eMedicine Specialties > Pediatrics: Cardiac Disease and Critical Care Medicine > Cardiology
Double-Chambered Right Ventricle
Updated: May 18, 2009
Introduction
Background
Like many other lesions associated with congenital heart disease (CHD), the terminology that surrounds double-chambered right ventricle (DCRV) has evolved over the past several decades. Double-chambered right ventricle was originally described more than 130 years ago. Clinical series began describing it extensively in the 1960s.
Double-chambered right ventricle is better understood as a form of septated right ventricle (RV) caused by the presence of abnormally located or hypertrophied muscular bands.
The abnormally located or hypertrophied muscle bundles divide the RV cavity into a proximal and a distal chamber. Those muscle bundles run between an area located in the ventricular septum, beneath the level of the septal leaflet of the tricuspid valve, and the anterior wall of the RV. Frequent associated lesions include ventricular septal defect (VSD), pulmonary valve stenosis, and discrete subaortic stenosis.
As outlined by Restivo et al, several subtypes of divided RV are noted.1 These subtypes include anomalous septoparietal band, anomalous apical shelf, hypertrophy of apical trabeculations, anomalous apical shelf with Ebstein malformation, and sequestration of the outlet portion of the ventricle from a circumferential muscular diaphragm in patients with tetralogy of Fallot. Double-chambered right ventricle, the most common form, is noted by the presence of anomalous muscle bundles (AMB) that divide the RV into 2 chambers. However, no uniformity is observed in the position of these anomalous muscle bundles or in the manner in which the RV is divided.
Right anterior oblique (RAO) angiogram demonstrating proximal and distal chambers of right ventricle (Image courtesy of R.M. Freedom, MD).
Lateral right ventriculography of a patient with double-chambered right ventricle. Large arrow indicates the presence of a fibromuscular obstruction with division of the right ventricle; small arrows outline pulmonary valve stenosis (Image courtesy of R.M. Freedom, MD).
Pathophysiology
Anomalous muscle bundles divide the RV into a high-pressure proximal chamber and a lower-pressure distal chamber. Evidence suggests that double-chambered right ventricle is an acquired disorder in those patients with appropriate substrate. Obstruction to pulmonary blood flow usually progresses with hypertrophy of the muscle and further obliteration of the RV cavity, although cases without progression of obstruction and even of spontaneous regression have been described.The origin of anomalous muscle bands has been debated. The embryologic basis for double-chambered right ventricle was attributed to failure to incorporate bulbus cordis into the RV or an elevated hypertrophied moderator band. However, Byrum et al used the pattern of electrical activation to determine that muscle bundles were not the result of a displaced moderator band and suggested that activation of the double-chambered right ventricle is similar to activation of the normal heart.2 Others, however, concluded that both the presence of bundle branch block in some patients and detection of a portion of the right bundle branch in a pathologic sample of the muscle bundle have proven the hypothesis that the moderator band is, in fact, the obstructing bundle.
A contemporary analysis of the origin of the muscle bundles determined the muscular shelf originates from the body of the septomarginal trabeculation. Two positions of muscle bundles are described as high (or horizontal) position and low (or oblique) position. Either position of the shelf divides the apical trabeculated RV in 2. This same analysis determined that the normal moderator band widely varies and that the anomalous muscle bundles do not represent an early takeoff from the moderator band in most cases. In a review of surgical cases, 45% of cases had more than one or nondiscrete muscle bundles.3
Muscle bundles and the RV itself are usually lined with thickened endothelium. Other, less common, forms of divided RV include those in which a fibromuscular diaphragm or atrioventricular valve tissue partition the RV. These other forms include the anomalous septoparietal band, anomalous apical shelf, hypertrophy of apical trabeculations, anomalous apical shelf with Ebstein malformation, and sequestration of the outlet portion of the ventricle from a circumferential muscular diaphragm in patients with tetralogy of Fallot. These forms are not discussed in this article.
Associated defects are present in approximately 80-90% of patients; a VSD that involves the membranous septum is the most common defect described. A VSD may communicate with either the proximal or distal chamber, leading to a greater shunt in the latter situation. Development of RV outflow tract obstruction occurs in 3-7% of patients with membranous VSDs within the first years of life. The mechanism responsible for acquired RV obstruction may be progressive hypertrophy and obstruction from anomalous RV muscle bundles.
A well-known relationship is described among patients with RV outflow tract obstruction, membranous VSD, and subaortic stenosis. Vogel et al described 36 patients with membranous VSD and double-chambered right ventricle, 88% of whom had echocardiographic evidence of subaortic stenosis, with evidence of progressive left ventricular outflow tract obstruction.4 Progression of subaortic stenosis may occur before or after VSD closure and/or muscle bundles are resected.
