Feline First-Degree AV Block: Vet Guide 2025 🐱⚡🩺

Hello caring cat parents! I’m Dr Duncan Houston BVSc 🩺. Let’s explore the mild but important heart rhythm change known as first-degree atrioventricular (AV) block in cats—what it is, why it happens, how we diagnose and monitor it, and how to support your cat at home. Complete with emojis to keep things friendly and clear! 😊

🔍 What Is First‑Degree AV Block?

First‑degree AV block is a delay (not a complete interruption) in electrical conduction from the atria to the ventricles, seen as a prolonged PR interval on an ECG 💓. It’s the mildest type of heart block and often causes no symptoms in cats :contentReference[oaicite:2]{index=2}.

🧬 Causes & Risk Factors

• High vagal tone: Especially in young, healthy cats—sometimes just natural physiology :contentReference[oaicite:3]{index=3}.
• Medications: Such as digoxin, calcium‑channel blockers, bethanechol—can slow conduction :contentReference[oaicite:4]{index=4}.
• Electrolyte imbalances: Low calcium, high potassium—often reversible :contentReference[oaicite:5]{index=5}.
• Heart inflammation or disease: Myocarditis, degenerative conduction disease, infiltrative conditions—amyloid, HCM :contentReference[oaicite:6]{index=6}.
• Drugs/procedures: Atropine, pilocarpine, physostigmine may affect AV node function :contentReference[oaicite:7]{index=7}.

👂 Signs & Symptoms

• Usually asymptomatic—found during routine check-up ECG :contentReference[oaicite:8]{index=8}.
• If caused by meds or imbalances—your cat might show decreased appetite, vomiting, diarrhea :contentReference[oaicite:9]{index=9}.
• No exercise intolerance or collapse unless more severe block develops.

🔬 Diagnostic Approach

• Physical exam: Often normal; no overt bradycardia unless advanced block.
• ECG: Primary tool—reveals prolonged PR interval without missed beats :contentReference[oaicite:10]{index=10}.
• Bloodwork: Check electrolytes, calcium, CBC, chemistry.
• Echo & X‑rays: Used to rule out structural heart disease when indicated :contentReference[oaicite:11]{index=11}.
• History: Review medications, toxicity, GI or endocrine issues.

⚕️ Treatment & Management

✅ When No Symptoms & No Cause Found

• No treatment needed—this condition is benign :contentReference[oaicite:12]{index=12}.
• Routine monitoring—ECG at regular intervals or if new symptoms appear.

🔧 When Meds or Electrolytes Involved

• Adjust or stop medications under vet guidance (e.g., reduce digoxin) :contentReference[oaicite:13]{index=13}.
• Correct electrolyte imbalances: supplement calcium or adjust fluids :contentReference[oaicite:14]{index=14}.
• Address underlying GI/endocrine issues—treat vomiting, diarrhea, Addison’s, thyroid disease.

🩺 When Heart Disease Is Found

• Treat primary condition—HCM, myocarditis, infiltrative disease :contentReference[oaicite:15]{index=15}.
• Monitor for progression to second- or third-degree AV block (holter or serial ECG) :contentReference[oaicite:16]{index=16}.

📈 Prognosis & Monitoring

• Generally excellent prognosis if isolated :contentReference[oaicite:17]{index=17}.
• Guarded if linked to heart disease or imbalances—requires ongoing vet care.
• Rare progression to advanced block—monitor PR interval and rhythm.
• Follow-up every 6–12 months via ECG; sooner if symptoms develop.

🏡 Home Care Tips

• Keep your kitty in a calm environment—stress and excitement can affect heart rhythm.
• Maintain hydration and balanced diet—fresh water & quality nutrition.
• Track meds and reminders using **Ask A Vet app** 📱.
• Use cozy beds and calm spaces—**Woopf & Purrz** products help reduce stress 🛏️.
• Listen for appetite changes, vomiting, diarrhea, fainting, or inappetence—report to vet.

📝 Key Takeaways

• First-degree AV block = delayed AV conduction, seen as prolonged PR interval on ECG.
• Mostly benign, often due to vagal tone, meds, or minor imbalances.
• Diagnosed with ECG; additional tests if underlying cause suspected.
• Treated only if symptomatic or reversible cause is found.
• Cat health and rhythm should be rechecked regularly to catch progression early.
• Supportive home care and vet partnership = best quality of life 🐾.

📞 When to Contact Ask A Vet

If your cat develops fainting, weakness, vomiting, diarrhea, or appetite changes—use the Ask A Vet app 💬 right away for advice and possible ECG monitoring.

✨ Final Thoughts

In most cases, feline first-degree AV block is a mild and manageable condition. With attentive vet oversight, smart medication monitoring, and stress-free home care—including the support of Ask A Vet, Woopf & Purrz—your cat can thrive comfortably in 2025 and beyond. 😊❤️