Right parasternal long axis modified (oblique) view.

This shows a large vein entering the right atrium from the direction of the left atrium. This is a PLCVC. The left and right cranial normally enter the right atrium on their cranial approach to the atrium. However the left cranial vena cava fails to do so in embryiological development, but coarses around the left atrium to join the right atrium caudally, merging with the coronary sinus.

This is not of clinical significance, but is important to recognise if performing any interventional procedures such as pacemaker implantation, balloon valvuloplasty or cardiac catheterisation.
(This dog also has a pulmonic stenosis - not highlighted in these series of views.)