All are true about pulmonary embolism except:

Ans: c (All cases of pulmonary ....) Ref: Harrison, 16 ed, p. 1561; 17th ed, p. 1652All cases of pulmonary embolism does not lead to infarction, majority of them are asymptomaticNote:Most common source of pulmonary emboli is pelvic or femoral veins.But most common site for deep vein thrombosis is calf vein (i.e., the tendency for these to embolize are less.)CXR of pulmonary embolism are usually normal 1st clinical sign is tachypnoeaInvestigationsNON IMAGINGD dimer- It is elevated in about more than 90% of patients but it is not specific.ECG: most common finding is sinus tachycardia and AF.S wave in lead 1Q wave in lead 3T wave in lead 3IMAGINGNon invasiveLung scanning: VQ scanning- This is the most commonly used methodChest CT: CT of chest with intravenous contrast is superseding lung scanning as the principal imaging test for diagnosis.Invasive imagingPulmonary angiographyIt is the most specific.But now pulmonary angiography is usually reserved for patients who will undergo interventions such as catheter embolectomy or catheter directed thrombolysis."WELLS Diagnostic Scoring system is now used for suspected pulmonary embolism- It has a maximum of 12.5 points"Me Connells sign- In pulmonary embolism there will be right ventricular free wall hypokincsis but normal right ventricular apical motion.