False Positive ST Elevation False Positive ST Elevation in Patients Undergoing in Patients Undergoing Direct Percutaneous Direct Percutaneous Coronary InterventionCoronary Intervention

David M. Larson MD, Katie M. Menssen, BS,, Scott David M. Larson MD, Katie M. Menssen, BS,, Scott W Sharkey MD, James Harris MD, Jeffrey T. W Sharkey MD, James Harris MD, Jeffrey T.

Meland, MD Robert Schwartz MD, Barbara T Unger Meland, MD Robert Schwartz MD, Barbara T Unger RN, Timothy D. Henry MD,RN, Timothy D. Henry MD,

Ridgeview Medical Center, Waconia, Minnesota and Ridgeview Medical Center, Waconia, Minnesota and Minneapolis Heart Institute Foundation, Minneapolis Heart Institute Foundation,

Minneapolis, Minnesota Minneapolis, Minnesota

IntroductionIntroductionPrevious data shows that up to 11% of Previous data shows that up to 11% of STEMI patients treated with thrombolysis STEMI patients treated with thrombolysis did not have a Myocardial Infarction (MI)did not have a Myocardial Infarction (MI)ACC/AHA guidelines recommend that the ACC/AHA guidelines recommend that the Emergency physician make the decision Emergency physician make the decision regarding reperfusion therapy for STEMIregarding reperfusion therapy for STEMIThere is limited data reporting the rate of There is limited data reporting the rate of “false positive” ECGs in STEMI patients “false positive” ECGs in STEMI patients treated with Percutaneous Coronary treated with Percutaneous Coronary Intervention.Intervention.

ObjectiveObjective

1)1) To determine the incidence and To determine the incidence and etiologies of “false positive” ECGs, etiologies of “false positive” ECGs, defined as: no culprit coronary vessel defined as: no culprit coronary vessel and negative cardiac markers (no MI), and negative cardiac markers (no MI), from a non-selected cohort of STEMI from a non-selected cohort of STEMI patients. patients.

2)2) To determine the incidence of “true To determine the incidence of “true false positive” ECGs defined as no false positive” ECGs defined as no culprit, no significant coronary disease culprit, no significant coronary disease and negative cardiac markers.and negative cardiac markers.

MethodsMethods

Minneapolis Heart Institute/Abbott Minneapolis Heart Institute/Abbott Northwestern Hospital (ANW) – a tertiary Northwestern Hospital (ANW) – a tertiary cardiac center with referral relationships cardiac center with referral relationships with 30 community hospitals (CH) in with 30 community hospitals (CH) in Minnesota and Wisconsin – instituted the Minnesota and Wisconsin – instituted the “MHI Level 1 MI Program” in 2003.“MHI Level 1 MI Program” in 2003.

MethodsMethodsLevel 1 MI Protocol: Includes STEMI (ST elevation Level 1 MI Protocol: Includes STEMI (ST elevation or new Left Bundle Branch Block) with symptom < or new Left Bundle Branch Block) with symptom < 24hrs. Diagnosis and decision to activate the cath 24hrs. Diagnosis and decision to activate the cath lab is made by the Emergency Physician at the lab is made by the Emergency Physician at the presenting hospital. Transferred patients go presenting hospital. Transferred patients go directly to cath lab for Primary or Facilitated PCIdirectly to cath lab for Primary or Facilitated PCI

Data obtained from a prospective registry of all Data obtained from a prospective registry of all “Level 1 MI” patients that includes clinical, “Level 1 MI” patients that includes clinical, laboratory, ECG, angiographic and follow up data.laboratory, ECG, angiographic and follow up data.

What is the prevalence and etiology What is the prevalence and etiology of “False Positive” Cath Lab of “False Positive” Cath Lab

Activation?Activation?

STEMI

Larson, DM et al JAMA 2007;298(23):2754-2760

The Clinical ChallengeThe Clinical Challenge

Denying Reperfusion

Falsely Declaring an Emergency

Larson, DM et al JAMA 2007;298(23):2754-2760

Definitions of “False Positive” Definitions of “False Positive” Cardiac Cath Lab ActivationCardiac Cath Lab Activation

No culpritNo culprit

No significant coronary diseaseNo significant coronary disease

Negative cardiac biomarkersNegative cardiac biomarkers

Larson, DM et al JAMA 2007;298(23):2754-2760

Results from the Level 1 Results from the Level 1 MI ProgramMI Program

From 3/03 to 11/06, 1,345 STEMI From 3/03 to 11/06, 1,345 STEMI patients enrolled in Level 1 MI program patients enrolled in Level 1 MI program including 1,048 transferred from 30 rural including 1,048 transferred from 30 rural or community hospitals.or community hospitals.

149 (11.2%) had normal cardiac 149 (11.2%) had normal cardiac biomarker levels.biomarker levels.

