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Centre for Clinical Nursing Research Deakin University Epworth Hospital

EASI ECG Monitoring _Final

Author: Bernice Redley 2

Table of Contents

What is EASI ECG Monitoring? ................................................................................3

Advantages of the EASI ECG monitoring system ...................................................4

Disadvantages of the EASI ECG monitoring System ..............................................4

Comparisons between the EASI and Mason-Likar 12 lead ECG systems ................5

Summary of the Research ...........................................................................................6

Methods..............................................................................................................6

Detection of acute ischaemia and Myocardial Infarction (MI) .............................6

Lead amplitudes .................................................................................................7

Conduction and rhythm disturbances ..................................................................7

Misdiagnosis ......................................................................................................7

Limitations .............................................................................................................8

Summary ................................................................................................................8

APPENDIX 1. Summary Table by Author ..............................................................9

APPENDIX 2. Summary Table by Parameter ....................................................... 13

References ............................................................................................................ 19

Centre for Clinical Nursing Research Deakin University Epworth Hospital



What is EASI ECG Monitoring? EASI is a method of continuous electrocardiogram (ECG) monitoring that is an

alternative to both the commonly used 5-electrode lead bedside monitoring system

and the traditional 10-electrode Mason-Likar 12lead ECG system. The EASI lead configuration enables continuous 12 lead ECG ambulatory monitoring using only 5

electrodes. The EASI 12 lead ECG is derived from this reduced lead set using a

method described by Dower et al. [1-3].

The EASI 12-lead ECG is derived from a set of 5 leads; 4 recording electrodes and

one grounding electrode. The placement of these leads is as follows [4].

E: Lower extreme of the sternum

A: Left mid-axillary line, same transverse line as E

S: Sternal manubrium

I: Right mid-axillary line, same transverse line as E

G: Fifth electrode is the ground and can be placed anywhere on the torso

Diagram of EASI electrode placement

[4 p. 180]



Advantages of the EASI ECG monitoring system

Easy to apply. The EASI is a 5 electrode system that provides a 12-lead ECG, making it easier to rapidly and accurately apply the leads in stressful situations [4].

Time saving for staff. As a continuous 12-lead ECG is produced, there is no need to perform traditional intermittent 12-lead ECGs.

Continuous 12-lead ECG. The reduced set of leads provides continuous 12-lead ECG monitoring as opposed to a snapshot 10-15 second view ECG with the

traditional ECG [5].

Better patient comfort. The reduced set of EASI leads is less bulky than a 10-electrode Mason-Likar system, improving patient comfort, simplifying application

and maintenance for continuous monitoring [5].

Less waveform interference. With less leads, the EASI system is less susceptible patient movement, signal interference or myeloelectric noise making it more

suitable and sensitive (than the 10 electrode system) for continuous ambulatory

ECG monitoring [6-8].

Better serial comparisons. EASI derived ECGs have better reproducibility for serial comparisons [6, 8, 9].

More leads viewed continuously. EASI provides a continuous 12-lead ECG allowing detection of transient myocardial ischaemia across multiple leads, while

the more common 5-lead ambulatory monitoring system does not allow monitoring

of all the precordial leads at the same time (usually lead II and V1 only)[5, 10-12].

Disadvantages of the EASI ECG monitoring System

Unfamiliar to staff. The EASI system is unfamiliar to clinicians so training in this system may be required [13]

Differs to traditional method. Some leads from the EASI derived ECG have been found to differ slightly to the standard ECG, requiring consideration during

interpretation. These differences are outlined below.

Placement error. Lead placement error may lead to discrepancies [4].

Less sensitive in detecting some conditions. Due to lower amplitudes in some leads, it is difficult to detect chamber enlargement (atrial and ventricular hypertrophy )

with EASI ECG [7, 12], though similar problems also exist with the standard ECG.



Comparisons between the EASI and Mason-Likar 12 lead ECG systems

Duration and amplitude of P, QRS, ST and T waves may differ between the EASI derived and standard ECG systems [5, 7, 9, 14], with the EASI system

demonstrating less amplitude. It is important that this is considered during analysis

and serial comparisons are made using the same system.

