Paroxysmal high-grade second-degree and persistent third-degree atrioventricular block in cats

Area of Science:

• Veterinary Cardiology
• Feline Medicine

Background:

• Atrioventricular block (AVB) is recognized in cats, presenting as either paroxysmal high-grade second-degree or persistent third-degree.
• This study investigates the clinical presentation, diagnostic findings, comorbidities, and outcomes of cats with AVB.

Purpose of the Study:

• To document the presentation, echocardiographic data, comorbidities, and outcomes of cats with atrioventricular block (AVB).
• To evaluate the efficacy and complications of epicardial pacemaker implantation (EPI) in cats with AVB.

Main Methods:

• Retrospective study of 64 cats diagnosed with persistent third-degree or paroxysmal high-grade AVB.
• Analysis included patient history, echocardiographic data, comorbidities, and survival data. Statistical methods included non-parametric testing, Kaplan-Meier curves, and Cox proportional hazard testing.

Main Results:

• Of 64 cats, 67% had persistent AVB and 33% had paroxysmal AVB. 74% were referred for cardiac complaints.
• Echocardiographic abnormalities were present in 63% of cats, and 20% presented with congestive heart failure. 70% had comorbidities.
• Fifteen cats underwent EPI, with 12 showing immediate sign resolution. Median survival time was 799 days; heart failure at presentation was an independent risk factor for cardiac death.

Conclusions:

• Outcome for cats with AVB is variable, but most achieve good medium- to long-term survival.
• Cardiac death occurred in a minority of cases.
• Epicardial pacemaker implantation (EPI) proved effective in alleviating clinical signs associated with AVB in cats.