<prompt> In acute pulmonary embolism, the most frequent ECG finding is :S1Q3T3 patternP. pulmonaleSinus tachycardiaRight axis detion  <response>: Answer is C Sinus Tachycardia Sinus tachycardia is the commonest ECG abnormality in pulmonary embolism- OHCM 5th 88 Classic Abnormalities on ECG in pulmonary Embolism Sinus Tachycardia Commonest : OHCM Right ventricular strain pattern T wave inversion in leads VI to V4 perhaps most frequent - Harrison SI QIII TIII Pattern :Classic pattern but rare OHCM Deeps S waves in lead I Q wave Inveed T wave in lead Ill New onset Atrial Fibrillation Atrial Flutter. Right Axis Detion RBBB. 