The next most common associated lesion is pulmonary valve stenosis. Various other associations have been reported, including double outlet RV, tetralogy of Fallot, anomalous pulmonary venous drainage, complete or corrected transposition of great arteries, pulmonary atresia with intact ventricular septum, and Ebstein anomaly. Double-chambered right ventricle has also been reported in patients with Down syndrome and Noonan syndrome, although differentiation from hypertrophic cardiomyopathy in the latter group is not straightforward.
Although Rowland et al considered patients in 4 groups, based on predominant physiology (pulmonary stenosis, tetralogy of Fallot, large VSD with left-to-right shunt, double-chambered right ventricle associated with other more hemodynamically significant lesions), most patients have moderate-to-restrictive VSD.5 Most of the remaining patients present with tetralogy physiology or have significant associated lesions.
Natural history varies depending on the presence of associated lesions. Progressive obstruction of the RV outflow tract has been observed and can lead to RV failure, especially in the presence of a VSD. Several report diagnosis in asymptomatic adults in whom anomalous muscle bundles and intact ventricular septum may have been associated with a VSD that underwent spontaneous closure.
Frequency
International
Double-chambered right ventricle is relatively rare as an isolated anomaly; a large pediatric center typically diagnoses fewer than 10 cases per year. The lesion makes up approximately 0.5-2% of CHD and occurs in as many as 10% of patients with VSD.
Mortality/Morbidity
Fatalities in the surgical literature are very rare. A recent series reports no hospital or late deaths.6 Much of reported morbidity and mortality results from a failure to diagnose double-chambered right ventricle. This failure has preoperatively led either to closure of one of the portions of the RV, with a fatal outcome, or to reoperation in cases where the VSD was closed, although an obstructed RV remained.
In the larger series, residual mild RV outflow tract obstruction, nonhemodynamically significant residual VSDs, tricuspid valve regurgitation, and aortic valve regurgitation have been described as long-term morbidity issues.
Sex
Male-to-female ratio is 2:1.
Age
Presentation can be as early as the newborn period; however, mean age at diagnosis is in early childhood. Both fetal and adult cases have been reported.
Clinical
History
- Most patients with double-chambered right ventricle (DCRV) initially present with no symptoms.
- The most common reason for referral is the detection of a murmur.
- Clinically, patients with double-chambered right ventricle and no ventricular septal defect (VSD) resemble patients with isolated pulmonary valve stenosis.
- When a VSD is present, the clinical picture relates to a VSD. Usually, the patient is diagnosed with a VSD or pulmonary outflow tract obstruction and, subsequently, may show signs of progression of the outflow obstruction, such as cyanosis, fatigue, and decreased exercise tolerance.
- Rowland et al describe 4 physiologic groups (see Pathophysiology) with patients presenting usually with left-to-right shunt or tetralogy of Fallot physiology.5
- Patients with severe right ventricle (RV) hypertension may present with cyanosis, RV failure, failure to thrive, and fatigue.
- Association with other syndromes is well recognized, and double-chambered right ventricle may be found during their workup.
Physical
- Most patients are nondysmorphic and acyanotic with normal peripheral examination findings. Auscultation reveals a variable intensity of the second heart sound.
- A holosystolic ejection murmur, which peaks in intensity near midsystole, with greatest intensity at mid-left and upper-left precordial areas, characterizes double-chambered right ventricle.
- An RV heave, hepatomegaly, and tachypnea indicate RV hypertension.
Causes
- No inheritance pattern has been described.
- No risk factors for developing the disease have been encountered.
- Sporadic cases have been described in patients with Down syndrome and Noonan syndrome.
Differential Diagnoses
Pulmonary Stenosis, Infundibular
Pulmonary Stenosis, Valvar
Other Problems to Be Considered
Foreign body simulating double-chambered right ventricle (one case report)
Workup
Imaging Studies
- Chest radiography may reveal either a left-to-right shunt with increased pulmonary vascular markings or a severe right ventricle (RV) obstruction with diminished pulmonary vascularity. The usual arrangement includes atrial situs solitus, levocardia, and left aortic arch. Cardiomegaly may be seen in some patients.
- Echocardiography currently enables diagnosis on a 2-dimensional Doppler echocardiogram; before its advent, diagnosis of double-chambered right ventricle (DCRV) could not be made noninvasively. In infancy, subxiphoid imaging is optimal; parasternal short-axis views may be more useful in older patients. The cardinal feature is demonstration of muscle bundles that traverse the RV cavity, with an accompanying gradient starting proximal to the infundibulum.
