Ebstein's disease. Electrovectorcardiographic and radiologic correlations

Electro-vectorcardiographic and electrophysiological aspects of Ebstein's anomaly

Ebstein's anomaly is a congenital heart disease where the most important anatomic feature is the inferior displacement of the tricuspid valve leaflets. Vectorcardiographic features are mainly forgotten and electrocardiographic features may be unrecognized by cardiologists handling adult patients.

Electrophysiologic characteristics of Ebstein's anomaly of the tricuspid valve

Electrophysiologic characteristics of five patients with Ebstein's anomaly of the tricuspid valve were defined with studies using luminal intracardiac electrode catheters. The diagnosis was made in each case from clinical data and confirmed at cardiac catheterization by the presence of an atrialized right ventricular chamber with atrial mechanical activity and ventricular electrical activity. In three cases intra-right atrial conduction was prolonged (P-A intervals of 50, 50, and 65 msec), a finding which reflected the presence of a characteristically large right atrium. The bundle of His electrogram was recorded in its usual anatomical location. Atrioventricular nodal conduction was prolonged in only one case. Intra-His delay was observed in two cases (bundle of His duration of 30 and 30 msec). Infranodal conduction was prolonged in four cases with H-V intervals of 60, 65, 65, and 80 msec. The anatomical abnormalities were least severe in the only patient with a normal H-V interval (50 msec). The prolonged H-V interval was thought to result from stretching of the conduction system over the atrialized right ventricle (ARV). The late depolarization during the splintered R' of the electrocardiogram found during intracardiac mapping of the ARV in three patients confirms the theory that the ARV produces the "second QRS" typically seen in this anomaly. The ARV was particularly irritable, and ventricular fibrillation was produced in two patients during catheter manipulation in this area. In one case the ARV had a shorter refractory period than the body of the right ventricle. Re-entrant supraventricular tachycardia was induced in the only patient with Wolff-Parkinson-White syndrome. In addition to the previously recognized electrophysiologic features reconfirmed here, patients with Ebstein's anomaly of the tricuspid valve usually have: normal position of the bundle of His, prolonged intra- right atrial conduction, prolonged infranodal conduction, and irritable ARV with delayed activation.

Sail sound in Ebstein's anomaly of the tricuspid valve

Ebstein's anomaly represents an anatomic, pathologic, and physiologic spectrum. There have been few hemodynamic correlates for the observed auscultatory events. Multiple components of the first sound and "ejection" sounds are frequently described.

Cardiac catheterization, intracardiac sound-pressure studies (Telco), and cineangiograms were performed in three patients with Ebstein's anomaly who had a prominent early systolic sound.

The right ventricular pressure pulse was abnormal in all; an initial delta-wave configuration, followed by a more rapid pressure rise, produced a prolonged rise to peak pressure. The right ventricular pressure pulse is not that of a conduction defect alone; rather it suggests that the altered pattern of ventricular contraction and abnormal leaflet placement are contributing factors.

The early systolic sound was recorded in the atrialized right ventricle or right ventricle in all. It occurred just after the peak of the c wave in the atrialized right ventricle. In the right ventricle the sound occurred at the point where initial slow delta portion of right ventricular pressure pulse gave rise to rapid upstroke. The early systolic sound most likely occurs when the large, sail-like tricuspid valve reaches the limit of systolic excursion. The sound has been designated as the "sail sound," and may be the most specific auscultatory event in Ebstein's anomaly.

Right bundle-branch block and left anterior fascicular block (left anterior hemiblock) following tricuspid valve replacement

Right bundle-branch block occurred in 42.8% and left anterior hemiblock in 35% of 14 patients after surgical replacement of the tricuspid valve. The combination of RBBB with left anterior hemiblock is caused by injury to the branching portion of the bundle of His or more likely, by a lesion involving the pseudobifurcation. This study provides further proof that left anterior hemiblock may be produced by a "central" lesion of the conduction system. An attempt was made to re-define the relationships of the bundle of His and bundle branches to the membranous septum and septal leaflet of the tricuspid valve and to correlate the site of surgical injury with the type of conduction disturbances produced.