Inferior ST Elevation with Hypotension and Bradycardia
A 49-year-old man with diabetes and a 30-pack-year smoking history has had 45 minutes of crushing substernal pressure that began while climbing stairs. He is diaphoretic, nauseated, and rates the pain 6/10. Vitals: BP 88/54, HR 52, RR 22, SpO2 95% on room air. His lungs are clear. He asks for "the spray under the tongue" that helped him last time. Your 12-lead shows roughly 2 mm of ST elevation in II, III, and aVF, about 1 mm of ST depression in I and aVL, and 1.5 mm of ST depression in V1 through V3 with prominent R waves in those leads.
1. Which leads show injury and which show reciprocal change, and how do you know the difference rather than just naming territories?
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The reasoning is about direction, not memorized lists. ST elevation marks the leads facing the injured myocardium; ST depression in leads anatomically opposite the injury is the mirror image of that same current, not a second injury.
- II, III, aVF face the inferior wall, so 2 mm of elevation there is the primary injury - an inferior infarct, most often the right coronary artery.
- I and aVL are high lateral and electrically opposite the inferior leads; their 1 mm depression is reciprocal. aVL is typically the most sensitive reciprocal lead in inferior injury, so depression there supports the inferior diagnosis.
Saying "inferior and lateral MI" because both elevation and depression appear would be the error this question tests. Ask of every depressed lead: is it geometrically opposite an elevated lead? If yes, treat it as reciprocal and count the elevated leads as the territory.
2. What do the V1–V3 findings mean here, and what would you ask the provider about?
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The temptation is to call V1–V3 depression "anterior ischemia." In this context that reading is probably wrong. When inferior elevation is present and V1–V3 show ST depression with tall R waves and upright T waves, the depression is most often the reciprocal mirror of posterior wall injury - the posterior wall is electrically silent from the standard anterior vantage point.
Confirming it means recording posterior leads (V7–V9), which are placed on the back at the same horizontal level as V4–V6. Elevation there turns a suspected posterior extension into a demonstrated one, with real implications for how much myocardium is at risk.
Your contribution as the tech: don't accept a generic "anterior changes" label downstream. State the pattern, state the interpretation you suspect, and ask whether posterior leads should be obtained - and do it before the patient leaves the department.
3. HR 52 with BP 88/54 - what does that suggest physiologically, why does it raise urgency, and what should you do about his request for nitroglycerin?
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Bradycardia with hypotension, clear lungs, and inferior injury suggests the right ventricle may be involved (or that the sinus node's blood supply, usually from the right coronary artery, is ischemic). A stiff, underfilled right ventricle depends on preload to maintain output; drop the preload and the pressure falls further.
That is why vasodilators such as nitroglycerin are risky in this picture - a patient with suspected right ventricular involvement can crash after a dose that would be routine otherwise. Nurses and providers make that decision; the tech does not administer or recommend medications. What you should do is not encourage him, tell him you will get the nurse right away, and report the vital signs and the EKG findings together - the combination is the message.
Urgency: do not route this through routine processing. Give the tracing directly to the provider or nurse caring for him now, state "inferior ST elevation with hypotension and bradycardia," and stay available for repeat tracings, especially after any intervention.