DCM – Update September 2012

I have looked through all the data from our Danes so far and the summary is as follows:

  • 130 Danes have had some form of screening – 125 Danes have had full echo. Of these:
    • 24 have been definitively diagnosed with DCM (18%)
    • 14 are considered likely to develop DCM in the future (11%)
    • 54 are equivocal (42%)
    • 32 are considered normal (25%)
    • 1 has been diagnosed with a congenital heart defect
    • Overall prevalence in this population may be about 30%
  • Data from 103 dogs was analysed based on a scoring system for DCM, where a score of 6 or more was considered to indicate DCM. Of these dogs:
    • 37 scored 6 or more. If these scoring system holds true, then the prevalence of DCM could be as high as 36%.
    • 38 dogs have returned for a repeat scan (5 dogs have had 3 scans, 1 has had 4)
    • Approximately 30 dogs have had Holter monitors
    • Data from a number of these dogs has been analysed and this shows that ventricular arrhythmias occur in dogs with DCM, that dogs with ventricular arrhythmias go on to die suddenly, and that dogs with ventricular arrhythmias are found in lines with a high incidence of sudden death.
    • This is summarised in a scientific abstract presented at the American College of Veterinary medicine Forum in May this year.
  • Data from about 40 normal dogs have been used to produce updated reference intervals for the breed for scanning. Results include:
    • Mildly reduced pumping ability of the heart can be normal in Danes
    • Bitches and dogs have different sized hearts, which should be taken in to account when screening for DCM
    • This is soon to be published in a scientific journal, but this is not yet available for me to attach for your information
    • Post mortem data is available for 5 dogs. 4 of these dogs have fibrofatty infiltrate type dilated cardiomyopathy, usually reported in Dobermanns.

Just a note on the grouping:

1. In the first bullet point, the following rules apply:

a. A dog is considered to have DCM if they fit all criteria on a heart scan for DCM, in the absence of other disease. This includes dogs diagnosed with heart failure and dogs identified as having DCM on post mortem.

b. A dog is considered ‘likely’ to develop DCM if they have some characteristics on a heart scan (e.g. dilated heart, slightly reduced pumping ability) but they do not satisfy all the criteria for our diagnosis of DCM yet.

c. Dogs are considered equivocal if they have mild abnormalities for which it is not clear if these are ‘normal’ for the dog, or may be an early sign of DCM

d. Normal dogs are those with strictly no significant abnormalities. In this category we have taken in to account the data that shows that very mild reduced pumping ability can be normal. A lot of these dogs have been scanned more than once, but some are also young dogs and therefore they may not remain normal.

2. With reference to the scoring system, some dogs can score 6 on this scoring system but still be with our ‘likely’ or ‘equivocal’ groups based on our overall assessment of the scan.