Teaching Case

A 27-year-old female presented with complaints of on and off breathlessness since 10 years of age, (NYHA class -II) with occasional palpitations and multiple syncopal attacks since childhood. She was diagnosed previously as Congenital Heart Disease possibly Tetralogy of Fallot with Hypoplastic Pulmonary artery. She was referred to our hospital for detailed workup of the congenital heart disease. 

Morphologic images revealed  Situs Inversus and Dextrocardia (Fig 2) with liver on  left side and Right sided Aortic Arch [Fig 1B]. Morphologic right ventricle gave  rise to  the Aorta & Main Pulmonary artery suggestive of Double outlet  right ventricle (DORV) (Fig 2). Both Aortic and Pulmonary valve are at the same level in anterior location with D- Malposition (Aortic valve located on left side to Pulmonary artery) (Fig 1A). Subaortic Ventricular septal defect (VSD)  noted measuring approximately 11.7 mm (Fig 3). Pulmonary Infundibular stenosis (Fig 7) with turbulent flow noted (Fig 5).

Cardiac MRI was done in a 3 Tesla MRI (Siemens Healthineers, Skyra, Erlangen, Germany). Morphology was evaluated with Haste axial, Trufi coronal and axial sequences with Cine Axial stack. Phase-contrast flow velocity imaging with Velocity encoding gradient (VENC) of 150 cm/s was chosen from a VENC Scout. A non-contrast angiogram sequence using 3D SPACE STIR sequence was also done. Contrast Pulmonary Angiogram was done with 3D Twist Angiogram protocol (with subtraction) using dual-head MR Compatible Pressure Injector at flow rate of 3ml/s. Gadodiamide was used at dose of 0.1mmol/kg.

Cono - Truncal Anomalies are complex Congenital Cardiac Anomalies resulting from abnormal formation and septation of the outflow tracts. The major anomalies include Tetralogy of Fallot, Transposition of Great Arteries, Truncus Arteriosus, Double Outlet Right Ventricle, Double Outlet Left Ventricle, Interrupted Aortic Arch. DORV is a type of ventriculoarterial connection in which both great arteries arise either entirely or predominantly from the right ventricle. The incidence of DORV is estimated at 127 per million live births. DORV is not a single cardiac anomaly; rather, the term is used to describe an aberrant position of the great arteries in association with various cardiac anomalies in which physiologic function is similar to that in ventricular septal defect, TOF, transposition of the great arteries, presence of a single ventricle, or atrioventricular atresia [1].

Clinical perspective

In early embryonic life, heart is formed from a straight cardiac tube which consists of Primitive Atria, Left Ventricular Structure, Bulbus Cordis (Primitive Right Ventricle), Truncus Arteriosus from proximal to distal in caudocephalad direction. The tube bends over itself in right or left direction. Normally it bends over rightward direction forming a D-Loop so that the bulbus cordis is positioned to the right of left ventricle [2].

Initially Embryonic Aortic valve is anterior to the Pulmonary valve but at the same level [3]. Later when the cardiac loop is formed the great vessels will be lying side by side. Then muscular conus will be laid down under each semilunar valve and there will be no atrioventricular valve discontinuity. The Muscle around the Aortic valve will be resorbed and positioned posterior to the Pulmonary Valve with Mitro- Aortic fibrous continuity and the pulmonary valve positioned more anteriorly with loss of Pulmonary- Tricuspid fibrous continuity.

Imaging perspective

DORV is classified into four types based on the location of the Ventricular Septal Defect (VSD)  and absence or presence of Pulmonary Stenosis [1].

• Type: 1 – Sub-Aortic (TOF like variant Associated with Pulmonary stenosis or atresia)
• Type: 2 – Sub- Pulmonary (Taussig Bing Anomaly resembling TGA)
• Type: 3 –Remote
• Type: 4 – Doubly Committed.

The Location of VSD and relation with great arteries, atrioventricular valves, outflow pattern and relative obstruction determine the physiological function, clinical course and management of the patient. It can be associated with other Cardiac Anomalies like PDA, ASD, various degrees of left and right ventricular hypoplasia, atrioventricular (AV) septal defects, coarctation, hypoplastic arch and interrupted aortic arch, Mitral Stenosis or Atresia, Straddling of Atrioventricular valves, Anomalies of Coronary Arteries (Duplication of Left Anterior Descending Artery, LAD originating from Right Coronary Artery and Right Coronary Artery (RCA) originating from Left Coronary Artery (LCA). Extracardiac anomalies, such as heterotaxy (polysplenia, asplenia, situs ambiguous) intestinal malrotation and ciliary dysfunction could be associated.