An unusual case of cor triatriatum mimicking mitral stenosis, whilst masking mitral regurgitation

Abstract

Edwin et al. reported a case of cortriatriatum in the setting of a common atrium and highlight some of the limitations of Transthoracic Echocardiography (TTE) in the process [1]. We present a 62 year old male, who was admitted with worsening dyspnoea (NYHA Class 2) and palpitations. Relevant past medical history includes a previous myocardial infarction, hypercholesterolemia and atrial fibrillation. Coronary angiography revealed three-vessel coronary artery disease on a background of previously diagnosed cortriatriatum sinistrum. The preoperative TTE showed the membrane to be thin and mobile, dividing the left atrium into two chambers. The presence of any fenestrations could not be detected via echocardiography. During the peri-operative period, Transoesophageal Echocardiography (TOE) was used (Fig. 1). Colour doppler ultrasound showed the presence of turbulent flow and revealed that the membrane was mimicking mitral stenosis, as would be expected in such cases, with resulting dilation of the left atrium. However, the mitral valve itself was revealed to be regurgitant. The regurgitant jet was located posteriorly and only ascended for approximately 2 cm before reaching the intra-atrial membrane and being diverted. This finding had not been detected pre-operatively. Additionally, there was Left Ventricular (LV) dilation and reduced LV function from good to moderate. Intraoperatively a small elliptical orifice was revealed and shown to be a continuation of the left atrial appendage. The membrane itself was calcified around the orifice. The membrane was completely excised and the mitral valve exposed to enable repair using an annuloplasty ring. Coronary artery bypass grafts were done to treat the three vessel disease.