Holter Monitoring

A Holter monitor is a machine that continuously records the heart's rhythms. The monitor is usually worn for 24 - 48 hours during normal activity.

How the Test is performed?
Electrodes (small conducting patches) are stuck onto your chest and attached to a small recording monitor. Your pet carries the Holter monitor in a pocket or small pouch worn around his/her waist. The monitor is battery operated.

While your pet wears the monitor, it records their heart's electrical activity. You should keep a diary of your pet's activities while wearing the monitor. After 24 - 48 hours, you return the monitor to your pet's veterinarian office. The doctor will look at the records and see if there have been any irregular heart rhythms.

It is very important that you accurately record the symptoms and activities so that the doctor can match them with your Holter monitor findings.

How to Prepare for the Test?
There is no special preparation for the test. Your veterinarian will start the monitor. You'll be told how to replace the electrodes should they fall off or become loose.

Why the Test is Performed?
Holter monitoring is used to determine how the heart responds to normal activity. The monitor may also be used:

• To diagnose heart rhythm problems
• To diagnose arrhythmogenic right ventricular cardiomyopathy in Boxers (Boxer cardiomyopathy)
• To diagnose venmtricular arrhythmias in Dobermans with occult asymptomatic dilated cardiomyopathy
• To monitor efficacy of antiarrhythmic treatment

It may be used to diagnose:

• Atrial fibrillation/flutter
• Supraventricular tachycardia
• Palpitations
• Paroxysmal supraventricular tachycardia
• Reasons for fainting
• Slow heart rate (bradycardia)
• Ventricular tachycardia

Normal Results
Normal variations in heart rate occur with activities. A normal result is no significant changes in heart rhythms or pattern. The normal heart rate varies between 30 bpm (while sleeping) and 240 bpm (when exercising). Ventricular premature betas may occur but should be less than 100 / day.

What Abnormal Results Mean?
Abnormal results may include various arrhythmias. Changes may mean that the heart is not getting enough oxygen, or that the blood pressure drops.

The monitor may also detect conduction block, a condition in which the atrial electrical activity is either delayed or does not continue into the ventricles of the heart.

Risks
There are no risks associated with the test. However, you should be sure not to let the monitor get wet.

Considerations
Electrodes must be firmly attached to the chest so the machine gets an accurate recording of the heart's activity.

While your pet is wearing the device, avoid:

• Electric blankets
• High-voltage areas
• Magnets
• Metal detectors

It is very important for you to keep a diary of pet's symptoms. The diary should include the date, time of day, type, and duration of symptoms.