Chest pain in acute pericarditis vs myocardial infarction

Hello

Acute myocardial infarction is one of the miscellaneous causes of acute pericarditis. Differentiating features of chest pain in these two cases are many, but the high-yield points to be noted are:-

- Pericardial pain changes with posture: The patient feels exaggeration/worsening of pain on lying down in supine position, while the pain is relieved by leaning/bending forwards. On the other hand, pain of cardiac ischemia does not change with posture.

- Radiation of pain: Chest pain radiates to jaw, left arm, mediastinum, epigastrium, and back; may occur in both the cases. But, if the radiation is to the scapular angle or trapezius ridge (due to irritation of phrenic nerve), it is an absolute pathognomic feature of pain due to pericarditis, until proved otherwise.

- Enzyme levels and ECG changes: Pericaditis almost always involves injury and inflammation of myocardium, thus the case scenario mimics that of AMI. So check the enzyme levels and ECG changes - mild increase in cardiac enzymes with widespread ECG changes (PR segment depression, diffuse ST segment elevation (except aVR and V1 leads), T-wave inversion - changes occur in three stages) - sureshot pointer towards acute pericarditis.

Also,
Pericardial pain must be differentiated from pleuritic chest pain, especially notable point being change with respiration. Ask the patient to stop breathing for a moment. If the pain is relieved, it raises the suspicion of pleuritic chest pain (due to decreased pleural rub). Pericardial pain is not affected by respiratory cycle.

Hope it helps :)
- Jaskunwar Singh