ARVC/ARVD family screening page

Research at St.Georges Hospital Medical School, London. U.K.

Arrhythmogenic Right Ventricular Cardiomyopathy

Current research at St.Georges Hospital Medical School and other international centres is trying to establish the cause of arrhythmogenic right ventricular cardiomyopathy.

The disease causes fatty replacement of the heart muscle. Originally when it was first recognised the disease appeared to affect only the right side of the heart and was therefore called right ventricular.

However, as more has become known about the disease over 40% of cases either at post-mortem or clinically have areas of left sided involvement also.

The gene responsible for causing this is still unknown.

There is however, a definite genetic basis to the disease. Within families with ARVC/ARVD several members of a family are seen to have the disease. The inheritance pattern that is seen is mainly autosomal dominant. That means that when we draw a family tree we can see that the disease is passed from one generation to the next with a 1 in 2 chance.

Studies have gone on to then look at linkage to further the knowledge of a genetic basis to try and find the gene. With linkage DNA is analysed from affected individuals within a family with ARVC to known chromosomal markers. The chromosomal markers are a map of the human genome. If we find people within a family with ARVC all have a particular gene map in common this is the area that we would focus upon as causing ARVC.

So far using these techniques several chromosomal locations causing ARVC are known. These are

  • 3p25 From a large Canadian Pedigree with lod score 5

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    We would like to identify more families with ARVC at St.Georges Hospital London, UK. To be able to find a gene for a disease linkage assessment requires 8-10 affected people within a family. Work is continuing in this vain so that we may understand ARVC more fully and eventually have more powerful therapies.

    Screening involves several tests, which are all non-invasive. The tests then have a score assigned to each of them to see if people fulfil diagnostic criteria for ARVC.

    There are several categories of tests (see below):

    1. Global and/or regional dysfunction and structural alterations of the right ventricle. Assessment is with echocardiography, or MRI.
    2. Tissue characterisation of the ventricular wall to look for fat either a biopsy or MRI is done
    3. Repolarisation abnormalities are looked for in the ECG these are inverted T waves in the precordial leads
    4. ECG depolarisation abnormalities these are either epsilon waves or incomplete right bundle branch block on the ECG, or late potentials on signal averaged electrocardiography
    5. Sustained or non-sustained left bundle branch block ventricular tachycardia an abnormal heart rhythm either on exercise testing or on 24hr tape recording
    6. Family history either post-mortem or clinical

     

    To see examples of these tests please see the ARVC web page:Click here

    From each category a score is assigned. If an individual has either 2 Major, One major and two minor, or four minor criteria they fulfil the diagnostic score for ARVC.

    It is important that all the tests are done in screening as a score of only two abnormalities may detect cases. Also perhaps more importantly screening should be done at a cardiac centre where cases of ARVC are seen frequently. The reason for this is that people having all the tests done have missed cases of ARVC, as the results are misinterpreted by inexperience.

    Page created by Dr.Mark Norman of St.Georges Hospital Medical School. The views expressed are those of Dr.Norman and not of St.Georges Hospital.

    ยท Any comments e-mail to mnorman@sghms.ac.uk
  • See Discussion forum for ARVC at http://www.med-edu.com/HyperNews/patient/get/arrhythmias/ARVD.html

    For work on hypertrophic cardiomyopathy click here

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