Frontal plane transition zone at V2-V3 in EASI and V3-V4 in traditional [7].

The correlation between EASI ECG and the standard ECG complex interpretations reached less than 90% agreement in some leads (particularly III, aVL, aVF, V4 and

V5) [9].

High levels of correlation have been found between the EASI and the standard ECG complexes in leads I, aVR, V1, V2, V3, and V6 [9].

Greater than 90% agreement for detection of small (100 V) ST segment changes indicating acute ischaemia [12, 13]

Greater than 90% agreement for detection of prior myocardial infarction (Q wave, isolated ST-T) [9, 12, 13].

Similar rates of false diagnosis or misinterpretation of ECGs by clinicians with both systems [12, 13]

100% agreement for rhythm identification [7, 12].

95-100% agreement for conduction problems (Bundle branch blocks, fascicular blocks) [7, 12].

Differences in axis of up to 30 degrees between the two systems [7, 12].



Summary of the Research Several studies have compared derived EASI 12-lead ECGs with the standard Mason-

Likar 12 lead ECG. Overall the two systems are similar for many of the parameters

examined, but some differences also exist. A summary of these studies is provided

below.

Methods

The strongest study design simultaneously collected the EASI derived and standard 12

lead ECGs continuously across a large population of subjects (540 patients) from

acute clinical areas (Emergency and cardiac catheter), then used a computer analysis

program to compare the recordings [12]. The authors then used a clinical expert to

examine the accuracy of the ECG interpretations in collaboration with clinical data

such as cardiac enzymes, echocardiography, patient history and clinical examination.

Use of computer analysis and simultaneous data collection were strengths as slightly

greater variations within and between EASI and standard ECG recordings have been

associated with human interpretations [7]; or ECGs that were not collected

simultaneously [4, 14]. Variations have also been noted between studies that used data

from healthy subjects in laboratory settings [4, 6] and those conducted in real clinical

circumstances with patients with variable diagnoses requiring cardiac monitoring [7,

9, 12-14]. Studies using patient population provide more useful clinically relevant

information. Few studies incorporated clinical findings to confirm the diagnosis

derived from the ECG [12, 14].

Detection of acute ischaemia and Myocardial Infarction (MI)

The rate of agreement between EASI ECG and the standard 12-lead ECG for the

detection of acute ischaemia was high in the majority of reviewed studies [9, 11-16].

Some ECG differences were detected between different types of ischemia. Both

inflation induced ischaemia during cardiac catheterisation and spontaneous ischaemic

events have been examined.

Rautaharju et al. [14] reported 85% agreement between EASI and standard ECGs in

the detection of inflation induced ischaemia during cardiac catheterisation. These

authors used 100 V (which is less than usually considered clinically significant) as

the ST segment threshold. The use of independent electro-cardiographers reading the

ECGs may have contributed to the lower agreement for ischaemic changes in this

study. Studies that used computer program analysis reported much higher agreement

(>99%) between EASI derived and standard ECGs for the detection of ischaemia [12,

13] than studies that used clinical experts with or without computer assistance [7, 14].

Drew et al. [12] reported the EASI system accurately detected 93% of acute transient

myocardial ischaemic events, while the leads routinely used for bedside monitoring

(Leads II and V1) detected only 42%. In this study, discrepancies between the EASI

and standards ECG were found in 17 of 238 ST events. Review by an expert clinician

revealed the EASI system was less sensitive in detecting low voltage ST segment

changes. None of these 17 discrepancy events were associated with chest pain, none

involved large changes (>200 V) and none involved the need for clinical

intervention. These findings suggest that these differences were not clinically

significant.



Similar findings were experienced in the detection of ECG changes suggesting old

MI. Comparisons of EASI derived and standard ECGs revealed 95% agreement for

anterior and 92% agreement for inferior Q-wave MI in a large study sample [12]. The

EASI system had greater sensitivity than the standard system in detecting these

changes (59% vs 55%) but slightly less specificity (95% vs 99%).