Larson, DM et al JAMA 2007;298(23):2754-2760

STEMI Diagnosis

N=1,345

Angiography

N=1,335

5 died prior to angio

5 Case canceled

Multiple potential culprits

N=10 (0.7%)

Clear culprit

N=1138 (85.3%

No Angiographic Culprit

N=187 (14%)

“ “False Positive” Cath lab ActivationsFalse Positive” Cath lab Activations

Larson, DM et al JAMA 2007

No Significant CAD

N = 127 (9.5%)

Positive Cardiac Markers

N= 48 (38%)

Negative Cardiac Markers

N = 44 (73%)

No Culprit

N=187 (14%)

Mod-Severe CAD

N =60 (4.5%)

Positive Cardiac Markers

N= 16 (27%)

Negative Cardiac Markers

N = 79 (62%)

Multiple Potential Culprits

N=10

Positive Cardiac Markers

N= 10

Negative Cardiac Markers

N = 26

Clear culprit

N=1138

Positive Cardiac Markers

N= 1112

Negative Cardiac Markers

N = 0

With a culpritWith a culprit

Larson, DM et al JAMA 2007

Positive Cardiac Markers

N= 64 (4.8%)

Negative Cardiac Markers

N = 123 (9.2%)

No Angiographic Culprit

N=187 (14%)

Early repolarizationEarly repolarization 2525

Non-diagnostic ECGNon-diagnostic ECG 2121

PericarditisPericarditis 2020

Prior MIPrior MI 2020

LBBBLBBB 1111

LVHLVH 88

VasospasmVasospasm 44

Tachycardia relatedTachycardia related 33

RBBBRBBB 33

PacemakerPacemaker 33

Brugada syndromeBrugada syndrome 11

Aortic dissectionAortic dissection 11

UnknownUnknown 33

Stress CardiomyopathyStress Cardiomyopathy 1717

MyocarditisMyocarditis 1515

Prior MIPrior MI 99

STEMI –embolic/spasmSTEMI –embolic/spasm 99

LBBBLBBB 44

NSTEMINSTEMI 22

Pulmonary embolusPulmonary embolus 22

Aortic neoplasmAortic neoplasm 11

Severe aortic stenosisSevere aortic stenosis 11

Drug overdoseDrug overdose 11

UnknownUnknown 33

Larson, DM et al JAMA 2007

No culprit and negative markers by No culprit and negative markers by Hospital ED VolumeHospital ED Volume

6.7

99.6

10.7

9.2

0

2

4

6

8

10

12

ANW > 20 K 20-10 K < 10 K Overall

percent

ED visits/yearNot significant Larson, DM et al

JAMA 2007

Left Bundle Branch BlockLeft Bundle Branch Block

New or presumed new LBBB observed in 36 New or presumed new LBBB observed in 36 (2.6%) of patients(2.6%) of patients– No culprit: 16 (44%)No culprit: 16 (44%)

– No significant CAD: 10 (27%)No significant CAD: 10 (27%)

– Negative cardiac biomarkers: 13 (36%)Negative cardiac biomarkers: 13 (36%)

30 day mortality in those with new LBBB was 30 day mortality in those with new LBBB was 8.3%8.3%

Larson, DM et al JAMA 2007;298(23):2754-2760

Gender differencesGender differences

381 (28.3%) women enrolled in Level 1 381 (28.3%) women enrolled in Level 1 registryregistry– No culprit: 17.1% women vs 12.7% men No culprit: 17.1% women vs 12.7% men

(p=0.04)(p=0.04)– No significant CAD: 13.6% women vs 7.9% No significant CAD: 13.6% women vs 7.9%

men (p=0.001)men (p=0.001)– Negative biomarkers: 12.3% women vs 10.6% Negative biomarkers: 12.3% women vs 10.6%

men (p=0.36)men (p=0.36)

Stress cardiomyopathy may account for Stress cardiomyopathy may account for differencesdifferences

Larson, DM et al JAMA 2007;298(23):2754-2760

Summary: Incidence of “False Summary: Incidence of “False Positive” Cath Lab ActivationPositive” Cath Lab Activation

No culprit: 14%No culprit: 14%

Normal or Minimal CAD: 9.5% Normal or Minimal CAD: 9.5%

Negative cardiac markers: 11.2%Negative cardiac markers: 11.2%

Combination of no culprit and negative Combination of no culprit and negative biomarkers: 9.2%biomarkers: 9.2%

Larson, DM et al JAMA 2007;298(23):2754-2760

ConclusionsConclusions

The incidence of “false positive” ECGs The incidence of “false positive” ECGs in STEMI patients treated with Primary in STEMI patients treated with Primary PCI is similar to previous data in PCI is similar to previous data in patients treated with thrombolytic patients treated with thrombolytic therapy.therapy.Patients presenting with “False Positive” Patients presenting with “False Positive” ST elevation are a heterogeneous ST elevation are a heterogeneous group, many with other serious cardiac group, many with other serious cardiac conditions.conditions.