ECG Commonly Asked Questions

How can ECG recordings in practice be used to diagnose cardiac disease while at the same time generate additional income?

Because of the new hand-held technology, recording an ECG is a simple task. By using the ECG, the quality of veterinary care is markedly improved. Arrhythmias and conduction disturbances can be quickly diagnosed and promptly treated. Hand-held units allow you to make a diagnosis quickly, and being portable you can easily perform the test in the exam room with the owner. If abnormalities are noted, the ECG can be printed and faxed for a telemedicine consult. You can easily pay for the ECG machine and generate additional income. A small screen ECG fee of $20-$25 can be charged since the tests is so easy to do. Considering how common heart disease is in dogs and cats, I would estimate that most veterinary practices should be running at least one ECG daily.

Does the ECG need to be recorded in right lateral recumbancy?

No. The position of the animal is not critical for analyzing abnormalities in cardiac rhythm and AV nodal conduction. Right lateral recumbency has been established as a standard procedure for recording the ECG. This positioning is not critical on the majority of ECG's that are done in veterinary medicine. Right lateral recumbency is only critical for recording the ECG when the size of the complexes and "mean electrical axis" are used to determine heart chamber enlargement patterns and to assess for interventricular conduction disturbances. The ECG however is not the most sensitive or specific test for heart enlargement and should be used mainly for rhythm evaluation. The best way to determine heart enlargement in animals is with a chest X-ray or echocardiogram! This is why the hand-held ECG technology is so useful in veterinary medicine. The electrocardiogram can be recorded and an accurate rhythm diagnosis obtained with the animal standing or sitting, on the floor, table or in the cage.

I have trouble recording and eCG on a cat; what can I do?

With cats, you may find that the ECG complexes are very small and the unit may not display the heart rate. This is a common occurrence in cats and is seen with all equipment including hand-held technology. It is first important to check that the cause is not actual fluid in the chest cavity. Other factors that can cause this small signal are obesity or poor electrode contact. With the hand-held ECG technology, the unit can be positioned in a different direction on the chest wall and sometimes this can make the complexes larger based on how the electrodes are aligned on that particular case. In many cases the complexes are actually increased in size with hand-held technology because the electrodes are actually in close proximity to the heart. The hand-held technology is also capable of recording all of the leads using actual electrodes that are attached to the animal's limbs. If the complexes are too small, all of the various leads should be recorded and in many cases, one of these leads will make it easier to see the complexes.

What is the best paper speed to record the ECG in veterinarian medicine?

The majority of ECG's are recorded at a paper speed of 25 or 50 mm/second. When the rate is rapid, as in cats, it often is desirable to record the ECG at a paper speed of 50. Even when the rate is not fast, it is often helpful to record a small portion at 50 mm/sec to make it easier to evaluate the complexes.

Why are the complexes on some of my hand-held recordings upside down complexes?

It is not uncommon with the hand-held recording to have complexes that have a negative polarity as the hand-held recording is actually recording in many cases a precordial chest lead, very similar to what is done when the fifth precordial chest lead of a ECG cable as positioned over the top of the heart on the left side. Precordial chest leads are quite useful as the complexes are often increased in size and are often easier to determine P-QRS complexes even though the complexes may be "upside down." Remember, primary focus with the ECG is heart rate, analyzing any arrhythmias, and also conduction analysis. To determine if the heart is enlarged, the chest X-ray or the ultrasound study is the most accurate test.

I'm in a large animal practice -- Are hand-held units useful in horses?

Yes. One advantage of the hand-held units in large animal practice is the portability. They are small and battery operated, so you can easily bring them into a barn, field, or racetrack and obtain an ECG. This can be quite useful for a horse that quits in a race or during training and you suspect a transient arrhythmia. Immediately after a race or training period, the hand-held unit can be placed on the horse's chest and the rhythm observed. Any abnormalities can be saved and printed for further analysis.