Lead amplitudes

Differences in the amplitudes of several leads have been consistent findings in studies

comparing the EASI derived ECG with the standard 12-lead. Most commonly

discrepancies were detected in V3-V4 [4, 7, 9, 13] or isolated ST-T segment changes

of low amplitude [12, 14]. Only minor differences of 14-30 degrees in frontal plane

axis were detected [7, 12]. These small differences are not usually clinically

significant.

Low amplitudes were also associated with low sensitivity in detecting chamber

enlargements using the both methods of ECG acquisition. These difficulties were

similar with both the EASI derived and standard ECG, except in the cases of left

ventricular hypertrophy where the EASI derived ECG had higher specificity than the

standard ECG [12].

EASI derived ECG have shown lower amplitude Q waves in V6, smaller amplitude R

wave in V1, V2 and V4, and less ST amplitude in V4 and V5 [14]. Horacek [9]

compared ECGs collected from clinical settings revealing less than a 90% correlation

between EASI derived and standard ECG in leads III, aVL for normal and post MI

ECGs, with Q waves, non-Q waves and history of VT.

Conduction and rhythm disturbances

Comparisons between the EASI derived and standard ECGs consistently demonstrate

high levels of agreement (95%-100%) in the detection of conduction problems such as

pre-excitation patterns, bundle branch blocks, fascicular blocks [7, 12, 16] and rhythm

disturbances such as VT and SVT [9, 12, 16]. Minor deviations of 0-2ms in the

cardiac intervals for the PR, QRS, QT and QTC have been detected. While the

observed difference of 1ms in QRS was statistically significant it was not clinically

significant [12]. Again the clinical significance of these findings must be questioned.

Misdiagnosis

Similar rates of misdiagnosis have been reported for the two types of ECGs with the

majority related to old MI changes. Drew et al. [7] reported two false positives and

four false negative in EASI derived ECGs from patients with prior myocardial

ischaemia, while six false negatives were reported from the standard ECGs from

patients with a prior MI. Similarly Rautaharju [14] reported 10% of ECGs had

significant differences between the EASI derived and standard method with 3.4%

involving Q-wave MI or ST changes in lead II. However, in this study none of the

new changes were identified as old, and none of the Q-wave MIs were missed using the EASI derived ECG for interpretation. Drew [13] found only one false negative

from 207 derived ECGs and in her 1999 study, two ECGs were misdiagnosed using

both the EASI derived and standard ECG methods.



Limitations

There are several variables to consider that pose limitations to these study findings.

The clinical significance of these limitations must be considered when deciding about

the appropriateness of the EASI methods for continuous ECG monitoring.

Various computer programs (Phillips, Marquette, Montana) and equipment were used

to collect ECG data across the studies. The types of electrode, the method used for

placement of ECG electrodes, the expertise of the person applying the electrodes and

the timing of data collected are all independent variables not addressed in many

studies. It has been established that slight variations in the placement of the

electrodes may increase error when making ECG comparisons [8]. The influence of

these factors on the quality of the recordings and subsequent comparisons is unknown.

The clinical conditions under which data were collected also varied. Laboratory

conditions and healthy subjects differed to clinical conditions and ill patients. Finally,

few studies confirmed the ECG diagnosis using other clinical diagnostic criteria,

suggesting that the error in patient diagnosis may have been higher with both methods

of ECG data acquisition.

Summary

EASI derived ECGs are comparable to the standard ECG for the diagnosis of wide

complex tachycardias [9, 12, 16] and myocardial ischaemia [9, 11-16]. The

reproducibility of the EASI derived ECG makes it more useful in serial comparisons

over time. The EASI derived system for continuous ambulatory monitoring has

advantages over the standard 5-lead monitoring systems and continuous 12 lead

monitoring systems with the benefits of both. The EASI system allows continuous 12

lead monitoring instead of the limited II and V1 capability of the traditional 5-

electrode method. The EASI system is less susceptible to noise and interference than

the bulky 10-electrode 12-lead system. These benefits enable significant

improvements in the detection of spontaneous ischemia during continuous ambulatory

monitoring.

