Recently in Pieneläinsairaala in Vantaa, I had an exciting cardiology case: a 3-year-old Havanese Dog Hugo came for a check-up before his planned eye surgery. He was referred to me for a cardiac ultrasound examination to sort out his newly found cardiac murmur.
In his scan, I found mild mitral valve regurgitation (most likely causing the murmur) and clearly dilated coronary sinus (CS). The main reasons for coronary sinus dilation (relatively uncommon) are:
right-sided heart disease
congenital anomaly: persistent left cranial vena cava (PLCVC)
With no evidence of underlying cardiac disease causing CS dilation (mitral regurgitation was considered unrelated problem), PLCVC remained the most likely diagnosis.
Additional examinations, such as angiography, CT scan, or contrast echocardiography, are necessary to confirm the suspected PLCVC.
Using a contrast cardiac ultrasound technique called a 'Bubble study' allowed us to confirm the presence of additional vessel PLCVC, without using more advanced techniques. 'Bubble study' involves injecting agitated saline (natrium chloride) into an IV catheter and contemporaneous ultrasound imaging of the heart to determine the blood flow direction. The examination is safe and easy to perform, and is commonly used to diagnose congenital defects, such as shunts.
In this case we used a modified technique: agitated saline was first injected into the right cephalic vein (front leg), confirming normal blood flow through the right side of the heart.
Subsequently, a second injection was performed into the left front limb, showing abnormal inflow to the right heart through the coronary sinus (confirming the presence of the anomaly (PLCVC).
PLVCVC is a benign finding in most cases and is unlikely to cause Hugo any problems. We will follow up on his mitral valve disease and wish him all the best with his eye surgery!