ESSENTIALS OF ECHOCARDIOGRAPHY #4 - Echo in Context

valve “atrialized” much of what should have been the right ventricle. Two-dimensionalechocardiography is the most reliable method available for the detection of this abnormality.Such patients usually have variable degrees of tricuspid regurgitation. Ebstein’s anomaly isfrequently associated with an atrial septal defect and the Wolff-Parkinson-White syndrome.When Chambers and Valves are Not in Normal Sequence or RelationshipSome of the most complex anatomic defects obviously occur when chambers and valves arenot in their normal sequence or position. Fuller understanding of these types of anomaly isobtained with an appreciation of the vocabulary mentioned previously.Anomalies of the Relationship Between Atria and VentriclesAnomalies of the relationship between the atria and the ventricles frequently result in the socalleduniventricular hearts. Such hearts may have both atrioventricular valves entering asingle ventricle or there may be an absent left or right atrioventricular connection.Double-inlet ventriclesBoth atria can enter the same ventricle through separate atrioventricular valves. Bothatrioventricular valves can be dedicated to either the left or right ventricle. In most cases ofdouble inlet ventricle, the ventricle receiving the flow from the atria is very large. The size ofthe other ventricle may be very small, or indeed, rudimentary. This is the common setting forso-called univentricular heart.The term univentricular heart is somewhat misleading since the other ventricle is frequentlypresent but rudimentary. Included under this heading is the heart previously described assingle ventricle, primitive ventricle, and common ventricle, as well as the heart with tricuspidor mitral atresia when these are due to absence of the atrioventricular connection. Thecommon feature of these conditions is that the atria communicate or are in potentialcommunication with only one ventricular chamber. This chamber is usually of the leftventricular type, but may rarely have right ventricular or indeterminate morphology. Whenthe main chamber is of left ventricular type, a rudimentary hypoplastic right ventricle isusually present; when the main chamber is of right ventricular type the small chamber has leftventricular morphology.The two most common types of univentricular atrioventricular connection are double-inletventricle (both atrioventricular valves can be seen in one ventricular chamber) and absentright or left ventricular connection. Fig. 31 demonstrates an apical four-chamber view from apatient with a double-inlet left ventricle with a single ventricle of left ventricularmorphology. Fig. 32 shows an anatomic specimen of a univentricular heart with absent rightatrioventricular connection.Atrioventricular discordanceAnother anomaly of the relationship of structures at the atrioventricular junction occurs whenthe ventricles are reversed. In this condition, the flow from the right atrium enters amorphologic left ventricle and flow from the left atrium enters a morphologic right ventricle.Almost invariably the relationship between the ventricles and the great vessels is alsodiscordant with the left ventricle giving rise to the pulmonary artery and the right ventriclegiving rise to the aorta.