It is estimated that 10% of dogs experience some form of heart disease, and up to 35% of older dogs encounter valvular heart disease within their lifetime.
These statistics encompass a large variety of heart diseases that veterinarians are screening for during all routine visits for your pet. In a checkup, your veterinarian will listen to your pet’s heart to assess for any abnormal sounds, rate or rhythm, as well as any abnormal surrounding lung sounds. Unfortunately, other outward signs of heart disease are generally signs that the heart is failing, so early diagnosis, treatment and monitoring is critical.
A common abnormal heart sound your vet may identify is a ‘murmur’. A heart murmur is an extra sound generally occurring outside of the normal ‘lub dub’ heart sounds. A heart murmur in some cases can be considered normal or transient (particularly in cats, greyhounds or young animals), but is more often considered abnormal and your vet will recommend investigation.
Investigation of a heart murmur is through a heart ultrasound, called an echocardiogram. An echocardiogram allows the vet to examine the heart for the source of the murmur, which could include any anatomical abnormalities and/or abnormalities in blood flow (direction or speed).
Another potentially abnormal heart sound is an ‘arrhythmia’. A cardiac arrhythmia refers to an irregular heart rate or rhythm. Like murmurs, some arrhythmias can be considered normal (e.g. sinus arrhythmia), however many are abnormal and your vet will recommend investigation. Investigation of a heart arrhythmia is performed using an electrocardiogram (or ECG). Further testing is likely to be indicated depending on ECG findings.
Early diagnosis and intervention of heart disease is important as it is associated with significantly longer survival times in some diseases.
A classic example is with mitral valve disease, where starting treatment with the drug ‘pimobendan’ prolonged signs of congestive heart failure by 15 months (EPIC study, linked at the end).
Mitral valve disease initially presents as a heart murmur and is commonly seen in the Cavalier King Charles Spaniel and their crossbreeds.
The mitral valve separates the main chambers (atrium and ventricle) of the left side of the heart and in some dogs can become thickened and faulty, causing the heart to lose efficiency. This is concerning as inefficiency can lead to cardiac remodeling, where the heart atria can become enlarged due to increased internal pressures. Increased pressure within the heart can cause congestion in vessels that are entering the heart – ultimately leading to a condition known as congestive heart failure.
An echocardiogram can diagnose mitral valve disease. Specific measurements are taken and used to assist veterinarians in deciding the optimal time to start medical treatment. Treatment initially involves medications aimed to increase the hearts contraction efficiency (Pimobendan) as well as reducing pressures within and surrounding the heart. In early stages of mitral valve disease, medications may not be indicated, and regular monitoring will be recommended to identify the optimal time to commence treatment.
At Allambie Vet we have the ability to perform echocardiograms and ECGs on pets with murmurs or arrhythmias detected on physical examination. In rare or complicated cases, we will sometimes recommend a specialist cardiologist assess the case and perform further testing.
Heart awareness week is all about learning what might be going on inside your pet and what your veterinarian is doing to identify heart disease and help your pets to have a long and happy life. If you have any further questions, or would like to book a checkup, please contact the clinic.
Further reading: EPIC Study - https://www.epictrial.com/
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