Asian Cardiovasc Thorac Ann 2005;13:127-130
© 2005 Asia Publishing EXchange Ltd
Double-Chambered Right Ventricle in Adulthood
Mitsugi Nagashima, MD,
Tetsuo Tomino, MD,
Harumitsu Satoh, MD,
Tatsuhiro Nakata, MD,
Takashi Ohtani, MD,
Hiroyuki Saito, MD
Department of Cardiovascular Surgery, Ehime Prefectural Central Hospital Ehime, Japan
For reprint information contact: Mitsugi Nagashima, MD Tel: 81 89 947 1111 Fax: 81 89 943 4136 Email: mitsugi{at}aqua.plala.or.jp, Department of Cardiovascular Surgery, Ehime Prefectural Central Hospital, 83 Kasuga-cho, Matsuyama city, Ehime 790-0024, Japan.
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ABSTRACT
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Patients with double-chambered right ventricle presenting with symptoms in adulthood are rare. From 1990 to 2004, 4 adults and 9 children with double-chambered right ventricle underwent surgical correction. The surgical results and clinical data of the adults were compared with those of the pediatric patients. All adult patients had dyspnea on exertion, 3 children showed growth delay but the others were asymptomatic. The mean age at operation was 44.5 ± 6.3 years in adults and 5.2 ± 1.9 years in children. The mean pressure gradient between the anatomically lower right ventricle and the pulmonary artery was significantly higher in adults than in children (91.8 ± 14.1 vs. 42.2 ± 5.9 mm Hg). The pulmonary-to-systemic flow ratio in adults was significantly lower than in pediatric patients (1.2 ± 0.2 vs. 1.8 ± 0.3). All adults and 8 of the 9 children survived. There were no late deaths or re-operations, and all survivors were in New York Heart Association functional class I. Surgical correction of double-chambered right ventricle in adults gave satisfactory midterm results although right ventricular outflow tract obstruction and clinical symptoms were severe in these patients.
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INTRODUCTION
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Double-chambered right ventricle (DCRV) is a congenital cardiac anomaly in which the right ventricle (RV) is separated into two chambers, a proximal high-pressure (anatomically lower) chamber and a distal low-pressure (anatomically higher) chamber, by anomalous muscles or fibrous tissues in the right ventricular cavity.1 Obstruction of the right ventricular outflow tract (RVOT) is generally progressive after infancy, and DCRV is usually diagnosed and repaired in childhood. Occasionally, patients with DCRV manifest symptoms in adulthood.2,3 Most of them remain undiagnosed and untreated until symptoms progress. This report describes our surgical experience in adults with DCRV, and compares their clinical data with those of pediatric patients.
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PATIENTS AND METHODS
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From November 1990 to February 2004, 13 patients with DCRV underwent surgical correction at our institution. Four of these were adults aged 30 to 58 years (mean, 44.5 ± 6.3 years). The ages of the 9 pediatric patients ranged from 1 to 16 years (mean, 5.2 ± 1.9 years). Double-chambered right ventricle was defined as obstruction by abnormal muscle bundles traversing the RV, which was established by echocardiography, cardiac catheterization, and 3-dimensional computed tomography (Figure 1
). Indications for surgery included pulmonary-to-systemic blood flow ratio (Qp/Qs) > 2.0, pressure gradient > 40 mm Hg between the anatomically lower RV and the main pulmonary artery, aortic regurgitation (AR) or symptoms of heart failure. Surgical correction consisted of resection of the abnormal muscle bundles and closure of any ventricular septal defect (VSD) through a transatrial and/or transpulmonary approach in 5 of the pediatric patients, and through a right ventriculotomy in the other 4 pediatric patients and in all 4 adults. All but one VSD were of the perimembranous type. One adult patient had a muscular outlet VSD that communicated with the anatomically lower chamber. The ventriculotomy, which was limited within the RVOT, was closed directly or with a Dacron or Gore-Tex patch. One pediatric patient required concomitant tricuspid annuloplasty. After discharge from hospital, the patients were followed up at regular intervals by pediatric cardiologists or physicians. The mean follow up period was 8.4 ± 2.7 years in adults and 4.5 ± 1.1 years in pediatric patients. Data were collected from hospital medical records retrospectively and all results were expressed as mean ± standard error. The unpaired Student’s t test was used to compare differences between groups. A value of p < 0.05 was considered statistically significant.
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Figure 1. Preoperative three-dimensional computed tomograms. The white arrows show the stenotic portion of the right ventricular outflow tract. Ao = aorta, LV = left ventricle, PA = pulmonary artery, P-valve = pulmonary valve, RA = right atrium, RV = right ventricle.
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RESULTS
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All 4 adult patients had dyspnea on exertion and decreased exercise tolerance. One adult had a slight yet sporadic fever; her blood culture study was positive for alpha streptococcus. Three of the pediatric patients had delayed growth related to excessive pulmonary blood flow or pulmonary hypertension. Although the other 6 pediatric patients had no symptoms, they underwent surgery because of a pressure gradient > 40 mm Hg between the anatomically lower RV and the main pulmonary artery, a large Qp/Qs, or the occurrence of AR. The clinical characteristics and associated anomalies of all patients are summarized in Table 1.
