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Feline Second‑Degree AV Block (Mobitz II): Vet Guide 2025 🐱⚡🩺
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Feline Second‑Degree AV Block (Mobitz II): Vet Guide 2025 🐱⚡🩺

🐾 Discover our **2025 vet guide** on feline second-degree AV block (Mobitz II) 🐱⚡—explore ECG signs, causes, pacing options 🏥 & home care 🏡✨

Duncan Houston
Duncan Houston
Veterinarian · Founder of ASK A VET
7 min read

Feline Second-Degree AV Block (Mobitz II): Vet Guide 2025 🐱⚡🩺

Hello devoted cat parents! I’m Dr Duncan Houston BVSc 🩺. Today we'll explore second‑degree AV block, Mobitz Type II, a potentially serious arrhythmia. Learn causes, symptoms, ECG detection, treatment (including pacemakers), and caring support at home with clarity and empathy. 😊

🔍 What Is Mobitz Type II AV Block?

This form features sudden non-conducted P‑waves (dropped beats) without PR interval prolongation—where one or more atrial impulses fail to pass to the ventricles, causing bradycardia and intermittent skipped beats :contentReference[oaicite:2]{index=2}.

🧬 Who Gets It & Why?

  • Often seen in older cats, especially with underlying heart disease :contentReference[oaicite:3]{index=3}.
  • Linked to cardiomyopathy, AV-node degeneration, fibrosis, infection, neoplasia, trauma, metabolic issues, or drug effects (like digoxin) :contentReference[oaicite:4]{index=4}.

👂 Signs & Symptoms

  • May be asymptomatic—or present with weakness, exercise intolerance, fainting, collapse, or congestive heart failure signs :contentReference[oaicite:5]{index=5}.
  • Digoxin toxicity may cause GI upset—vomiting, poor appetite, diarrhea :contentReference[oaicite:6]{index=6}.

🔬 Diagnosing Mobitz II AV Block

  • Physical exam: irregular soft or absent beats during dropped complexes.
  • ECG: key test—static PR intervals with intermittent non-conducted P waves (e.g., 2:1, 3:1 ratios) :contentReference[oaicite:7]{index=7}.
  • Holter monitor: detects intermittent block episodes :contentReference[oaicite:8]{index=8}.
  • Diagnostics: bloodwork (CBC/chem/electrolytes), echo, chest X-ray, blood pressure, and underlying disease screening (thyroid, infection) :contentReference[oaicite:9]{index=9}.

🏥 Treatment & Management

1. Acute, Symptomatic Support

  • Vagal tone reversal—trial of atropine or glycopyrrolate :contentReference[oaicite:10]{index=10}.
  • Positive chronotropes—terbutaline, dobutamine, theophylline—help increase heart rate temporarily :contentReference[oaicite:11]{index=11}.
  • Treat symptoms of CHF—oxygen, diuretics (furosemide), ACE inhibitors (benazepril) :contentReference[oaicite:12]{index=12}.

2. Definitive Therapy

  • Pacemaker implantation is often recommended if symptomatic—prevents progression and sudden collapse :contentReference[oaicite:13]{index=13}.
  • Even asymptomatic cats should be closely monitored—Mobitz II often progresses to complete block :contentReference[oaicite:14]{index=14}.

3. Treat Underlying Conditions

  • Correct metabolic disturbances—electrolytes, hyperthyroidism, infections.
  • Reduce/remove AV-nodal drugs (e.g., digoxin, calcium-blockers) :contentReference[oaicite:15]{index=15}.
  • Manage cardiomyopathy or inflammatory disease.

📈 Prognosis & Monitoring

  • Mobitz II can rapidly progress to high-grade or complete block—pacemaker greatly improves outcomes :contentReference[oaicite:16]{index=16}.
  • Symptomatic cats have guarded prognosis without pacing.
  • Follow-up every 3–6 months—ECG, echo, device checks if paced.

🏡 Home Care Tips

  • Keep environment calm and stress-free 🧘‍♀️.
  • Use **Ask A Vet app** 📱 for medication reminders and vet chats.
  • Coziness matters—**Woopf & Purrz** beds help ease rest.
  • Monitor for fainting, weakness, breathing difficulties—seek vet care at once.
  • Maintain scheduled check-ups and tests—you’ll catch changes early.

📝 Key Takeaways

  • Mobitz II AV block is a serious arrhythmia with dropped beats and fixed PR intervals.
  • Typical signs: weakness, fainting, heart failure, GI upset if drug-related.
  • Requires ECG/Holter and full diagnostic evaluation.
  • Treatment options: pacing, drugs, underlying disease management.
  • Proactive monitoring and home care boost safety and quality of life.

📞 When to Contact Ask A Vet

If your cat experiences fainting episodes, dizziness, sudden weakness, or breathing trouble—or is scheduled for anesthesia—reach out via the Ask A Vet app 💬. Early intervention can make a lifesaving difference.

✨ Final Thoughts

Feline Mobitz II AV block is uncommon but important. With diligent vet management—especially pacemaker use—and thoughtful home support, many cats live well. Ask A Vet, Woopf & Purrz can help you navigate every step of this journey 🐾❤️.


For personal vet advice and ongoing care, visit AskAVet.com and download the Ask A Vet app today! 📱🐱

This article is general veterinary education and does not diagnose or treat an individual animal. Always confirm medication names, doses and interactions with the veterinarian who knows your pet.

If your animal is struggling to breathe, collapsed, bleeding heavily, seizing, or has eaten something toxic, contact your vet or the nearest emergency clinic now.

Animal Poisons Helpline (AU) 1300 869 738 · Animal Poisons Helpline (NZ) 0800 869 738 · ASPCA Animal Poison Control (US) (888) 426-4435

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Dr Duncan Houston
About the author
Dr Duncan Houston
Veterinarian · Founder of ASK A VET

Ask A Vet articles are written by Dr Duncan Houston BVSc, a practising veterinarian, unless another author is named in the byline.

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