underwood
D. A., Gates K. B., Topol E. J., Califf R.M., and Wagner G.
S. (1996). Electrocardiographic diagnosis of evolving
acute myocardial infarction in the presence of left bundle-
branch block. GUSTO-1 (Global Utilization of
Streptokinase and Tissue Plasminogen Activator for
Occluded Coronary Arteries) Investigators. N Engl J Med,
334(8), 481-487.
• Thygesen,T., et al (2012). Third universal definition
of myocardial infarction. Journal of American
College of Cardiology, 60(16), 1581-1598.
• http://www.mc.vanderbilt.edu/documents/7north/files
/MP5%20Rev_%20G%20Training%20Guide.pdf
56