Why do vets recommend electrocardiograms (ECG)?

The decision to perform an ECG is often arrived at after a thorough physical exam of your pet. Some of the important reasons for performing an ECG include:

1. A heart rhythm that may not be clear during your pet’s physical exam.

2. An Irregular heartbeat (cardiac arrhythmia) - An irregular heartbeat is brought about by an abnormal pattern of electrical activity in the heart muscles. Any variation from the normal heart rate or rhythm is considered an arrhythmia.

3. Heart murmur - A heart murmur is characterized by an abnormal sound caused by turbulent blood flow through abnormal heart valves or defective structures within the heart. A heart murmur can be detected when your vet listens to your pet’s heart with a stethoscope. The condition is not always caused by an abnormality in the heart. It can also occur when a dog is excited or engaged in physical activities that cause the blood to flow very fast across normal heart structures.

4. To monitor any side effects on the heart after certain medications are administered - Some medications can cause adverse reactions involving the heart, especially when the heart has an abnormality.

5. Your pet has been exhibiting respiratory symptoms - Poor exercise tolerance, shortness of breath, coughing, and fainting spells are important indications that your pet might need an ECG.

6. To monitor heart activity before and after general anesthesia - During an ECG, your vet can monitor your pet for adverse reactions to sedatives or anesthesia given during the procedure. Valuable information about the depth of anesthesia your pet is under can also be monitored. It is also possible for your vet to determine the pain level your pet may experience during surgery so appropriate adjustments can be made.

7. If your pet needs to undergo a procedure that needs general anesthesia, an ECG can help determine the presence of heart defects beforehand. Certain heart abnormalities can place your pet at risk for complications and even death while undergoing anesthesia and surgery.

8. To confirm the preliminary diagnosis of an imaging procedure - An ECG is often combined with chest x-rays and/or an echocardiogram (ultrasound of the heart) to confirm the initial diagnosis.

Heart Defects That Can Be Detected by an ECG

An electrocardiogram provides crucial information about cardiac health, integrity, and function.

1. Heart Rate - An ECG can reveal whether your pet’s heart rate is normal or if it’s beating too quickly or too slowly. A faster than normal heart rate is known as ‘tachycardia’. Some conditions in which tachycardia is a prominent symptom include atrial fibrillation and ventricular tachycardia. These problems are associated with fainting or advanced cardiac disease.

2. Heart Rhythm - Analysis of the ECG results can help identify the exact arrhythmia that is present and the likely underlying cause of the abnormal heart rhythm.

3. Heart size and abnormalities in the electrical impulses - There’s a difference in the electrical conduction between a normal heart and an enlarged heart. An ECG can detect abnormal conduction of electrical impulses. Changes in the size and structure of specific chambers of the heart can also be detected.

4. Congenital heart defects

5. Damage to the heart valves and/or pericardium

How an ECG is Performed on Dogs and Cats

An ECG is rarely performed while your pet is sedated or under general anesthesia unless used specifically for monitoring during these procedures. Otherwise, the test can be performed while your pet is awake.

While your pet is lying down on his side, electrodes are attached to his elbows, knees, and/or the chest wall. Sometimes, it may be necessary to shave the areas where the electrodes are attached to make sure that they’re in direct contact with your pet’s skin.

The entire test will just take a few minutes and your pet won’t feel any pain at all. Once the results are generated, your vet will analyze the results and discuss them with you. If there are certain concerns about the results, you may be referred to a veterinary cardiologist for more tests and treatments.

What is a Holter ECG?

A Holter ECG, or Holder monitor, is an ambulatory or portable cardiac monitor that is wrapped around a dog’s torso. It records heart activity for 24 to 72 hours. The results are then evaluated by a veterinary cardiologist. It’s worn like a halter, and your pet won’t feel any discomfort while wearing the Holter ECG. Most dogs continue with their daily routine without any problems or discomfort.

The Holter monitor is especially important for dogs that experience frequent fainting spells. It can show whether fainting is caused by an abnormal heart rhythm (arrhythmia). If your pet has been diagnosed with an arrhythmia, a Holter ECG can help determine the frequency and severity of the arrhythmia throughout the period it’s attached to your pet.

In a nutshell, an ECG for pets is only a part of a diagnostic plan that veterinarians perform when a cardiac irregularity is suspected. If you have any questions and/or concerns about the procedure, don’t hesitate to discuss them with your vet.

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