Mixed variety of total anomalous pulmonary venous connection: diagnosis by 2D echocardiography and Doppler colour flow imaging.

Of the many types of total anomalous pulmonary venous connection, mixed type is the least common. Its accurate non-invasive diagnosis by echocardiography poses a diagnostic challenge. We report our experience of echocardiography in 21 infants with mixed type of total anomalous pulmonary venous connection aged 25 days to one and half years. Multiple windows were used to identify individual pulmonary veins and various sites of drainage. Cardiac catheterisation and angiography were performed for 17 cases. In 11 of 21 cases, the left upper pulmonary vein was seen draining into vertical vein and the left lower and right-sided pulmonary veins were draining into the coronary sinus. Cardiac and supracardiac combinations of other types were seen in eight more cases. Both drainage sites were supracardiac in one case and supracardiac and infracardiac in another. On comparing echocardiographic findings with those obtained at cardiac catheterisation and/or surgery (carried out in 18 cases), there were three instances of error. In two cases (echocardiography performed without the use of colour flow imaging) the second site of drainage could not be defined. These patients were catheterised as all four pulmonary veins were not delineated by echo. The third error occurred in a case where although two sites of drainage were picked up by echo but at surgery, the right lower pulmonary vein was noted to have a double connection, both to coronary sinus and to vertical vein. We conclude that mixed type of total anomalous pulmonary venous connection can be accurately diagnosed by echocardiography and Doppler colour flow imaging. The diagnostic errors are rare and would not alter the surgical management.