Post-carvedilol myocardial function in cats with obstructive hypertrophic cardiomyopathy

Area of Science:

• Cardiology
• Veterinary Medicine
• Pharmacology

Background:

• Hypertrophic cardiomyopathy (HCM) is common in cats, often presenting as obstructive HCM with dynamic left ventricular outflow tract obstruction (DLVOTO).
• Myocardial function is typically reduced in cats with obstructive HCM compared to non-obstructive forms.
• The efficacy of carvedilol on myocardial function in cats with obstructive HCM and DLVOTO has not been previously reported.

Purpose of the Study:

• To evaluate the effects of carvedilol on myocardial function in cats diagnosed with obstructive HCM and DLVOTO.
• To assess changes in left ventricular outflow tract pressure gradients following carvedilol administration.

Main Methods:

• A retrospective observational study involving 16 cats with obstructive HCM treated with carvedilol.
• Conventional echocardiography combined with layer-specific 2D speckle tracking echocardiography to measure strain and strain rates.
• Comparison of echocardiographic variables before and after carvedilol treatment.

Main Results:

• Carvedilol administration resolved DLVOTO in all cats, evidenced by a decrease in maximal LV outflow tract blood flow velocity to <2.5 m/s (P < 0.01).
• Significant improvement in circumferential strain (epicardial and whole layer) was observed post-treatment (P < 0.01, P = 0.04).
• No significant changes were noted in systolic longitudinal strain before and after treatment.

Conclusions:

• Carvedilol treatment effectively improved DLVOTO and enhanced myocardial function in cats with obstructive HCM.
• The treatment did not induce a negative inotropic effect, suggesting carvedilol's potential as a therapeutic agent for feline obstructive HCM.