PAGE 1 • THE PRESENTATION
The first five minutes of the consultation seemed to confirm what everyone before had concluded. The danger was that the sixth minute changed the story. The setting was emergency, and the working diagnosis was uncomplicated inferior STEMI. The patient had already received a reasonable first-line approach for that label, yet the trajectory was wrong: symptoms persisted, objective abnormalities failed to settle, or a new feature appeared that did not belong comfortably inside the original diagnosis.
The history was retaken from the beginning rather than edited around the existing label. The chronology mattered. Symptoms that had previously been recorded as separate complaints began to line up on the same timeline. Medication exposure, occupational and environmental history, family history, travel, diet, sleep, substance use and previous apparently unrelated episodes were revisited. The examination was repeated with one rule: do not look only for findings that confirm the first diagnosis.
A few details began to resist the original explanation. Look again…The decisive cluster was: hypotension, raised JVP and relatively clear lungs.
None of those clues alone was dramatic enough to force a diagnostic reset, but together they changed the pre-test probabilities. The patient was not simply “failing treatment”; the treatment may have been aimed at the wrong mechanism.
The initial investigations were reviewed as raw data rather than as the interpretation printed beside them. Trends were more useful than isolated values. The team asked whether every abnormality could be explained by uncomplicated inferior STEMI, whether any expected feature was conspicuously absent, and whether a single alternative diagnosis could connect the apparently unrelated findings. This was the first turning point.
A green-highlight moment in the case came from the mismatch between the expected course and the actual course. When a common diagnosis behaves uncommonly, the next step is often not simply “more treatment”; it is to reopen the diagnosis.
PAGE 2 • SOMETHING DOESN’T FIT
The diagnostic strategy was deliberately narrowed. Instead of ordering a broad panel with no hierarchy, the next test was chosen because it could meaningfully move probability in either direction. The pivotal investigation was right-sided ECG leads and bedside echocardiography. It was interpreted alongside the bedside findings, not in isolation.
At this stage, the team explicitly reconstructed the differential diagnosis. The original label — uncomplicated inferior STEMI — remained on the list because common diseases remain common. But mimics, multisystem disorders, medication effects and physiology-driven alternatives were ranked according to the new clues. The question changed from “What else can cause this symptom?” to “What mechanism best explains the entire sequence?”
The result did not instantly announce the answer. It created a pattern. A second review of the chronology made the pattern harder to ignore. One clue that had looked incidental now became central; another abnormality that had been blamed on illness severity turned out to be part of the same process. The case moved from a collection of abnormalities to a coherent syndrome.
The clinical reasoning trap was pattern completion without hemodynamic localization. This is common in real practice because the first diagnosis is often sensible. Errors do not always begin with ignorance; many begin with a plausible explanation that is never challenged after the patient stops behaving as expected. A useful safeguard is to create a “diagnostic timeout” whenever there is treatment failure, unexpected physiology, a new organ system involved, or a laboratory trend that contradicts the working model.
By the end of the second page, the team had not yet spoken the final diagnosis aloud. But they had reached the point where the original diagnosis could no longer explain the patient without multiple exceptions. The alternative explanation required fewer exceptions and predicted the findings that had seemed surprising.
PAGE 3 • THE REVEAL
The final synthesis was built from the timeline, the bedside pattern and the targeted investigation.
FINAL DIAGNOSIS
Right ventricular infarction
The point of the case was not that this diagnosis is always difficult; it was that it became difficult because the early presentation resembled uncomplicated inferior STEMI and because the first label shaped everything that followed.Why did the diagnosis fit? The key was the combination of hypotension, raised JVP and relatively clear lungs, together with the information provided by right-sided ECG leads and bedside echocardiography. Once those pieces were considered together, the prior contradictions became expected features rather than noise.
Management then shifted from symptom control to mechanism-directed care. The broad principles were: maintain appropriate preload, avoid precipitous venodilation, reperfuse promptly and manage bradyarrhythmia when present. Patient-specific decisions still depend on severity, comorbidity, local protocols, contraindications, diagnostic certainty and specialist input. The educational value is in recognizing the pivot early enough that definitive management is not delayed.
The team also reviewed what could have prevented the delay. First, treatment failure should trigger diagnostic reconsideration rather than automatic escalation. Second, trends and physiology deserve as much attention as single test results. Third, a problem list should be periodically recombined: if several “separate” problems start together, one unifying process may be more likely than several coincidences. Finally, a negative test only reduces probability according to that test’s sensitivity, timing and pre-test probability; it does not erase a strong clinical signal.
TAKE-HOME MESSAGES
• Revisit the diagnosis when the clinical course does not match the expected response.
• Build the differential from mechanisms, not from memorized lists alone.
• Ask which clue the current diagnosis explains least well.
• Use targeted investigations to change probability, not simply to accumulate data.
• The final diagnosis in this case was Right ventricular infarction.