NT-proBNP in the coughing dog: cardiac or respiratory?
11-year-old Yorkshire Terrier with a dry “honking” cough for weeks, worse when pulling on the lead. Grade 2/6 mitral systolic murmur, resting respiratory rate of 24 breaths/min and marked respiratory sinus arrhythmia.
| Parameter | Result | Reference |
|---|---|---|
| NT-proBNP | 420 pmol/L | < 900 (dog) |
| Heart rate | 110 bpm | 70–160 |
What is the most appropriate interpretation?
chevron_right Show answer and explanation
A. Furosemide should be started because cough in a dog with a murmur is heart failure
Many small dogs with mild MMVD cough because of tracheal collapse or chronic bronchitis. Giving diuretics without confirming oedema is a common mistake.
B. A normal NT-proBNP rules out any heart disease
The dog has a mitral murmur and probably MMVD. A low NT-proBNP indicates that the heart disease is not significant or causing the signs, not that it is absent.
C. Heart failure is an unlikely cause of the cough; the airway should be investigated
Correct. A low NT-proBNP has a high negative predictive value for congestive heart failure. Together with the normal respiratory rate and marked sinus arrhythmia (high vagal tone), it points towards tracheal collapse or bronchitis.
D. NT-proBNP is not useful in small breeds and should not be interpreted
It is useful in dogs of any size, especially to distinguish cardiac from respiratory cough or dyspnoea. Cut-offs depend on the laboratory, not the breed.
lightbulb Key takeaway
NT-proBNP is more useful for ruling out (low value) than for ruling in. A high value supports significant heart disease, but does not replace radiography or echocardiography. Sinus tachycardia and loss of sinus arrhythmia accompany heart failure; marked sinus arrhythmia makes it unlikely.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.