Large Dog Study: The Risk of Cardiac Death Can Be Predicted Early in Life – University of Copenhagen

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11 January 2018

Large Dog Study: The Risk of Cardiac Death Can Be Predicted Early in Life


Examinations of the heart’s pumping function among dogs aged one-three years can predict whether the dogs have an increased risk of dying from a heart disease later in life, a study conducted at the University of Copenhagen shows. The researchers also believe the research results are interesting in connection with heart valve disease in humans.

Maria Reimann examining dog

(Maria Reimann listening for leaks in the dog’s heart valve using a stethoscope)

For the sake of breeding it is important early in the dog’s life to identify any increased risks of developing diseases. This was done by researchers from the University of Copenhagen in a study conducted in cooperation with Odense University Hospital and the Swedish University of Agricultural Sciences.

The study has been published in the scientific Journal of Veterinary Internal Medicine. Here the researchers examined whether early signs of heart valve disease increases Cavalier King Charles Spaniels’ risk of developing myxomatous mitral valve disease later in life.

‘Moderate to severe leaks in the large valve in the left ventricle of the heart in young dogs increase their risk of dying from a heart disease. This risk also applies to dogs where the leak is only seen in some heartbeats, a phenomenon which previously was not considered significant. However, the death rate of dogs with minor leaks in the heart valve was not higher than in dogs with no leaks at all. It is the first time these findings have been shown in dogs this young’, says PhD Student Maria Reimann from the Department of Veterinary and Animal Sciences.

More than 1,000 Heart Examinations Conducted and Studied by a Few Veterinarians
The study has drawn on data from a total of 1,125 privately owned dogs examined at one point in the years 1996-2012. All dogs were examined before turning three. A lot of the dogs were examined in connection with a compulsory heart examination, and all the dogs were examined in the exact same way by only two veterinarians. In addition, all heart ultrasound recordings were subsequently studied by a single veterinarian, PhD Student Maria Reimann. The fact that so few veterinarians were involved causes less variation in the collected data.

Following the heart examinations of the young dogs the owners were contacted on the phone to learn whether the dog had died later on and, if so, what the cause of death was. Based on this data the researchers have discovered the increased risk of general mortality and of death due to heart disease.

Important New Knowledge to Many Dog Breeders and Dog Owners
The new knowledge can help veterinarians identify dogs with increased risk of cardiac death, and this is useful within breeding.

Furthermore, it can make it easier for veterinarians to advise owners of dogs with a risk of developing heart failure about which clinical signs to be aware of, just as it can make it easier to monitor the progression of the disease more closely. This will increase the chances of starting life-sustaining medical treatment at the right time.

About half of all Cavalier King Charles Spaniels have a leak in the mitral valve which can be heard in a stethoscope as a cardiac murmur at the age of six or seven. Luckily the existing Cavalier King Charles Spaniel heart breeding programme in Denmark has turned out to have a positive effect, reducing the number of dogs with a cardiac murmur. Myxomatous mitral valve disease is the most common heart disease in dogs, and the researchers also believe the results of the study can be used in connection with heart diseases found in other dog breeds than Cavalier King Charles Spaniels.

Believed Heart Contractility Was of Secondary Importance
The study also showed that if the contractility of the heart in the young dogs is substandard it increases the risk of cardiac death, even if the heart’s contractibility can still be considered normal.

’We were surprised to learn that the heart’s contractibility already at this age can be used to predict the dog’s risk of dying from a heart disease. In fact, we believed it to be secondary to the heart valve disease in later stages of the disease. But the finding supports the theory that myxomatous mitral valve disease involves not just the heart valve, but also the myocardium ’, says Professor with Special Responsibilities, DVSc Lisbeth Høier Olsen from the Department of Veterinary and Animal Sciences.

The research may also tell us something about similar diseases in humans. In humans suffering from the disease the heart’s pumping function does not always normalise following the implantation of a new mitral valve, and doctors are still trying to work out the optimal time of the procedure with regard to maintaining the function of the cardiac muscle.

The PhD study was funded by the Novo Nordisk LIFE In Vivo Pharmacology Centre (LIFEPHARM) and the heart examinations by the Danish Council for Independent Research, Medical Sciences.

Read the entire study: ‘Mitral regurgitation severity and left ventricular systolic dimension predict survival in young Cavalier King Charles Spaniels’