Natural history of ventricular septal defect with right-sided aortic arch

Development of a double-chambered right ventricle after repair of tetralogy of Fallot

OBJECTIVES

We sought to determine the frequency, etiology and progressive nature of midcavity obstruction in patients after primary repair of tetralogy of Fallot (TOF).

BACKGROUND

Midcavity obstruction (double-chambered right ventricle [DCRV]) represents a significant portion of reoperations in patients who have had TOF repair. This group is still poorly defined.

METHODS

A retrospective review of clinical, echocardiographic and catheterization data for all patients with TOF who later underwent reoperation for DCRV was performed.

RESULTS

Between 1973 and 1995, 552 children <2 years of age underwent primary TOF repair (median age 6.7 months). Long-term follow-up (median 50 months) was available in 308 children. Of these, 17 children subsequently developed DCRV requiring reoperation. The median age at initial operation was 7.9 months. During a median follow-up interval of 43.2 months, murmur intensity increased in all patients, and the average subpulmonary gradient at catheterization increased from 24+/-10 to 80+/-27 mm Hg in seven children (p = 0.002) and at Doppler echocardiography from 14+/-16 to 89+/-18 mm Hg in five children (p = 0.002). Before reoperation, 6 of the 17 children were symptomatic. During the operation (median age 55.4 months), obstruction was relieved by incision of hypertrophied anomalous muscle bundles in all 17 patients, with prominent fibrosis noted in 8 patients. Excessive septal and parietal hypertrophy was noted in one child. No new transannular patches were required. Recurrent obstruction has reappeared in 3 of these 17 children during follow-up.

CONCLUSIONS

DCRV is a medium-term complication of TOF repair in infants, with a minimal incidence of 3.1% (95% CI 1.8% to 4.9%). The condition is progressive and is due to anomalous muscle bundle hypertrophy or fibrosis, or both, which may represent displaced insertion of a moderator band. Further reobstruction does occur; continued careful follow-up is therefore essential.

Malalignment-type ventricular septal defect in double-chambered right ventricle

Double-chambered right ventricle (DCRV) is commonly associated with ventricular septal defect (VSD). In this study, an assessment was made of the relevance of a malalignment-type VSD to hemodynamic and morphologic features in DCRV. During an 8.5-year period, 53 patients with DCRV were enrolled after study with echocardiography, catheterization, and angiography. Patients were divided into 2 groups: group I included 40 patients, aged 3.7 +/- 3.2 years, with a malalignment-type VSD; group II consisted of 13 patients, aged 8.6 +/- 2.7 years, without a malalignment-type VSD. History of congestive heart failure in infancy was present in 21 group I and 2 group II patients (53% vs 15%, respectively, p <0.05). The mean pulmonary-to-systemic flow ratio was significantly higher in group I than in group II (1.89 +/- 0.74 vs 1.14 +/- 0.21, respectively, p <0.05). The mean pressure gradient across the right ventricular outflow tract was lower in group I than in group II (41 +/- 16 vs, 73 +/- 33 mm Hg, respectively, p <0.05). Among 42 patients who had a series of echocardiograms recorded, progression of pressure gradient was evident in 35: 28 in group I and 7 in group II. A subaortic ridge was present exclusively in 29 group I patients (73%). Prolapse of the aortic valve was present in 26 (49%): 20 group I (50%) and 6 group II (46%) patients. Aneurysm formation of the septal defect was found in 17 (43%) and 7 (54%) group I and II patients, respectively. It can be concluded that a history of congestive heart failure was more common in DCRV patients with a malalignment-type VSD. Malalignment-type VSD is significantly associated with a larger pulmonary-to-systemic flow ratio and subaortic ridge.

