Is ST elevation a common finding in patients with acute pericarditis?

ST Elevation in Acute Pericarditis

ST elevation occurs in approximately 60% of patients with acute pericarditis, making it a common but not universal finding. 1

Frequency and Pattern of ST Elevation

• Widespread ST-segment elevation is present in less than 60% of acute pericarditis cases, contrary to older teaching that suggested it was nearly universal 1, 2

• The ST elevation in pericarditis is characteristically widespread, concave upward, and appears in anterior and inferior leads (I, II, aVL, aVF, V3-V6) without reciprocal ST depression in other leads 1, 3

• ST depression occurs reciprocally in lead aVR, frequently in V1, and occasionally in V2 1, 3

• The absence of classic ECG changes does not exclude pericarditis—many patients present with normal ECGs or atypical patterns 2

Why ST Elevation Occurs

• ST elevation in pericarditis reflects epicardial inflammation, not parietal pericardial injury, since the parietal pericardium itself is electrically inert 1

• The ECG changes imply superficial myocardial or epicardial involvement, which explains why troponin I is detectable in 49% of acute pericarditis patients, particularly those with ST elevation 3, 4

Critical Diagnostic Considerations

The presence of widespread ST elevation with PR depression is the electrocardiographic hallmark of pericarditis, though these changes are nonspecific and may be transient. 1

Key Differentiating Features from STEMI:

• Pericarditis shows widespread ST elevation without reciprocal ST depression (except in aVR), whereas STEMI shows regional ST elevation with reciprocal changes 3

• In lead V6, if the J point is >25% of the height of the T wave apex, pericarditis is more likely than early repolarization 3

• QRS widening and QT interval shortening in leads with ST elevation suggest STEMI rather than pericarditis 5

Important Pitfall:

• Left circumflex artery occlusion can mimic pericarditis with PR depression, multilead ST elevation, and ST depression in aVR—always consider acute coronary syndrome in chest pain patients even when ECG appears typical for pericarditis 5

Temporal Evolution

• ECG changes in pericarditis are highly variable and temporally dynamic, evolving rapidly during the disease course and influenced by treatment 1, 2

• The four-stage ECG evolution described in older literature is not reliably observed in clinical practice 3

• Serial ECGs should be performed to monitor disease evolution and response to anti-inflammatory therapy 3

• ECG may be normal at initial presentation or for days after chest pain onset, but serial tracings can reveal specific patterns during recurrent episodes 2

Clinical Context is Essential

Diagnosis of acute pericarditis requires at least 2 of 4 criteria: pericarditic chest pain, pericardial rub, new widespread ST-elevation or PR depression on ECG, and pericardial effusion. 1

• ECG is a Class I recommendation for all patients with suspected acute pericarditis 3

• The ECG must be interpreted alongside clinical symptoms (sharp, pleuritic chest pain improved by sitting forward), pericardial friction rub, elevated inflammatory markers (CRP, ESR), and troponin elevation 1, 3, 6

• Elevated troponin does not worsen prognosis in pericarditis patients and should not be misinterpreted as indicating acute coronary syndrome 1