Atrial fibrillation - Electrical properties of the equine heart

Projektleder: Lektor Rikke Buhl, e-mail: rib@sund.ku.dk

Atrial fibrillation (AF) is a cardiac disease characterized by chaotic contractions in the atria of the heart resulting in reduced tolerance to hard exercise in horses. The exact reason(s) underlying the development of AF in horses is still researched, but it is well-accepted that training of horses can initiate AF secondary to training-induced cardiac hypertrophy (enlargement of the heart). AF occurs primarily due to an altered function of the ion channels located in heart cells. These ion channels are responsible for the initial depolarization and repolarisation of the cells.

The molecular and cellular changes causing and maintaining AF in the equine atria have not previously been investigated. To date the medical treatment of AF in horses is limited (to a single drug, oral quinidine, which is used regardless the timeframe of the disease in individual horses). In human medicine, research and development of new drugs have led to a much more nuanced treatment protocol taking sex, age, time of disease onset and any other underlying cardiac disease into consideration. Our research in equine AF contributes significantly to develop a more nuanced, effective and safe treatment protocol for horses suffering from AF.

Furthermore, animal experimentation of atrial fibrillation is predominantly done on small animals as rats, dogs and pigs, which have limitations in the context of large animals (including human) as large animals have slower heart rates, hence a different ion channel distribution compared to smaller animals. Studies in horses may therefore provide us with some new insights into atrial fibrillation, not only in horses but also in humans.

Perspectives of the research

Expand the research project and potentially use the horse as a model for human atrial fibrillation. Increase understanding of AF in horses and hopefully develop a more specific treatment of the disease in the animals. 

Partners on the project

  • PhD student Eva Zander Hesselkilde, Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen.
  • PhD student Maria Haugaard, Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen.
  • PhD student Helena Carstensen, Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen.
  • Associate Professor Thomas Jespersen, Head of Laboratory of Membrane Protein Physiology, Department of Biomedical Sciences, Laboratory of Experimental Cardiology, Faculty of Health and Medical Sciences, University of Copenhagen.
  • Associate Professor Jørgen Kanters, Department of Biomedical Sciences, Laboratory of Experimental Cardiology, Faculty of Health and Medical Sciences, University of Copenhagen

 Illustration of ECG showing atria fibrillation (AF) in a horse

Fig. 1. ECG showing atria fibrillation (AF) in a horse