Today, in this Dear Carolyn episode (our 11th in the occasional series featuring Heart Sisters readers sharing their heart patient perspectives), we’ll attempt to address my reader Eva’s observations about how our heart attacks are currently classified:
“I take issue with the terms STEMI (the most serious type of heart attack) and NSTEMI (a slightly less serious heart attack). But both types of heart attack have a serious impact on our lives and how we live them.”
The day I first read your comment in response to an earlier Heart Sisters post coincided with the tragic heart attack death of a woman in an American hospital’s Emergency Department.
The case involved a 70-year old woman who had been experiencing chest pain for approximately one week, and more recently profuse sweating with extreme fatigue. The cardiac catheterization lab at the unidentified hospital was activated when she first arrived by ambulance to the Emergency Department, but the cardiology team insisted that the woman’s ECG test results “did not meet STEMI criteria”, so cancelled the cath lab activation.
According to current diagnostic criteria, certain electrical waves on an ECG result can show what kind of heart attack may be taking place:
- in a STEMI, the S- and the T-waves are elevated on a 12-lead ECG, suggesting a higher risk that heart muscle is in danger.
- in a NSTEMI (non-STEMI), those ECG changes in the S- and T-waves are not seen, suggesting a lower risk.
Because you’re a regular Heart Sisters reader, you won’t be surprised by now to learn that the people most likely to be diagnosed with NSTEMI are women.(1) Women diagnosed with NSTEMI are less likely than their male counterparts to receive guideline-recommended treatments and interventions. The 5-year risk of death from NSTEMI for women is 42% (vs. 29% in men).
According to Emergency physician Dr. Pendell Meyers (who was not involved in this woman’s case, but reported on it later), her ECGs “clearly show what’s called an Occlusion Myocardial Infarction (OMI) which occurs when a Type 1 Acute Myocardial Infarction (heart attack) is caused by total or near-total occlusion (blockage) of a coronary artery with insufficient collateral circulation.”
Physicians who are proponents of replacing the identifying names STEMI and NSTEMI with this newer terminology propose that, instead of asking “Is the patient having a STEMI?”, the more appropriate question might be: “Does the patient have an acute coronary occlusion that would benefit from immediate intervention?“ The universally recommended STEMI criteria, they suggest, may likely be missing more than one-fourth of patients with an acute coronary artery blockage.(2)
Their preferred terms: OMI (Occlusion Myocardial Infarction) and NOMI (Non-Occlusion Myocardial Infarction – no blockage, or sufficient collateral circulation to avoid active infarction).
Meanwhile, back in that Emergency Department, over 90 minutes had passed since this woman had first arrived at the hospital, and the team was still debating. She was clearly in trouble and getting worse while experts continued to disagree with each other about whether she was sick enough.
The Emergency physicians pointed out evidence for OMI. The cardiologists said they would “consider urgent cath after further stabilization.”
Her heart rate was dangerously slow. Her cardiac enzyme (troponin) blood test was positive (a marker for heart attack). A bedside echocardiogram showed abnormality in wall motion of the heart’s left ventricle. The cardiology team “requested a head CT scan before cath for unknown reasons” (which was negative).
The Emergency team again pointed out evidence of OMI, this time using diagnostic criteria called “Modified Sgarbossa criteria”. The cardiologists “were not familiar with this term”. The patient was intubated, and a transvenous pacemaker was implanted.
Two and a half hours after she arrived at that hospital, the woman died without ever making it to the cath lab.
She didn’t die because she couldn’t get to the hospital in time, or because no doctor was available to help her. She died surrounded by dueling experts arguing with each other whether her heart attack was a STEMI or not.
It’s common to play armchair quarterback after the fact – and physicians are no exception. Following this patient’s death, many of them subsequently attempted to make sense of what had just happened.
Dr. Ken Grauer was one. He’s Professor Emeritus at the University of Florida College of Medicine, and specializes in interpreting ECG results. His assessment of the timeline and the ECG findings was included in Dr. Meyers’ report, describing these findings as “further confirmation that there has been a recent acute cardiac event that is still ongoing:“
“I do not understand why the cardiology team was ‘stuck’ on requiring STEMI criteria in this case.
“This profoundly symptomatic 70-something year-old woman had symptoms for a week prior to admission. Regardless of whether STEMI criteria are (or are not) strictly met, a recent acute event in a dramatically symptomatic patient is clear indication for prompt diagnostic/therapeutic cardiac catheterization.
“While the additional history of ‘acute worsening’ of symptoms might indicate the time of acute occlusion (given that she had symptoms for days prior to calling 911), the cardiology team should clearly have considered the possibility that the initial event occurred before the day of admission to the hospital.