Subcostal right anterior oblique (RAO) echocardiograph view demonstrating right ventricle muscle bundles separating proximal from distal (*) chamber. PV = Pulmonary valve (Image courtesy of J. Smallhorn, MD)
Subcostal right anterior oblique (RAO) echocardiograph view with color Doppler demonstrating ventricular septal defect jet to proximal chamber. (*) = Distal chamber (Image courtesy of J. Smallhorn, MD).
- Wong et al describe a "displacement index," which is determined by dividing the distance from the pulmonary annulus to the septal insertion of the moderator band by the tricuspid annulus diameter.7 An index less than 1 may predict that infants with ventricular septal defect (VSD) are at risk of developing an obstruction from a displaced moderator band.
- Transesophageal echocardiography has been used to define structures in older patients with poor windows.
- Further evidence of double-chambered right ventricle includes the angiographic demonstration of a filling defect dividing the RV, as well as the absence of infundibular hypoplasia. Double-chambered right ventricle should be differentiated from tetralogy of Fallot by the absence of infundibular hypoplasia and pulmonary artery anomalies in double-chambered right ventricle. Entering both components of the RV is important; ideally, perform angiography from the RV apex in the frontal and lateral projections with craniocaudal angulation.
- MRI and contrast CT scanning have been used in addition to echocardiography. These modalities may add to the anatomic delineation of the muscle bundles, although echocardiography is typically sufficient.
Other Tests
- ECG findings in double-chambered right ventricle were reviewed in one series of 30 patients.8 Almost 50% of the patients had evidence of right ventricular hypertrophy (RHV), 40% of them demonstrated an upright T wave in V3 R in the absence of other findings of RVH, and the remainder had normal ECG findings. Similar findings are reported in other series.
Electrocardiogram of an 18-month-old boy with double-chambered right ventricle. Note the upright T waves in the right precordial leads.
Procedures
- Cardiac catheterization still has a role in ruling out other lesions that may be difficult to detect and that may influence operative strategy, although the diagnosis can be made accurately based on echocardiography findings. Recording of the pressure gradient (which widely varies in magnitude) within the RV cavity, remote from the infundibulum, strongly suggests a diagnosis of double-chambered right ventricle.
Treatment
Medical Care
- Symptoms of double-chambered right ventricle (DCRV) that require therapy are generally an indication for operative repair.
Surgical Care
- The first successful surgical repair was reported in 1962. The initial approach was through a ventriculotomy; contemporary series describe both transatrial and transventricular approaches.
- Time to intervene naturally depends on the associated lesions; the current practice is to address associated lesions (ventricular septal defect [VSD], subaortic stenosis, pulmonary stenosis) at the time of double-chambered right ventricle repair.
- In the absence of a significant associated lesion, observation may be appropriate as long as the intracavitary gradient is not greater than 40 mm Hg and the degree of obstruction is not progressive.
- Although attempted, balloon dilatation likely has no role in the management of double-chambered right ventricle. Recently, Tsuchikane et al reported a patient who underwent a percutaneous myocardial ablation with an alcohol-induced conus branch occlusion for relief of a significant pressure gradient in double-chambered right ventricle.9
Activity
- Before repair, according to the degree of right ventricular outflow tract obstruction and associated lesions, exercise tolerance may be impaired and cyanosis may be present. After surgical repair and without significant residual anatomic lesions, activity tolerance should be normal.
- Guidelines for physical activity and recreational sports participation in children with genetic cardiovascular diseases have been established.10
Medication
- Drug therapy is not currently a component of the standard of care for double-chambered right ventricle (DCRV). See Treatment.
Follow-up
Further Outpatient Care
- Prior to surgical therapy for double-chambered right ventricle (DCRV), the follow-up is based on the degree of obstruction, associated lesions, and symptoms. Regular evaluation by a cardiologist is recommended.
- The residual lesions determine the follow-up of these patients after surgery. The patients are initially frequently evaluated in order to monitor the progress after repair.
- Exercise tolerance and quality of life, endocarditis prophylaxis, and recurrence of obstruction comprise the major issues during the long-term follow-up.
Prognosis
- Long-term results in earlier series are excellent, with current results showing improvement. Ruling out residual lesions and providing follow-up care for patients with recurrent right ventricle (RV) obstruction are important.
Patient Education
- For excellent patient education resources, visit eMedicine's Heart Center. Also, see eMedicine's patient education article Tetralogy of Fallot.
