There may be times when your vet will need to monitor the function of internal organs. Tests such as ECGs, which monitor the heart, help us to do this. Here, our Lacey vets talk about ECGs for pets, what they are, and how they help us to diagnose and treat conditions affecting your dog or cat.
What are ECGs and how do they help with treating 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 diagnostic tool allows us to gain valuable insight into the function of your pet's heart in a non-invasive manner.
What can we learn from an ECG?
An ECG provides us with a great deal of information about how your pet's heart functions. 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 ECGs Safe for my pet?
Yes, dog (canine) and cat ECGs are an incredibly safe diagnostic method. ECG is a non-invasive diagnostic test that passively monitors the heart.
When might my cat or dog need to have an ECG?
Some of the situations where your vet may request that your pet have an ECG 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.
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.
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.
Your pet will need to be placed under anesthetic for an ECG. This is to ensure that they remain still so we can get an accurate reading. Before placing a dog or cat under anesthesia, it can be helpful to obtain a complete understanding of the patient’s cardiovascular status.
We will also speak with you about the safety of your pet during anesthesia. This will include not allowing your pet to eat prior to their appointment in order to avoid complications.
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 only and Olympia Pet Emergency does not offer diagnostics using an ECG at the time this post was written.