Researchers found that the left ventricular ejection fraction was significantly higher and early diastolic velocities were significantly lower in those with the beta-myosin gene mutation, regardless of whether they had left ventricular hypertrophy.
Researchers determined a cut-off velocity of 13.5 centimeters per second (cm/sec) as being about 86 percent accurate in identifying individuals with the genetic defect. The combination of ejection fraction of greater than 68 percent and early diastolic myocardial velocity of less than 15 cm/sec was 100 percent specific and 44 percent sensitive in predicting affected genotype.
"Although velocity alone was not sufficiently sensitive as a sole diagnostic criterion, the combination of early diastolic myocardial velocity and ejection fraction was highly predictive of the gene mutation in individuals without overt manifestations of the disease," he says.
According to Robert Roberts, M.D., Don W. Chapman Professor of Medicine, Baylor College of Medicine, who wrote an accompanying editorial: "Familial hypertrophic cardiomyopathy is a most unusual and puzzling disease. The heart is supernormal and thus not infrequently seen in the most elite of athletes. It is treacherous since sudden death is often the first manifestation, yet elegantly clothed in deception since the defect is present from conception."
Roberts further notes that knowledge of genetics has advanced rapidly with at least ten genes for cardiomyopathy identified and over 150 mutations for the disease. However, there are several barriers to the clinical application of this knowledge.
"Multiple genes make screening individuals formidable in te
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Contact: Carole Bullock
carole.bullock@heart.org
214-706-1279
American Heart Association
3-Jun-2002