There are a lot of questions surrounding the issue of cardiac testing in the Boerboel world. A lot of phrases are thrown out and more breeders are doing some level of cardiac testing than in the previous years. I am writing this blog in hopes to help the average owner, breeders and prospective owner understand the differences between levels of testing and results. This is not to tell people what they should do or look for, I’m just providing information to help people decide what to do.
OFA Cardiac clear can mean many different things. OFA allows a dog to be certified clear with two different tests. I’ll describe the tests first, then the results and how the same result can get a different conclusion than another. There is also an additional test that is not OFA certified that I’ll explain.
Auscultation is listening to the heart. It is performed by a cardiologist putting a stethoscope to the dogs chest and listening for murmurs and rhythm. If nothing abnormal is heard, the cardiologist signs an OFA form stating the dog is clear.
Echocardiogram. In this process, the dog either stands or lies down while the cardiologist first listens to the heart and then performs a sonogram of the heart called an echocardiogram. This live image has color portions to it which will show blood flow through the valves and each artery. It measures heart rate, blood pressure, ect. It is a COMPLETE visual and measurement of the heart. Any structural issues will be seen, along with blood flow restrictions or excess.
A dog can have a normal auscultation with an abnormal echocardiogram. Why? Because not all structural abnormalities will cause a murmur or poor rhythm; and some murmurs may be so slight that they are difficult to hear.
OFA Echocardiogram results: One of three results will be given:
· Normal – the structure and blood flow of the heart is normal.
· Equivocal – there may be an abnormality in the structure or a slight flow problem, but the dog is not affected with a condition; or the condition is not considered an issue.
· Affected Grade I – VI Affected dogs are assigned a grade of the issue based on the sound of the murmur and severity of the affected area of the heart. A dog that has a high severity of malformation of the heart, will also have a highly audible murmur. A Grade I may barely be heard and need an echo for confirmation that there is a problem.
Can a dog have a slight murmur and a clear echocardiogram? Yes. Why? Because as with humans, we sometimes have unexplained heart arrythmia’s.
Interpretation: As with x-rays, an echocardiogram is subject to each cardiologist’s interpretation. For example: mastiffs are known to have some leaky heart valve issue that are not cause for concern. Cardiologist A may say “this is normal for mastiff’s, so he gets a normal report” Whereas Cardiologist B may say “this might be normal for mastiff’s, but it’s not a perfect heart”, therefore he gets an equivocal report. A cardiologist can also choose to give borderline results. For instance: A dog has a barely audible murmur; an echo shows a very slight narrowing of an artery, but the dog is not affected by it and it’s not at a Grade I. The cardiologist can give the dog a borderline equivocal/affected result. Therefore the result assigned can vary according to the cardiologist overall experience.
Non OFA testing: EKG’s are also being performed by some. An EKG measures the electrical currents of the heart, and whether there is a normal pattern. It can detect if the overall size and shape is abnormal, but not specific structural issues. I’ve included a link to the difference between an EKG and an ECHO.