J Feline Med Surg. 2026 Mar 6:1098612X261433060. doi: 10.1177/1098612X261433060. Online ahead of print.
ABSTRACT
OBJECTIVES: To investigate the effects of high-dose carvedilol treatment (HD) in client-owned cats with Stage B1 obstructive hypertrophic cardiomyopathy (oHCM) where standard-dose (SD) had failed to adequately alleviate left ventricular outflow tract obstruction (LVOTO).
METHODS: A prospective, interventional study was conducted in which cats underwent echocardiography, including evaluation of myocardial strain using speckle-tracking echocardiography. Myocardial injury was quantified using a cTnI assay. Echocardiographic variables and the cTnI level were compared, pre-treatment, and post SD and HD.
RESULTS: Although, LVOT velocity (LVOTV) decreased post SD compared to pre-treatment in all cats, but remained >2.5 m/s post SD (pre-treatment, 4.9 [4.3-5.0] m/s; SD, 4.3 [3.9-4.7] m/s). Whereas HD decreased LVOTV to <2.5 m/s in 10/11 cats (1.6 [1.5-2.0] m/s). Longitudinal strain was improved post SD and HD compared to that pre-treatment (endocardial layer: pre-treatment, 12.1 [9.6-15.8] %; SD, 20. 0 [15.9-21.7] %, HD, 18.9 [12.9-22.8] %, P =0.003 and P =0.006, respectively; epicardial layer: pre-treatment, 9.4 [7.0-10.7] %; SD, 11.6 [10.0-12.7] %, HD, 12.5 [10.0-13.3] %, P =0.013 and P =0.001, respectively). Circumferential strain demonstrated no changes. The cTnI level decreased after SD and HD compared to pre-treatment, and HD compared to SD (pre-treatment, 0.334 [0.117-0.931] ng/mL; SD, 0.192 [0.111-0.377] ng/mL; and HD, 0.018 [0.009-0.161] ng/mL; P =0.043, P =0.043, and P =0.043 respectively). No cats experienced adverse effects such as bradycardia or hypotension.
CONCLUSIONS AND RELEVANCE: HD improved LVOTV, myocardial function, and cTnI level without adverse effects in cats with Stage B1 oHCM.
PMID:41792123 | DOI:10.1177/1098612X261433060