Hello, I am sorry to hear that Holly had such a difficult night.While Revoution should not affect her heart at all if she is stressed, itchy and uncomfortable that will. Has she ever had Revolution applied before? Some dogs do have a sensitivity to it and that will cause reddened, itchy skin or sometimes a "skin crawling" type effect as the medication distributes in the fat layers/oil glands of the skin.Sometimes this effect only lasts for a short period of time until the medication is distributed. If it persists I would pick another medication for heartworm prevention and flea control for her.Dogs with uncontrolled congestive heart failure do seem to have more trouble at night than during the day, when they lay down they have more difficulty breathing and pressure on the trachea increases.How is she this morning?Does her skin seem pinker than normal?What is her gum/tongue color? Bubblegum pink, gray, blueish?
If her cough persists today, especially if her appetite seems off, I do recommend you have her rechecked by her veterinarian. In the meantime you might try bathing her with an oatmeal shampoo and cool water to soothe her skin. I suspect that she is sensitive to Revolution and her difficult night was a stress response to that more than her heart disease,. But if you are unsure and her gum/tongue color isn't normal then it never hurts to have her rechecked.Let me know if you have any further questions.