At cardiac catheterization, the mean pressure gradient between the right inflow chamber and the pulmonary artery was significantly higher in the adult group than in the pediatric group (91.8 ± 14.1 vs. 42.2 ± 5.9 mm Hg; p < 0.05). The pulmonary-to-systemic flow ratio in adult patients was significantly lower than in pediatric patients (1.2 ± 0.2 vs. 1.8 ± 0.3; p < 0.05). One child died from right heart failure in the early postoperative period. No residual RVOT obstruction was detected in any of the patients. There were no late deaths and no re-operations, and all survivors were in New York Heart Association functional class I. Preoperative AR was detected in 1 adult, but it resolved postoperatively. In the pediatric patients, 2 adolescents had preoperative trivial AR due to cusp prolapse. In 2 other pediatric patients, AR, which had not been detected preoperatively, developed 5 and 6 years after their operations. No intermittent or sustained ventricular tachycardia, atrial fibrillation, or atrial flutter was documented in any of the patients during the follow-up period.
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DISCUSSION
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Symptoms in DCRV patients usually appear after infancy.4 A typical case of DCRV follows the diagnosis of simple VSD during infancy, then a subpulmonary abnormal muscle band develops during childhood. This process can divide the RV into two chambers, and the blood pressure in the anatomically lower RV gradually increases. Although this can result in decreasing Qp/Qs, clinical symptoms do not appear in most children who have DCRV with a small VSD or they may be diminished even in symptomatic pediatric patients with a large VSD. Most patients are advised to undergo surgery because of high right ventricular pressure or the occurrence of AR before adulthood. Even if clinical follow up is discontinued due to a lack of symptoms, some patients survive and grow to adulthood. Usually, they do not seek treatment until serious symptoms appear. For these reasons, patients presenting with DCRV in adulthood are uncommon. To our knowledge, only 37 adult cases have been reported.2,3,5–14 The most frequent symptoms in adult patients are dyspnea on exertion and decreased exercise tolerance. The poor exercise intolerance probably relates to decreased cardiac output or right heart failure due to severe stenosis of the RVOT. In our series, all adult patients had dyspnea on exertion and decreased exercise tolerance. As serious stenosis of the infundibulum develops, some patients have syncope or dizziness due to a transient blood flow disturbance.2 Fever and lethargy, which are related to infective endocarditis, were also reported in some patients.9
Aortic regurgitation is uncommon in pediatric patients with DCRV; incidences of associated AR are as low as 5%–20%.9,13 In contrast, the prevalence of AR is comparatively high in adults with DCRV. In our series, one adult and two adolescents (13 and 16 years of age) had AR, although it was trivial to mild and did not require surgical correction. Even in pediatric patients, older age has a tendency to increase the incidence of AR. Similar rates of AR in adult patients were reported by Kveselis and colleagues9 (40%, 2/5 patients) and McElhinney and colleagues2 (33%, 1/3 patients). Two causes of AR in patients with DCRV have been considered: coronary cusp prolapse and subaortic ridge.15 Although prolapse of the aortic cusp is frequent in the subaortic type of VSD, it is uncommon in perimembranous VSD. The prevalence of aortic cusp prolapse in perimembranous VSD was only 4% of all cases of simple perimembranous VSD in our institution. Compared with simple VSD, the rate of aortic cusp prolapse in DCRV was quite high. It has been speculated that negative pressure produced by turbulence at the RVOT might be related to cusp prolapse.15 Subaortic ridges occur with a high incidence (18%–70%) in DCRV patients.15 A subaortic ridge is considered to result in valve deformity due to the adjacent turbulence. Aortic prolapse and subaortic ridge would lead in time to AR, and may account for the high incidence of AR in adults with DCRV.
A transatrial or transatrial-pulmonary approach is preferred to a transventriculotomy because it is believed to prevent late RV dysfunction and lethal ventricular arrhythmias.16 However, it should not be essential to avoid a ventriculotomy if an excessive right ventricular incision is prevented. Hachiro and colleagues13 reported that ventriculotomy may still be necessary for the release of severe RVOT obstruction in some older patients. It was demonstrated that surgically treated patients with DCRV were in excellent condition even decades after the repair.9,13 Severe RV dysfunction was rarely reported, and even less frequent was lethal ventricular tachycardia in patients with DCRV. These findings are quite different form the long-term results in patients with tetralogy of Fallot.17 In most DCRV patients, the pulmonary valve is normal and the ventriculotomy can be limited within the RVOT (no transpulmonary-annular incision) and this may prevent late RV dysfunction due to pulmonary regurgitation. Downar and colleagues18 reported that in patients with tetralogy of Fallot, the earliest activation of sustained ventricular tachycardia after surgical repair was located within the subendocardium in the RVOT. Even if a ventriculotomy is avoided in patients with DCRV, ventricular arrhythmias may result from the essentially inevitable resection site at the inner RV muscle.
It was concluded that in adults with DCRV, the manifestation of symptoms such as dyspnea on exertion was due to right heart failure or low-output syndrome caused by serious progression of the RVOT obstruction. Mid-term surgical results for adults with DCRV are excellent even though RVOT obstruction and clinical symptoms were severe.
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ABSTRACT
INTRODUCTION
