Double outlet right ventricle is a congenital heart disease in which the pulmonary trunk and the aorta both arise from the right ventricle, with several anatomical variations and additional cardiac malformations. Hypoxia and other accompanying manifestations may be life-threatening. Echocardiography and other imaging studies of the heart and major vessels are used to confirm double outlet right ventricle.
Presentation
In double outlet right ventricle (DORV), the pulmonary trunk and a significant portion (> 50%) of the aorta (or sometimes the entire vessel) stem from the right ventricle, resulting in the transfer of primarily deoxygenated blood into systemic circulation [1] [2] [3] [4]. The severity of manifestations significantly depends on the presence of various accompanying defects, most notable being atrial septal defect (ASD), stenosis of the pulmonary valve, hypoplasia (or hypertrophy) of the left ventricle, mitral atresia, mitral stenosis, and coarctation of the aorta [5] [6]. In virtually all cases, however, a ventricular septal defect (VSD), arising as a compensatory mechanism of the heart, almost universally develops, but its location (subaortic, subpulmonary, non-committed or doubly-committed) may determine the amount of oxygenated blood that reaches the right ventricle from the left heart [2] [3]. Moreover, rare cases with an intact ventricular septum have been described [3]. Regardless, one of the most important clinical presentations of this rare congenital heart disease (CHD) is the onset of cyanosis during the first few months of life, often characterized by hypoxic spells, whereas tachycardia, tachypnea, sweating, deprivation of growth and inability to gain weight due to poor feeding and lethargy are additional features [3] [5] [6] [7]. Infants are often unresponsive and extremely tired after minor tasks, which are followed by marked increases in heart and respiration rate [7]. Arrhythmias, pulmonary hypertension and the formation of aneurysms are known complications that can be life-threatening [5].
Workup
The appearance of cyanosis during the neonatal period or infancy in the absence of an obvious cause must raise clinical suspicion to a CHD. This illustrates the importance of a detailed patient history and a proper physical examination. Firstly, the onset of symptoms and their course must be determined with the parents, as patients are mainly too young to provide adequate information. Family history is also an important component of the workup, as preexisting congenital malformations (but also other congenital diseases) within the family seem to increase the risk for many CHDs, including DORV. In addition, maternal use of antidepressants, such as selective serotonin reuptake inhibitors (SSRIs) during pregnancy, was also confirmed as a risk factor [7]. Physical examination can reveal tachycardia, a heart murmur, tachypnea and signs of central cyanosis, after which echocardiography, the gold standard in detecting CHD, should be employed [2] [8]. Echocardiography is highly useful due to the fact that it can detect CHD both prenatally and postnatally. Supplementary to traditional transthoracic 2D cross-sectional cardiac ultrasonography, limited by the experience of the physician and a very narrow field of observation, the introduction of 3D echocardiography has greatly improved the diagnostic accuracy, and is performed whenever possible and feasible [1] [8]. However, digital subtraction angiography (DSA), an invasive procedure carrying potential for catheter-related complications, and electrocardiographically (ECG)-gated dual-source computed tomography (DSCT), used in the pediatric population without arrhythmias, have been postulated as most reliable methods when it comes to detection of DORV [2].
Treatment
Treatment for DORV usually involves surgical intervention to correct the heart's anatomy and improve blood flow. The specific surgical approach depends on the type of DORV and associated defects. Common procedures include the creation of a tunnel (baffle) within the heart to direct blood flow correctly or the arterial switch operation to reposition the great arteries. In some cases, multiple surgeries may be required over time. Post-surgical care is crucial to monitor heart function and manage any complications.
Prognosis
The prognosis for individuals with DORV varies based on the specific anatomy and the success of surgical interventions. With advances in surgical techniques and postoperative care, many patients can lead relatively normal lives. However, some may experience long-term complications, such as arrhythmias or heart failure, requiring ongoing medical management. Regular follow-up with a cardiologist specializing in congenital heart defects is essential for monitoring and maintaining heart health.
