Here's a great case submitted by a faithful reader who wishes to remain anonymous.
On arrival patient is found sitting on his living room couch. He appears anxious and acutely ill.
He states that he was riding his bike when he became anxious, had a "coughing spell" and started to experience chest discomfort. The location of the chest discomfort is in the center of his chest and slightly to the left.
Onset: Sudden while riding a bike
Provoke: Nothing makes the pain better or worse
Quality: Difficult to describe but with prompting the patient calls it "pressure"
Radiate: Left jaw and left arm
Severity: 7/10
Time: No previous episodes
The patients skin is warm and moist. The color is normal.
The patient denies shortness of breath. Breath sounds are clear bilaterally.
He is nauseated but he has not vomited.
Past medical history: Healthy
Medications: None
Vital signs are assessed.
Resp: 22
Pulse: 98
BP: 140/84
SpO2: 100 with oxygen via NRB @ 15 LPM
The cardiac monitor is attached.
A 12-lead ECG is captured.
What is your impression?
*** Update 05/14/2010 ***
The importance of serial ECGs cannot be over-emphasized.
In this case, a second 12-lead ECG was captured just prior to arrival at the hospital.
Does this new information shed any light on the probably diagnosis?
What else could you have done?
*** Update 05/14/2010 ***
The importance of serial ECGs cannot be over-emphasized.
In this case, a second 12-lead ECG was captured just prior to arrival at the hospital.
Does this new information shed any light on the probably diagnosis?
What else could you have done?
First, lets talk about the presentation. A young patient typically doesn't make you think STEMI. However, the OPQRST findings are all indicative of an ACS event. Pressure not sharp pain is more indicative of AMI. Referred pain. Sudden onset. Also, this patient was riding a bike so we assume he is fit, does he have any other risk factors?
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Now the three lead:
First degree AVB with alight variation in PR-interval (unlike Mobitz I), single non-conducted P wave. Single PVC.
This first ECG strip wouldn't make me bat an eye on most of our elderly patients. However, a 26 y/o with this ECG rhythm is of more concern.
The SA node appears to be sick, possibly ischemic. We know that in 55% of patients the SA is fed by the RCA. In 90% the AV is fed by the RCA, so if either are the culprit, an occlusion of the RCA is likely the cause.
Now to the 12-leads.
Shortened QT, young patient though, its expected.
ST-depression isolated in V3 in first 12-lead could be RV strain. Seeing it progress in second 12-lead indicates posterior wall infarction. Early R-waves in V1 & V2 could also indicate RV strain without the ST-depression evolution, but in this case they are indicative of posterior wall MI as well.
The posterior wall of the heart is usually fed by a posterior extension of the RCA, but could be fed by the circumflex. Without lateral changes, we look at the inferior wall.
Isolated ST-elevation in lead III. Not STEMI, but with some posterior chest leads (V7, 8, & 9) it would be. In lead III the depth of the Q wave is not of concern (deep benign Qs common), but the width is, about 40 ms (not conclusive, but something to watch).
The inferior wall is fed by the marginal branch of the RCA, so with isolated changes in lead III, it probably isn't the entire marginal branch being occluded. The direction of lead III is the most right out of all three inferior leads. If you look at the way the RCA wraps around the heart after the connection to the marginal branch, it would make sense to consider the infarcted inferior portion to be to the right of the rest of the inferior wall.
Now the patient's BP is fine, but R-sided chest leads should be considered, with the changes in atrial conduction, a proximal occlusion is a possibility. The early R-waves in V1-V2 indicate a transmural infarct to the posterior wall, which could be causing the ischemia to the SA/AV node.
Dx. First degree AVB with Inferior-Posterior STEMI.
Culprit artery - Probable distal occlusion to the of the RCA just after the bifurcation with the marginal branch.
Very unlikely in such a young patient. Excellent case.
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