Epigastric pressure and nausea for four hours

Type 2 diabetes on metformin, hypertension on ramipril and indapamide. Ex-smoker. Seen at an out-of-hours clinic two hours ago and given omeprazole for indigestion; no ECG was recorded there.

Stage 1 of 2

Dilys Morgan came back because the pressure under her ribs had not settled and she had started to feel sick. She is uncomfortable rather than distressed and can talk in full sentences. The abdomen is soft with no tenderness, the chest is clear and the heart sounds are normal. This twelve-lead was recorded four minutes after she arrived, while the pressure was still there.

Tracing 1 of 2 for the quiz “Epigastric pressure and nausea for four hours”. — Twelve-lead recorded at triage, 25 mm/s, 10 mm/mV. Open this tracing in the studio

What is the acute abnormality on this tracing?

AAcute injury to the posterior wall Correct answer Your answer
BFrequent atrial ectopy with no acute ST change Your answer
CLeft ventricular strain from long-standing hypertension Your answer
DSubendocardial ischaemia of the anterior wall Your answer

The tracing shows ST depression of 3 to 4 mm in V1 to V4 with upright T waves. In the context of acute chest discomfort, horizontal ST depression maximal in V1 to V3 is the reciprocal change of a posterior wall ST-elevation infarction. Left ventricular strain from hypertension produces ST depression that is deepest in the lateral leads with asymmetric T-wave inversion, not in V1 to V3. Subendocardial anterior ischaemia can look similar, but the distribution here, deepest in the right precordial leads, points to a posterior rather than an anterior territory.

Which additional recording settles that reading?

ALeads V3R and V4R across the right praecordium Your answer
BThe same twelve leads repeated in fifteen minutes Your answer
CA Lewis lead arrangement across the upper sternum Your answer
DLeads V7 to V9 across the left posterior chest Correct answer Your answer

Posterior chest leads V7 to V9, placed across the left posterior thorax, directly overlie the territory in question and will show ST elevation if a posterior infarction is present. This converts an indirect sign, the reciprocal depression in V1 to V3, into a direct one. Right-sided leads V3R and V4R look at the right ventricle rather than the posterior wall. A Lewis lead is used to identify atrial activity in arrhythmias and has no role here. Repeating the same twelve leads adds time without resolving the question the first tracing has already raised.

Stage 2 of 2

The registrar reviewing the first tracing reads it as strain from long-standing hypertension and asks for a repeat before anyone is referred. Posterior leads recorded while she waits show ST elevation in V7 to V9. Forty minutes have passed since she arrived, the pressure is unchanged and she has vomited once. The first high-sensitivity troponin T is 310 ng/L. The primary PCI centre is twenty-five minutes away and takes direct referrals.

Tracing 2 of 2 for the quiz “Epigastric pressure and nausea for four hours”. — Twelve-lead repeated forty minutes after arrival, 25 mm/s, 10 mm/mV. Open this tracing in the studio

Observations

HR: 84
SpO₂ (%): 96
Respiratory rate: 18
Temperature (°C): 36.7
Systolic BP (mmHg): 138
Diastolic BP (mmHg): 80

Bloods

Haemoglobin (g/L): 132
Troponin T (ng/L): 310
Potassium (mmol/L): 4.3
Creatinine (umol/L): 92

What does the second tracing commit you to?

ARefer now for primary percutaneous coronary intervention Correct answer Your answer
BWait for the three-hour troponin before referring Your answer
CStart fondaparinux and book angiography within 72 hours Your answer
DRepeat the twelve leads after a further thirty minutes Your answer

The deeper ST depression in V1 to V4 on the repeat tracing, together with confirmed ST elevation on posterior leads and a troponin of 310 ng/L, makes this an evolving ST-elevation myocardial infarction. The ESC and Resuscitation Council UK guidelines are unambiguous that a STEMI requires immediate reperfusion, and with a primary PCI centre twenty-five minutes away the referral should be made now. Waiting for a three-hour troponin or scheduling angiography within seventy-two hours are strategies for non-ST-elevation acute coronary syndromes, not for a confirmed STEMI with ongoing symptoms.

Diagnosis

Acute posterior ST-elevation myocardial infarction

This case is a posterior ST-elevation myocardial infarction presenting as epigastric discomfort and initially misread as strain. The first tracing shows ST depression of 3 to 4 mm across V1 to V4, which is the reciprocal image of posterior ST elevation. The second tracing forty minutes later shows the depression deepening to over 5 mm, confirming that the injury is evolving.

The practical lesson is that anterior ST depression in the right clinical setting is a posterior STEMI until proven otherwise, and posterior leads settle it. Once V7 to V9 show ST elevation, this is an ST-elevation myocardial infarction and the pathway is primary percutaneous coronary intervention without waiting for serial troponins or a further repeat.

References

Collet JP, Thiele H, Barbato E, et al. 2020 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation. European Heart Journal. 2021;42(14):1289-1367.
Ibanez B, James S, Agewall S, et al. 2017 ESC Guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation. European Heart Journal. 2018;39(2):119-177.

Epigastric pressure and nausea for four hours

The case

On arrival

Observations

Bloods

Diagnosis

References

Discussion