Left atrial dissection: pathogenesis, clinical course, and transesophageal echocardiographic recognition.

Left atrial dissection is an uncommon entity. It is generally associated with mitral valve replacement, but other predisposing factors should be considered in pathogenesis. We discuss a series of 11 patients with pathologically confirmed left atrial dissection who had been diagnosed previously by transesophageal echocardiography. Predisposing factors and surgical or pathologic findings were reviewed to identify the pathogenic mechanism and to explain the clinical course, hemodynamic disorder, and echocardiographic features. 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 echocardiography identified a mobile intimal flap of the atrial wall that was creating a false chamber and allowed accurate diagnosis of prosthetic mitral valve function, endocarditis complications, and a left ventricular pseudoaneurysm after acute myocardial infarction. Color flow Doppler was particularly useful in identifying complications: communication between the false chamber and true left atria, permitting mitral regurgitation through the periannular route; development of atrial shunts; and severe tricuspid regurgitation caused by disruption of the anterior papillary muscle.