This is another huge subject. Some disease can be congenital (i.e. present at birth) or heart disease may develop. There are some breeds (in both dogs and cats) that are more susceptible to certain types of heart disease and as our pets live longer heart disease becomes more likely.
Heart disease shows itself in some recognisable ways. Coughing, exercise intolerance, swollen abdomen and fainting are the commoner ways for it to show itself in dogs. In cats laboured breathing and swollen abdomen is more likely. There are some powerful drugs nowadays to help in all sorts of heart disease cases so early detection is the key. If worried come in. We will check heart and circulation at pretty well every examination and certainly at the annual booster vaccination.