Tissue doppler imaging in hypertrophic cardiomyopathy without left ventricular hypertrophy.
BACKGROUND
Diastolic function abnormalities determined by Doppler echo (especially those recorded by tissue velocity imaging) may be useful in determining carriers of an abnormal gene in hypertrophic cardiomyopathy who do not yet show clinical evidence of the disease.


METHODS
In a single extended family, seven carriers of a mutation involving the cardiac myosin-binding protein C gene who did not show any features of the disease on 2-D echocardiography were examined by 2-D, M-mode Doppler and tissue Doppler imaging. The results were compared with a group of eight aged-matched people from the same family who did not have the gene mutation or clinical evidence of the disease. In both groups, as well as measuring the basal posterior and anteroseptal walls, the entire left ventricle was inspected for localised hypertrophy.


RESULTS
Localised hypertrophy was absent from the left ventricle in both groups. There were significant differences in the tissue Doppler peak velocity measurements made at the lateral border of the mitral annulus in systole and especially early diastole. A systolic velocity of <10 cm/s was strongly suggestive of gene positivity and, if combined with an early mitral diastolic velocity (mitral E velocity) of <14 cm/s, was present only in gene-positive individuals. If the mitral E velocity was >14 cm/s, this was present only in gene-negative patients.


CONCLUSIONS
Tissue Doppler imaging may be a valuable tool for screening first-degree relatives of patients with hypertrophic cardiomyopathy who do not show 2-D echo evidence of the disease.
McTaggart
Donald R
DR
Launceston, Tasmania, Australia. dmctagga@netspace.net.au