While there are differences between ECG data collected using the EASI derived and

standard 12-lead ECG methods, the clinical significance of these changes is

questionable. The lower amplitude of some leads in the EASI derived ECG may be

overcome by adjusting the thresholds used to determine clinical significance and

training staff in interpretation. Similar limitations in terms of clinical diagnosis and

variation in interpretation by clinicians affect both methods of 12-lead ECG

collection.



APPENDIX 1. Summary Table by Author

AUTHOR TITLE STUDY DESIGN Number of

Comparisons

FINDINGS

Drew [12] Accuracy of the

EASI 12 lead ECG

compared to the

standard 12 lead

ECG for

diagnosing cardiac

abnormalities

Two methods of

continuous ECG

monitoring

simultaneously from

ED admission or from

catheter based

intervention. Computer

analysis program used

to compare ECGs.

Disagreements

examined and diagnosis

made by specialist and

clinical and echo

criteria.

All ED patients over 2

year period. 540

patients enrolled, 426

with acute coronary

syndromes. Some not

diagnosed with acute

ischaemia and ruled

out.

EASI and standard ECG compared for cardiac

rhythm, cardiac intervals, QRS axis, chamber

enlargement-hypertrophy, BBB and fascicular

blocks and prior MI. 100% agreement on

rhythm identification 84-89% agreement on

chamber enlargement, 997% agreement on R &

L BBB, 97-98% agreement on fascicular

blocks, and 92-95% agreement on prior MI.

Drew [13] Comparison of

standard and

derived 12 lead

ECG for diagnosis

of coronary

angioplasty

induced myocardial

ischaemia

Compared standard and

derived continuous

ECG

Threshold of >1 lead of

>100 V, 80 ms post j

point used to define

ischaemia

207 patients with timed

measurements (derived

analysed every 20 secs,

standard continuously),

151 during procedure

Agreement regarding ischaemia in 150 of 151

patients with both methods.

Different time ratio for measurement may have

led to error in one care but may also have led to

agreement in others.




Comparisons

FINDINGS

Drew [16] Comparison of a

new reduced lead

set ECG with

standard ECG for

diagnosing cardiac

arrhythmias and

myocardial

ischaemia

Compared EASI with

Interpolated standard

limb leads and V1 and

V5

649 patients (CP in ED

= 509 and Tachycardia

in EP Lab = 140).

Identical for BBB, LAH, RVH, prior MI. 99.2%

agreement of ischaemia in the ED. Appears to

have higher agreement than EASI model.

Applied to patients by expert.

Drew [7] Comparison of a

vectorcardiography

derived 12-lead

ECG with the

conventional ECG

during wide QRS

complex

tachycardia, and its

potential

application for

continuous bedside

monitoring.

Compare during EP

studies. Simultaneous

recordings and two

expert investigators

independently

compared using

standard criteria

including QRS pattern,

sequence, width,

morphology and

voltages.

64 episodes of wide

QRS complex

tachycardia in 49

patients

9 pts had LVH, only 6 with evidence on derived

ECG. 6 pts with WPW identical delta wave

morphology, 45 pts with prior MI 92%

agreement Lower voltages present in V3 and

V4 of derived ECG. QRS morphology

dissimilar in 35% of pts in V3 and 51% in V4.

(early transition of the RV rS to the LV qR in

derived). Transitional zone generally appeared

in V3 or V4 or the ECG appeared in V2-V3 of

the derived ECG. QRS voltage less in the

precordial leads of the derived ECG affecting

Dx of LVH. Derived ECG had false positive in

2 cases prior MI in young person with no

history, 2 false negative of inferior MI.




Comparisons

FINDINGS

Horacek [9] Diagnostic

accuracy of derived

compared to

standard 12-lead

ECG

290 normal subjects

and 497 with prior MI

(36 with non Q, 282 Q-

wave, 179 with history

of VT)

V6 best derived lead with highest agreement

closely followed by V1 and V2. V3-V5 not

reproduced well in the MI subgroups as they are

in normal subjects. Worse as the structural

damage to the myocardium increases the

diagnostic performance markedly increases.

