Effect of echocardiographic imaging view and methods on left ventricular wall-thickness measurements in normal cats and cats with hypertrophic cardiomyopathy

Figures

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  Figure 1. End-diastolic thickness of the IVS and LVFW were evaluated by 2D and M-mode echocardiography from both RPSax and RPLax views: M1 (method 1), assessment of IVS and LVFW thickness by 2D from the RPLax 4-chamber view; M2 (method 2), assessment of IVS and LVFW thickness by M-mode from the RPLax 4-chamber view; M3 (method 3), assessment of IVS and LVFW thickness by 2D from the RPSax view; and M4 (method 4), assessment of IVS and LVFW thickness by M-mode from the RPSax view. Abbreviations: 2D = 2-dimensional; IVS = interventricular septum; LA = left atrium; LV = left ventricle; LVFW = left ventricular free wall; RA = right atrium; RPLax = right parasternal long-axis; RPSax = right parasternal short-axis; RV = right ventricle. The bolded red lines indicate the location of left ventricular wall measurements.

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  Figure 2. Flow chart demonstrating selection of study cats. Cats enrolled were imaged between November 2013 and August 2023, and the search terms “normal cardiovascular findings” and “hypertrophic cardiomyopathy” were used for case identification.

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  Figure 3. Bland–Altman plots illustrating difference (Y-axis) vs average (X-axis) of LV wall-thickness measurements using 4 echocardiographic methods in control cats. Individual data points, bias between methods (solid lines), and 95% LOA between methods (dashed lines) are displayed. (A) M1 vs M2 for the IVS. Bias 0.10 mm, SD of the bias 0.60 mm, 95% LOA −1.08 to 1.28 mm. (B) M1 vs M2 for the LVFW. Bias 0.30 mm, SD 0.47 mm, 95% LOA −.63 to 1.22 mm. (C) M3 vs M4 for the IVS. Bias 0.04 mm, SD 0.58 mm, 95% LOA −1.09 to 1.17 mm. (D) M3 vs M4 for the LVFW. Bias 0.22 mm, SD 0.53 mm, 95% LOA −0.81 to 1.25 mm. M, method; M1, right parasternal long-axis (RPLax) view, 2D measurements; M2, right parasternal long-axis (RPLax) view, M-mode measurements; M3, RPSax view, 2D measurements; M4, RPSax view, M-mode measurements. Abbreviations: 2D = 2-dimensional; IVS = interventricular septum; LOA = limits of agreement; LV = left ventricular; LVFW = left ventricular free wall.

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  Figure 4. Bland–Altman plots illustrating difference (Y-axis) vs average (X-axis) of LV wall-thickness measurements using 4 echocardiographic methods in cats with hypertrophic cardiomyopathy. Individual data points, bias between methods (solid lines), and 95% LOA between methods (dashed lines) are displayed. (A) M1 vs M2 for the IVS. Bias −1.13 mm, SD 0.97 mm, 95% LOA −3.05 to 0.78 mm. (B) M1 vs M2 for the LVFW. Bias −0.27 mm, SD 0.93 mm, 95% LOA −2.09 to 1.55 mm. (C) M3 vs M4 for the IVS. Bias −1.07 mm, SD 0.98 mm, 95% LOA −2.99 to 0.84 mm. (D) M3 vs M4 for the LVFW. Bias 0.22 mm, SD 0.96 mm, 95% LOA −1.75 to 2.03 mm. Abbreviations: IVS = interventricular septum; LOA = limits of agreement; LV = left ventricular; LVFW = left ventricular free wall. See Figure 2 for key.