Sharp central chest pain for two days, worse lying flat

A head cold and sore throat the week before. No cardiac history. No regular medication other than the combined oral contraceptive, stopped four years ago.

Stage 1 of 2

Ingrid Haugen walked into the department after two nights of poor sleep. The pain is sharp rather than heavy, sits behind the sternum and catches when she lies back on the trolley. Sitting forward eases it. She points to her left shoulder blade when asked where else she feels it. There is a scratchy sound at the left sternal edge that comes and goes with the heartbeat. The chest is clear, the calves are soft and she is not breathless at rest.

Tracing 1 of 2 for the quiz “Sharp central chest pain for two days, worse lying flat”. — Twelve-lead recorded at triage, 25 mm/s, 10 mm/mV. Open this tracing in the studio

Apart from the rate, what is abnormal on this tracing?

APathological Q waves in III and aVF Your answer
BThe PR segment is depressed, and elevated in aVR Correct answer Your answer
CThe PR interval is prolonged beyond 200 ms Your answer
DNothing; the tracing is within normal limits Your answer

The PR segment is depressed below the TP baseline in the inferior and lateral leads, and elevated in aVR. This is the earliest electrocardiographic marker of pericardial inflammation, appearing before widespread ST elevation. The PR interval itself is about 173 ms, which is normal and should not be confused with first-degree block. There are no pathological Q waves in the inferior leads.

Taking that finding with her history and examination, which diagnosis does it most support?

AMusculoskeletal chest wall pain Your answer
BAnterior ST-elevation myocardial infarction Your answer
CAcute pericarditis Correct answer Your answer
DPulmonary embolism Your answer

PR depression in a patient with sharp positional chest pain, a preceding viral illness, and a pericardial friction rub is strongly suggestive of acute pericarditis. An anterior STEMI would produce localised ST elevation with reciprocal depression and would not explain the positional nature of the pain or the rub. Pulmonary embolism can cause chest pain and tachycardia but does not produce PR-segment changes, and the examination here does not support it.

Stage 2 of 2

She is kept overnight. The troponin taken on arrival and again at three hours are both below the assay limit, and the echocardiogram shows no pericardial fluid and normal ventricular function. She has slept sitting up. This twelve-lead is recorded before the morning ward round.

Tracing 2 of 2 for the quiz “Sharp central chest pain for two days, worse lying flat”. — Repeat twelve-lead the following morning. Open this tracing in the studio

Observations

HR: 88
SpO₂ (%): 98
Respiratory rate: 16
Temperature (°C): 37.4
Systolic BP (mmHg): 118
Diastolic BP (mmHg): 72

Bloods

Crp Mg L: 48
Troponin TNg L: 5

The troponin is negative and there is no effusion. What is the treatment?

AThrombolysis for the widespread ST elevation Your answer
BDischarge with no treatment and no follow-up Your answer
CUrgent pericardiocentesis Your answer
DA non-steroidal anti-inflammatory with colchicine Correct answer Your answer

Uncomplicated acute pericarditis is treated with a non-steroidal anti-inflammatory drug at full dose combined with colchicine. Colchicine significantly reduces the rate of recurrence and is recommended as part of first-line therapy. Thrombolysis is contraindicated because the ST changes are pericardial, not ischaemic, and pericardiocentesis is not indicated without haemodynamic compromise or a significant effusion. Discharge without treatment risks recurrence and prolonged symptoms.

Diagnosis

Early acute pericarditis with isolated PR depression

PR-segment depression is the earliest and most specific electrocardiographic sign of acute pericarditis, often appearing before the widespread ST elevation that follows in the classical four-stage sequence. It is easy to overlook because it is a small deflection in a segment most readers step over on the way to the QRS. On this first tracing the PR depression in the inferior and lateral leads, with PR elevation in aVR, is the only abnormality.

First-line treatment for uncomplicated pericarditis is an anti-inflammatory agent combined with colchicine. Colchicine reduces the recurrence rate substantially and is recommended by current ESC guidelines. Neither thrombolysis nor pericardiocentesis is indicated without haemodynamic compromise or a large effusion.

References

Spodick DH. Diagnostic electrocardiographic sequences in acute pericarditis: significance of PR segment and PR vector changes. Circulation. 1973;48(3):575-580.
Adler Y, Charron P, Imazio M, et al. 2015 ESC Guidelines for the diagnosis and management of pericardial diseases. Eur Heart J. 2015;36(42):2921-2964.
Imazio M, Bobbio M, Cecchi E, et al. Colchicine in addition to conventional therapy for acute pericarditis: results of the COlchicine for acute PEricarditis (COPE) trial. Circulation. 2005;112(13):2012-2016.

Sharp central chest pain for two days, worse lying flat

The case

On arrival

Observations

Bloods

Diagnosis

References

Discussion