Angiotensinogen and angiotensin II type 1 receptor gene polymorphisms and changes in repolarization parameters in elderly Chinese: a 4-year follow-up study.

Ventricular repolarization abnormality plays a crucial role in cardiac arrhythmia. Polymorphisms in renin-angiotensin system genes are associated with occurrence of ventricular arrhythmia. We previously demonstrated that subjects carrying the angiotensin converting enzyme (ACE) D-allele but not the angiotensinogen (AGT) M235T polymorphism had a higher magnitude of QT dispersion (QTd) prolongation. The aim of this study was to test whether the AGT [-6G > A] and angiotensin II type 1 receptor (AT1R) [1166A > C] polymorphisms influence repolarization parameters, including QTd and the peak and end of the T wave interval (Tpe). Of 1,500 people screened, 106 normotensive, non-diabetic participants aged > or = 60 were recruited. ECGs were recorded at baseline and in the second and fourth years. QTd and Tpe were manually calculated. Gene polymorphisms were analyzed by polymerase chain reaction. Mean age was 72.7 +/- 4.1 years (range, 62-81 years). QTd and Tpe were significantly prolonged in the second and fourth years (all p < 0.001). Neither gene polymorphism was associated with the magnitudes of QTd and Tpe prolongations. This longitudinal study shows that the AT1R [1166A > C] and AGT [-6G > A] polymorphisms do not influence repolarization parameters in this Chinese population in Taiwan, and so are not suitable markers to identify individuals susceptible to changes in these parameters.