Abstract
Spontaneous interatrial hematoma is a rare clinical entity leading to the obliteration of the left atrial cavity and causing haemodynamic compromise, necessitating immediate surgical intervention. Herein, we report a patient with acute chest pain with normal coronaries and echocardiographic evidence of left atrial mass. The investigations revealed the mass to be a thrombus rather than tumour. The patient underwent surgery to remove a large thrombus completely enclosed within the interatrial septum. The septum was then repaired using a pericardial patch. No apparent etiological factor was found. Spontaneous atrial wall dissection should be considered in the differential diagnosis of acute chest pain.