An ECG can be an important tool to keep track of your pet's heart health. In this post, our Columbia vets discuss ECGs for dogs and cats, when your vet will order one, and how to understand your pet's results.
What is an ECG?
An ECG, also called an EKG, is an acronym for electrocardiogram. In this test, little sensors are attached to the skin to read electrical activity. This reading then gives an accurate representation of what the heart is doing. This is a non-invasive way of observing the heart in pets.
What does an ECG tell your veterinarian about your pet?
An ECG tells your vet several things about your pet's heart. First and foremost, it gives the rate and rhythm of the heartbeat. It also gives them an understanding of the electrical impulses that are going through each section of the heart.
A typical ECG consists of a pattern: a small bump that rises up, called the P-wave, then a large spike upward, called the QRS complex, and then another small bump called the T-wave.
The P-wave represents the atria contracting. The QRS complex is when the ventricles depolarize, or the large contraction of the heart that is the typical 'heartbeat'. The T-wave represents the heart repolarizing.
Your vet will make sure the shape of the wave is correct, and also measure the distance between the various parts of the wave. Often, the concerns are the information provided by the P-Wave and the QRS complex interval. These tell how fast the heart is taking in blood and how fast it is pumping it.
The next major source of information is the peaks of the QRS complex and the distance between them. If there is a constant distance between the spikes, you have a regular heartbeat. If they vary, you have an irregular heartbeat.
What are normal cat and dog ECGs?
For a normal canine, the ECG should show a rhythm of 60 to 170 beats per minute. The normal rhythm of cats should be 140 to 220 beats per minute.
Are ECGs safe?
Yes, ECG tests are safe. ECG is a non-invasive diagnostic test that passively monitors the heart.
When an ECG be needed?
Some examples of when a vet may order an ECG are:
Abnormal Cardiovascular Rhythm
Cardiac murmurs, gallop sounds, and arrhythmias are some obvious abnormalities that may necessitate an ECG. These can often be an indication of diastolic dysfunction and an ECG is always warranted when this occurs in dogs and cats. An ECG can also help rule out primary cardiomyopathy and/or infiltrative cardiac disease, as well as help to determine appropriate anti-arrhythmic therapy for the individual patient.
Breed Screening
Many breeds of dogs and cats are genetically predisposition for heart disease, such as the Doberman Pinscher, the Great Dane, the Boxer, and the Cocker Spaniel. The Maine Coon, the Persian, the Ragdoll, and some American Shorthairs are all breeds of cats that are predisposed to heart disease.
Thoracic Radiographic Changes
Cardiomegaly noted on x-rays can be due to cardiac enlargement, pericardial fat accumulation, and/or patient variability. An ECG is the most specific tool for determining the size of each cardiac chamber and is very important in determining a cause for radiographic cardiomegaly.
Feline Echocardiography
Cats can be particularly challenging cardiology patients because they can have severe cardiomyopathy, or other heart diseases, despite having no clinical signs. An ECG is often the only appropriate diagnostic test that is sensitive enough for cats.
Purebred cats have a higher incidence of heart disease, therefore an ECG evaluation is often recommended to confirm the presence of heart disease and determine the therapeutic needs of the patient.
How much is an ECG for a dog or cat?
It's always best to contact your vet directly if you're curious about the cost. They should be able to provide you with an accurate estimate.
Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.