Science / Medicine : Cardiomyopathy Links Studied

The inherited form of a rare heart disease known as cardiomyopathy may be far more common than medical researchers believe, according to researchers at the Mayo Clinic and the University of Michigan. They reported last week in the New England Journal of Medicine that, in at least 20% of the cardiomyopathy cases they studied, other close family members had the condition as well. Previous studies have suggested that the illness is inherited in only 6% to 9% of cases.

The results may help doctors understand the cause and natural history of inherited cardiomyopathy, in which the heart muscle gradually deteriorates. The disease strikes about four out of every 10,000 people. For many sufferers, the only chance of survival is a heart transplant.

In a study led by Dr. Virginia V. Michels at the Mayo Clinic in Rochester, 59 patients and their 315 relatives--including parents, siblings and children--were examined between 1987 and 1989. Twelve of the 59 had at least one affected relative, indicating that the disease was inherited in at least 20% of the cases. The rate might be even higher because the researchers were not sure if the cardiomyopathy was inherited in another 23% of the cases.