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Atrial fibrillation is the most common abnormal heart rhythm in dogs.
It is characterised by a very irregular rhythm and fast heart beat – a normal dog’s heart tends to beat between 80-120 beats/min, while a dog with atrial fibrillation can reach heart rates over 240-260 beats/min.
This rhythm is usually associated with significant heart disease and enlargement of the left or right atrium (small chambers in the heart), but rarely can also occur in giant breed dogs without any obvious heart disease.
Echocardiographic image of a normal dog. The left atrium is normal dimensions and the heart rate is within normal limits. LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.
Echocardiographic image of a dog with heart failure and atrial fibrillation with a very fast heart rate. LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.
The majority of dogs with atrial fibrillation however will be in heart failure and their survival time is directly worsened by the development of this rhythm.
Dogs affected by atrial fibrillation tend to show marked clinical signs: they are lethargic, exercise intolerant, sometimes they can have breathing difficulties and rarely may even collapse.
We know that controlling atrial fibrillation can improve the clinical signs and longevity of our patient. It is therefore important to treat atrial fibrillation appropriately from the time of initial diagnosis as this will give every dog the best chances.
Our cardiology team is actively involved in ground breaking clinical research that is taking place to better understand this rhythm and improve the outcomes for dogs with this condition. The results of our latest study showed that the best treatment strategy appears to be based on controlling the heart rate (slowing it down to values similar to normal and healthy dogs), as this will improve the survival time of the affected dogs. This is usually achieved with anti-arrhythmic medications, but it is not always easy. The study also showed that as well as improving the outcomes for our dogs affected with this atrial fibrillation, the medications used were safe.
We are currently leading an international multi-centre study to further investigate the impact of this rhythm on the quality of life and life expectancy of the affected dogs. It is expected that this study will revolutionise the way in which this condition is treated in dogs around the world, both improving their day-to-day lives as well as giving them longer at home with their families.
Fixed price package available for atrial fibrillation assessment – please contact us for details
For further information and to download a PDF document (329KB) of this study:
Retrospective Evaluation of the Effect of Heart Rate on Survival in Dogs with Atrial Fibrillation.