ECG features of Pericarditis

- Widespread concave ST elevation and PR depression
throughout most of the limb leads (I, II, III, aVL, aVF) and
precordial leads (V2-6)

- Reciprocal ST depression and PR elevation
in lead aVR (± V1)

- Tachycardia is also common due to pain

Stages of ECG features

• Stage 1 – widespread ST Elevation and PR depression with reciprocal changes in aVR (occurs during the first two weeks)

• Stage 2 – normalization of ST changes;
generalized T wave flattening (1 to 3 weeks)

• Stage 3– Flattened T waves become inverted (3 to several weeks)

• Stage 4 – ECG returns to normal (several weeks onwards)

Benign Early
Repolarisation

ST segment height = 1 mm

T wave height = 6 mm

ST / T wave ratio = 0.16

A ST / T wave ratio < 0.25 is
consistent with BER

Pericarditis vs STEMI

Pericarditis can cause localised ST elevation but there 
should be no reciprocal ST depression (except in AVR and V1)

STEMI, like pericarditis, can also cause concave ST elevation

Only STEMI causes convex or horizontal ST elevation

ST elevation greater in III than II strongly suggests a STEMI

PR segment depression is only reliably seen in viral pericarditis, not by other causes
It is often only an early transient phenomenon (lasting only hours)

MI can also cause PR segment depression due
to atrial infarction (or PR segment elevation in aVR)

You can’t rely on history either — STEMI
can also cause positional or pleuritic pain.

Steps to distinguish pericarditis
from STEMI

Is there ST depression in a lead other than AVR or V1? This is a STEMI

Is there convex up or horizontal ST elevation? This is a STEMI

Is there ST elevation greater in III than II? This is a STEMI

Now look for PR depression in multiple
leads… this suggests pericarditis (especially if there is a friction rub!)

Pericarditis

ST segment height = 2 mm

T wave height = 4 mm

ST / T wave ratio = 0.5

A ST / T wave ratio > 0.25 is
consistent with pericarditis