**2. Embryology of heart**

*Advanced Concepts in Endocarditis - 2021*

**90**

**Figure 1.**

three vessel view (3vv) and three vessel trachea view (3VT) obese patients. Color flow Doppler may facilitate imaging of various cardiac structures and in obese patients. Guidelines involve situs determination and a sequential segmental analysis of Atria, Ventricles and great arteries and their connections. Documentation fetal heart rhythm should be performed. Fetal echo should be performed by real time imaging with acquisition of recording or digital video clips and still images. It is important to note that screening for cardiac malformations in the low risk population includes minimum views of four chambers and outflow tracts. It is not specified to screen three vessel trachea view, but it is relatively easy plane to obtain and

*(A) Selected views of fetal cardiac screening recommended by ISUOG. (B) Sagittal view as recommended by AIUM. (C) Standardized transverse scanning planes as recommended in the guidelines of the AIUM. (D) Low* 

provides significant information on outflow tracts and arches.

*and high short axis views as recommended by AIUM.*

In third week of post conception, the embryo consists of three basic germ layers–the Ectoderm, Mesoderm and Endoderm. The lateral splanchnic mesoderm involves in the formation of single heart tube. The major steps in development of embryonic heart are (1) primitive heart tube, (2) looping, (3) atria, ventricles and outflow tracts septations, (4) septation of the atria, (5) septation of ventricles, (6) septation of the outflow tracts.

During cardiac looping, the primitive ventricles move downward to the right while the primitive atrium moves upward and to the left behind the ventricle. In the folded cardiac tube various regions are recognized and are separated by transitional zones. These regions will develop into cardiac cavities and the zones will become the septa and valves. Systemic veins begin with the formation of three paired veins the vitelline, umbilical and common cardinal veins, but the pulmonary veins develop separately.
