Page 200 - Small Animal Internal Medicine, 6th Edition

172 PART I Cardiovascular System Disorders

and subsequent intravascular fluid shift, precipitating volume Suggested Readings
overload and acute CHF. Presumably, preexisting structural Connolly DJ, et al. Assessment of the diagnostic accuracy of circu-
VetBooks.ir heart disease (i.e., occult cardiomyopathy) could play a role cats with cardiac and non-cardiac causes of respiratory distress.
lating natriuretic peptide concentrations to distinguish between
in making certain cats more susceptible to corticosteroid-
J Vet Cardiol. 2009;11(suppl 1):S41–S50.
induced CHF.
An acute onset of lethargy, anorexia, tachypnea, and Cote E, et al. Assessment of the prevalence of heart murmurs in
overtly healthy cats. J Am Vet Med Assoc. 2004;225:384–388.
respiratory distress is described in affected cats. Most cats Ferasin L, et al. Feline idiopathic cardiomyopathy: a retrospec-
have normal auscultatory findings without tachycardia. tive study of 106 cats (1994-2001). J Feline Med Surg. 2013;5:
Moderate cardiomegaly, with diffuse pulmonary infiltrates 151–159.
and mild or moderate pleural effusion, appears to be typical Finn E, et al. The relationship between body weight, body condi-
on radiographic examination. Possible ECG findings include tion, and survival in cats with heart failure. J Vet Intern Med.
sinus bradycardia, intraventricular conduction abnormali- 2010;24:1369–1374.
ties, atrial standstill, atrial fibrillation, and VPCs. On echo- Fox PR. Endomyocardial fibrosis and restrictive cardiomyopathy:
cardiogram, most affected cats have some degree of LV wall pathologic and clinical features. J Vet Cardiol. 2004;6:25–31.
or septal hypertrophy and LA enlargement. Some have AV Fox PR. Hypertrophic cardiomyopathy: clinical and pathologic cor-
valve insufficiency or SAM. relates. J Vet Cardiol. 2003;5:39–45.
CHF is treated as for other feline cardiomyopathies; in Fox PR, et al. Spontaneously occurring arrhythmogenic right ven-
addition, corticosteroids should be discontinued. Resolution tricular cardiomyopathy in the domestic cat: a new animal model
similar to the human disease. Circulation. 2000;102:1863–1870.
of abnormal cardiac findings and successful weaning from Fox PR, et al. Utility of N-terminal pro-brain natriuretic peptide
cardiac medications have been reported in some cats. (NT-proBNP) to distinguish between congestive heart failure
and non-cardiac causes of acute dyspnea in cats. J Vet Cardiol.
MYOCARDITIS 2009;11(suppl 1):S51–S61.
Inflammation of the myocardium and adjacent structures Fox PR, et al. Multicenter evaluation of plasma N-terminal pro-
can occur in cats, as it does in other species (see p. 153). brain natriuretic peptide (NT-proBNP) as a biochemical screen-
Severe, widespread myocarditis could cause CHF or fatal ing test for asymptomatic (occult) cardiomyopathy in cats. J Vet
arrhythmias. Cats with focal myocardial inflammation could Intern Med. 2011;25:1010–1016.
be asymptomatic. Acute and chronic viral myocarditis have Freeman LM, et al. Body size and metabolic differences in Maine
been suspected, though a viral cause is rarely documented. Coon cats with and without hypertrophy cardiomyopathy. J
Feline Med Surg. 2012;15:74–80.
Feline coronavirus has been identified as a cause of Fries R, Heaney AM, Meurs KM. Prevalence of the myosin-binding
pericarditis-epicarditis. In one study, myocarditis was histo- protein C mutation in Maine Coon cats. J Vet Intern Med. 2008;22:
logically identified in samples from more than half of car- 893–896.
diomyopathic cats but none from cats in the control group; Gordon SG, et al. Effect of oral administration of pimobendan in
viral deoxyribonucleic acid (panleukopenia) was found in cats with heart failure. J Am Vet Med Assoc. 2012;241:89–94.
about one third of the cats with myocarditis. However, the Granstrom S, et al. Prevalence of hypertrophic cardiomyopathy in
possible role of viral myocarditis in the pathogenesis of car- a cohort of British Shorthair cats in Denmark. J Vet Intern Med.
diomyopathy is not clear. 2011;25:866–871.
Endomyocarditis has been documented, mostly in young Harvey AM, et al. Arrhythmogenic right ventricular cardiomyopa-
cats. Acute death, with or without preceding signs of pulmo- thy in two cats. J Small Anim Pract. 2005;46:151–156.
nary edema for 1 to 2 days, is the most common presentation. Jackson BL, Lehmkuhl LB, Adin DB. Heart rate and arrhythmia
Histopathologic characteristics of acute endomyocardi- frequency of normal cats compared to cats with asymptomatic
hypertrophic cardiomyopathy. J Vet Cardiol. 2014;16:215–225.
tis include focal or diffuse lymphocytic, plasmacytic, and Koffas H, et al. Pulsed tissue Doppler imaging in normal cats and
histiocytic infiltrates with few neutrophils. Myocardial cats with hypertrophic cardiomyopathy. J Vet Intern Med.
degeneration and lysis are seen adjacent to the infiltrates. 2006;20:65–77.
Chronic endomyocarditis may have a minimal inflamma- Linney CJ, et al. Left atrial size, atrial function and left ventricular
tory response but significant myocardial degeneration and diastolic function in cats with hypertrophic cardiomyopathy. J
fibrosis. RCM or UCM could represent the end stage of Small Anim Pract. 2014;55:198–206.
nonfatal endomyocarditis. Therapy involves managing CHF Liu SK, Maron BJ, Tilley LP. Feline hypertrophic cardiomyopathy:
signs and arrhythmias. gross anatomic and quantitative histologic features. Am J Pathol.
Bacterial myocarditis may develop in association with 1981;102:388–395.
sepsis or as a result of bacterial endocarditis or pericarditis. MacDonald KA, et al. Effect of spironolactone on diastolic function
Experimental Bartonella sp. infection can cause subclinical and left ventricular mass in Maine Coon cats with familial hyper-
trophic cardiomyopathy. J Vet Intern Med. 2008;22:335–341.
lymphoplasmacytic myocarditis, but it is unclear whether MacGregor JM, et al. Use of pimobendan in 170 cats (2006-2010).
natural infection plays a role in the development of cardio- J Vet Cardiol. 2011;13:251–260.
myopathy in cats. Toxoplasma gondii has occasionally been Machen MC, et al. Multi-centered investigation of a point-of-care
associated with myocarditis, usually in immunosuppressed NT-proBNP ELISA assay to detect moderate to severe occult
cats as part of a generalized disease process. Traumatic myo- (pre-clinical) feline heat disease in cats referred for cardiac evalu-
carditis is recognized infrequently in cats. ation. J Vet Cardiol. 2014;16:245–255.