Miscellaneous
Medicolegal Pitfalls
- Failure to recognize double-chambered right ventricle (DCRV) in the presence of associated defects, particularly ventricular septal defect (VSD), which may result in reoperation
- Failure to rule out residual lesions
- Failure to provide follow-up care for patients with recurrent right ventricle obstruction
Special Concerns
- Once the associated lesions have been repaired and the abnormal muscle bundles have been resected, pregnancy carries no additional risks. The same applies if mild gradients across the right ventricular outflow tract exist.
Multimedia
Media file 1: Electrocardiogram of an 18-month-old boy with double-chambered right ventricle. Note the upright T waves in the right precordial leads.
Media file 2: Right anterior oblique (RAO) angiogram demonstrating proximal and distal chambers of right ventricle (Image courtesy of R.M. Freedom, MD).
Media file 3: Lateral right ventriculography of a patient with double-chambered right ventricle. Large arrow indicates the presence of a fibromuscular obstruction with division of the right ventricle; small arrows outline pulmonary valve stenosis (Image courtesy of R.M. Freedom, MD).
Media file 4: Subcostal right anterior oblique (RAO) echocardiograph view demonstrating right ventricle muscle bundles separating proximal from distal (*) chamber. PV = Pulmonary valve (Image courtesy of J. Smallhorn, MD)
Media file 5: Subcostal right anterior oblique (RAO) echocardiograph view with color Doppler demonstrating ventricular septal defect jet to proximal chamber. (*) = Distal chamber (Image courtesy of J. Smallhorn, MD).
References
Restivo A, Cameron AH, Anderson RH, Allwork SP. Divided right ventricle: a review of its anatomical varieties. Pediatr Cardiol. Jul-Sep 1984;5(3):197-204. [Medline].
Byrum CJ, Dick M 2nd, Behrendt DM, et al. Excitation of the double chamber right ventricle: electrophysiologic and anatomic correlation. Am J Cardiol. Apr 1 1982;49(5):1254-8. [Medline].
Hubail ZJ, Ramaciotti C. Spatial relationship between the ventricular septal defect and the anomalous muscle bundle in a double-chambered right ventricle. Congenit Heart Dis. Nov 2007;2(6):421-3. [Medline].
Vogel M, Smallhorn JF, Freedom RM, et al. An echocardiographic study of the association of ventricular septal defect and right ventricular muscle bundles with a fixed subaortic abnormality. Am J Cardiol. Apr 1 1988;61(10):857-60. [Medline].
Rowland TW, Rosenthal A, Castaneda AR. Double-chamber right ventricle: experience with 17 cases. Am Heart J. Apr 1975;89(4):455-62. [Medline].
Telagh R, Alexi-Meskishvili V, Hetzer R, Lange PE, Berger F, Abdul-Khaliq H. Initial clinical manifestations and mid- and long-term results after surgical repair of double-chambered right ventricle in children and adults. Cardiol Young. Jun 2008;18(3):268-74. [Medline].
Wong PC, Sanders SP, Jonas RA, et al. Pulmonary valve-moderator band distance and association with development of double-chambered right ventricle. Am J Cardiol. Dec 15 1991;68(17):1681-6. [Medline].
Goitein KJ, Neches WH, Park SC, et al. Electrocardiogram in double chamber right ventricle. Am J Cardiol. Mar 1980;45(3):604-8. [Medline].
Tsuchikane E, Kobayashi T, Kirino M, et al. Percutaneous myocardial ablation in double-chamber right ventricle. Catheter Cardiovasc Interv. Jan 2000;49(1):97-101. [Medline].
[Guideline] Maron BJ, Chaitman BR, Ackerman MJ, et al. Recommendations for physical activity and recreational sports participation for young patients with genetic cardiovascular diseases. Circulation. Jun 8 2004;109(22):2807-16. [Medline].
Alva C, Ho SY, Lincoln CR, et al. The nature of the obstructive muscular bundles in double-chambered right ventricle. J Thorac Cardiovasc Surg. Jun 1999;117(6):1180-9. [Medline].
Ceyran H, Narin N, Tasdemir K, et al. Double-chambered right ventricle mimicking asymmetric septal hypertrophy. Turk J Pediatr. Jan-Mar 2003;45(1):80-2. [Medline].
Freedom RM, Mawson JB, Yoo SJ. The divided right ventricle: anomalous right ventricular muscle bundles and other entities. In: Congenital Heart Disease: Textbook of angiocardiography. Futura Publishing Company, Inc; 1997:389-407.
