In case of a pulmonary embolism several clinical features may be present:
- Deep S in I
- Q and negative T in III
- T wave inversion anterior 
Pulmonary embolism cannot solely be diagnosed using an ECG, but it may be helpful.
ECG of a patiënt with pulmonary embolism
Another example of an ECG of a patiënt with pulmonary embolism. Note the tachycardia and right axis.
An example of right ventricular hypertrophy (and right atrial enlargement) in a patient with chronic pulmonary hypertension due to peripheral embolisation.
A 12 lead ECG of a patient with pulmonary embolism
- Rodger M, Makropoulos D, Turek M, Quevillon J, Raymond F, Rasuli P, and Wells PS. Diagnostic value of the electrocardiogram in suspected pulmonary embolism. Am J Cardiol. 2000 Oct 1;86(7):807-9, A10.