The classical ECG signs of acute pulmonary embolism are SIQIIITIII, which are mnemonics representing deep S wave in lead I, pathological Q wave in lead III, and inverted T wave in lead III:
Other nonspecific signs include (see ECG above):
|Sinus tachycardia and atrial and ventricular ectopic beats.|
|Right axis deviation.|
|Right ventricular strain pattern with inverted T waves in right chest leads.|
|Incomplete or complete right bundle branch block pattern.|
|Slow R wave progression in chest leads|
But all these ECG signs may not be present even in frank pulmonary embolism.