You have probably heard of the EPIC study, maybe even read it but do you really know what it means for you and your patients?
The EPIC study
The EPIC (Evaluation of Pimobendan in dogs with Cardiomegaly) study is the largest of its kind to date with 360 dogs included. The conclusions of the study were as EPIC as the name; pimobendan was shown to extend the asymptomatic period by around 15 months in dogs with cardiomegaly related to Mitral Valve Disease (MVD) and they also lived longer compared with the placebo group.
The first step to identifying whether a dog with a murmur would benefit from pimobendan is describing the murmur. Murmurs associated with MVD are typically most intense on the left side and focal over the mitral region (left apex). Dogs exhibiting a murmur of grade 3 or above are most likely to exhibit cardiomegaly. In these cases, it is recommended to perform further investigation to assess this.
The next step is to identify whether there is concurrent cardiomegaly. You can either perform a lateral thoracic radiograph and/or cardiac ultrasound (echo) to check the heart for enlargement. If a radiograph is obtained, the Vertebral Heart Score (VHS) is used to measure the heart. A VHS of ≥11.5 will benefit from treatment with pimobendan, a VHS of <10.5 should be reassessed in 6-12 months and a VHS of 10.5-11.5 should be examined further via echocardiography to determine the presence or absence of cardiac enlargement.
Why is echocardiography prefered?
The advantage of preferentially performing echocardiography over radiography is that it allows for more detailed examination of the heart and there is no requirement for borderline patients to undergo additional radiographic examination to complete assessment. A canine patient with a left atrial:aortic (LA:Ao) ratio ≥1.6 will benefit from treatment with pimobendan. A canine patient with a normalised left ventricular internal dimension in diastole (LVIDDN) of ≥1.7 would also benefit from treatment with pimobendan. If neither are enlarged, but a murmur (Grade 3 or higher) is present, then a repeat examination in 6-12 months’ time is recommended.
Pimobendan is only licensed for use in dogs with MVD once there is evidence of cardiomegaly.
These measurements are simple to perform and can be achieved even with a basic black and white ultrasound machine and micro-convex probe in most cases. Many people think Doppler function in combination with a phased array probe is needed to get started in the world of cardiology, but even without these you can make a huge difference to your patients. The only thing holding most people back is confidence! Learning to obtain basic right-sided echocardiography views is quick and easy. If you would like to know more and learn how to perform them, please see our link below for information on our cardiology CPD courses.
Boswood, A. et al. (2016) Effect of Pimobendan in Dogs with Preclinical Myxomatous Mitral Valve Disease and Cardiomegaly: The EPIC Study—A Randomized Clinical Trial. Journal of Veterinary Internal Medicine, 30, 6:1765-1779.
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