A vertebral heart score (VHS) is a measurement used to determine if a patient’s heart is enlarged.
The VHS can provide valuable insight to complete your clinical picture, especially at times when you hear a heart murmur, for a general pre-anesthetic check, or to look for cardiac changes on breeds that are predisposed.
It’s a simple, non-invasive way to get more information and to monitor for changes over time.
How to calculate a vertebral heart score
Obtain a high-quality lateral thoracic radiograph. Be sure…
To collimate.
That the patient is straight and not twisted or at an angle.
That you can see enough detail, especially the thoracic vertebrae and the borders of the cardiac silhouette.
Make your first measurement along the longest axis of the cardiac silhouette, from the ventral border of the carina of the mainstem bronchus to the apex of the cardiac silhouette.
You don’t need to measure this in centimeters or inches—instead, just hold up a sheet of paper to your x-ray viewer and make a mark for your measurement, or use calipers. Or, with your digital x-ray system, use the VHS function to mark the measurement right on your screen.
Now, hold the measurement up to the vertebrae, starting with the cranial edge of T4—this is the 4th vertebra to have a rib connected. Count the number of vertebrae (including the vertebral body and the following disc space) that fall into the long axis measurement.
Measure to a decimal place of 0.1 (for example, let’s say your first measurement was 5.2 vertebrae).
Make your second measurement. This time, you’ll measure along the short axis, which is the widest part of the cardiac silhouette. It should be perpendicular (at a 90-degree angle) to your first measurement.
Repeat the process of transferring this measurement to the thoracic vertebrae, starting with the cranial edge of T4. For this example, let’s say your measurement was 4.5 vertebrae.
Add these two numbers together.
In this example, your VHS would be 5.2 + 4.5 = 9.7
How to interpret the results
For dogs, a normal vertebral heart score is less than 10.7 (with an average range of 8.5 to 10.5). For cats, an average VHS is 7.5 (with a range of 6.8 to 8.1).
Anything larger than that is considered abnormal.
Of course, this doesn’t tell you exactly what’s going on—you’ll need further information such as an echocardiogram to determine whether there is DCM, HCM, or some other issue causing the enlargement of the cardiac silhouette.
However, the VHS is a great screening tool to let you know to investigate further. And, if you have a patient who already has cardiac disease, a VHS can help you monitor their disease progression over time, and provide tangible information to a client who wants to know how their pet is doing on treatment.
Keep in mind that, as with any diagnostic tool, there is some individual variation. Some pets—especially certain breeds such as boxers—may fall outside the normal VHS range even if they’re completely healthy.
So, look at the overall clinical picture when assessing a patient. But with that in mind, a VHS is a quick, easy, valuable addition to your toolkit when it comes to evaluating and monitoring cardiac health.
Vetebral heart score tool video
Disclaimer: This article is for general informational purposes only, and not intended as a guide to the medical treatment of any specific animal.
Written by: Dr. Tammy Powell, DVM
