In this post, our Santa Clarita 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 (electrocardiogram) provides valuable insights about your pet's heart to your veterinarian. It reveals the heart's rate, rhythm, and the electrical impulses traveling through each section of the heart.
During a typical ECG, you'll notice a distinct pattern. It starts with a small upward bump known as the P wave, followed by a prominent spike called the QRS complex, and ends with another small bump called the T wave.
The P wave indicates the contraction of the atria, while the QRS complex signifies the depolarization of the ventricles, which represents the typical heartbeat. The T wave indicates the repolarization of the ventricles.
When analyzing the ECG, your veterinarian pays attention to the shape and distances between the various parts of the wave. They focus on specific data, such as the PR interval and the QRS complex interval. These measurements provide crucial information about how efficiently the heart is receiving and pumping blood.
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.
The rate and rhythm of cats and dogs can vary please consult your veterinarian about what are the expected values for your bread of pet.
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 exhibits noticeable physical exam abnormalities such as cardiac murmurs, gallop sounds, or arrhythmias, it is a clear indication for an echocardiogram. In both dogs and cats, the presence of diastolic dysfunction often warrants an echocardiogram to further investigate the issue. Arrhythmias, which can be caused by intracardiac or extracardiac conditions, also call for an echocardiogram.
This diagnostic tool helps exclude primary cardiomyopathy or infiltrative cardiac disease as potential causes of the arrhythmia. Furthermore, the echocardiogram assists in determining the most suitable anti-arrhythmic therapy for the individual patient.
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.
Diagnosing heart conditions in cats can pose challenges as they may have severe cardiomyopathy even without apparent physical exam abnormalities, radiographic changes, or clinical signs.
To accurately detect heart disease in cats, an echocardiogram is usually the most appropriate diagnostic test. It offers both specificity and sensitivity in identifying cardiac issues.
Purebred cats, in particular, have a higher likelihood of developing heart disease, making echocardiographic evaluation particularly valuable for these individuals. If heart disease is suspected based on the initial test results, an echocardiogram is recommended to confirm the diagnosis and assess the necessary treatment for the patient.
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.