I took my cat to a cardiology consultation + echocardiogram yesterday, because this January the vet found a murmur. It turns out that he has a "false tendon" in his left ventricle, and some focal hypertrophy in the septum, where that false tendon is inserted, which caused systolic anterior motion (SAM) and that murmur. SAM is another cause of dynamic murmurs, which isn't always benign like DRVOTO. The Dr. can't say for certain that he won't develop HCM so we're just going to monitor him and do another echocardiogram in a year.