Background. In myocardial infarction patients, heart rate-adjusted QT interval (QT), an electrocardiographic indicator of sympathetic balance, is prognostic for survival.

Low heart rate variability is associated with high risk of sudden death in myocardial infarction patients. This has been attributed to unfavorable autonomic cardiac control. In the present study, the predictive value of heart rate variability for sudden death, mortality from coronary heart disease, and from all causes was investigated in the general population, using brief electrocardiographic recordings. From 1960 to 1985, 878 middle-aged Dutch men, aged 40-60 years, were followed and repeatedly examined as part of the Zutphen Study. In 1985 the remaining cohort was extended to 885 elderly men, aged 65-85 years, and followed until 1990. Heart rate variability (standard deviation of duration of normal RR intervals) was determined from the resting 12-lead electrocardiogram. The 5-year age-adjusted relative rate of total mortality of men with heart rate variability of < 20 milliseconds (msec) compared with men with heart rate variability of 20-39 msec was 2.1 (95 percent confidence interval 1.4-3.0) in middle-aged men and 1.4 (95% confidence interval 0.9-2.2) in elderly men. Death from noncoronary causes, especially cancer, contributed significantly to this elevated risk. The association of low heart rate variability with sudden death or coronary heart disease mortality was less consistent. In conclusion, in middle-aged men and probably in elderly men, low heart rate variability is predictive of mortality from all causes. This suggests that low heart rate variability is an indicator of compromised health in the general population.

A mismatch of minor histocompatibility antigen HA-1 can cause GVHD in adult recipients of allogeneic bone marrow from HLA-identical donors. Prospective HA-1 typing may improve donor selection and identify recipients who are at high risk for GVHD.

These data indicate that in patients without intraventricular conduction defects and cardiac dysfunction, QTc prolongation measured from the standard electrocardiogram is a risk factor for sudden death independent of age, history of myocardial infarction, heart rate, and drug use. In patients with cardiac dysfunction, QTc duration is not related to the risk for sudden death.

The minor histocompatibility antigen (mHag) HA-1 is the only known mHag for which mismatching is correlated with the development of severe graft versus host disease (GvHD) after human leukocyte antigen-identical bone marrow transplantation. HA-1 was found to be a nonapeptide derived from an allele of the KIAA0223 gene. The HA-1-negative allelic counterpart encoded by KIAA0223 had one amino acid difference from HA-1. Family analysis with HA-1 allele-specific polymerase chain reaction showed an exact correlation between this allelic polymorphism and the HA-1 phenotype. HA-1 allele typing of donor and recipient should improve donor selection and allow the determination of bone marrow transplantation recipients with high risk for HA-1-induced GvHD development.