Cardiovascular disease in cetaceans

Cetaceans possess a highly specialized cardiovascular system that supports prolonged apnea, selective perfusion of vital organs, and tolerance to marked hemodynamic fluctuations during diving. Nevertheless, pathological and clinical observations show that they can develop a broad spectrum of cardiovascular disease (CVD). This review summarizes current knowledge on CVD in cetaceans across species and ecological contexts. We discuss the major disease phenotypes described to date, including stress cardiomyopathy, chronic myocardial fibrosis and cardiomyopathy-like remodeling, inflammatory cardiac disease, vascular and ischemic lesions, valvular and functional abnormalities, and congenital defects. Among these, acute stress-associated myocardial injury is one of the best-supported phenotypes in stranded cetaceans, whereas chronic cardiomyopathy-like remodeling is most clearly documented in pygmy and dwarf sperm whales. Inflammatory cardiac disease appears less frequent and is usually associated with systemic infection, while vascular disease includes not only atherosclerotic and thrombotic lesions but also embolic and decompression-related pathology. Current knowledge remains limited by strong species and sampling biases, with most evidence derived from stranded animals and a smaller body of work from managed dolphins. Overall, cetacean cardiovascular pathology reflects the interaction between extreme physiological specialization, environmental exposure, systemic disease, and acute stress.