A 17-year follow-up study of a family with idiopathic hypertrophic cardiomyopathy and WPW syndrome.

Long term clinical courses of a patient and her family with idiopathic cardiomyopathy and WPW syndrome were described. The mother and her brother (the first generation) had died of heart disease, and 1 sibling had also died suddenly of heart disease when the study began. Seven out of the 8 siblings (the second generation) were followed for 17 years from 1958 to 1976. The 4 siblings had both typical or atypical WPW syndrome and cardiomegaly in 1958, 2 of them died suddenly and unexpectedly, 1 of them died of congestive heart failure, and 1 of them did not have any complaint during the period. One was normal in 1958 but developed cardiomegaly and atypical WPW syndrome in 1976. The other 2 were normal in both 1958 and 1976. The 2 children of the second sibling (the third generation) were followed simultaneously for 15 years. Both had WPW syndrome without cardiomegaly. It was suggested that a late onset of the disease could occur in the family with young onset, that the clinical course might become different mainly by sudden cardiac death which occurred only in the members with abnormal findings, and that WPW syndrome and cardiomegaly could be inherited or occur together in the same generation but separately in the different generation.