481 Mass compromising left atrium

Abstract A 47-year-old woman presented to the ER with a sudden-onset left side chest pain of less than one hour in duration that started at rest. The pain was severe and radiated to the left shoulder. This was accompanied with symptoms of shortness of breath and sweating but no similar episodes in the past. There was no significant history of coronary artery disease or any other illness in the family. She had dyslipidemia and a smoking habit of 1 pack/day for the previous 10years. In the ERt, she was hemodynamically stable and her physical examination was within normal limits. ECG showed ST-segment elevation in the inferior leads. No prior ECG was available for comparison. She underwent emergent PCI which showed spontaneous proximal segment circumflex (dominant) artery dissection with TIMI angiographic flow grade 0. All other coronaries were patent with TIMI III flow and no atherosclerotic changes. PCI was carried out, but unfortunately, it was complicated with coronary rupture having to implant a drug eluting stent in order to seal the vessel rupture, with optimal final result (TIMI 3). An urgent TTE was performed for evaluation of the patient due to persistence of chest pain after coronariography, revealing an echogenic mass at the left atrium suggesting extracardiac hematoma vs. left atrium dissection. TC scan confirmed space compromise of the left atrium by a mass, without being able to rule out active bleeding. The patient was transferred to our center for emergent CABG surgery. Upon arrival, the patient had persistent chest pain, sinus tachycardia, and hypertension. Intraoperative TOE findings consisted of a mass compromising left atrium and minimal pericardium effusion. Comprehensive study identified a mobile intimal flap of the atrial wall that was creating a false chamber. Intraoperative surgery findings were compatible with a huge left atrial desiccant hematoma . Two orifices were performed on the epicardium of the inferior and lateral border of the left atrium, in order to drain the retained blood and lavage. No active bleeding was evidenced. TTE control evidenced disappearance of the left atrium mass a The patient had a satisfactory evolution and discharged without complications. Even though left atrial desiccant hematoma is a rare STEMI complication , in this patient, we concluded the etiology was iatrogenic due to the performance of PCI. Conclusion Left atrial dissection is an uncommon entity. It is generally associated with mitral valve replacement, but other predisposing factors should be considered in pathogenesis. Its diagnosis requires a high index of suspicion. Predisposing factors and catheterization, surgical or pathologic findings should be reviewed in order to identify the pathogenic mechanism . Dissection of the coronary sinus secondary to retrograde cardioplegia, endocarditis, cardiac rupture after myocardial infarction, blunt chest trauma and iatrogenic PCI are related to its development. Abstract 481 Figure. MASS COMPROMISIN LEFT ATRIUM