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. 2018 Jan;32(1):48-56.
doi: 10.1111/jvim.14897. Epub 2017 Dec 15.

Transient Myocardial Thickening in Cats Associated with Heart Failure

Affiliations

Transient Myocardial Thickening in Cats Associated with Heart Failure

J Novo Matos et al. J Vet Intern Med. 2018 Jan.

Abstract

Background: Cats with hypertrophic cardiomyopathy (HCM) and congestive heart failure (CHF) can have resolution of both left ventricular hypertrophy and CHF.

Objectives: To describe the clinical characteristics of cats with transient myocardial thickening (TMT) and CHF compared with a control population of cats without resolution of HCM.

Animals: A total of 21 cats with TMT, 21 cats with HCM.

Methods: Retrospective study. Clinical records at 4 veterinary centers were searched for TMT cases and a control group of cats with HCM and CHF. TMT was defined as initial maximal left ventricular wall thickness (LVWT) ≥6 mm with left-sided CHF, with subsequent resolution of CHF, reduction in left atrium/aorta (LA/Ao), and LVWT<5.5 mm. HCM was defined as persistent LVWT ≥6 mm.

Results: Cats with TMT were younger (2 [0.4-11.4] years) than cats with HCM (8 [1.6-14] years) (P < 0.0001), and antecedent events were more common (15/21 versus 6/21, respectively) (P = 0.01). In cats with TMT, LVWT normalized from 6.8 [6.0-9.7] mm to 4.8 [2.8-5.3] mm and LA/Ao decreased from 1.8 [1.6-2.3] to 1.45 [1.2-1.7] after a mean interval of 3.3 (95% CI: 1.8-4.7) months. CHF recurred in 1 of 21 TMT and 15 of 21 cats with HCM. Cardiac treatment was discontinued in 20 of 21 cats with TMT and 0 of 21 HCM cats. All cats with TMT survived, whereas 8 of 19 cats with HCM died during the study period.

Conclusions and clinical importance: TMT occurs in younger cats, and antecedent events are common. The prognosis is better in cats with CHF associated with TMT than HCM.

Keywords: HCM phenocopy; Hypertrophic cardiomyopathy; Myocarditis; Takotsubo cardiomyopathy.

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Conflict of interest statement

Authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Left ventricular wall thickness (LVWT) (A) and left atrial size (LA/Ao) (B) in cats with TMT and HCM at presentation and final echocardiographic examination. At presentation, left ventricular walls were thicker in cats with HCM. The left atrium was larger in cats with HCM at presentation and remained dilated over time, while it decreased over time in the TMT population. By definition, the LVWT and LA/Ao decreased between the initial and the final echo in the TMT population, and so those two datasets were not subjected to statistical analysis. Echo, echocardiogram; TMT, transient myocardial thickening; HCM, hypertrophic cardiomyopathy.
Figure 2
Figure 2
Right parasternal long‐axis (A, B, E, F) and short‐axis views (C, D, G, H) at end‐diastolic frame from 2 TMT cases at initial presentation (A, C and E, G) and 7 months later (B, D and F, H). The initial severely increased left ventricular wall thickness (A, C, E, G) and mild pericardial effusion (E, G) resolved completely, with a morphologically normal heart 7 months later.
Figure 3
Figure 3
Left atrial fractional shortening (LA%FS) in cats with TMT (A) and HCM (B) at presentation and final echocardiographic examination. LA%FS was reduced in both groups at presentation but improved in the TMT group over time. Echo, echocardiogram.
Figure 4
Figure 4
Long‐term follow‐up in 15 cats with TMT. Normal left ventricular wall thickness was defined as <5.5 mm (normal echo), but all cats with serial echos showed a further decreased in wall thickness over time. Echo, echocardiogram.

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