In dogs with hypertrophic cardiomyopathy (HCM), which drug is contraindicated?

In the context of hypertrophic cardiomyopathy (HCM) in dogs, digoxin is contraindicated primarily due to its effects on myocardial contractility and electrical conduction. Digoxin is a positive inotropic agent that increases the force of cardiac contractions, which may exacerbate the already impaired diastolic filling that characterizes HCM. This condition involves a thickening of the heart muscle, particularly the left ventricle, which can lead to obstruction and difficulty for the heart to fill adequately with blood. Utilizing digoxin could potentially worsen the clinical signs associated with HCM.

In contrast, furosemide is often used to manage fluid overload in various heart conditions, including congestive heart failure that may arise from HCM. Diltiazem, a calcium channel blocker, is sometimes used to relax the heart muscle and improve diastolic function, which can be beneficial in HCM cases. Atenolol, a beta-blocker, might be prescribed to reduce heart rate and improve diastolic filling time. Each of these medications can play a role in managing the symptoms or complications related to HCM but digoxin poses a risk of further complicating the heart’s function in this condition.