Double-Chambered Right Ventricle and Situs Inversus With Dextrocardia
We report the case of a 74-year-old woman with a history of complex congenital heart disease consisting of double-chambered right ventricle (DCRV) and situs inversus with dextrocardia. To our knowledge, this is the first reported case with the combination of these 2 congenital abnormalities. The patient was transferred to our hospital after experiencing abdominal discomfort, malaise, and cold sweats for 3 days. Initial examination revealed slightly elevated cardiac troponin T (peaked at 0.56 ng/mL). With her known history of dextrocardia, 12-lead surface electrocardiography (ECG) with both standard precordial leads (Figure 1A) and right-sided precordial leads (Figure 1B) was performed. The standard ECG was notable for inverted P waves in the lateral leads (I and aVL), suggesting rightward atrial electric forces and poor R wave progression. The right-sided precordial lead ECG showed normalized R wave progression. These summations of ECG findings are suggestive of dextrocardia. There were also pseudo-Q waves in the limb leads and T wave inversions in I and aVL, which are also consistent with dextrocardia but less specific than the other findings. In addition, her right-sided ECG showed ST depression and T wave inversion in the anterior leads, which in the setting of troponin elevation was concerning for acute coronary syndrome. She subsequently underwent cardiac catheterization (Movies I and II of the online-only Data Supplement), which revealed nonobstructive coronary artery disease, and her troponin elevation was attributed to demand ischemia. Multimodality imaging studies were performed to assess her anatomy and its functional significance. Owing to her inability to maintain adequate breath-holds during cardiac magnetic resonance imaging, she also underwent contrast-enhanced ECG-gated cardiac dual-source computed tomography for visualization of her anatomy.
We confirmed the presence of dextrocardia with situs inversus by chest radiography, cardiac magnetic resonance imaging, computed tomography, and fluoroscopy (Figure 2). In addition to the dextrocardia, she had a DCRV with right ventricular outflow tract (infundibular) stenosis (Figure 3, Movies III–V in the online-only Data Supplement). The peak and mean instantaneous gradients across the infundibular stenosis were 56 and 32 mm Hg by transthoracic echocardiography (Figure 4A), and a peak–peak systolic pressure gradient between the pulmonary artery and right ventricle of 56 mm Hg was measured by cardiac catheterization (Figure 4B). Phase-contrast cardiac magnetic resonance imaging confirmed the infundibular stenosis with a peak velocity of 3.8 m/s, corresponding to a right ventricular intracavity peak gradient of 58 mm Hg.
Double-chambered right ventricle is a form of subvalvular right ventricular outflow tract obstruction caused by anomalous muscle bundles that divide the right ventricle into a high-pressure proximal chamber and a lower-pressure distal chamber.1 The anomalous muscle bundles, which can range from 1 to many in number, usually arise from the body of the septal band (septomarginal trabeculation) and pass through the chamber of the right ventricle to the anterior free wall. DCRV is exceptionally rare as an isolated anomaly. Most commonly (in approximately 90% of affected individuals) it is associated with a membranous-type ventricular septal defect. Other coexisting lesions include subaortic stenosis, pulmonary valve stenosis, double-outlet right ventricle, tetralogy of Fallot, or anomalous pulmonary venous drainage, among others.2–4 We are unaware of any report of DCRV with dextrocardia. Although case reports of isolated DCRV have been published,5,6 we herein describe the first case, to our knowledge, of DCRV and situs inversus with dextrocardia, and we show images of this combination of complex congenital lesions and of its hemodynamic significance using multimodality imaging, including chest radiography, transthoracic echocardiography, cardiac computed tomography, cardiac magnetic resonance imaging, and cardiac catheterization.
Dr Truong has received support from National Institutes of Health Grants T32HL076136 and L30HL093896. Dr Heist has received grants and honoraria from Biotronik, Boston Scientific, Medtronic, Sorin, and St. Jude Medical. Dr Mansour has received research grants from and is a consultant to both Biosense Webster and St. Jude Medical.
The authors thank the clinical services at the Massachusetts General Hospital for providing excellent care to the patient.
The online-only Data Supplement is asvailable with this article at htt://circ.ahajournals.org/cgi/content/full/121/9/e229/DC1.
McElhinney DB, Goldmuntz E. Double chambered right ventricle. In: Gatzoulis MA, Webb GD, Daubeney PEF, eds. Diagnosis and Management of Adult Congenital Heart Disease. New York: Elsevier; 2003: 305–311.
Ibrahim T, Dennig K, Schwaiger M, Schomig A. Assessment of double chamber right ventricle by magnetic resonance imaging. Circulation. 2002; 105: 2692–2693.