You are in: eMedicine Specialties > Pediatrics: Cardiac Disease and Critical Care Medicine > Cardiothoracic Surgery Cor Triatriatum: Surgical PerspectiveArticle Last Updated: Oct 16, 2006AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: John Kupferschmid, MD, Director of Congenital Heart Surgery, Department of Surgery, Methodist Children's Hospital at San Antonio John Kupferschmid is a member of the following medical societies: American Academy of Pediatrics, American College of Surgeons, Society of Thoracic Surgeons, and Society of Thoracic Surgeons Editors: Daniel S Schwartz, MD, FACS, Clinical Assistant Professor of Cardiothoracic Surgery, New York University School of Medicine; Consulting Staff, Department of Surgery, Division of Thoracic Surgery, North Shore University Hospital/Long Island Jewish Medical Center; Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine.com, Inc; John Myers, MD, Director, Pediatric and Congenital Cardiovascular Surgery, Departments of Surgery and Pediatrics, Professor, Penn State Children's Hospital, Milton S Hershey Medical Center; Daniel Rauch, MD, FAAP, Director, Pediatric Hospitalist Program, Associate Professor, Department of Pediatrics, New York University School of Medicine; Mary C Mancini, MD, PhD, Director of Cardiothoracic Transplantation, Professor, Department of Surgery, Louisiana State University Health Sciences Center Author and Editor Disclosure Synonyms and related keywords: cor triatriatum, accessory atrium, subdivided left atrium INTRODUCTIONSection 2 of 11
  Although Borst first applied the name cor triatriatum to the malformation in 1905, the entity of cor triatriatum was first described in 1868 by Church. It represents a membranous diaphragm dividing the left atrium into 2 chambers, the proximal chamber accepting the pulmonary veins and the distal chamber communicating with the mitral valve and the left atrial appendage. History of the ProcedureCor triatriatum is often observed in infants with a small opening between the common pulmonary venous chamber and the left atrium. These infants usually present with evidence of low cardiac output syndrome, including poor peripheral pulses, pallor, pulmonary edema, pulmonary hypertension, tachypnea, and growth failure. If an opening is present between the proximal left atrial chamber and the right atrium, associated left-to-right shunting and evidence of pulmonary overcirculation exist. When obstruction is mild, the patient usually is asymptomatic, and if this is an isolated lesion, disease is not usually suspected. FrequencyCor triatriatum is an unusual congenital anomaly, but it is not as rare as reports seem to indicate. Jegier et al reported a frequency of 0.4% in 474 autopsied patients with congenital cardiac disease. On the other hand, Fyler reports cor triatriatum in only 25 of 14,000 patients with cardiac disease and in 5 of 2251 infants with heart disease. This calculates to 1 case per 700 children, 1 per 450 infants with heart disease, or 0.0045 per 1000 live births. EtiologyNo unified embryologic theory for the genesis of cor triatriatum exists. However, most who work in this area believe that cor triatriatum represents a failure of incorporation of the common pulmonary vein into the left atrium, although some of the variants of cor triatriatum are clearly inconsistent with this theory. PathophysiologyNormally during cardiogenesis, the common pulmonary vein is absorbed into and becomes part of the left atrium. Incomplete absorption, leaving varying degrees of obstructing tissue at the line of connection between the left atrium and the common pulmonary vein, results in cor triatriatum. Typically, the foramen ovale and the left atrial appendage communicate with the distal left atrium and provide a means to distinguish between cor triatriatum and obstructing supravalvar rings. However, atrial septal defects can communicate between the right atrium and either the proximal or the distal left atrial chamber. The physiologic consequences of cor triatriatum are a direct function of the size of the orifice between the pulmonary venous chamber and the left atrium. When obstruction is sufficient to raise the pulmonary venous pressure, pulmonary hypertension may reach or exceed systemic levels. In this regard, the clinical picture and the course of patients with cor triatriatum are comparable to those for infants with mitral stenosis. ClinicalWhen obstruction is mild, no symptoms are present, and if this is an isolated lesion, disease is not suspected. With severe obstruction, the patient may have pulmonary edema, pulmonary hypertension, and respiratory symptoms (eg, tachypnea, dyspnea) early in infancy. Cor triatriatum should be suspected whenever a patient has unexplained pulmonary edema. Infants with classic cor triatriatum, with a small opening between the common pulmonary venous chamber and the left atrium, usually present with evidence of low cardiac output, including pallor, tachypnea, poor peripheral pulses, and growth failure. In children and young adults, the classic presentation is with the signs and symptoms of pulmonary venous hypertension. INDICATIONSSection 3 of 11
As discussed previously, the natural history of cor triatriatum is closely linked to the aperture, or opening, between the common pulmonary venous chamber and the portion of the left atrium containing the mitral valve. Classic cor triatriatum, with a restrictive opening in the partition between the proximal common pulmonary venous sinus and the distal left atrium, is an urgent indication for operation. In most patients, this opening is critically narrowed, and approximately 75% of patients born with classic cor triatriatum die in infancy. As such, symptoms usually develop early, and operation is usually necessary in the first year of life. Similarly, operation is indicated on an urgent basis in more complex forms of cor triatriatum, when the common pulmonary venous chamber empties into the right atrium and a restrictive opening is present between the common pulmonary venous chamber and the distal left atrium associated with a restrictive patent foramen ovale. Finally, cor triatriatum can appear later in life, often in the teenage years. When such patients present with chronic symptoms and evidence of severely restricted inflow into the distal left atrium, operation is indicated on an urgent basis. RELEVANT ANATOMYSection 4 of 11
