Heart Murmur Advice

My chinchilla (18 years) has a heart murmur that went from a stage 2 to a stage 4. When I counted his breaths, it appears as though he has 108 breaths/min. (I'm not sure if that's good or concerning).

I would be grateful to hear any suggestions and advice about how to treat a heart murmur. I'm open to both medications and supplements.

Thank you!