NAVLE® Question of the day

MO TU WED TH FR
October 19, 2023
NAVLE

A six-year-old male neutered Yorkshire terrier is presented for routine examination. The owner has no current concerns. 

Exam reveals a grade 3/6 left-sided systolic heart murmur. Pulse quality is strong and synchronous and there are no other abnormalities. 

What is the most likely cause of the heart murmur?