PRIME ECG Mapping:The Science and the Practice

Brian O’Neil MD, FACEPProfessor,

Emergency Medicine, Wayne State University,

Research Director,William Beaumont Hospital

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15 is better than 12Comparison of 12- and 15-lead ECGS in ED

– Brady WJ et al. Am J Emerg Med. 2000;18:239-43• 600 pts in each group• each group 30% had AE

• USA/MI 10:1

The 15 ECG provided a more complete description of myocardial injury

without changing-ED diagnosis, -ED-based therapy-hospital disposition

18 is better than 15Zalenski RJ, J Electrocardiol. 1998;31:164-71

• prospective trial of seven EDs

– > 35 yo and CCU admission

• ECG leads were test positive if ST ↑ was > 0.1 mV.

• Outcome was inpatient

– VF, VT, high grade block, shock, arrest, or death

18 is better than 15 Zalenski RJ, J Electrocardiol. 1998;31:164-71

• 533 patients,

– 64.7% AMI

– 15.8% had events.

• 18 v 15 lead for events:

– Sens increased by 5.8%

– specificity decreased by 8.2%

• Independent predictors of events

– V1 (odds = 3.2)

– V6R (odds = 3.1)

80 Lead Body Mapping and AMI• Kornreich F. Body surface potential mapping of ST

segment changes in acute myocardial infarction. Implications for ECG enrollment criteria for thrombolytic therapy. Circ 1993; 87:773-82

+/- = ST , circled leads were best discriminators for A anterior, I inferior, and P posterior MIs

Comparison of the 80-lead body surface map to physician and to 12-lead electrocardiogram in

detection of acute myocardial infarction. – McClelland AJJ et al. Am J Cardiol 2003;92:252-7

• AMI-prevalence (53/103)

12-lead algorithm Physician & 12 lead 80-lead algorithm

Sens 0.32 (17/53) 0.45 (24/53) 0.64 (34/53)

Spec 0.98 (49/50) 0.94 (47/50) 0.94 (47/50)

PPV 0.94 (17/18) 0.89 (24/27) 0.92 (34/37)

NPV 0.57 (49/85) 0.62 (47/76) 0.71 (47/66)

80 Body Mapping in the ED80-lead body surface mapping detects acute STEMI

missed by standard 12-lead ECG

Ornato JP, et al. JACC, 2002;332A• 481 ED CP pts with 107 AMIs

– pretest probability to 0.22

Standard12-lead 80-lead BSM

Sensitivity 0.252 (27/107) 0.336 (36/107)

Specificity 0.976 (365/374) 0.965 (361/374)

PPV 0.750 (27/36) 0.735 (36/49)

NPV 0.820 (365/445) 0.836 (361/432)

80-Lead ECG increases sensitivity and maintains specificity when compared to 12-lead ECG

Conclusion: The 80-Lead ECG is more sensitive for detecting STEMI The 80-Lead ECG is more sensitive for detecting STEMI than the 12-Lead ECG, but has comparable specificity.than the 12-Lead ECG, but has comparable specificity.

   NN12-Lead12-Lead

SensitivitySensitivity80-Lead 80-Lead

SensitivitySensitivity pp12-Lead 12-Lead

SpecificitySpecificity80-Lead 80-Lead

SpecificitySpecificity pp

CKMB-MICKMB-MI 22/36522/365 72.7%72.7% 100%100% 0.020.02 97.1%97.1% 96.5%96.5% nsns

TROP-MITROP-MI 28/22528/225 57.1%57.1% 92.9%92.9% 0.0080.008 96.5%96.5% 94.9%94.9% nsns

CLIN-MICLIN-MI 41/64741/647 75.6%75.6% 90.2%90.2% 0.090.09 98.0%98.0% 96.7%96.7% nsns

J Am Coll Cardiol 2002; 39(5); p. 332A.

80-Lead ECG is associated with greater sensitivity compared to 12-lead in detection of MI

– In 3 head-to-head, blinded studies, the 80-lead ECG identified more MIs than 12-lead upon presentation

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Ornato, et.al.* McClelland, et.al.** Owens, et.al.***

12-L

PRIME ECG

*Ornato JP, et al; 80-lead Body Map Detects Acute ST-elevation Myocardial Infarction Missed by Standard 12-lead Electrocardiography, Journal of the American College of Cardiology, 2002; 39(5): 332A **McClelland, et al; Comparison of 80-lead Body Surface Mapping Algorithm to Physician and to 12-Lead Electrocardiogram in Detection of Acute Myocardial Infarction, American Journal of Cardiology, 2003; 92: 252-257 ***Owens CG, et al; Pre-hospital 80-lead mapping: Does it add significantly to the diagnosis of acute coronary syndromes?, Journal of Electrocardiology, 2004; 37: 223-232

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n=481 n=103 n=294

PRIME ECG has consistently demonstrated superior performance vs.

