Introduction: Hypothesis of different theories of development of the pulmonary vein

Methods: Study of various theories regarding the development of pulmonary vein available in current data is done. On the basis of these studies we have developed new theory (TheoryNo.3).

Results: Human embryos between 24–34 days showed that common pulmonary vein develops as outgrowth from superior wall of left auricle on medial side and unites with angioblastic plexus of developing lung bud. No evidence was found that vein connects directly with sinus venosus in early stages and later shifts in position as atrial septum grows. Initially the early cardiac development is complicated because it is associated with other processes of development such as embryonic folding of coelomic–cavity and vascular development. Due to this it is necessary to integrate experimental and morphological analyses. Observational controversies are frequent rather than result from differences in interpretation. In development of pulmonary vein and systemic venous sinus (sinus venosus), a 3D study in the chicken embryo of the developing venous pole shows that pulmonary vein separates from a greater vascular plexus within splanchanic mesoderm. The development of systemic venous sinus at junction between somatic and splanchnic mesoderm. Pulmonary vein in human heart originates from systemic venous sinus appears as new structure draining to left atrium. In addition, we examined  sequence of incorporation of the initially solitary pulmonary vein to the stage at which four venous orifices opened to left atrium.

Discussion: According to TheoryNo–1&2, a development of single embryonic pulmonary vein as an outgrowth of posterior left atrial wall just to left of septum primum.