Identification of two preclinical canine models of atrial fibrillation to facilitate drug discovery

Heart Rhythm. 2021 Apr;18(4):632-640. doi: 10.1016/j.hrthm.2020.12.015. Epub 2020 Dec 17.


Background: Atrial fibrillation (AF) is the most common arrhythmia occurring in humans, and new treatment strategies are critically needed. The lack of reliable preclinical animal models of AF is a major limitation to drug development of novel antiarrhythmic compounds.

Objective: The purpose of this study was to provide a comprehensive head-to-head assessment of 5 canine AF models.

Methods: Five canine models were evaluated for the efficacy of AF induction and AF duration. We tested 2 acute models: short-term atrial tachypacing (AT) for 6 hours with analysis of AF at hourly increments, and carbachol injection into a cardiac fat pad followed by short-term AT. We also tested 3 chronic models: pacemaker implantation followed by either 4 weeks of AT and subsequent atrial burst pacing or intermittent long-term AT for up to 4-5 months to generate AF ≥4.5 hours, and finally ventricular tachypacing to induce heart failure followed by atrial burst pacing to induce AF.

Results: Careful evaluation showed that acute AT, AT for 4 weeks, and the heart failure model all were unsuccessful in generating reproducible AF episodes of sufficient duration to study antiarrhythmic drugs. In contrast, intermittent long-term AT generated AF lasting ≥4.5 hours in ∼30% of animals. The acute model using carbachol and short-term AT resulted in AF induction of ≥15 minutes in ≥75% of animals, thus enabling testing of antiarrhythmic drugs.

Conclusion: Intermittent long-term AT and the combination of local carbachol injection with successive short-term AT may contribute to future drug development efforts for AF treatment.

Keywords: Arrhythmia; Atrial fibrillation; Canine; Drug discovery; Tachypacing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Atrial Fibrillation / drug therapy*
  • Carbachol / administration & dosage*
  • Cardiotonic Agents / administration & dosage
  • Disease Models, Animal
  • Dogs
  • Dose-Response Relationship, Drug
  • Drug Discovery / methods*
  • Injections
  • Treatment Outcome


  • Cardiotonic Agents
  • Carbachol