In classic cor triatriatum, the common pulmonary venous chamber is usually somewhat larger than the distal left atrium. The wall partitioning between the 2 chambers often appears rather thick and fibromuscular. The proximal chamber is typically thick-walled. The distal chamber is usually thin-walled. The anatomic differentiation between cor triatriatum and a supramitral ring is based on the position of the wall relative to the left atrial appendage. In cor triatriatum, the left atrial appendage is located in the distal chamber, whereas in a supramitral ring, it is located in the proximal chamber. The pulmonary veins are not typically dilated in cor triatriatum, despite the high pressure present in them. The anatomic relationship of the pulmonary veins to the right atrium and superior vena cava is normal. The fossa ovalis may be located on either side of the partition, joining the right atrium to the proximal chamber or the distal chamber, depending upon its location. CONTRAINDICATIONSSection 5 of 11
No contraindications to surgical correction of isolated cor triatriatum exist. However, if cor triatriatum is found in association with other severe forms of congenital heart disease, the associated defects may dictate the need or usefulness of surgical palliation. WORKUPSection 6 of 11
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TREATMENTSection 7 of 11
Medical therapyIn the patient with pulmonary edema or right heart failure, the usual medical management should be instituted. However, at this stage, the disease is usually quite progressive, and surgical therapy should be instituted as soon as possible. Preoperative detailsPreoperatively, the surgeon must try to determine with near certainty the connections and drainage of all of the pulmonary and systemic veins. Particular attention is paid to the drainage of the individual pulmonary veins and the presence and drainage of a left superior vena cava. Intraoperative detailsThe approach to these patients varies with the echocardiographic presentation. In general, the largest atrial chamber appearing on the right side of the heart should be initially opened at operation. The enlargement of the proximal left atrial chamber in typical cor triatriatum makes approach through an incision in the right side of this chamber the easiest. A right atrial approach can also be useful, particularly if a septal defect is open between the proximal left atrial chamber and the right atrium. After the usual preparations, moderately hypothermic cardiopulmonary bypass using bicaval cannulation is instituted. Cold blood cardioplegia is instituted after clamping the aorta. The common pulmonary venous chamber is opened through a vertical incision anterior to the right pulmonary veins, exactly as for mitral valve surgery. The diaphragm is exposed by appropriate retraction. The opening in the diaphragm is identified. One or two radial incisions from the opening of the diaphragm outward to the atrial wall or septum enhance exposure considerably. Most of the diaphragm is excised only after the pulmonary veins are identified. If exposure is obtained through the right atrium, the atrial septal defect is enlarged to provide good exposure with the common pulmonary venous chamber and the right atrium. As before, the diaphragm is identified, and radial incisions from the center of the orifice outward are used to aid in exposure distal to the diaphragm. The cardiotomy is closed, the patient rewarmed, and the left heart deaired per routine. The remainder of the operation is carried out in the usual fashion. Postoperative detailsPostoperative care for these infants is typical for infant atrial or ventricular septal defects. However, the exception is that those infants presenting with severe obstruction, pulmonary edema, and pulmonary hypertension should be considered to be at risk for pulmonary hypertensive crises postoperatively and treated accordingly. Follow-upRarely, these children can develop pulmonary vein stenosis or restenosis of the orifice between the proximal and distal left atrial chambers (although this generally implies incomplete resection). Most restenoses occur within the first 1-2 years following resection, as observed following repair for total anomalous venous return. For this reason, follow-up care should be fairly frequent until the child no longer appears to be at risk for the development of restenosis. COMPLICATIONSSection 8 of 11
Hospital fatalities are uncommon after repair of cor triatriatum, except in the case of infants with critical illness. Early complications are not dissimilar to any other operation performed on the left side of the heart in infants. Late complications generally consist of pulmonary vein stenosis or restenosis of the left atrial orifice as described above. OUTCOME AND PROGNOSISSection 9 of 11
Following complete resection, the life expectancy after repair of classic cor triatriatum is not significantly different from the general population. This is particularly true when the operation is performed in infancy. MULTIMEDIASection 10 of 11
REFERENCESSection 11 of 11
Cor Triatriatum: Surgical Perspective excerpt Article Last Updated: Oct 16, 2006 | ||||||||||||||||||||||||||
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