This lecture will give a brief overview of the main cardiac diseases seen in veterinary practice, using the current consensus statements that stage the diseases, into either 3 or 4 categories. The categories are: Being a breed predisposed to heart failure, but no evidence of heart disease A pre-clinical phase Heart failure either historical or current. In cats this includes aortic thromboembolism A refractory stage The lecture will provide guidelines for diagnostic tests, treatment protocols and nursing requirements. A focus will be placed on how to obtain diagnostic tests with patients that are respiratory compromised.