Congenital membranous ostial stenosis of the left atrial appendage as a secondary finding in a patient with ST elevation myocardial infarction: a case report.

Background: Stenoses of the left atrial appendage (LAA) represent a common complication after incomplete surgical ligation. However, the idiopathic entity is very rare. So far, there is uncertainty about the thromboembolic risk and potential benefit of anticoagulation in these patients. We report on congenital ostial stenosis of the LAA as a secondary finding in a patient with myocardial infarction. Case summary: A 56-year-old patient presented with acute heart failure secondary to ST elevation myocardial infarction (STEMI) and eventually progressed to cardiogenic shock. A percutaneous coronary intervention and stent placement in the first diagonal branch and in the left anterior descending artery was performed in two sessions. There was a new onset of typical atrial flutter and paroxysmal atrial fibrillation with haemodynamically relevant tachycardia. Before synchronized electrical cardioversion, we performed transoesophageal echocardiography. Left atrial thrombi were ruled out. Surprisingly, we found membranous ostial stenosis of the LAA, resulting in a bidirectional flow pattern. After 28 days of treatment in the intensive care unit the patient had full clinical recovery. Discussion: Given the very rare cases of congenital LAA ostial stenosis, there is uncertainty about the thrombogenicity and the potential benefit of anticoagulation or even a percutaneous closure of the LAA. We discuss possible similarities regarding the thromboembolic risk of patients with an idiopathic narrowing of the LAA to patients with incomplete surgical ligation and patients with a device leak after percutaneous LAA closure. Congenital ostial LAA stenosis represents a clinically relevant condition and may be considered as a potential hazard for thromboembolism.