Etiology
DORV is a congenital condition, meaning it is present at birth. The exact cause is not well understood, but it is believed to result from abnormal development of the heart during fetal growth. Genetic factors may play a role, as DORV can occur in association with other genetic syndromes. Environmental factors, such as maternal health and exposure to certain substances during pregnancy, may also contribute to the development of congenital heart defects.
Epidemiology
DORV is a rare condition, accounting for approximately 1-3% of all congenital heart defects. It affects males and females equally and can occur in any ethnic group. The incidence of DORV may be higher in populations with a higher prevalence of consanguinity or certain genetic syndromes. Early diagnosis and intervention are crucial for improving outcomes in affected individuals.
Pathophysiology
In DORV, the abnormal positioning of the great arteries leads to the mixing of oxygen-rich and oxygen-poor blood. This results in reduced oxygen delivery to the body, causing symptoms like cyanosis and fatigue. The specific pathophysiology can vary depending on the presence of other heart defects, such as a ventricular septal defect (VSD), which is a hole between the heart's ventricles. The VSD often plays a critical role in determining the direction and degree of blood flow mixing.
Prevention
Currently, there are no known methods to prevent DORV, as it is a congenital condition. However, maintaining good maternal health and avoiding harmful substances during pregnancy may reduce the risk of congenital heart defects in general. Genetic counseling may be beneficial for families with a history of congenital heart defects to assess potential risks and discuss reproductive options.
Summary
Double Outlet Right Ventricle is a complex congenital heart defect requiring careful diagnosis and management. It involves both great arteries arising from the right ventricle, leading to mixed blood flow and reduced oxygenation. Treatment typically involves surgical correction, and the prognosis depends on the specific anatomy and success of interventions. While the exact cause is unknown, genetic and environmental factors may contribute to its development.
Patient Information
For patients and families dealing with DORV, understanding the condition and its implications is crucial. DORV is a congenital heart defect that affects how blood flows through the heart, often requiring surgery to correct. Symptoms can include bluish skin, difficulty breathing, and fatigue. With proper treatment and follow-up care, many individuals with DORV can lead healthy lives. It's important to work closely with a healthcare team to manage the condition and monitor heart health over time.
References
- Zidere V, Pushparajah K, Allan LD, Simpson JM. Three-dimensional fetal echocardiography for prediction of postnatal surgical approach in double outlet right ventricle: a pilot study. Ultrasound Obstet Gynecol. 2013;42(4):421-425.
- Shi K, Yang Z, Chen J, Zhang G, Xu H, Guo Y. Assessment of Double Outlet Right Ventricle Associated with Multiple Malformations in Pediatric Patients Using Retrospective ECG-Gated Dual-Source Computed Tomography. Dettman RW, ed. PLoS ONE. 2015;10(6):e0130987.
- Li S, Ma K, Hu S, et al. Surgical outcomes of 380 patients with double outlet right ventricle who underwent biventricular repair. J Thorac Cardiovasc Surg. 2014;148(3):817-824.
- Porter RS, Kaplan JL. Merck Manual of Diagnosis and Therapy. 19th Edition. Merck Sharp & Dohme Corp. Whitehouse Station, N.J; 2011.
- Lin CH, Huddleston C, Balzer DT. Transcatheter Ventricular Septal Defect (VSD) Creation for Restrictive VSD in Double-Outlet Right Ventricle. Pediatr Cardiol. 2013;34(3):743-747.
- Özgür S, Ceylan Ö, Doğan V, Örün UA. Double outlet right ventricle with intact ventricular septum. Turk Kardiyol Dern Ars. 2014;42(2):190-193.
- Baig SA, Saeed Z, Fatima A, Chagani H, Aziz S. Double outlet right ventricle, atrioventricular canal defect with severe pulmonary artery stenosis: a rare cyanotic congenital heart disease. J Pak Med Assoc. 2014;64(8):980-982.
- Gelehrter S, Owens ST, Russell MW, van der Velde ME, Gomez-Fifer C. Accuracy of the fetal echocardiogram in double-outlet right ventricle. Congenit Heart Dis. 2007;2(1):32-37.