Pseudoaneurysm causing partial obliteration of the left atrium: case report and review

Left atrial impression: a sign of extra-cardiac pathology

Compression of the left atrium by extra-cardiac structures is a rare cause of dyspnoea or reduced exercise tolerance and can easily be visualized by transthoracic echocardiography (TTE). An impression of the left atrium visualized by TTE could be the first indication of the presence of a pathological structure dorsal to the left atrium; such a structure can, in time, compress the left atrium. The existence of this phenomenon and its clinical implications will be reviewed. The impressing structures are divided into four anatomic groups: (i) gastrointestinal structures, which are the most common, (ii) mediastinal structures, (iii) aorta and intrapericardial structures, and (iv) pulmonary structures. Explanatory examples of left atrial impression with different causes and various levels of severity are presented.

Contained myocardial rupture: a variant linking complete and incomplete rupture

Myocardial rupture is an uncommon complication of myocardial infarction, often with devastating haemodynamic consequences. Although rupture is usually fatal, when patients do survive, the majority present with a pseudoaneurysm in which the rupture is sealed by a haematoma on the epicardial surface of the heart. Cases in which all myocardial layers are dissected except the epicardium or visceral pericardium have been included under this subheading. The authors describe such a case and suggest the pathological description of a "contained myocardial rupture". This link between complete and incomplete myocardial rupture may allow a more conservative management approach to be pursued.

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.