Disopyramide Therapy in Cats with Obstructive Hypertrophic Cardiomyopathy Non-Responsive to Carvedilol

Hypertrophic cardiomyopathy (HCM) is the most common cardiomyopathy in cats and is classified as obstructive (HOCM) or non-obstructive based on anatomical differences in the left ventricular outflow tract (LVOT). In severe obstructive cases, while beta-blockers are the recommended initial treatment in humans, some patients exhibit treatment resistance. For these cases, the addition of the antiarrhythmic agent disopyramide is common. However, its use in cats has only been documented in a case report. In this study, the use of disopyramide resulted in a significant reduction in the LVOT velocity and cardiac troponin I levels. Additionally, no significant adverse effects were observed. These findings suggest that disopyramide could be a potential therapeutic option for the treatment in cats with HOCM.