Isolated double-chambered right ventricle – A rare entity
Ashok Garg1, Deepak Agrawal2, GL Sharma2 1 Department of Preventive and Noninvasive Cardiology, Jaipur Heart Institute, Jaipur, Rajasthan, India 2 Department of Cardiology, Jaipur Heart Institute, Jaipur, Rajasthan, India
Source of Support: None, Conflict of Interest: None
A double-chambered right ventricle (DCRV) is a rare congenital heart disease and an uncommon cause of congestive heart failure. An anomalous muscle band divides the right ventricle into two cavities: the proximal high-pressure chamber and the distal low-pressure chamber. Most cases are diagnosed and treated during childhood. Furthermore, there is a tendency for progression, if not treated early. Echocardiography is considered useful for the diagnosis of this ailment. Most of the patients have associated congenital anomalies, such as ventricular septal defect, pulmonary stenosis, and subaortic stenosis. Isolated DCRV is a rare entity. Hence, we report a case of an isolated DCRV in an adult patient.
Double-chambered right ventricle (DCRV) is a developmental cardiac anomaly characterized by aberrant muscular bands which obstruct the body of the right ventricle, dividing it into a high-pressure proximal chamber and a low-pressure distal chamber. Frequent associated lesions include ventricular septal defect (VSD), pulmonary valve stenosis, and discrete subaortic stenosis. It typically presents in infancy or childhood, but isolated DCRV in adult is a rare entity.
An 18-year-old male presented to us with the complaint of gradually progressive shortness of breath for the past 2 months. There was no history suggestive of rheumatic fever in the past. Besides this, there was no history of any other comorbid conditions. His blood pressure was 110/72 mmHg, and his heart rate was 86/min. During physical examination, a prominent Grade 5/6 systolic ejection murmur was heard on the left parasternal border. His electrocardiogram showed increased amplitude of the R wave on V1, inverted T waves on V1–V6, and right-axis deviation suggestive of right ventricular pressure overload [Figure 1]. Two-dimensional transthoracic echocardiogram was done using a 3.0 MHz transducer and a Vivid S5 cardiac ultrasound system (GE Healthcare, Milwaukee, WI, USA). Parasternal long-axis view showed a marked muscle band protruding from the right ventricular free wall to the interventricular septum [[Figure 2] and Video 1]. Parasternal short-axis view also showed similar muscle band dividing the right ventricle into two cavities [Figure 3]. A turbulent Doppler color flow jet with a mosaic pattern was seen through the stenotic mid-right ventricle on the parasternal short-axis view [[Figure 4] and Video 2]. Continuous-wave Doppler across this turbulent jet revealed flow acceleration of 6.0 m/s, corresponding to a pressure gradient of approximately 144 mmHg calculated using the simplified Bernoulli equation [Figure 5].
Figure 1: Electrocardiogram showing increased amplitude of the R wave on V1, inverted T waves on V1–V6, and right-axis deviation suggestive of right ventricular pressure overload
With these echocardiographic findings, a presumptive diagnosis of DCRV was made. Usually, DCRV is associated with other congenital anomalies and very rare as an isolated finding, therefore we performed saline contrast echocardiography to rule out VSD or any other congenital heart defect. Agitated saline contrast was injected through the right antecubital vein, which showed the presence of bubbles only in the right chambers of the heart and there was no communication between either both atria or ventricles [Figure 6] and Video 3]. Then, it was injected through the left antecubital vein which also showed the presence of bubbles only in the right chambers of heart and there was no evidence of persistent left superior vena cava. Based on the above findings, we tried to perform transesophageal echocardiography, but the patient was non-cooperative and refused for test even after starting it. Therefore, he was referred to a thoracic and cardiovascular surgery clinic for surgical correction, but there also he refused for operative correction.
Figure 6: Saline contrast echocardiography showing the presence of bubbles only in the right chambers of heart and no communication between either both atria or ventricles
DCRV is a rare form of congenital heart disease, in which the right ventricle is divided into a proximal high-pressure chamber and a distal low-pressure chamber. There are several subtypes of DCRV. A simple classification of the associated pathology was proposed by Galiuto, who divided DCRV into two distinct types of intracavitary obstruction. Type 1 DCRV is characterized by an anomalous muscle bundle crossing the right ventricular cavity, recognized as the cause of the intraventricular obstruction. In Type 2 DCRV, no anomalous muscle bundle is found. The obstruction in this case is caused by marked parietal and septal muscle hypertrophy. The intraventricular pressure gradient of Type 1 DCRV is greater than that of Type 2 DCRV, whereas VSD was found to be highly associated with Type 2 DCRV. The patient in our case falls under the category of Type 1 DCRV associated with high intraventricular pressure gradient and no VSD as confirmed by contrast echocardiography.
Associated cardiac anomalies are common in DCRV. The most common associated cardiac anomaly is VSD, present in 63%–77% of the cases, whereas other reported associated anomalies include valvular pulmonary stenosis, atrial septal defect, aortic valve regurgitation, tricuspid valve regurgitation, persistent left superior vena cava, ruptured sinus of Valsalva aneurysm, tetralogy of Fallot, complete or corrected transposition of the great arteries, and Ebstein anomaly., Thus, it was necessary to look for associated congenital anomalies when DCRV is diagnosed, which was done in our case. Similar type of case report was published by Park et al., in which they reported a case of isolated DCRV presenting in an asymptomatic person. One another case report was published by Pansari et al., in which they reported a case of isolated DCRV presenting with congestive heart failure.
DCRV has a tendency toward progressive obstruction by the muscle bundles. Patients can develop severe and varied symptoms, such as easy fatigue, shortness of breath, and recurrent chest infection. Therefore, treatment of most DCRV cases is surgical which often constitutes a part of the corrective procedure. In general, surgical procedures consist of the resection of the anomalous muscular bundle and correction of the associated anomalies. The time for surgical repair depends on the associated cardiac anomalies. In the absence of any other significant coexisting defect, observation is possible as long as the intracavitary pressure gradient is not more than 40 mmHg and the obstruction is not progressive. The long-term prognosis for patients after repair of DCRV is excellent, but postoperatively, three-quarters of the patients were shown to have had complete or incomplete right bundle branch block in some studies. There are some cases, however, where antiarrhythmic agents or catheter ablation is required to treat ventricular tachycardia, or the insertion of a permanent pacemaker is required to treat the atrioventricular block during the postoperative period.,
DCRV should be kept as a differential diagnosis in a young patient presenting with breathlessness. DCRV is a potentially treatable condition by surgery. Isolated DCRV is a very rare entity, therefore before surgical correction, other associated congenital abnormalities should be ruled out by various imaging modalities.
I, Dr. Ashok Garg, am thankful to Dr. Deepak Agrawal for collecting all relevant and useful data from various resources for writing this case report and also for proofreading and submission of the article. I acknowledge the valuable support of my senior Dr. G. L. Sharma for his inspiration in doing research work and providing hardware for patient management and for research purpose.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Kim J, Park TI, An SG, Lee HC, Kim JH, Chun KJ, et al. Electrical storm late after surgery for a double-chambered right ventricle, aortic regurgitation and a ventricular septal defect: A case of successful catheter ablation. Korean Circ J 2008;38:60-5.