Fetal Echo- The rule of Three

Sonologically-conducive matter, conducive fetal position, good equipment and well-trained operator are the pre-requisites of a fetal cardiac examination.

To check a fetal echo, one should follow the rule of three: general examination, B-mode of heart, and rate and rhythm. All the factors can be taken care of by a simple method called 'Pass….s'. The abbreviation stands for P-position, A-axis, S-size, S-symmetry and S-squeeze (of the heart).

In general examination, examination of cytus is very important. Once the doctor comes to know which is the left side of the foetus, then he should have a sequential approach to find out the size of the heart. Later, as pregnancy advances, the doctor must continuously check the heart beat of the foetus. Under B-mode of heart, the doctor should identify the RV and tricuspid value. Also, checking the septo-aortic continuity is very important. Always see the relationship between the two outflow tracts. First, at the root check for the crisscross and then beyond the root see the parallel formation. The three vessel view is very important to check. Although all the three vessels are away from the heart, but all the three meet here at the criss cross section. The three vessels are pulmonary artery, aorta, and SVC.

In addition, the four chamber view is also a vital factor. Where fetal echocardiagram is concerned, always look beyond the four chamber view and you will find a problem hidden somewhere. The indications beyond four chamber view can be history of cardiac disease of the patient's family, poor penetration and many more.

Doctors must always keep in mind to use a doppler for fetal echo, and also must do arch imaging for the same. Pitfalls can be overcome by waiting for a good position of the fetal before doing ultrasound. The future of fetal echo is 4D imaging and we all should look forward to it.

(Dr S Suresh spoke during IRIA)
The writer is with Mediscan