By: Asaf Dagan, DVM, Dip. ABVP specializing in canine and feline medicine,

Veterinary Center Ramat-Hasharon

What Is an Electrocardiogram (EKG, ECG)?

An electrocardiogram (EKG) is a diagnostic test that measures the electrical activity of the heart. It is non-invasive and not painful. The heart's electrical activity is detected by attaching small electrodes to the limbs of the dog or cat. The signal is then recorded and printed onto a specially marked paper to allow for specific measurements.The EKG is a great test for diagnosis of abnormal heart rhythms and also can be useful for identification of heart enlargement or certain drug effects on the heart. Therefore, it is indicated whenever heart rhythm problems are suspected or as part of a thorough evaluation of the heart function. 


What Does an EKG Reveal? 
An EKG is used to reveal abnormalities of heart rate and rhythm (arrhythmias). However it does not detect all heart problems. In fact, the EKG is actually a complementary examination to the physical exam, chest X-ray, blood pressure measurement and echocardiogram (ultrasound), which together comprise a thorough cardiac evaluation. It is important to remember that the routine EKG test is done at a vet clinic and lasts several minutes only. When there are sporadic or intermittent electrical disturbances of the heart, these may not be detected by a routine exam. In such cases, a Holter or Event monitor EKG, which are devices that are attached to the dog for home monitoring, is needed to diagnose the problem.


How Is an Electrocardiogram Done? 
Specialized equipment is required to obtain an EKG. The EKG is recorded with the pet either standing or lying on its right side. Clip or plate electrodes are attached to the pet's limbs and sometimes to the chest wall - the position of each wire is important and the operator must follow the guidelines carefully. The typical EKG recording is 30 seconds to two minutes in duration and results are immediately available. Many veterinarians read the results immediately, but in some situations, your veterinarian may seek consultation with a cardiology specialist. This can be accomplished by faxing the EKG to the specialist or by transmitting the EKG using trans-telephonic equipment. 


Is an EKG Painful? 
The EKG exam is noninvasive and is not painful. Some animals resent the restraint, clips or bands used to connect the EKG machine to the skin, but most do not seem to mind the procedure. 


Is Sedation or Anesthesia Needed for an EKG? 
Neither sedation nor anesthesia is needed in most patients. Some pets, though, may struggle and resent the brief restraint needed for the examination and may need sedation. However, in general, tranquilizers and sedatives should be avoided to reduce the drug influence on the heart.