PE

Pulmonary embolism can cause right heart strain with findings that mimic cardiac ischemia. The most common 'abnormality' seen is sinus tachycardia. PE findings can produce a variety of pulmonary disease patterns with increasing concern. The more minor manifestations may be signs of right atrial enlargement, T wave inversions in V1-V4 +/- inferior leads, or right axis deviation. More significant findings are incomplete or complete right bundle branch block, RV hypertrophy, and ST elevations or depressions in the rightward chest leads (V1-V3/V4). The worse the findings, the worse the prognosis with PE. Sometimes, patients have atrial tachyarrhythmias, though this is quite rare. The most specific finding is T wave inversions in the inferior leads and V1-V4. The S1Q3T3 pattern has been discussed previously as being pathognomonic for PE, though this is not true. In fact, patients with this pattern have been found to have an acute PE in about 25% of cases.

These findings all may be seen with MI, though there is rarely pure right-sided findings unless there is RV MI. One of the best ways to help differentiate PE from MI is the presence of tachycardia. Tachycardia is fairly commonly seen in PE, though rarely seen in MI unless there is cardiogenic shock (even compensated) or arrhythmia. Again, the most specific finding to differentiate PE from MI is the presence of TWI in the inferior leads and V1. However, there are no EKG findings that are pathognomonic for PE.

Examples:

Further Reading:

https://litfl.com/ecg-changes-in-pulmonary-embolism/

http://hqmeded-ecg.blogspot.com/search/label/pulmonary%20embolism