Coronary artery fistula is a rare cardiac disease which could be diagnosed by multiple imaging modalities and could be effectively treated by surgical or percutaneous closure. The patient is a 21 years old man initially presented with palpitation and paroxysmal atrial fibrillation. For further evaluation he underwent transthoracic echocardiography on which a mass like structure was found in right atrium. On transesophageal echocardiography this cystic structure was in continuation with dilated left circumflex coronary artery and based on data from both CT angiography and coronary angiography , coronary artery fistula with abnormal drainage right atrium was defined and percutaneous closure was proposed. Learning objective: As coronary artery fistula is a rare condition, making the acquaintance of its clinical presentation, the role of imaging modalities in diagnosis and therapeutic options is our concern. In this patient paroxysmal atrial fibrillation and then a cystic mass like structure in right atrium led us to the diagnosis in stepwise approach.