Taussig Bing anomaly (named after the authors that first described it- Helen B. Taussig and Richard J. Bing) is a cyanotic congenital heart disease characterized by the dual presence of a subpulmonic ventricular septal defect (VSD) along with a double outlet right ventricle (DORV).
Taussig Bing anomaly was initially described in 1949 in a 5.5-year-old girl who died after injection of contrast during angiocardiography. An autopsy revealed a peculiar structural abnormality of the heart- both the aorta and the pulmonary artery originated from the right ventricle. At the same time, a subpulmonic ventricular septal defect (VSD) was observed and the right ventricle was hypertrophic [1] [2].
Hemodynamic changes seen in the Taussig Bing anomaly include:
- blood flow from the left ventricle (LV) through the VSD to the pulmonary artery preferentially
- blood flow from the right ventricle (RV) through the aorta preferentially
Another important characteristic of this disease is the absence of continuity of the mitral and semilunar valves [3] [4] [5]. This feature differentiates this condition from transposition with VSD and an overriding pulmonary artery.
As a consequence of this malformation, very small quantities of oxygenated blood enter the systemic circulation. This results in low oxygen saturation and cyanosis, which may be present at birth. Dyspnea at rest and developmental delay are the other typical features seen. Compensatory erythrocytosis may also be observed.
Death in the first described patient of the Taussig Bing anomaly, occurring after rapid injection of contrast material in the superior vena cava, was due to the elevation in pressure of the right side of the heart. This decreased the left-to-right shunt, leading to extremely low volumes of oxygenated blood being pumped towards the systemic circulation [6].
Echocardiography is the most common method used for the diagnosis of Taussig Bing anomaly. The primary four criteria that support the diagnosis include:
This congenital heart anomaly can also be diagnosed prenatally via real-time 2-dimensional echocardiography. Real-time 3-dimensional echocardiography offers no special benefits over the 2-dimensional mode [9].
A chest X-ray in these patients may show non-specific changes that include cardiomegaly, increased pulmonary vascular markings and a prominent pulmonary artery (PA) segment. However, normal cardiac anatomy may be observed in patients who have pulmonary stenosis in addition to the primary defects.
Other imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI), especially 3-dimensional MRI, can be used for the precise evaluation of the cardiac and blood vessel anatomy.
Physical examination may reveal findings suggestive of a large septal defect, such as a holosystolic murmur and a thrill at the base of the heart. No pathological blood pressure gradients between the upper and lower limbs have been observed [10].
Resting electrocardiogram (ECG) may show a right axis deviation, hypertrophy of the right ventricle, intraventricular conduction defects and negative T waves in leads I, avL and V5-V6. Holter monitoring may show evidence of arrhythmias such as a wide complex tachycardia and ventricular/ supraventricular premature beats. Stress testing may reveal a reduction in exercise capacity and a decreased consumption of maximal oxygen.