Aberrant muscle bundle of the right ventricle

Initial clinical manifestations and mid- and long-term results after surgical repair of double-chambered right ventricle in children and adults

OBJECTIVE

By means of retrospective analysis of our institutional experience, we reviewed the clinical manifestation and outcomes of patients subsequent to surgical repair of double-chambered right ventricle.

METHODS

Between 1988 and 2005, we performed surgical repair in 35 of 37 patients diagnosed with double-chambered right ventricle. The patients ranged in age from 4 to 69 years, with a mean of 21.3 years. Most presented in infancy, with initial manifestation of a short systolic murmur in 34 (92%) of all cases. Pressure gradients were measured invasively across the right ventricular outflow tract of between 30 and 140 mmHg, with a median of 60 mmHg. An associated ventricular septal defect was present in 26 patients (70%). Of the group, 4 patients were aged over 40 years, and 2 had previously undergone operative closure of a ventricular septal defect.

RESULTS

The operative interval ranged from 2 months to 41 years, with a median of 9 years. In all, we resected muscular bundles and enlarged the right ventricular outflow tract. There was no hospital or late death. Median follow-up subsequent to surgery was 7 years, with a range from 0.4 to 11 years. No patient required further surgery to relieve any obstruction of the right ventricular outflow tract, nor long term medical therapy or pacing because of cardiac arrhythmia.

CONCLUSIONS

Surgical repair of a double-chambered right ventricle yields excellent haemodynamic and functional results over the mid to long term.

The nature of the obstructive muscular bundles in double-chambered right ventricle

OBJECTIVE

Our goal was to establish the morphologic nature of the obstructive muscular lesions in double-chambered right ventricle.

METHODS

We based our morphologic observations on 10 normal hearts and on the surgical findings in 26 patients, aged 0.5 to 24 years, with a mean of 6.9 years (SD 5.8 years). In the normal hearts, we measured the distance from the pulmonary valve to the apex of the right ventricle and from the takeoff of the moderator band to the ventricular apex. From angiograms available in 20 patients, using the frontal view, we then measured the distance from the pulmonary valve to the apex of the right ventricle and from the midpoint of the obstructive lesion to the apex of the right ventricle. This permitted calculations of multiple ratios.

RESULTS

In the 10 normal hearts, the moderator band took origin at a mean ratio of 0.48 (SD 0.16) of the ventricular length. On the basis of the angiographic findings, we identified 2 basic forms of double-chambered right ventricle. In 9 patients, the obstructive muscular shelf was positioned low and diagonally across the apical component, with a mean ratio of 0.38 relative to the ventricular length (SD 0.02). In the other 11 patients, the obstructive shelf was high and horizontal, with a mean ratio of 0.27 (SD 0.02). The difference was statistically significant (P =.001). Surgical repair was performed successfully in all 26 patients through a right ventriculotomy.

CONCLUSIONS

Double-chambered right ventricle is the consequence of a high or low muscular division of the apical component of the right ventricle. The abnormal muscular bundle probably represents accentuated septoparietal trabeculations, rather than always being an abnormal moderator band.

Anomalous muscle bundle of the right ventricle. Its recognition and surgical treatment

This communication presents our experience with 14 cases of congenital heart disease associated with anomalous muscle bundle inside the right ventricular cavity dividing it into two chambers. The clinical picture, natural history, and diagnostic characteristics are described. It can be diagnosed by right ventricular cineangiogram in the anteroposterior position. It can be resected surgically, safely.

Isolated anomalous right ventricular muscle bundle in the asymptomatic adult

Muscular obstruction to right ventricular outflow is usually at the infundibular level, but, less commonly, it can occur within the body of the ventricle due to an anomalous muscle bundle. This lesion is almost always associated with a ventricular septal defect or other cardiac lesions, and is usually discovered in infancy or childhood. Two asymptomatic adults with severe obstruction due to right ventricular muscular band as an isolated lesion are presented. The lesion can be tentatively diagnosed on clinical grounds and confirmed by angiocardiography. The advisability of surgical correction in the asymptomatic adult with such an isolated lesion is uncertain.