To the Editor,
We have read with interest the letter to the Editor published recently in the magazine by Sanchez-Brotons et al, with the title Cor triatriatum dexter (CTD) in the adult age. The authors diagnose this pathology accidentally in 2 elderly patients, they show the echo images and finally they stress that it is necessary to be cautious in the diagnosis since a prominent Eustaquian and/or Tebesian valve can simulate a true CTD.1
We would like to emphasize this last affirmation and add several ideas. In our group we would be very reluctant to diagnose a CTD in case of no obstruction, since today an exact definition does not exist. The fact that the embryologic explanation of CTD is the same as that of the normal formation of the valve of Eustachio and Thebesius (persistence of the right valve of the venous sinus) gives us no possible distinction between the normal spectrum variants and a definitive alteration of the embryological development.2 Therefore, we think that although the term CTD seems to us very appropriate from a descriptive point of view, it is not as much so from a conceptual point of view. On the contrary, the most common equivalent, cor triatriatum sinister, conceptually corresponds with a malformation clearly differentiated from the normal anatomy of the left atria, although its embryology is still not more than an hypothesis (stenosis of the incorporation of the common pulmonary vein).3
On the other hand, in the fetus and in childhood it is exceptional to find an obstructive CTD without associate anomalies, and in our experience it is also exceptional to find it associated with right-sided heart malformations. That perception is corroborated by the lack of description of this issue, limited to a few cases published in literature.4-6 In addition, the published cases at the adult age are limited to non obstructive CTD and without attention to detail.7
For these reasons we think that categorizing the spectrum of residual right valve of the venous sinus must not be given too much importance and that functional analysis must be sufficient to rule out obstruction of the flow at this level. The reality is that in our daily practice, and supported by the literature, it is very frequent to find prominent Chiari net, Eustachian or Thebesian valve simulating a CTD; sometimes there are even non significant flow accelerations at these levels without any type of repercusion.8
In conclusion, we want to note, as did Sanchez-Brotons et al1, that the findings of residual right valve of the venous sinus are frequent in the normal population, and are not sufficient to diagnose a CTD. In our opinion, it is necessary to add that we must be skeptical at the time of making this diagnosis in adults and most of all when significant obstruction to the venous flow is not demonstrated.