Rautaharju [14] Comparability of

12-lead ECGs

derived from EASI

leads with standard

12-lead ECG in

classification of

AMI and old MI

Read by two

independent expert

ECG readers and

analysis program.

ECGs printed side by

side in random order.

Readers blinded.

Coding forms used to

classify the ECGs

40 patients recorded

prior to and at peak

inflation during PCTA,

382 with old MI ECGs

472 with non MI.

No significant differences between ECG

readers in acute ischaemia. Suggest need for

modified prior MI criteria and ST thresholds for

AMI specific for EASI. Significant differences

within readers and the program

10% with clinically significant differences,

3.4% classed as q-MI and 11 as isolated ST-T

evolution

Sejersten [4] The relative

accuracies of ECG

precordial lead

waveforms derived

from EASI leads

and those acquired

from paramedic

applied standard

leads

Compared waveforms

from Gold Standard ECG with paramedic

applied and EASI

derived ECGs. First

acquired from

paramedic the two

simultaneously by

technician. Difference

threshold of 10 V.

20 paramedics

collected data on each

other. Paired to act as

experimental technician

and study participant. 3

ECGs on each. 720

comparisons of

precordial leads.

EASI and paramedic waveforms were equally

accurate in 47%, paramedic more accurate in

31% and EASI in 22% when compared to Gold

Standard. Significant difference in paramedic

placement of leads mean 30mm misplacement.

Review of discrepancies revealed that EASI

more accurate for ST changes in V4 & V5. and

T in V6. Paramedic more accurate Q amplitude

in V6, R amplitude in V1, V2, V4 and ST

deviation in V1




Comparisons

FINDINGS

Welinder [6] Comparison of

signal quality

between EASI and

Mason-Likar 12-

Lead ECG during

physical activity

Compared baseline

wander and myoelectric

noise amplitudes of

EASI and traditional.

Simultaneous

recordings. Inter-rater

not addressed. Range

thresholds (?valid)

established for noise.

20 healthy volunteers

with simultaneous

measurements

EASI winner significantly more often in treadmill and supine to L in precordial.

Traditional winner significantly more often in Supine to R limb and precordial leads



APPENDIX 2. Summary Table by Parameter

Parameter

Examined

Drew (1992) Rautaharju,

(2002)

Welinder,

(2004)

Drew (1997) Sejersten,

(2003)

Drew (1999) Horacek

(2000)

Acute

Ischaemia

Inflation

induced

ischaemia using

100 V as

threshold 85%

agreement,

27/40 positive

and 7/40

negative

3.4%

differences in

New Q MI

6.1% difference

in ST-T

segments

99% agreement

in Cx artery

peak ST in V3

for derived and

V3 or V4 for

standard

138 patients with 238 ST

events. 26 had acute ST

elevation patterns. 63

angioplasty induced

ischaemia and 150

spontaneous ischaemia. 89%

agreement, the (14 standard

and 3 EASI) events with

discrepancy were not

associated with chest pain

and none involved large

changes (>200 V). EASI

detected 93% of ischaemic

events while the leads

routinely used for bedside

monitoring (II and V1)

detected 42%.

EASI low amplitude ST

changes ? clinical

significance, none resulted

in clinical interventions or

poor outcomes..



Parameter

Examined


(2002)

Welinder,

(2004)

Drew (1997) Sejersten, (2003) Drew (1999) Horacek

(2000)

Prior MI (Q-

wave)

92%

agreement

85% agreement

with computer,

57% agreement

for isolated ST-

T in old MI

Agreement 95% for

anterior and 92% for

inferior. In prior

inferior MI, EASI had

greater sensitivity than

standard (59% vs 55%)

but lower specificity

(95% vs 99%)

Correlations

between

EASI and

standard less

than 90% in

leads II, III,

aVL, aVF,

V4 and V5

for q wave

MI.

Normal ECG 80% agreement

with computer

98%

agreement

Similar deviations

between paramedic

and EASI.

