The current methods for the ultrasonographic assessment of the left/right axis in the fetal heart are reliable and adequate for physicians performing advanced level studies. On the other hand, there is a need for a fast, reliable, and practical method for centers performing level one routine studies. The Sezgin method provides rapid diagnosis of the cardiac malposition for physicians in every level.
The first step in the assessment of the fetal heart is to see whether the heart has a proper alignment and angulation in the thoracic cavity. (1,2) The axis of the heart is approximately 45 (22-75) degrees.(1) Confirming that the axis of the heart points to the left may not be as easy as determining its angle.(1,2) Observing that the heart is in the correct left/right axis is essential for evaluation of the correct position of not only the heart but also of the viscerae.(3) Situs assessment that utilizes abdominal and thoracic organ locations will not work in the presence of situs inversus totalis.(4) Identification of the left/right axis of the heart is also necessary for the detection of heterotaxy syndromes.(3,4)
Although determining the axis of the heart is crucial, it may be not be performed during routine ultrasound studies due to orientation difficulties or time constraints. Also, the variable position of the fetus inside the uterus further increases the difficulties.(4)
We herein suggest the Sezgin method for assessment of the fetal heart axis as a practical method that does not require orientation or mental calculations. This method is not affected by fetal movements or the position of the spine. Also, the angle of the heart can be determined while observing the left/right axis of the heart. The Sezgin method requires less time compared to other methods of determination of the fetal cardiac axis, therefore it may be a good solution for clinics with a high patient load.
This method is valid in the standart abdominal ultrasound position, the physician must be seated on the right side of the patient, holding the probe with the right hand. The left side of the probe should be on the left side of the physician’s screen.
The thoracic cavity must be accepted as a watch dial. The spine constitutes the 12 o’clock position. If the head is at the bottom, the axis of the heart must be always 5:30 (±40 minutes). If the head is at the top, the axis of the heart must always be 7:30 (±40 minutes)
In the transverse posture, which is very rare in routine studies, the right side is accepted as the top and the probe is shifted from the right to the left. When the head is located on the right (since it is accepted as the top) the apex of the heart should be again at 7:30.
Figure 1 : The cardiac apex shows approximately 7:30. Either the head is at the top, or there is a cardiac malposition.
Figure 2: The apex of the heart shows approximately 5:30. Either the head is at the bottom or there is a cardiac malposition.
The motto “seven-up” can be used to facilitate easy recall of the head up position.