Modified Simpson’s method of disc in the diagnosis of dilated cardiomyopathy in dogs

Dilated cardiomyopathy, the second most common canine acquired heart disease, is one of the leading cause morbidity and mortality in middle to old aged large breed dogs. The cases presented with signs suggestive of cardiac diseases were screened for DCM with the aid of standard B mode and one dimentional M-mode echocardiography. Totally eight confirmed cases of DCM were selected for the present study and subjected to modified Simpson’s method of discs for LV volume measurement and biplanar EF. All the parameters under study were repeated in six healthy control dogs also. The data was analysed statistically by paired t-test. The results showed a statistically significant increase in LV EDVI and ESVI and significant reduction in EF BP, compared to control. This study demonstrated that the twodimensional modified Simpson’s method of discs as a superior alternative to M-mode measurements for assessing left ventricular (LV) volume. Since, M-mode relied on a one-dimensional approach based on LV geometry, which might lead to inaccuracies, especially in cases of LV dyssynchrony in diseased heart. In contrast, the Simpson’s method accurately captures the complex three-dimensional shape of the LV by summing elliptical discs, providing a more precise assessment of LV volume. This improved accuracy is essential for diagnosing the chamber enlargement and volume and managing conditions like DCM, making the 2D modified Simpson’s method the preferred choice in veterinary cardiology. Keywords: Dilated cardiomyopathy, Simpson’s method of discs, Simpson’s rule, echocardiography, end-diastolic volume, end systolic volume