Sometimes, your vet will need to monitor the function of your pet's heart. This can be for a number of reasons. In this post, our Crystal Lake vets will discuss ECGs for dogs and cats, what they show about your pet and when they may be needed.
What are ECGs for pets?
An ECG, or as it is sometimes called an EKG, stands for electrocardiogram. This diagnostic test is used to monitor the function of the heart. Little sensors are attached to the skin and they monitor electrical activity to give a representation of what the heart is doing. This is a non-invasive way of observing the heart in pets and people.
What Does an ECG Tell Your Veterinarian About Your Pet?
There are a few different things that an ECG can tell your vet about how your pet's heart os working. It gives the rate and the rhythm of the heartbeat along with an understanding of the electrical impulses that are going through each section of the heart.
A normal dog or cat ECG will consist of a pattern where it will be a small bump that rises up that is 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 where the ventricles depolarize (The large contraction of the heart that is the typical heartbeat). And The T wave in the ventricles is repolarizing.
Your vet will look at the overall shape of each wave and the distance or timing between them. Often the concerns are the information provided by the PR interval 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 information is to look at the peaks of the QRS complex (the big spike) and measure the distance between them. If they are a constant distance between the spikes you have a regular heartbeat if they vary in the distance you have an irregular heartbeat.
Last but not least you can read how many QRS complexes there are and calculate how many there are over a time interval and you will have the heart rate.
Are ECG Safe
Yes, ECGs are an incredibly safe diagnostic method. ECG is a non-invasive diagnostic test that passively monitors the heart.
When would dogs and cats need an ECG?
Some of the times when your vet may order an ECG for your cat or dog include:
Abnormal Cardiovascular Physical Exam
Cardiac murmurs, gallop sounds and arrhythmias are some obvious physical exam abnormalities that are clear indications for an echocardiogram. This can often be an indication of diastolic dysfunction and an echocardiogram is always warranted when this occurs in dogs and cats. Arrhythmias can be caused by intracardiac or extracardiac disease. An echocardiogram helps rule out primary cardiomyopathy and/or infiltrative cardiac disease that may explain the arrhythmia. The echocardiogram also helps to determine appropriate anti-arrhythmic therapy for the individual patient.
Breed Screening
Depending on the breed, some pets have a predisposition to heart conditions. In some cases, auscultation by a board-certified cardiologist is indicated to rule out the presence of a murmur. If a murmur is auscultated, then an echo is indicated for a complete evaluation. In some breeds, however, an echo is always indicated to screen for heart disease.
Thoracic Radiographic Changes
Cardiomegaly noted on radiographs can be due to cardiac enlargement, pericardial fat accumulation, and/or patient variability. An echocardiogram is the most specific tool for determining the size of each cardiac chamber and is a very useful tool in delineating a cause for radiographic cardiomegaly. The echocardiogram is highly specific and sensitive for congestive heart failure and pulmonary hypertension.
Feline Echocardiography
Cats can be particularly challenging cardiology patients because they can have severe cardiomyopathy despite the absence of physical exam abnormalities, radiographic changes, and/or clinical signs. An echocardiogram is often the only appropriate diagnostic test that is both specific and sensitive for heart disease in cats. Purebred cats have a higher incidence of heart disease, and therefore echocardiographic evaluation is often high yield in these patients. If this test results in suspected heart disease, an echocardiogram is recommended in these patients to confirm the presence of heart disease and determine the therapeutic needs of the patient.
Pre-Anesthetic Evaluation
Before placing a dog or cat under anesthesia, it can be helpful to obtain a complete understanding of the patient’s cardiovascular status.
How much is an ECG for a dog or cat?
The cost of ECGs, like other diagnostic tests, depends on a number of factors. These include but are not limited to the location of the clinic, the veterinarian, the type of pet and more. Speak with your vet about an estimate for the cost of your pet's diagnostic testing.
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.