Pulmonary embolism (PE) is a blockage of an artery in the lungs by a blood clot (thrombus) that has moved from elsewhere in the body through the bloodstream. Usually arises from a thrombus that originates in the deep venous system of the lower extremities.
lightheadedness or dizziness
leg pain or swelling, or both, usually in the calf caused by a deep vein thrombosis
Pulmonary embolism cannot entirely be diagnosed using just an ECG, it is neither sensitive nor specific for PE.
ECG changes are related to
dilatation of the right heart
right ventricular ischemia
increased stimulation of the sympathetic system
T wave inversion in the precordial leads V1-V4 (best correlated to the severity of the PE)
complete or incomplete RBBB - associated with increased mortality
dominant R wave in V1 - sign of acute right ventricular dilatation
P pulmonale - peaked P wave in lead II > 2.5 mm
right axis deviation
non-specific ST segment and T wave changes, including ST elevation and depression
S I, Q III, T III - sign of acute cor pulmonale
Deep S in I
Q and negative T in III
T wave inversion anterior
ECG 1 Pulmonary embolism (sinus tachycardia, RBBB, neg. T waves V1-V4, S I, Q III, T III)
ECG 2 Pulmonary embolism (sinus tachycardia, iRBBB, flat T waves V1-V2, S I, Q III, T III)
Levis JT. ECG Diagnosis: Pulmonary Embolism. Perm J. 2011;15(4):75. doi:10.7812/tpp/11-112
EMILE, Ferrari, Imbert ALAIN, Chevalier THIERRY, Mihoubi ALAIN, Morand PHILIPPE a Baudouy MARCEL. The ECG in Pulmonary Embolism*: Predictive Value of Negative T Waves in Precordial Leads-80 Case Reports. Chest [online]. 1997, 111(3), 537-538 [cit. 2021-02-06]. ISSN 00123692.