In this post, our San Diego 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?
Electrocardiogram (ECG), also known as an EKG, is a test that measures the electrical activity of the heart. The non-invasive test monitors your pet's heart. Small sensors attach to the skin and monitor electrical activity to provide an image of the heart's activity.
What does an ECG tell your veterinarian about your pet?
An ECG tells your vet several things about your pet's heart. For one, it reads 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 occurs when the ventricles depolarize, or when the heart contracts in the typical 'heartbeat' rhythm. The T-wave represents the heart repolarizing (repolarizing just means the heart is undergoing a phase of relaxation and resetting its electrical state).
Your veterinarian will examine the wave's shape and measure the distance between its various parts. The P-Wave and QRS complex interval information is frequently of concern. These indicate the rate at which the heart takes in and pumps blood.
Knowing this is important because it directly affects a pet's overall health and well-being. A healthy heart delivers oxygen and nutrients to all parts of the body, allowing your pet to maintain proper organ function and energy levels. Additionally, a normal heart rate removes waste products from tissues, supports a strong immune system, and promotes optimal cardiovascular fitness.
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?
The normal rhythm for a canine ECG should be 60 to 170 beats per minute. The normal rhythm of a cat’s ECG 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 would a vet use an ECG?
Your vet may order an ECG for your cat in any of these circumstances:
Abnormal Cardiovascular Rhythm
Cardiac murmurs, gallop sounds, and arrhythmias are a few examples of obvious abnormalities that may necessitate an ECG. These are common symptoms of diastolic dysfunction in dogs and cats, and an ECG is always recommended in these cases.
Intracardiac or extracardiac disease can cause arrhythmias, and an ECG can help diagnose primary cardiomyopathy and/or infiltrative cardiac disease. The ECG also helps doctors determine the best anti-arrhythmic therapy for each patient.
Breed Screening
Many dog and cat breeds inherit heart disease. This disease commonly affects dog breeds such as the Doberman Pinscher, Great Dane, Boxer, and Cocker Spaniel, while it is more likely for American Shorthair, Persian, and Maine Coon cats to be diagnosed compared to other feline breeds.
Thoracic Radiographic Changes
X-rays can show enlargement of the heart or fat tissue around the heart. However, an ECG accurately measures the dimensions of each cardiac chamber and helps determine the cause of an enlarged heart detected in X-rays.
Feline Echocardiography
Cats with severe cardiomyopathy or other heart conditions may pose a particular challenge as cardiac patients, even if they show no outward symptoms. Cats frequently rely on an ECG as the only specific diagnostic procedure available to detect heart problems with sufficient sensitivity.
As heart disease is more common in purebred cats, an ECG evaluation is frequently advised to confirm the presence of heart disease and identify the patient's therapeutic requirements.
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 only. San Diego Bay Animal Hospital is unable to provide ECGs at this time.