Myocardial fluid balance in dogs with naturally acquired heartworm infection.
OBJECTIVE
To determine the effect of naturally acquired heartworm (Dirofilaria immitis) infection on myocardial fluid balance as indicated by myocardial water content and the dynamics of transepicardial fluid flow.


METHODS
7 dogs infected with adult heartworms and 8 dogs free of heartworm infection.


METHODS
Infected dogs had heartworms in the right ventricle, pulmonary artery, or both but no evidence of cardiovascular disease on physical examination. A hemispheric capsule was attached to the epicardial surface of all dogs for determination of transepicardial fluid dynamics and permeability of the epicardium to water and protein. Myocardial water content and hydroxyproline content were assessed at necropsy.


RESULTS
Myocardial water content was significantly lower in heartworm-infected dogs. No differences in myocardial hydroxyproline content, transepicardial fluid flow, or epicardial water or protein permeability were detected.


CONCLUSIONS
Heartworm infection significantly altered myocardial fluid balance in dogs, possibly because of a change in the myocardial interstitial pressure-volume relationship. These changes may be associated with increased vulnerability to cardiovascular stressors in heartworm-infected dogs.
Stewart
Randolph H
RH
Michael E. DeBakey Institute, Texas A&M University, College Station, TX 77843, USA.
Uray
Karen
K
Cox
Charles S
CS
Laine
Glen A
GA
D000818:Animals; D009202:Cardiomyopathies / Q000378:metabolism / Q000469:parasitology*; D004182:Dirofilaria / Q000254:growth & development*; D004184:Dirofilariasis / Q000378:metabolism* / Q000469:parasitology*; D004283:Dog Diseases / Q000378:metabolism* / Q000469:parasitology*; D004285:Dogs; D005260:Female; D006909:Hydroxyproline / Q000378:metabolism; D008297:Male; D009997:Osmotic Pressure; D014882:Water-Electrolyte Balance / Q000502:physiology*
D006909:Hydroxyproline