Massive and Acute Pulmonary Embolism results in acute dilatation of the right atrium and ventricle, followed by reflex vasoconstriction of the pulmonary arterioles due to mediators such as serotonin and catecholamines that are released in response to the decreased perfusion of the lungs.
The ECG manifestations of Acute Pulmonary Embolism are :-
- Sinus Tachycardia
- T wave inversion in >2 precordial leads
- Incomplete or Complete RBBB
- P Pulmonale
- Right Axis Deviation (RAD)
- Supraventricular arrhythmias
- S1Q3T3 pattern , which means :-
- The prominent S wave in standard lead I
- The prominent Q wave in standard lead III
- T wave inversion in standard lead III