Left atrial dissection: Pathogenesis, clinical course, and transesophagealechocardiographic recognition

Left atrial dissection is an uncommon entity. It is generally associated wi th mitral valve replacement, but other predisposing factors should be consi dered in pathogenesis. We discuss a series of 11 patients with pathological ly confirmed left atrial dissection who had been diagnosed previously by tr ansesophageal echocardiography. Predisposing factors and surgical or pathol ogic findings were reviewed to identify the pathogenic mechanism and to exp lain the clinical course, hemodynamic disorder, and echocardiographic featu res. Dissection of the coronary sinus secondary to retrograde cardioplegia, endocarditis, cardiac rupture after myocardial infarction, and blunt chest trauma also could be related to its development. Transesophageal echocardi ography identified a mobile intimal flap of the atrial wall that was creati ng a false chamber and allowed accurate diagnosis of prosthetic mitral valv e function, endocarditis complications, and a left ventricular pseudoaneury sm after acute myocardial infarction. Color flow Doppler was particularly u seful in identifying complications: communication between the false chamber and true left atria, permitting mitral regurgitation through the periannul ar route; development of atrial shunts; and severe tricuspid regurgitation caused by disruption of the anterior papillary muscle.