45 year old male with “numb hands” – Discussion

Go back to 45 year old male with “numb hands” to read about the presentation, and see the ECGs.

 

The culprit artery?

After arriving at the hospital, the patient bypassed the ED, going directly to the cardiac catheterization lab. The patient was found to have a total occlusion of the proximal RCA, and the cardiologist was able to deploy a stent without problem.

 

Excellent D2B, but …

Despite prompt activation of the 911 system, excellent EMS care, field activation of the cath lab, and an uncomplicated percutaneous coronary intervention, he was left with moderate ventricular dysfunction. The system “did everything right,” but the patient still had significant heart damage – why?

 

Faster STEMI treatment, but no change in mortality?

A recent study in the New England Journal of Medicine describes this question on a larger scale. The authors of  “Door-to-Balloon Time and Mortality among Patients Undergoing Primary PCI” found that, although D2B times for STEMI have decreased significantly over the past few years, the mortality for STEMI hasn’t changed.

The researchers looked at 515 hospitals across the country, using a Medicare database. Over a period of 4 years, the percent of STEMI patients who received PCI within 90 minutes of hospital arrival increased from 60% to 83%. Unfortunately, mortality rates in those STEMI patients did not change. Even when they looked only at the high-risk sub-groups (> 75 years-old, anterior infarct, or cardiogenic shock), they failed to find any improvement.

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So why have we (EMS, EM, and cardiology) been able to improve the process so much, but not the outcomes, at least in term of mortality in this population? Clearly, this is a multifaceted issue, with no single explanation. For example, the adjunctive medical care of these patients has improved in many ways over the years, which might “hide” the benefit of the shorter D2B. Also, cardiologists may be bringing more patients with unmeasured comorbid conditions for emergent cath, which would also serve to understate the benefits of the faster process.

However, some suggest that part of the problem has to do with how long many of these patients wait to call EMS, if they call at all. As the D2B interval shrinks, the time from symptom onset to first medical contact (FMC) takes on a greater significance. A decrease of 10 minutes in the D2B time won’t help much if the time to FMC exceeds, say, 3 hours! But that didn’t seem to be the problem with Tim’s patient, right?

 

Why the 90 minute “on-scene” time?

In the case of our patient, EMS was called fairly soon after the symptoms started. However, you can see that the 2 ECGs are separated by about 90 minutes. Why?

Because he declined transport the first time EMS arrived. Although EMS and the patient’s girlfriend did all they could to convince him to go to the hospital, he refused to go. After EMS left his symptoms did not improve, and indeed worsened. EMS was called back, with the same paramedic responding, and the patient was willing to be transported at that point.

In the hospital, his first troponin was 6 times normal, suggesting that his infarct had been going on for several hours, leading to significant myocardial loss, leading to the moderate heart failure he left the hospital with.

 

Any signs on the first ECG?

So, was there anything on that first ECG? I think it’s very difficult to say, but there are certainly no obvious features which would warrant cath lab activation. Indeed, the relative “normalness” of this ECG could have worked against the patient. What I mean by this is …

 

One last thought

Frankly, this ECG only makes it more surprising that ECG #2 was ever obtained.

Consider the context: A young-ish opioid addict, with a history of “anxiety,” who is clearly hyperventilating, and has a chest pain that is reproduced on palpation. Some paramedics, upon being called back to a patient who had just refused transport, would not bother to acquire a second ECG. It speaks volumes about this medic’s clinical sense, and their professionalism, that they immediately obtained ECG #2 without delay, and acted on it.

3 Comments

  • Chris N says:

    Regarding the “Any Signs on the First ECG”.

    I think the first ECG actually did have some subtle indicators, specifically in the inferior leads and AVL. While they do not meet the rigid guidelines of 2mm in contiguous leads, it has become more accepted that the guidelines are just that – guidelines and should only “guide” the clinicians overall judgment. Additionally, we also know that the amplitude of the R-waves and corresponding ST-elevations are relatively proportional, so as to say that if you have a smaller amplitude QRS complex, the corresponding ST-elevation in a STEMI case MAY also have a lower amplitude and still be indicative of a STEMI. Additionally, and what has really been driven home in multiple cases posted on this site, is the inverted T-waves (especially with ST-depression) in aVL. That should always increase the index of suspicion when a pt is c/o chest pain, back pain, jaw pain, arm pain, heaviness in chest, SOB, diaphoresis, nausea/vomiting or any other MI signs/symptoms with correlating hx.

    While STEMI triage guidelines set standards for cath lab activation, such as the 2mm elevations, sbargossa criteria with BBB, etc., at a minimum, cases like these should be monitored closely for evolution, as we can see from the second ECG (even though it was 90-minutes later), the “subtle” identifications from the first ECG played out to a classic inferior STEMI in the second. As one person posted previously, it is easy to be an “armchair quarterback” and whether another clinician may have identified the subtleties in the field given the circumstances is hard to say. However, I can tell you that this case has given me some food for thought in the event I am ever presented with a case like this, where subtle ECG findings in connection with clinical signs, symptoms and pt hx may give me cause to argue harder with a “difficult pt” to go to the hospital.

    What we do not know is, had the medics in this case transported the pt after the first ECG (meaning the refusal portion of the story did not happen), would the Inferior STEMI have shown on the ECG early enough to activate the cath lab (using the normal STEMI guidelines). This may have had a direct effect on the D2B time and the subsequent ventricular dysfunction. Conversely, the pt’s prior hx and life choices may have already caused the hypertrophy noted in the ECGs and the damage to the ventricles may have already occurred. We will not know for this case, but interesting nonetheless.

    Great case – thank you for sharing and the follow-up.

    • brooksw says:

      I agree that the cases presented at this website have served to increase awareness of the subtle ways in which an acute coronary occlusion can manifest on the ECG. And indeed, not all ST elevation has to be > 1 mm to be significant, for the reasons you lay out.

      However, even in hindsight, I’m not sure we can make too much of the initial ECG. The ST elevation in the inferior leads in concave upwards, the J-point in the inferior and lateral leads is “notched,” and ST depression in aVL, in my view, is arguable (the slight variation in the baseline confuses things). Furthermore, the QTc isn’t prolonged. It looks more like a good example of early repolarization, than a nice case of early inferior STEMI. Perhaps a true ECG Jedi could have picked this up, but I’m skeptical.

      Check out a case and ECG at Dr Smith’s ECG Blog for a similar ECG that is interpreted as classic ER.

  • Chris N says:

    I think the main takeaway here is that this case, while not being an easy identification, certainly warranted extra attention. The human body usually tell us when there is something going on that should not be…we simply have to be able to read the signs. While it may be a little too “Jedi-ish” to make any determinations off the first ECG, understanding that cardiac etiology can evolve is crucial to creating a plan of assessment, re-assessment, treatment and transport decisions. Obviously, this case had the additional hiccup of a difficult pt that refused despite the urgings of EMS personnel, however, even if that were not the case…a lazy clinician could have stopped at the first ECG and taken the pt to a local ED without PCI capabilities and the D2B could have been delayed.

    I have been trying to take everything I am seeing in the field as well as what I read on the various education sites and put it all together as time goes on. I try to create a knowledge bank instead of a specific set of cases and treatments…when a new case presents itself, I use all the collective knowledge to see if I notice something I may have otherwise overlooked.

    I am truly enjoying these cases and the dialogue. Thanks again.

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