12-lead ECG

In 3 studies of 878 patients compared to 12-lead ECG, PRIME on average:

• identified 40% more MIs

• 18% increase in sensitivity • more true MIs, True +

• Maintains specificity • similar False MIs, False +

Comparison of a cardiac mapping device with standard 12-Lead ECG in the

diagnosis of acute coronary syndrome

90 ED CP pts eval for ACS Physicians given 12 and 80 lead

estimate the prob of AMI on Likert scale Asked if adds information or assist with

treatment Outcome = 30 day ACS

Fermann G et al. Annals of EM, 2004;44:s73

Comparison of a cardiac mapping device with standard 12-Lead ECG in the

diagnosis of acute coronary syndromeFermann G et al. Annals of EM, 2004;44:s73

• 21% ACS, 19% with adverse event

12 lead 80 lead

AUC (ECG) 0.69

(0.55-0.82)

0.74

(0.62-0.86)

SENS (TnI) 20% 40%

SPEC (TnI) 91.8% 92.9%

PRIME ECG Improves ED Diagnosis and Management of Moderate- to High-Risk Unstable Angina/Non-ST

Elevation Myocardial Infarction Patients.

Objective: Does bedside evaluation with PRIME:– Diagnosis– Disposition– Therapy

• Higher risk pts TIMI > 3

68% had MACE Death AMI Stenosis >

50%PCI Stent CABG

# / 35 (%) 0 (0) 13 (38%) 17 (50%) 15 (44) 10 (29) 5 (15)

Batton AL, O’Neil B, et al Annals of Emerg Med, 2004 (320)S99

PRIME ECG Improves Emergency Department Diagnosis and Management of Moderate- to High-Risk

Unstable Angina/Non-ST Elevation Myocardial Infarction Patients

Batton AL, O’Neil B, et al Annals of Emerg Med, 2004 (320)S99

Added Information to 12 lead ECG

Changed Therapy or Disposition

Number with MACE Number inappropriately

triaged Attending Physician

20/34 7/34 6/7 1/7

Resident 18/34 11/34 10/11 1/11

PRIME supplied additional information in 59%

PRIME changed disposition in 1/5 to 1/3

Advantages of 80-Lead ECG in Diagnostic Dilemmas:

1. Posterior MI

2. RV infarct

3. Left Bundle Branch Block

Example of potential misdiagnosis with a 12-lead ECG

Shown here is the 12-Lead ECG of a patient that presented with substantial chest pain. Note that there is no evidence of ST segment elevation.

www.wikidoc.orgwww.wikidoc.org

Leads 68, 69 & 72 meet criteria for STEMI

[In this example, a series of sequential beats can be observed by placing a cursor over any beat (shows instantly in the pop-up window).]

80-lead Single-Beat Display with pop-up window.

PosteriorAnterior

3+ contiguous leads; >.5mm ST elevation, with reciprocal depression (seen in V3/V4 area)

[Actual screen shot for same patient.]

Shown here is the color representation of the same patient’s 80-Lead ECG.

The area of injury is shown in red on the patient's back, corresponding to the inferior-posterior location of the MI.

Example of potential misdiagnosis with a 12-Lead ECG (cont.)

www.wikidoc.org

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)80-Lead ECG more often detects posterior ST elevation

> 0.5 mm than augmented anterior 12-lead

Menown et al, Am J Cardiol 2000;85:934-8

Posterior V7

Posterior V9

Posterior V7 & V9

6%6%8%8%

10%10%

36%36%

80-LeadPosterior

Augmented 12-Leads

Right Ventricular MI

Torso map localizes & demonstrates injury extent

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80-Lead ECG more often detects right ventricular ST elevation > 1.0 mm than augmented 12-lead

Menown et al, Am J Cardiol 2000;85:934-8

Right V2

RightV4

Right V2 & V4

16%16%

42%42% 42%42%

58%58%

80-LeadRV Map

Augmented 12-Leads

Inferior MI

Torso map localizes & demonstrates injury extent

Advantages of 80-Lead ECG in Diagnostic Dilemmas:

Left Bundle Branch Block

STEMI and Left Bundle Branch Block: the 12-lead picture

V leads are swamped by deep, wide QRS of LBBB

STEMI and Left Bundle Branch Block: the 80-lead view

12 lead area swamped by LBBB complexes, unable to tell position of ST0 (J point)

STEMI and Left Bundle Branch Block: the 80-lead view

ECG from unaffected area sets ST0 (J point), the middle marker

12 lead area swamped by LBBB complexes, unable to tell position of ST0 (J point)

STEMI and Left Bundle Branch Block: the 80-lead view

ECG from unaffected area sets ST0 (J point), the middle marker

12 lead area swamped by LBBB complexes, unable to tell position of ST0 (J point)

Now see true ST0 elevation – Inferior MI

80 Lead Mapping and LBBB• Maynard SJ et al. Body surface mapping improves early diagnosis

of acute myocardial infarction with LBBB Heart 2003;89:998-1002 – 56 CP pts and LBBB,

• 32% AMI

12-lead (Sgarbossa criteria)

12-lead (Hands criteria)

80-lead lost reversal

Sens 0.33 (6/18) 0.17 (3/18) 0.67 (12/18)

Spec 0.97 (37/38) 0.87 (33/38) 0.71 (27/38)

PPV 0.86 (6/7) 0.38 (3/8) 0.52 (12/23)

NPV 0.76 (37/49) 0.69 (33/48) 0.82 (27/33)