Hoffman P, Wojcik AW, Rozanski J, et al. The role of echocardiography in diagnosing double chambered right ventriclein adults. Heart. Jul 2004;90(7):789-93. [Medline]. [Full Text].
Kurosawa H, Becker AE. Surgical anatomy of the atrioventricular conduction bundle in anomalous muscle bundle of the right ventricle with subarterial ventricular septal defect. Pediatr Cardiol. 1985;6(3):157-60. [Medline].
Kveselis D, Rosenthal A, Ferguson P, et al. Long-term prognosis after repair of double-chamber right ventricle with ventricular septal defect. Am J Cardiol. Dec 1 1984;54(10):1292-5. [Medline].
Nagashima M, Tomino T, Satoh H, et al. Double-chambered right ventricle in adulthood. Asian Cardiovasc Thorac Ann. Jun 2005;13(2):127-30. [Medline].
Penkoske PA, Duncan N, Collins-Nakai RL. Surgical repair of double-chambered right ventricle with or without ventriculotomy. J Thorac Cardiovasc Surg. Mar 1987;93(3):385-93. [Medline].
Pongiglione G, Freedom RM, Cook D, Rowe RD. Mechanism of acquired right ventricular outflow tract obstruction in patients with ventricular septal defect: an angiocardiographic study. Am J Cardiol. Oct 1982;50(4):776-80. [Medline].
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Keywords
double-chambered right ventricle, divided right ventricle, anomalous right ventricular muscle bundles, AMB, two-chambered right ventricle, 2-chambered right ventricle, DCRV, separated right ventricle, ventricular septal defect, VSD, pulmonary valve stenosis, discrete subaortic stenosis, anomalous septoparietal band, anomalous apical shelf, hypertrophy of apical trabeculations, anomalous apical shelf with Ebstein malformation, bundle branch block, right ventricular outflow tract obstruction, tetralogy of Fallot, left ventricular outflow tract obstruction, pulmonary valve stenosis, Down syndrome, Noonan syndrome, treatment, diagnosis
Contributor Information and Disclosures
Author
Shubhayan Sanatani, MD, Associate Professor, Department of Pediatrics, University of British Columbia at Vancouver; Consulting Staff, Division of Pediatric Cardiology, British Columbia Children's Hospital
Shubhayan Sanatani, MD is a member of the following medical societies: British Columbia Medical Association, Canadian Cardiovascular Society, Canadian Heart Rhythm Society, Canadian Heart Rhythm Society, Canadian Medical Association, Heart Rhythm Society, and Royal College of Physicians and Surgeons of Canada
Disclosure: Nothing to disclose.
Coauthor(s)
Alejandro R Peirone, MD, Head, Section of Pediatric Cardiology, Hospital Privado de Cordoba; Consulting Staff, Division of Pediatric Cardiology, Hospital Espanol Medical Plaza and Children's Hospital of Cordoba
Disclosure: Nothing to disclose.
Medical Editor
Juan Carlos Alejos, MD, Clinical Professor, Department of Pediatrics, Division of Cardiology, University of California at Los Angeles
Juan Carlos Alejos, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Cardiology, American Heart Association, American Medical Association, and International Society for Heart and Lung Transplantation
Disclosure: Actelion Honoraria Speaking and teaching
Pharmacy Editor
Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from financial planner; Avanir Pharma Stock Investment from financial planner ; WebMD Salary and stock Employment and investment from financial planner
Managing Editor
Julian M Stewart, MD, PhD, Associate Chairman of Pediatrics, Director, Center for Hypotension, Westchester Medical Center; Professor of Pediatrics and Physiology, New York Medical College
Julian M Stewart, MD, PhD is a member of the following medical societies: American Academy of Pediatrics
Disclosure: Nothing to disclose.
CME Editor
Gilbert Z Herzberg, MD, Assistant Professor, Department of Pediatrics, Section of Pediatric Cardiology, New York Medical College; Consulting Staff, Department of Pediatrics, Sound Shore Medical Center
Gilbert Z Herzberg, MD is a member of the following medical societies: American Academy of Pediatrics
Disclosure: Nothing to disclose.
Chief Editor
Stuart Berger, MD, Professor of Pediatrics, Division of Cardiology, Medical College of Wisconsin; Chief of Pediatric Cardiology, Medical Director of Pediatric Heart Transplant Program, Medical Director of The Heart Center, Children's Hospital of Wisconsin
Stuart Berger, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Cardiology, American College of Chest Physicians, American Heart Association, and Society for Cardiac Angiography and Interventions
Disclosure: Nothing to disclose.