Clinical course of isolated ventricular septal defect: an Indian experience

To define the clinical course of ventricular septal defect, 410 consecutive patients with isolated ventricular septal defect were evaluated over a period of 13 years. Their age ranged from 12 days to 24 years at the time of first visit to the hospital. Patients with less than 2 years follow-up period were excluded. One hundred and fifty seven patients were one year of age or less. The left to right shunt size remained the same in 52.4% of cases. In 34.4% the shunt size decreased, with complete closure of ventricular septal defect in 8.8%. Closure of ventricular septal defect was observed even in patients who had initially presented with large left to right flow, and congestive heart failure in infancy. Right ventricular outflow tract obstruction developed in 8.5% of patients usually between 2 and 10 years of age. Murmur of aortic regurgitation appeared in 8.9% on follow-up. Infective endocarditis developed in 6 cases. The unfortunate complication of Eisemenger's complex was seen in 3 patients; they had not returned for follow up for a long period of time. Hence, our data show that the left to right shunt across the ventricular septal defect decreases in about one-third of patients. However, a regular follow up is essential to prevent development of Eisenmenger's complex and for early detection of other complications like aortic regurgitation and right ventricular outflow tract obstruction.

Confirmation that the velo-cardio-facial syndrome is associated with haplo-insufficiency of genes at chromosome 22q11

The velo-cardio-facial syndrome (VCFS) and DiGeorge sequence (DGS) have many similar phenotypic characteristics, suggesting that in some cases they share a common cause. DGS is known to be associated with monosomy for a region of chromosome 22q11, and DNA probes have been shown to detect these deletions even in patients with apparently normal chromosomes. Twelve patients with VCFS were examined and monosomy for a region of 22q11 was found in all patients. The DNA probes used in this study could not distinguish the VCFS locus and the DGS locus, indicating that the genes involved in these haploinsufficiencies are closely linked, and may be identical. The phenotypic variation of expression in VCFS and DGS may indicate that patients without the full spectrum of VCFS abnormalities but with some manifestations of the disorder may also have 22q11 deletions.

Mechanism of acquired right ventricular outflow tract obstruction in patients with ventricular septal defect: an angiocardiographic study

Right ventricular outflow tract obstruction can complicate the natural history of patients with isolated ventricular septal defect. Although numerous pathologic mechanisms may be responsible for this phenomenon, it is less clear what the frequency is of each of these mechanisms in any cohort of patients studied in a single institution. We identified 20 patients with isolated ventricular septal defect from 1970 to 1981 who acquired a right ventricular outflow tract gradient of 25 mm Hg or more. They ranged in age at the initial catheterization investigation from 4 days to 23 months and at the subsequent study from 13 months to 8 years. Angiographically, 2 mechanisms were implicated in the 20 patients. Hypertrophy of right ventricular anomalous muscle bundles was identified in 19 of the 20 while hypertrophy of a malaligned infundibular septum (that is, classic tetralogy type) was identified in only 1 patient. These data indicate that acquired right ventricular outflow tract obstruction is rarely of the classic tetralogy type.

Right ventricular anomalous muscle bundle. Clinical and laboratory presentation and natural history

Eighteen patients with right ventricular anomalous muscle bundles associated with ventricular septal defect and one patient with isolated anomalous muscle bundle were studied. The clinical differentiation of these patients from those with isolated ventricular septal defects or tetralogy of Fallot was difficult. Eleven patients were asymptomatic at the time of diagnosis; eight had various degrees of dyspnea on exertion, with three of these having cyanosis. A physiologically split second sound with a pulmonic component of normal intensity and a diffuse thrill and holosystolic murmur maximal at the lower left sternal border suggest the diagnosis. Chest X-rays and electrocardiograms usually show evidence of right ventricular hypertrophy, but may suggest left ventricular hypertrophy in the presence of a large left-to-right shunt. However, the diagnosis is best made by cardiac catheterization with measurement of a pressure gradient in the body of the right ventricle and by selective angiography with the demonstration of a wedge-shaped filling defect in the right ventricle. Progressive obstruction by the muscle bundle occurred in four of seven patients who had repeated catheterization associated with the development of electrocardiographic changes of right ventricular hypertrophy. To date, 11 patients have had surgery; one died before surgery; and surgery is being planned for the remaining patients.