False Positive ST Elevation in Patients Undergoing Direct Percutaneous Coronary Intervention David M. Larson MD, Katie M. Menssen, BS,, Scott W Sharkey MD, James Harris MD, Jeffrey T. Meland, MD Robert Schwartz MD, Barbara T Unger RN, Timothy D. Henry MD, Ridgeview Medical Center, Waconia, Minnesota and Minneapolis Heart Institute Foundation, Minneapolis, Minnesota

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

Objective 1) To determine the incidence and etiologies of “false positive” ECGs, defined as: no culprit coronary vessel and negative cardiac markers (no MI), from a non-selected cohort of STEMI patients. 2) To determine the incidence of “true false positive” ECGs defined as no culprit, no significant coronary disease and negative cardiac markers.

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

Methods Level 1 MI Protocol: Includes STEMI (ST elevation or new Left Bundle Branch Block) with symptom < 24hrs. Diagnosis and decision to activate the cath lab is made by the Emergency Physician at the presenting hospital. Transferred patients go directly to cath lab for Primary or Facilitated PCI Data obtained from a prospective registry of all “Level 1 MI” patients that includes clinical, laboratory, ECG, angiographic and follow up data.

What is the prevalence and etiology of “False Positive” Cath Lab Activation? STEMI Larson, DM et al JAMA 2007;298(23):

The Clinical Challenge Denying Reperfusion Falsely Declaring an Emergency Larson, DM et al JAMA 2007;298(23):

Definitions of “False Positive” Cardiac Cath Lab Activation No culprit No significant coronary disease Negative cardiac biomarkers Larson, DM et al JAMA 2007;298(23):

Results from the Level 1 MI Program From 3/03 to 11/06, 1,345 STEMI patients enrolled in Level 1 MI program including 1,048 transferred from 30 rural or community hospitals. 149 (11.2%) had normal cardiac biomarker levels. Larson, DM et al JAMA 2007;298(23):

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 Activations “ False 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 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 repolarization 25 Non-diagnostic ECG 21 Pericarditis20 Prior MI 20 LBBB11 LVH8 Vasospasm4 Tachycardia related 3 RBBB3 Pacemaker3 Brugada syndrome 1 Aortic dissection 1 Unknown3 Stress Cardiomyopathy 17Myocarditis15 Prior MI 9 STEMI –embolic/spasm 9 LBBB4 NSTEMI2 Pulmonary embolus 2 Aortic neoplasm 1 Severe aortic stenosis 1 Drug overdose 1 Unknown3 Larson, DM et al JAMA 2007

No culprit and negative markers by Hospital ED Volume ED visits/year Not significant Larson, DM et al JAMA 2007

Left Bundle Branch Block New or presumed new LBBB observed in 36 (2.6%) of patients –No culprit: 16 (44%) –No significant CAD: 10 (27%) –Negative cardiac biomarkers: 13 (36%) 30 day mortality in those with new LBBB was 8.3% Larson, DM et al JAMA 2007;298(23):

Gender differences 381 (28.3%) women enrolled in Level 1 registry –No culprit: 17.1% women vs 12.7% men (p=0.04) –No significant CAD: 13.6% women vs 7.9% men (p=0.001) –Negative biomarkers: 12.3% women vs 10.6% men (p=0.36) Stress cardiomyopathy may account for differences Larson, DM et al JAMA 2007;298(23):

Summary: Incidence of “False Positive” Cath Lab Activation No culprit: 14% Normal or Minimal CAD: 9.5% Negative cardiac markers: 11.2% Combination of no culprit and negative biomarkers: 9.2% Larson, DM et al JAMA 2007;298(23):

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