ANGIOTENSIN-CONVERTING ENZYME AND ANGIOTENSINOGEN GENE POLYMORPHISMS AND HEART-RATE-VARIABILITY IN TWINS

Decreased heart rate variability (HRV) is associated with congestive h eart failure, post-myocardial infarction, ventricular arrhythmias, sud den cardiac death, and advancing age. A deletion/insertion polymorphis m in the angiotensin-converting enzyme (ACE) gene and a substitution ( M235T) in the angiotensinogen gene have been associated with risk for heart disease. The aim of this study was to determine the heritability of HRV and related parameters in monozygotic and dizygotic twins and to assess the influence of ACE and angiotensinogen polymorphisms. We s tudied 95 MZ pairs and 46 DZ pairs. We measured HRV and related parame ters, ACE and angiotensinogen levels, plasma norepinephrine, ACE, and angiotensinogen genotypes. We found that HRV and related parameters we re significantly influenced by genetic variability, although nonshared genetic effects were also important. Angiotensinogen and plasma norep inephrine were generally correlated with decreased HRV, whereas ACE wa s correlated with perturbances of normal rhythmic HRV. Nevertheless, t he DD ACE genotype was associated with increased HRV (p <0.05), wherea s angiotensinogen polymorphisms had no effect. We conclude that HRV an d related parameters are in part heritable. Interestingly, the DD ACE genotype is associated with increased HRV. (C) 1998 by Excerpta Medica , Inc.