EXPRESS: Evaluation of Left Atrial Reservoir Strain by Two-Dimensional Speckle-Tracking Echocardiography in Cats with Stage B1 Hypertrophic Cardiomyopathy.

Objectives

Left atrial reservoir strain (LA S_R), assessed by two-dimensional speckle-tracking echocardiography (2D-STE), reflects left atrial (LA) function and may reveal subtle alterations in LA mechanics in cats with American College of Veterinary Internal Medicine (ACVIM) stage B1 hypertrophic cardiomyopathy (HCM) compared with healthy cats. This study aimed to determine whether LA S_R differs between cats with HCM (stage B1) and healthy cats using 2D-STE.

Methods

Sixty-one client-owned cats were retrospectively identified and included from medical databases. These cats were classified as healthy controls (Stage A; n=30) or preclinical HCM (Stage B1; n=31) according to ACVIM consensus guidelines. All cats underwent a comprehensive conventional echocardiographic examination, including two-dimensional, M-mode, color Doppler, pulsed-wave Doppler, and tissue Doppler imaging, as part of clinical care or screening protocols. Conventional two-dimensional assessment of LA size and function included the LA/Ao ratio, LA diameter, LA area, LA fractional shortening (LA FS), and LA ejection fraction (LA EF). LA S_R was subsequently measured offline using automated function imaging software. Reproducibility was assessed via intra- and inter-observer intraclass correlation coefficients (ICC). Receiver operating characteristic (ROC) curve analysis was performed to compare the discriminatory performance of LA S_R and the evaluated LA variables between the predefined study groups.

Results

Cats with ACVIM stage B1 HCM had significantly lower LA S_R than healthy controls (19.0% [IQR, 14.5-22.0%] vs 38.0% [IQR, 30.25-42.50%], respectively; P < 0.001). LA S_R reproducibility was high with an intra-observer ICC of 0.974 and an inter-observer ICC of 0.894.

Conclusions

AND RELEVANCE Assessment of LA S_R was feasible in cats with stage B1 HCM. LA S_R values differed between affected cats and healthy controls, with lower values observed in the affected group and good reproducibility. These findings suggest that LA S_R may provide complementary information on LA function in cats with this stage of disease.