My dog has heart issues. How can I clean their teeth at home?

I am so sorry that your pet has dental disease and a heart condition. Unfortunatley the tartar that causes dental disease is mostly underneath the gumline, hence the name periodontal disease. So most of the tartar that we see on the surface of the tooth is not the main issue here. It is the tartar that is touching the gum and underneath the gum that is the problem. This isn't tartar that you will be able to get off with the pet awake, because it will be uncomfortable for the pet. Also, you have a good chance of causing damage to the gum trying to do this in any awake dog. What you are asking is not possible unfortunatley.

However, there are a number of heart dogs that can actually go under anesthesia for a dental cleaning, even with a heart condition. I would suggest taking Chhutki to get an echocardiogram of her heart to determine if she is a good candidate for anesthesia and then go from there. If she isn't, then the only thing you can really do here is to do a daily oral rinse and water additive such as this one --> https://www.chewy.com/nylabone-advanced-oral-care-liquid/dp/47912
Dental disease and at home care recommendations --> https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4951515

I do hope that your pet Chhutki proves to be ok to go under general anesthesia, just like many other heart disease pets, and can appropriateliy address her dental disease condition. Best of luck moving forward. Take care. : )