Go back to 45 year old male with â€œnumb handsâ€ 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 â€œdid everything right,â€ 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 Â â€œDoor-to-Balloon Time and Mortality among Patients Undergoing Primary PCIâ€ found that, although D2B times for STEMI have decreased significantly over the past few years, the mortality for STEMI hasnâ€™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.
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 didnâ€™t seem to be the problem with Timâ€™s patient, right?
Why the 90 minute â€œon-sceneâ€ 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 patientâ€™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 itâ€™s very difficult to say, but there are certainly no obvious features which would warrant cath lab activation. Indeed, the relative â€œnormalnessâ€ 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 â€œanxiety,â€ 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 medicâ€™s clinical sense, and their professionalism, that they immediately obtained ECG #2 without delay, and acted on it.