Background
Ebstein anomaly is a rare congenital cardiac defect/malformation. The primary pathologic finding is abnormal development of the tricuspid valve marked by a downward displacement of the annular attachments of the septal and posterior leaflets of the tricuspid valve into the inlet portion of the right ventricle (see the image below). This downward displacement of the leaflets reduces the distal chamber of the right ventricle, leaving part of the ventricle above the valve as an extension of the right atrium. The entire wall of the right ventricle, both above and below the tricuspid valve, is often thin, dilated, and dysfunctional. In most patients, annular dilatation and malformation of the leaflets result in moderate-to-severe insufficiency of the tricuspid valve. Most patients have an atrial septal defect or a patent foramen ovale, which allows predominant right-to-left shunting at the atrial level. A high incidence of atrial and ventricular arrhythmia, including an association with Wolff-Parkinson-White Syndrome, occurs in these patients.
Anatomic features of Ebstein anomaly. Note the atrialized portion of the right ventricle and displacement of the tricuspid valve. AV = atrioventricular.
Ebstein anomaly is characterized by remarkable morphologic variability and a broad spectrum of clinical presentations. Consequently, the diagnosis of Ebstein anomaly may be made in symptomatic newborn infants, young adults, or middle-aged adults, depending on the severity of the defect and clinical manifestations.
This defect accounts for less than 1% of all congenital heart disease.
Geographic variation in the prevalence of this defect, inside or outside the United States, has not been documented. Although no increase in prevalence has been documented, an improvement in diagnostic techniques has led to earlier diagnosis. The anomaly occurs in both sexes with equal frequency.
History of the surgical procedure
In 1866, Wilhelm Ebstein, a young physician in Breslau, Poland, reported findings from a postmortem examination performed 2 years earlier.
The patient was a 19-year-old laborer who presented with dyspnea and palpitations and was noted to be profoundly cyanotic. In his report, Ebstein described in great detail the morphology and clinical correlations of the congenital cardiac malformation that bears his name. His report provided a strong basis for the subsequent development of surgical techniques for the treatment of this anomaly 100 years later.
Early surgical attempts to treat Ebstein anomaly using palliative shunts resulted in extremely high mortality rates.
In 1958, Hunter and Lillihei described a technique of surgical repair that involved plication of the atrialized right ventricle, closure of the atrial septal defect, and tricuspid valve annuloplasty.
In 1964, Hardy reported the first successful repair of Ebstein anomaly using this technique.
During the 1960s, most attempts to repair the tricuspid valve were unsuccessful, and prosthetic valve replacement became the preferred approach. In 1962, Christian Barnard described the first successful tricuspid valve replacement in a patient with Ebstein anomaly using a mechanical valve.
In the early 1970s, interest once again focused on tricuspid valve repair with a successful technique described by Danielson and colleagues at the Mayo Clinic.
Several modifications of tricuspid valve repair have been described recently, and early results have been successful.