Double Chamber Right Ventricle (DCRV) is a congenital heart disease (CHD) that affects the structure of the heart’s lower right chamber. DCRV accounts for approximately 0.5% to 2% of all congenital heart defects. In this condition, the right ventricle (RV) is abnormally divided into two separate compartments by a band of tissue. This division creates an obstruction that impedes the normal flow of deoxygenated blood from the heart to the lungs.
The Anatomy of Double Chamber Right Ventricle
The structural abnormality in DCRV involves a partition of the right ventricle, which is a single cavity designed to pump blood to the pulmonary artery. This division is caused by anomalous, hypertrophied muscle bundles or fibromuscular tissue traversing the ventricular space. These obstructing bands often originate from the septoparietal trabeculations or the septomarginal trabecula within the RV.
The obstruction separates the right ventricle into two distinct functional chambers. The first is a high-pressure proximal chamber, corresponding to the inflow tract or apical region. The second is a low-pressure distal chamber, located in the infundibulum or right ventricular outflow tract (RVOT), which leads directly to the pulmonary artery. This arrangement creates a blockage in the path of blood flow, forcing blood through a restricted opening.
The obstruction causes pressure overload within the proximal chamber. The right ventricular muscle must work harder to push blood past the narrow opening and into the distal chamber. This increased workload causes the right ventricular muscle walls to thicken, a process known as hypertrophy. This thickening can worsen the obstruction over time, creating a progressive disease state.
The pressure difference, or gradient, between the two chambers impairs the heart’s efficiency in delivering blood to the lungs for oxygenation. This results in subpulmonary stenosis, where the obstruction occurs beneath the pulmonary valve. The degree of obstruction measures the severity of the condition and dictates the need for intervention.
Recognizing DCRV and Diagnostic Methods
The clinical signs of DCRV are variable. Patients with a mild obstruction may remain without symptoms for many years, sometimes even into adulthood. More severe obstruction often presents with symptoms like a heart murmur detected during a routine examination, exertional fatigue, or shortness of breath (dyspnea).
Diagnosis relies on non-invasive imaging techniques that visualize the heart’s internal structure and measure blood flow dynamics. Echocardiography, or ultrasound of the heart, is the primary diagnostic tool. It allows cardiologists to visualize the anomalous muscle bundles that divide the right ventricle and assess the resulting right ventricular wall thickness.
The echocardiographic assessment includes measuring the pressure gradient across the obstruction. Doppler technology calculates the speed of blood flow through the narrow opening, translating this velocity into a pressure difference in millimeters of mercury (mmHg). This measurement quantifies the obstruction and guides treatment decisions.
An electrocardiogram (ECG) may show signs of right ventricular hypertrophy, suggesting the muscle is strained from the increased pressure. A chest X-ray can potentially indicate heart enlargement, though it offers less detail about the internal structure. For more complex or unclear cases, a Cardiac Magnetic Resonance Imaging (MRI) study provides a detailed anatomical view of the muscle bundles and the extent of the obstruction.
Causes and Related Heart Defects
DCRV is classified as a congenital heart defect, though the condition can become more prominent later in life. The exact reason why these anomalous muscle bundles develop is not fully understood, and the condition is often considered idiopathic. One theory suggests that while the anatomical potential for the obstruction is congenital, the actual muscular hypertrophy may be an acquired response to abnormal blood flow.
DCRV is rarely an isolated finding and is linked to the presence of other heart defects that create turbulent or increased blood flow within the right ventricle. The most common co-existing condition is a Ventricular Septal Defect (VSD), a hole in the wall separating the two lower heart chambers.
VSDs are found alongside DCRV in a high percentage of cases, ranging from 75% to 90%. The turbulent, high-velocity blood flow from the left ventricle through the VSD is thought to stimulate the hypertrophy of the nearby right ventricular muscle, leading to the formation or progression of the obstructing bands. The VSD is typically of the perimembranous type, located near the area where the obstruction forms.
Other congenital heart defects that may be present alongside DCRV include Pulmonary Stenosis, a narrowing of the pulmonary valve, and Tetralogy of Fallot, a complex condition involving four separate defects. The presence of these associated defects further complicates the heart’s function and influences the overall clinical picture.
Surgical Correction and Post-Operative Care
Treatment for DCRV is surgical, aiming to remove the physical obstruction and restore unrestricted blood flow to the lungs. The decision to intervene is based on the severity of the measured pressure gradient across the two chambers. Intervention is recommended when the gradient exceeds 40 mmHg, indicating a moderate to severe obstruction.
The procedure involves open-heart surgery, often performed through a small incision in the right ventricle, known as a ventriculotomy. The surgeon excises, or resects, the anomalous muscular and fibromuscular tissue causing the blockage. This resection eliminates the division, turning the two-chambered right ventricle back into a single, functional cavity.
If an associated Ventricular Septal Defect is present, it is closed with a patch during the same operation. The immediate goal of the surgery is to reduce the pressure gradient to an acceptable level, ideally below 20 mmHg. Successfully operated patients often experience a significant decrease in pressure gradient and a resolution of symptoms.
The long-term prognosis following successful surgical correction is favorable. Post-operative care requires lifelong, regular follow-up appointments with a cardiologist specializing in adult congenital heart disease. Monitoring is important to watch for any residual obstruction, recurrence of muscular hypertrophy, or potential late complications such as heart rhythm disturbances (arrhythmias).