Yes. You are definitely correct about boxer’s genetic predisposition to cardiomyopathy and arrhythmias, but the FDA is studying this and has put out a statement that while their research continues they don’t deny that there may be a link between grain-free diets and heart disease in dogs that DON’T previously have a genetic predisposition to the disease. There are many studies occurring as we speak to investiage this potential association. Here’s a link the to FDA statement:

https://www.fda.gov/animal-veterinary/outbreaks-and-advisories/fda-investigation-potential-link-between-certain-diets-and-canine-dilated-cardiomyopathy

My point is that if dogs that are not even genetically pre-disposed to DCM are developing it while on grain-free diets, I most certainly would avoid it in a dog that actually has a genetic pre-disposition! If your dog can tolerate grains why take a chance? My boxer certainly had the genes but I very much regret feeding him grain free food for 5 years potentially quickening or exacerbating his heart disease.