Atrial septal defect is a congenital acyanotic heart disease that can cause increased frequency of thrombotic episodes such as deep venous thrombosis . This can be due to alteration of blood flow ,increase in pro coagulation factors and increased inflammation . Deep venous thrombosis can be a common cause of pulmonary embolism , when a thrombus gets dislodged and blocks the main pulmonary artery or its segmental branches and can cause significant hemodynamic compromise . An acute Pulmonary embolism can have varied presentations ranging from a gradually progressing dyspnea to a significant hemodynamic disturbance presenting with chest pain , severe dyspnea , syncope and palpitations and can have lethal complications . Here , we describe a case report of a 10 year female child with a small ostium secundum atrial septal defect on regular follow up who presented with giddiness, and one episode of syncope. There was a History of Progressive tiredness to physical activity over the past few months . Child had tachycardia , tachypnea and decreased oxygen saturation . Chest X-Ray showed bilateral pulmonary infiltrates , atelectasis , and wedge shaped pulmonary opacities .ECG showed sinus tachycardia , Right Ventricular strain pattern , Right atrial and Right Ventricular enlargement .Echocardiogram with doppler study showed small OS ASD with right atrial and ventricular dilatation and pulmonary artery hypertension . D-Dimer , Hs-TnT levels , CPK-MB levels were elevated . PT/INR levels , Antithrombin III levels , protein C & protein S levels were all within normal limits .There was no factor V leiden mutation detected . CT Pulmonary angiography showed bilateral pulmonary artery thrombus extending to segmental arteries. Doppler study of bilateral lower limbs showed deep vein thrombosis in the left calf . The child was managed on anticoagulation with low molecular weight heparin and other supportive measures . The child improved and was discharged on oral warfarin .

PULMONARY THROMBOEMBOLISM ,ATRIAL SEPTAL DEFECT,DEEP VEIN THROMBOSIS,CONGENITAL HEART DISEASE