Deadly 12 Lead ECG Diagnosis: Pulmonary Embolism

Its well known that there are things other than STEMI that stand ready to confound, perturb, and otherwise confuse your clinical impression. Pulmonary embolism (PE)  is one of those things. Massive PE has been linked to all sorts of ECG changes. A recent article printed in the American Journal of Emergency Medicine highlighted some of the ECG features associated with cardiogenic shock:

• The S1 Q3 T3 sign
• qR in lead V1
• T wave inversions in V2-V4
• STE in lead V1
• STE in lead aVR

These problematic ECG signs come as no surprise to fellow ECG enthusiasts. The incomplete right bundle branch pattern + T wave inversion indicate "heart strain" that accompanies large pulmonary emboli, 

Here's a recent prehospital 12 lead concerning for pulmonary embolism: 

Bottom line:

The ECG represents a valuable screening tool. Though its not particularly sensitive or specific for pulmonary embolism, there are definitely patterns that should alert the clinician to an adverse outcomes. In the setting of suspected pulmonary embolism, for example, watch out for:

• Right bundle branch block
• Anterior T wave inversions
• STE in aVR or V1