Disputatio Medica Inauguralis De Circulo Sanguinis in Corde
The smallest cardiac veins or Thebesian veins or veins of Thebesius are minute valveless veins in the walls of all four heart chambers and they are often confused with the distinct set of arterial connections, the "vessels of Wearn". They are reportedly most abundant in the right atrium and least in the left ventricle. They drain the myocardium and pass through the endocardial layer to empty mostly into the right atrium, but a few empty into the ventricles. This is different from most cardiac veins, which normally empty into the cardiac sinus, which then empties into the right atrium. The openings of the chambers are called the foramina venarum minimarum.
The Vessels of Thebesius, therefore, open from the ventricles and auricles into a system of fine branches that communicate with the coronary arteries and veins by means of capillaries, and with the veins but not with the arteries - by passages of somewhat a larger size." -Pratt
This effectively means that vessels of Thebesius are Thebesian veins and it is no surprise that any tissue has capillaries connecting arteries and veins.
WHAT DO YOU CALL A CONNECTION BETWEEN A CORONARY VESSEL AND A HEART CHAMBER?
B. vessel of Wearn
C. Thebesian vein
1. Did trauma cause it, eg, a bullet through the heart?
1. If yes, => it is a fistula, connecting to a coronary vessel. Call Surgery / Cardiology, etc..
1b If no => go to question 2.
Is the it connecting a heart chamber to an artery or a vein.
2a. To an artery => vessel of Wearn (or whatever you prefer to call it and get internationally adopoted).
2b. To a vein => Thebesian vein.
Heart chamber connects to a "larger" heart vessel intramyocardial & subepicardial coronary vessels)