Lead

differences

Transition

zone V2-V3

in EASI and

V3-V4 in

traditional

EASI-Gold

compared with

Paramedic-Gold

revealed significant

differences; inc Q

amp in V6, smaller

R amp in V1, V2

and V4. Less ST in

V1, inc ST in V4

and V5 and inc T

amp in V6

Correlations

less than

90% in III,

aVL for

normal and

post MI

patients with

no Q, Q and

VT



Parameter

Examined


(2002)

Welinder,

(2004)

Drew (1997) Sejersten, (2003) Drew (1999) Horacek

(2000)

Axis Frontal plane

Axis in

Precordial

leads only

Difference 19

deg. 95% CI

of 14-24 deg.

Mean differences in P

wave and QRS and T-

wave axis were 21

degrees, t-wave axis

differed more between

the two ECG types

mean 30 degrees.

Conduction 100%

agreement on

BBB and

fascicular

blocks

Agreement for BBB

and fascicular blocks

ranged from 95-99%.

EASI closer to expert

in RBBB.

False

diagnosis

EASI False

positive in 2

and false

negative in 4

with prior MI

and traditional

False negative

in 6 pts with

prior MI

10% clinically

significant

differences B/W

EASI and

traditional 3.4%

q-MI and 11 ST

changes. None

of normal

classed as old

MI and none of

Q-wave missed.

No false

positives and

1 false

negative with

derived ECG

2 misdiagnosed by

both the EASI and

standard 12 lead due to

low amplitude p

waves.



Parameter

Examined


(2002)

Welinder,

(2004)


(2003)

Drew (1999) Horacek

(2000)

Cardiac

rhythm

100% agreement

in diagnosis and

misdiagnosis for

Wide complex

tachycardia

Difference in axis

17 deg with CI

95% 12-22 deg.

SVT Vs VT

criteria agreement

in V1, V2, V6

100% agreement Correlations

less than

90% for

leads II, III,

aVL, aVF,

V3, V4, V5

between

EASI and

patients with

VT.

Chamber

enlargement

Lower V3-V4

voltages, leading

to inability to

detect LVH in 1/3

of patients with

wide complex

tachycardia 39%

in V3 and 55% in

V4

177 evaluated for atrial

enlargement using Echo.

RAH in 17 patients and

LAH in 46 patients, RVH

in 15 and LVH in 68.

Agreement was between

84-98%. Both methods

had low sensitivity but

high specificity. For LVH

EASI had higher

specificity than standard

(98% vs 88% respectively)

Both methods insensitive

to chamber enlargement.



Parameter

Examined


(2002)

Welinder,

(2004)


(2003)

Drew (1999) Horacek

(2000)

Others Ventricular pre-

excitation

patterns 100%

agreement

Cardiac intervals for PR,

QRS, QT and QTC varied

by 0-2ms. The observed

difference of 1ms in QRS

was statistically significant

but not clinically

significant.

Artifact Less muscle

artifact after

DCCR and on

arm movement.

Similar

baseline

wander,

EASI less

noise for

treadmill

and supine

to L.

No MI 80%

agreement



Other Variables to consider:

Parameter

Examined


(2002)

Welinder,

(2004)


(2003)

Drew (1999) Horacek

(2000)

Electrodes

used

Not identified Not identified Identified Not identified No specified

Method of

deriving

traditional

ECG

(machine

used)

Marquette

computer

program.

Simultaneous

measurement

Standard

measure

ECGs

collected in

time sequence

Identified

Simultaneou

s collection

of ECGs

Described

ECGs

collected

simultaneousl

y during

procedure

Identified

Three

independent

recordings on

same subject.

Identified

Simultaneous monitoring

Simultaneou

s recording

supine for 15

seconds

Application

of electrodes

by whom/

position

In the ED and

PCTA procedure

Not identified

Method of

application

Not identified,

position id.

Identified I V4 used in

study and

EASI for

latter

Paramedic

and expert

(Traditional

and EASI)

Position

described

Not identified, presumed

to be in the ED/ cath lab

Nor

specified.

