Effect of spironolactone on diastolic function and left ventricular mass in Maine Coon cats with familial hypertrophic cardiomyopathy.
BACKGROUND
Myocardial fibrosis occurs in cats with hypertrophic cardiomyopathy (HCM), and is one factor that leads to diastolic dysfunction. Spironolactone (SPIR) reduces myocardial fibrosis in several models of HCM and in humans with cardiac disease.


OBJECTIVE
SPIR will improve diastolic function and reduce left ventricular (LV) mass in Maine Coon cats with HCM.


METHODS
Maine Coon cats with familial HCM were included if there was concentric hypertrophy (> or =6 mm end diastolic wall thickness) and decreased early lateral mitral annular velocity (Em) or summated early and late mitral annular velocity (EAsum) measured by pulsed wave tissue Doppler imaging echocardiography. Cats were paired by Em-EAsum and randomized to receive 2 mg/kg SPIR (n = 13) or placebo (n = 13) PO q12 h for 4 months. Em-EAsum, systolic velocity, LV mass, and the ratio of left atrial to aortic diameter were measured at baseline, 2 months, and 4 months. Statistical analysis included 2-way repeated measures analysis of variance and the Student's t-test.


RESULTS
Plasma aldosterone concentration increased in cats treated with SPIR (235 ng/mL, baseline; 935 ng/mL, 2 months; 1,077 ng/mL, 4 months; P < .001 at 2 and 4 months). No significant treatment effect was identified for early or early-late summated diastolic mitral annular velocity or any other variable except plasma aldosterone concentration. Severe facial ulcerative dermatitis developed in 4 of 13 cats treated with SPIR, requiring discontinuation of the drug.


CONCLUSIONS
SPIR did not improve Em or EAsum of the lateral mitral annulus or alter LV mass over 4 months. One third of cats treated with SPIR developed severe ulcerative facial dermatitis.
MacDonald
K A
KA
Department of Medicine and Epidemiology, University of California, Davis, CA, USA. kamacdonald@ucdavis.edu
Kittleson
M D
MD
Kass
P H
PH
White
Stephen D
SD
D000704:Analysis of Variance; D000818:Animals; D024741:Cardiomyopathy, Hypertrophic, Familial / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D002371:Cat Diseases / Q000188:drug therapy* / Q000235:genetics; D002415:Cats; D003971:Diastole / Q000187:drug effects; D004232:Diuretics / Q000009:adverse effects / Q000627:therapeutic use*; D003875:Drug Eruptions / Q000473:pathology / Q000662:veterinary; D020022:Genetic Predisposition to Disease; D006352:Heart Ventricles / Q000473:pathology*; D008297:Male; D013148:Spironolactone / Q000009:adverse effects / Q000627:therapeutic use*
D004232:Diuretics; D013148:Spironolactone