my dog is acting weird

Question
could you plz help me with the ? my shih tzu's behavior has been really out of the normal day to day . he's sticking to me like glue...hiding in places that he would not think of going other times. he's 7yrs old he has a heart disese  Myocardial Disease.could you plz help me with this ?

Answer
please follow up with your vet, your little boy sounds like he is seeking comfort from pain.  Is he swollen or looking like he is taking on weight around the chest/abdomen?
I tried to send links to you on some meds but the servers were down and I will try again later.  For now it is important you get him to be checked.  If he is lethargic, not eating, acting strangely, he is seeking help and it is up to you to get it for him.  Let me know how things go, I am not familiar with the type of heart condition he has and Myocardial Disease is a way for a vet to generalize a very serious condition and without me knowing the specific type  of condition I really can not help much, sorry.