The invention provides methods for diagnosing chronic valvular disease in an animal. The methods comprise obtaining a sample from the animal; analyzing the sample for an amount of a microRNA (miRNA) associated with chronic valvular disease; comparing the amount of the miRNA identified in the sample to a corresponding amount of the miRNA present in a sample from one or more comparable control animals that do not suffer from chronic valvular disease; and diagnosing the animal with chronic valvular disease if the amount of the miRNA found in the animal's sample is differentially expressed in the control animal's sample.