“I hope feedback is provided to the involved cardiology team.”
I asked the senior first responder who had told me this woman’s story what he thought could be learned from such a tragedy. Would her case be discussed at hospital rounds? Taught at medical school? Published as a case study in Emergency Medicine or Cardiology journals? His despairing response to me:
“I guarantee this will NOT be considered a missed STEMI, and will NOT be included in official first medical contact statistics. The system is broken and needs to be fixed. No one will learn anything, and they will rinse and repeat.”
A 2019 article in the journal Emergency Physicians – written by the University of New Mexico Emergency Medicine resident and former Critical Care paramedic Andrew Merelman and Emergency physician, researcher, author and University of Minnesota Professor of Emergency Medicine Stephen W. Smith – had already made the case for a systemic change in how heart attacks are identified:
“The classical STEMI criteria were developed to ensure that obvious myocardial infarction is not missed in the acute setting.
“However, emergency providers must be familiar with many other ECG manifestations of acute coronary artery occlusion. STEMI is only one of many potential presentations of Occlusion Myocardial Infarction (OMI).
“There are a few principles that apply to diagnosis of OMI in every case. The first is that serial ECGs should be performed in all cases where acute coronary syndrome is suspected. This can prevent missing an obvious OMI, as ECG findings can evolve over a very short (often 5-15 minutes) period of time.
“Changes in ST segment or T-wave morphology over a short period of time are strongly suggestive of an unstable coronary lesion requiring intervention. But absence of changes does NOT mean the patient no longer requires emergent catheterization.
“Patients presenting with symptoms of Acute Coronary Syndrome must be assumed to have acute coronary artery occlusion until proven otherwise. Assessment can be augmented by performing serial ECGs and bedside echocardiography. The ECG is one of many tools used to diagnose OMI and the astute clinician must be able to recognize ECG signs of OMI that are outside of traditional STEMI guidelines.”
About this particular woman’s case, Dr. Meyers’ report concluded:
“We must not let STEMI criteria prevent identification and/or treatment of Occlusion MI. We must hold ourselves and our consultants to a higher standard to protect our patients.”
Dr. Smith told me last week via Twitter (in response to my post about the 2021 Chest Pain Guidelines) that the terms OMI and NOMI have been recently endorsed by cardiologists in the journal Circulation (“Occlusions, Inclusions and Exclusions: Time to Reclassify Infarction?“) – although, as he pointed out to me, the authors did not acknowledge Dr. Smith or his colleagues for originating that terminology. This publication by cardiologists in a cardiology journal, however, might be significant: so far, the movement to replace STEMI and NSTEMI classifications with the new terminology seems to be championed by Emergency physicians, not necessarily cardiologists.
A name change, by the way, is not a foreign concept in medicine: STEMI and NSTEMI were themselves new classification names for heart attack just 21 years ago when those terms replaced “Q-wave” and “non-Q-wave” myocardial infarctions. (Braunwald et al, JACC, Guidelines for Unstable Angina, 2000).
OMI and NOMI are not simply different names, but a unique way to reclassify heart attacks with the ultimate goal of improving patient care.
So I think you’re correct, Eva: “Both types of heart attack have a serious impact on our lives and how we live them.”
1. Bellasi A et al.”New insights into ischemic heart disease in women”. Cleveland Clinic Journal of Medicine.74:585–594.
2. Aslanger EK, Meyers PH, Smith SW. “STEMI: A transitional fossil in MI classification?” Journal of Electrocardiology 2021 Mar-Apr; 65:163-169.
NOTE FROM CAROLYN: I wrote more about the many critical thinking skills physicians use when making a cardiac diagnosis in my book, A Woman’s Guide to Living with Heart Disease (Johns Hopkins University Press). You can ask for it at your local library or favourite bookshop, or order it online (paperback, hardcover or e-book) at Amazon – or order it directly from my publisher, Johns Hopkins University Press (use their code HTWN to save 30% off the list price).
Q: Is it time to revisit how our heart attacks are classified?
– Visit my patient-friendly, jargon-free glossary of hundreds of confusing cardiology terms and abbreviations.
– My 2012 post called “No Such Thing As a ‘Small’ Heart Attack”
-DOWN WITH STEMI: The OMI Manifesto by Dr. Pendell Meyers
– Dr. Stephen W. Smith‘s ECG training site (if you love nerding out with ECG experts who post diagnostic ECG challenges for other experts to interpret!)
-Dr. Stephen W. Smith’s book “The ECG in Acute MI: An Evidence-Based Manual of Reperfusion Therapy“ (free PDF-version of this textbook for healthcare professionals)