the use of ekg to detect coronary ischemia

The Use of EKG to Detect

Coronary Ischemia: Pearls and

PitfallsNCANA District 3 & 4 Meeting

February 21, 2015

Karen Lucisano, CRNA, PhD

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

PRE-OPERATIVE

ASSESSMENT

Disease PrevalenceAre we likely to encounter this disease?

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6040a1.htm

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

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

EKG changes that indicate

low or no flow states

ISCHEMIA

9

Causes of ST Segment

Depression

10

Ischemic ST Depression

11

Types of ST Depression &

Their Specificity for Ischemia

12

T Wave Abnormalities

INJURY

Injury

Prinzmental’s Angina

Pericarditis

Ventricular Aneurysm

Early Repolarization

14

ST Segment Elevations

Causes

15

Acute MI

16

Prinzmetal’s Angina

17

Pericarditis

18

Ventricular Aneurysm

19

Early Repolarization

INFARCTION

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

A Variety of QRS Mophologies

23

Significant vs Non-Significant

Q waves

24

Progression of an Infarct

Few hours

2-3

days

Several Weeks

25

Myocardial vessels and their

distribution

anterior

inferior

IIIII aVF

V1---- V4

IaVL

26

Anatomy & Lead Correlation

High Lateral I & aVL

Low Lateral V5 & V6

Inferior

II, III & aVF Septal

V1 & V2

Anterior

V1-V4 orV3 & V4

27

Anterolateral Infarction

28

Anterior Infarction

29

Inferior Infarction

30

Posterior Infarction

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.

Normal Variant for Altered

Ventricular Depolarization

• Normal Variant for LBBB

32Retrieved from http://lifeinthefastlane.com/ecg-library/basics/sgarbossa/2/25/2014

Sgarbossa’s Criteria

Score > 3 has a specificity of 90% for

diagnosing MI

33

A comparison

Normal variant

Discordant

Abnormal variantsConcordance

ST depression

Excessive ST elevation

MI detection and RBBB

• Any new ST elevation or Q waves

may indicate ischemia or infarction

35

INTRAOPERATIVE

MONITORING PLAN

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

Schematic of the Systematic

Review of the Literature

Coronary Artery

Ischemia

EKG Monitoring

Specificity

Sensitivity

Intra- Operative

& & & &

Total Articles=751

Medline via EBSCO

HOST

N=87

CINAHL

N=0

PubMED

N=19

Web of Science

N=1

Science Direct

N=644

Key

Word

s

Da

ta

ba

ses

Sea

rch

ed

Articles Included after Title Review N=87

Articles Included after abstract review N=18

Prospective Study

N=5

Quasi- Experimental

Design

N=2

Meta- Analysis

N=1

Ty

pes o

f

Research

Stu

dies

Total articles remaining after full article review N=8

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.

Results Level of Evidence

EvidenceHierarchies/Strength of Evidence

# Leads MostSensitive for Ischemia

(IA) Meta-analysisStrongly recommended; good

evidence

1 V4,V5,III

(IIB) Experimental DesignRecommended; 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

Most Sensitive Leads

0

1

2

3

4

5

6

II III V2 V3 V4 V5 V6

Nu

mb

er o

f S

tud

ies

Lead

Most Sensitive Leads for Ischemia Detection

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

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+

ST Set Points Adjustments

Continuous ST segment

analysis

V Lead

• Where should it be placed??

What Leads to Monitor

• Do we need to choose?

• Maybe not!

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

Leads configuration yield

Available Leads

EASI Lead Configuration

What does the manufacturer

say?

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

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.

EASI Mode

12 lead EKG capture

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

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