The heart is triggered to beat by electrical impulses from the brain. If there is an interruption to this signal, the heart may cease to beat completely, with obvious consequences. More commonly, though, a patient will suffer from a condition that causes an irregular heartbeat, or arrhythmia.
We have classified arrhythmias within the acquired disease category, because this is thought to be the most common form. However, dogs with congenital heart disease or no underlying heart disease may also suffer from arrhythmias.
There are different types of arrhythmias, some of which are breed specific (see below).
In this illustration, the heart is beating irregularly as a result of an interruption to the impulses sent by the brain.
In some cases, the heart may simply cease to beat. In most cases, though, the heart will beat less effectively than it should, thereby reducing the volume of blood pumped around the body.
All breeds may suffer from different types of arrhythmia, but the following are known to be at higher risk: Cavalier King Charles, Pugs, Miniature Schnauzers, Boxers, German Shepherds, Dobermanns and Irish Wolfhounds.
The symptoms of arrhythmia are very variable. Some types will prevent the dog from carrying on any normal activity. Others lead to a sudden collapse from which the dog may or may not recover. If suffered long term, an arrhythmia may well lead to the symptoms of heart failure.
As with symptoms, the outlook for patients with an arrhythmia is highly variable. Dogs with an arrhythmia are at very much greater risk of sudden death. Having said that, specialist veterinary cardiologists are now able to treat certain types of arrhythmia by implanting a pacemaker, exactly as in people. There are also various drug therapies that may also assist in treatment.
Novartis Animal Health is dedicated to find solutions to the health problems that cats and dogs face.