Objectives—To determine whether attenuated wavy fibers may be found in the myocardium of Newfoundlands without clinical or echocardiographic evidence of heart disease.
Animals—15 Newfoundlands from a kennel with a known predisposition to dilated cardiomyopathy (DCM) and 32 dogs of other breeds that died suddenly or were euthanatized for reasons unrelated to heart disease and did not have gross postmortem evidence of heart disease.
Procedure—Echocardiography was performed on all Newfoundlands on a yearly basis. Necropsy specimens from all dogs were evaluated for attenuated wavy fibers (ie, myocardial cells < 6 µm in diameter with a wavy appearance).
Results—None of the Newfoundlands had clinical signs of heart disease, and results of echocardiographic examinations were within reference ranges. Seven Newfoundlands had histologic evidence of attenuated wavy fibers, whereas attenuated wavy fibers were not found in the remaining 8 Newfoundlands or in any of the 32 dogs of other breeds.
Conclusions and Clinical Relevance—Findings suggest that attenuated wavy fibers in dogs with a known predisposition for DCM may indicate an early stage of the disease. However, further studies on a larger number of dogs are needed to confirm this hypothesis. (Am J Vet Res 2000;61:238-241)