ECG changes in Pericarditis

Synonyms: Acute pericarditis, Viral pericarditis, Infectious pericarditis

Definition: Diffuse inflammation of the pericardial lining surrounding the heart and characterized by sharp pleuritic, retrosternal chest pain worsened with recumbency and relieved by leaning forwards.

Causes of Pericarditis:

a. Infectious:

Viral: Coxsackievirus, Echovirus, Ebstein-Barr virus, Influenza, HIV, Mumps virus
Bacterial: Staphylococcus, Hemophilus, Pneumococcus, Salmonella, Tuberculosis, Meningococcus, Syphilis
Miscellaneous: Histoplasmosis, Blastomycosis, Coccidiodomycosis, Aspergillosis, Amebiasis, Rickettsia

b. Rheumatogenic: SLE, Rheumatoid arthritis, Ankylosing spondylitis, Sarcoidosis, Scleroderma, Vasculitis

c. Neoplastic: Secondaries, Sarcomas, Mesothelioma

d. Drugs: Hydralazine, Procainamide

e. Immunologic: Celiac sprue, Inflammatory Bowel Disease

f. Other: Chest trauma, Uremia, Myxedema, Aortic dissection, Radiation therapy, Myocardial infarction, Dressler’s syndrome

g. Idiopathic

Stages of ECG changes in Pericarditis:

The duration for evolution through each of the 4 ECG stages is highly variable ranging from hours to weeks. Practically, Stage I is the only diagnostic phase because Stage II looks normal and Stage III mimics ischemia.

Stage	ECG changes	Electrical basis or Mechanism
I (Everything is up)	Diffuse, concave ST elevation	Generalized pericardial inflammatory process and associated myocarditis
II (Transition or pseudonormalization)	ST segment returns to baseline	Resolution of superficial myocarditis
	T-wave flattening
	PR depression (ST segment appears to be elevated)	Generalized epicardial atrial injury
III (Everything is down)	T wave inversion	Delay in repolarization of whole subepicardial healing epicardium
IV (Normalization)	ECG abnormalities normalizesT wave inversions may become permanent	Resolution of pericarditis

Since, the secondary myocarditis is usually superficial:
Q waves do not form
R waves are unaffected
QRS is not prolonged
QT is not prolonged

Differential diagnoses:

a. Acute Myocardial Infarction (AMI):

ECG features	Acute Pericarditis	Acute Myocardial Infarction
PR segment depression	Common	Rare
Q-waves	Absent	Present
St-segment elevation	DiffuseConcave-up	LocalizedConvex-up
Reciprocal T-wave changes	Absent	Often
T-wave inversion	After ST normalization	Concomittantly

Summary to approach:
A. Evaluate for STEMI
ST depression in leads other than V1 and aVR or
ST Elevation convex upwards or horizontal or
ST Elevation in Lead III more than Lead II
B. Evaluate for Pericarditis (if all 3 ECG criteria above are negative)
PR Segment depression in multiple leads
Clinically search for pericardial rub

b. Benign Early Repolarization (BER):

ECG features	Acute Pericarditis	Benign Early Repolarization
ST elevation	Generalized	Limited to precordial leads
PR depression	Present	Absent
T waves	Normal amplitude	Prominent
ST segment/T wave ratio	>0.25	<0.25
J-point elevation with “Fish-hook” appearance in lead V4	Absent	Present
Evolution	Progressive	Stable or non-progressive