Ebstein’s anomaly is characterised by the distal displacement of the septal and posterior leaflets of the tricuspid valve. The anterior leaflet is not displaced and hence is quite large and sail like. Closure of the large anterior tricuspid leaflet produces the ‘sail sound’ characteristic of Ebstein’s anomaly. The distal displacement of the tricuspid valve causes atrialisation of a portion of the right ventricle. This region can be identified during cardiac catheterisation as showing ventricular electrogram, but an atrial pressure tracing. This finding is sought by Zucker catheter which has a lumen for pressure recording as well as an electrode for electrogram recording. The finding is called Hernandez sign.
Ebstein’s anomaly has been associated with maternal intake of lithium during pregnancy. Right sided accessory pathways are seen in Ebstien’s anomaly of the tricuspid valve. A similar anomaly of the left sided AV valve has been associated with congenitally corrected transposition of the great arteries. The tricuspid valve in Ebstein’s anomaly can have tricuspid stenosis, regurgitation or a combination of both together. Associated atrial septal defect can cause a right to left shunt and cyanosis.
Clinically they have multiple heart sounds due to split first and second heart sound. A superficial scratchy tricuspid murmur is also often heard. ECG shows splintered polyphasic QRS complexes, tall P waves (Himalyalan P waves) and sometimes features of pre-excitation and atrioventricular re-entrant tachycardia. X-ray chest shows the huge right atrial enlargement, which can be confirmed by echocardiography. M-mode echo shows the delay between the mitral and tricuspid valve closures. Both valves are imaged in the same parasternal view in Ebsteins anomaly. The distal displacement of the septal tricuspid leaflet is the characteristic echocardiographic finding in Ebstein’s anomaly.