Setting ED & EP studies, PCTA, AMI

pts with

enzyme ?

from location

suggests

clinical

situations.

Laboratory

Healthy

participants.

PCTA. Experimental

conditions at

conference

Healthy

participants.

ED and catheter lab Not specified

but presumed

to be a

clinical

environment

and clinical

diagnostic

criteria used.



References

1. Dower, G.E., The ECGD: a derivation of the ECG from VCG leads. Journal of

Electrocardiology, 1984. 17(2): p. 189-91.

2. Dower, G.E., H.B. Machado, and J.A. Osborne, On deriving the

electrocardiogram from vectorcadiographic leads. Clinical Cardiology, 1980.

3(2): p. 87-95.

3. Dower, G.E., et al., Deriving the 12-lead electrocardiogram from four (EASI)

electrodes. Journal of Electrocardiology, 1988. 21 Suppl: p. S182-7.

4. Sejersten, M., et al., The relative accuracies of ECG precordial lead

waveforms derived from EASI leads and those acquired from paramedic

applied standard leads. Journal of Electrocardiology, 2003. 36(3): p. 179-85.

5. Drew, B.J., et al., Practice standards for electrographic monitoring in hospital

settings. Circulation, 2004. 110: p. 2721-2746.

6. Welinder, A., et al., Comparison of signal quality between EASI and Mason-

Likar 12-lead electrocardiograms during physical activity. American Journal

of Critical Care, 2004. 13(3): p. 228-234.

7. Drew, B.J., M.M. Scheinman, and G.T. Evans, Jr., Comparison of a

vectorcardiographically derived 12-lead electrocardiogram with the

conventional electrocardiogram during wide QRS complex tachycardia, and

its potential application for continuous bedside monitoring. American Journal

of Cardiology, 1992. 69(6): p. 612-8.

8. Adams, M.G. and B.J. Drew, Body position effects on the ECG: implication

for ischemia monitoring. Journal of Electrocardiology, 1997. 30(4): p. 285-91.

9. Horacek, B.M., et al. Diagnostic accuracy of derived compared to standard

12-lead electrocardiograms. in International Society for Computerized

Cardiology. 2000. Yosemite, California: Journal of Electrocardiology.

10. Drew, B.J., et al., Value of a derived 12-lead ECG for detecting transient

myocardial ischemia. Journal of Electrocardiology, 1995. 28 Suppl: p. 211.

11. Drew, B.J. and B. Ide, Diagnosing ischemia from the bedside monitor.

Prognostic Cardiovascular Nursing, 1996. 11(1): p. 45-6.

12. Drew, B.J., et al., Accuracy of the EASI 12-lead electrocardiogram compares

to the standard 12-lead electrocardiogram for diagnosing multiple cardiac

abnormalities. Journal of Electrocardiology, 1999. 32: p. 38-47.

13. Drew, B.J., et al., Comparison of standard and derived 12-lead

electrocardiograms for diagnosis of coronary angioplasty-induced myocardial

ischemia. American Journal of Cardiology, 1997. 79(5): p. 639-44.

14. Rautaharju, P.M., et al., Comparability of 12-lead ECGs derived from EASI

leads with standard 12-lead ECGS in the classification of acute myocardial

ischemia and old myocardial infarction. Journal of Electrocardiology, 2002.

35 Suppl: p. 35-9.

15. Drew, B.J., et al., Derived 12-lead ECG. Comparison with the standard ECG

during myocardial ischemia and its potential application for continuous ST-

segment monitoring. Journal of Electrocardiology, 1994. 27 Suppl: p. 249-55.

16. Drew, B.J., et al., Comparison of a new reduced lead set ECG with the

standard ECG for diagnosing cardiac arrhythmias and myocardial ischemia.

Journal of Electrocardiology, 2002. 35 Suppl: p. 13-21.

easi ecg monitoring _final

Documents

lead ecg ambulatory

lead ecg systems

easi lead configuration

bedside monitoring system

electrode system

lead amplitudes

reduced lead set

final author