What Is an Atropine Response Test in Dogs?
Sometimes a dog’s heart rate is slower than normal. When this happens, we need to find out why.
One simple test we may perform is called an Atropine Response Test.
The test helps us decide whether a slow heart rate is functional (nerve-related) or structural (heart-related), guiding the next step in treatment.
What is atropine?
Atropine is a medication that temporarily increases heart rate by blocking the influence of the vagus nerve (the nerve that can slow the heart).
Why do we use this test?
If your dog has:
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A very slow heart rate
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Suspected heart rhythm abnormalities
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Possible conduction problems (like AV block)
We may give a small dose of atropine (0.04 mg/kg) and monitor the ECG post injection.
What does it tell us?
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If the heart rate increases significantly: The slow heart rate may be due to high vagal tone (often reversible or physiological).
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If the heart rate does NOT increase much: This suggests a possible intrinsic conduction problem within the heart itself, which may require further evaluation.
