Higher-dose carvedilol shows promise in cats with obstructive HCM

Cats with obstructive hypertrophic cardiomyopathy that don't respond enough to a standard carvedilol dose may benefit from going higher, according to a new prospective study in the Journal of Feline Medicine and Surgery. Investigators followed 11 client-owned cats with stage B1 obstructive HCM whose left ventricular outflow tract obstruction remained above the study target after standard-dose carvedilol, then increased the dose to 150% to 200% of that starting regimen. Median carvedilol dosing rose from 0.29 mg/kg every 12 hours at the standard-dose phase to 0.48 mg/kg every 12 hours at the high-dose phase, and 10 of 11 cats reached the target outflow velocity below 2.5 m/s after escalation. The study also found improvement in longitudinal myocardial strain and a drop in cardiac troponin I, with no reported bradycardia or hypotension. (journals.sagepub.com)

Why it matters: For veterinarians managing feline cardiology cases, the findings suggest some cats with obstructive HCM may be undertreated if carvedilol is stopped at a conventional dose despite persistent obstruction on echocardiography. That said, this was a small, prospective study in stage B1 cats, not a randomized outcomes trial, so the signal is best viewed as practice-informing rather than practice-changing. Current ACVIM guidance still frames feline HCM management around phenotype, risk, and clinical stage, and obstructive disease remains an area where treatment decisions are often individualized. (journals.sagepub.com)

What to watch: Whether larger studies confirm that dose escalation improves not just echo variables and biomarkers, but also clinical outcomes, survival, and progression risk in cats with obstructive HCM. (journals.sagepub.com)