In this post, our Clackamas vets will discuss ECGs for dogs and cats, when your vet will order one as well as how to understand your pet's results so you can make the best decisions regarding their health care.
What is an ECG?
An ECG, or as it is sometimes called an EKG, stands for electrocardiogram. This is a test that is used to monitor 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?
An ECG provides important information about your pet's heart. It reveals the rate and rhythm of the heartbeat and shows the electrical activity in different sections of the heart.
In a typical ECG pattern, there is a small bump called the P wave, followed by a large spike called the QRS complex, and then another small bump called the T wave.
The P wave represents the contraction of the atria, while the QRS complex indicates the depolarization of the ventricles (the normal heartbeat). The T wave shows the repolarization of the ventricles.
Your vet pays attention to the shape and distance between the different parts of the wave. The PR interval and the QRS complex interval are particularly important, as they indicate how quickly the heart is receiving and pumping blood.
Another crucial aspect is examining the peaks of the QRS complex (the big spike) and measuring the distance between them. If the distance remains consistent, the heartbeat is regular; if it varies, the heartbeat is irregular.
Lastly, by counting the number of QRS complexes over a specific time interval, the heart rate can be calculated. It's important to note that the rate and rhythm can vary in cats and dogs, so consult your veterinarian for the expected values for your pet's breed.
Are ECG 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
Some examples of when a vet may order an ECG test are:
Abnormal Cardiovascular Physical Exam
If your pet has noticeable abnormalities during a physical examination like cardiac murmurs, gallop sounds, or irregular heart rhythms, it's a clear sign that an echocardiogram is needed. In dogs and cats, these abnormalities can often indicate diastolic dysfunction, which makes an echocardiogram necessary.
Arrhythmias, which can be caused by problems within or outside the heart, are another reason to consider an echocardiogram. It helps rule out underlying issues like primary cardiomyopathy or infiltrative cardiac disease that might be causing the arrhythmia.
Additionally, the echocardiogram assists in determining the most suitable anti-arrhythmic treatment for the individual patient.
Breed Screening
Many breeds of dogs and cats have a heritable predisposition for heart disease. 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 present a challenge in cardiology cases since they can develop severe cardiomyopathy even without noticeable physical exam abnormalities, changes on X-rays, or obvious clinical signs. In such cases, an echocardiogram is usually the most suitable and reliable diagnostic test for identifying heart disease in cats.
Purebred cats are more prone to heart disease, making echocardiographic evaluation highly valuable for these patients. If the initial test suggests the presence of heart disease, it is recommended to proceed with an echocardiogram to confirm the diagnosis and determine the necessary treatment for 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.
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.