In this article, our vets in North Providence will explain when and why dogs and cats may need an electrocardiogram (ECG), and how to interpret the results to help you make informed decisions about your pet's health.
What is an ECG?
An ECG, also known as an EKG, is an abbreviation for electrocardiogram. This test is used to observe the heart's activity by attaching small sensors to the skin that monitor electrical activity. This non-invasive method is often used to monitor the heart in pets and humans.
What Does an ECG Tell Your Veterinarian About Your Pet?
An electrocardiogram (ECG) test provides important information about your pet's heart. It measures the rate and rhythm of the heartbeat and the electrical impulses passing through each section of the heart.
During an ECG, your vet will look for specific waveform patterns. These patterns include a small bump called the P wave, a large spike called the QRS complex, and another small bump called the T wave. The P wave represents the atria contracting, while the QRS complex shows the ventricles depolarizing (i.e., contracting). The T wave indicates that the ventricles are repolarizing.
Your veterinarian will look for the correct shape and distance between the various parts of the waveform. They will pay special attention to the PR interval and the QRS complex interval, which tell them how fast the heart takes blood and pumps it out.
The vet will also measure the distance between the peaks of the QRS complex. If the distance is constant, the pet has a regular heartbeat. If the distance varies, the heartbeat is irregular.
Finally, the vet will count the number of QRS complexes over a given time interval to determine the heart rate. Keep in mind that the rate and rhythm of cats and dogs can vary, so it's important to consult your veterinarian about what is normal 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
Cardiac murmurs, gallop sounds, and arrhythmias are some physical exam abnormalities that may indicate the need for an echocardiogram. Diastolic dysfunction is a common cause of these abnormalities in dogs and cats, and an echocardiogram is always necessary to confirm the diagnosis.
Arrhythmias, on the other hand, can be caused by a number of different factors, including both intracardiac and extracardiac diseases. An echocardiogram can help rule out primary cardiomyopathy and infiltrative cardiac disease as a possible cause of arrhythmia. Furthermore, an echocardiogram can help determine the most appropriate anti-arrhythmic therapy for the individual patient.
Breed Screening
Certain breeds of dogs and cats are more likely to develop heart disease due to their genetic makeup. In such cases, a thorough examination by a board-certified cardiologist may be necessary to identify any presence of a heart murmur. If a murmur is detected, then an echocardiogram is recommended for a comprehensive evaluation. Moreover, in some breeds, screening for heart disease through an echocardiogram is always recommended.
Thoracic Radiographic Changes
Radiographs can show cardiomegaly, which may be caused by cardiac enlargement, pericardial fat accumulation, or patient variability. An echocardiogram is the most specific tool available to determine the size of each cardiac chamber and identify the root cause of radiographic cardiomegaly. The echocardiogram is highly accurate in detecting congestive heart failure and pulmonary hypertension.
Feline Echocardiography
Cats can present a difficult case when it comes to heart disease. This is because they can have severe cardiomyopathy even when there are no physical exam abnormalities, radiographic changes, or clinical signs. An echocardiogram is the most appropriate diagnostic test that is specific and sensitive for heart disease in cats. Purebred cats are at a higher risk of heart disease, making echocardiographic evaluation a high-yield diagnostic tool in these patients. If a heart disease is suspected following the echocardiographic evaluation, an echocardiogram is recommended to confirm the diagnosis and determine the patient's therapeutic needs.
Pre-Anesthetic Evaluation
Before placing a dog or cat under anesthesia, obtaining a complete understanding of the patient's cardiovascular status can be helpful.
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.