Temporal dispersion of ventricular repolarization phase and autonomic nervous system control: clinical and experimental evidences

Abstract- Sudden cardiac death (SCD) is the most dreadful complication of many cardiac diseases. No study has already investigated the myocardial temporal dispersion indexes as possible tools in stratifying the overall cardiovascular mortality in patients with coronary risk factors and preserved left ventricular systolic function. Method- We retrospectively compared the short-term (5-minutes) heart rate variability (HRV), QTe variability index ( QTeVI), QTp variability index QTpVI), calculated from q to T wave peak and Te variability index calculated from T wave peak to the T wave end (TeVI) in coronary risk factor deceased (n:10) or survived (n:94) patients in two years follow-up. Results- All of the QT variability indexes and the most of HRV spectral components coherence variables differed in the two subjects groups. Multivariate logistic regression analysis identified the increase of QTeVI, QTpVI, TeVI and the decrease of SDNN, lnTP, lnLF and lnHF, predicting cardiovascular mortality. Conclusions- In a population with common coronary risk factors and normal systolic function all temporal dispersion indexes and RR spectral analysis variable seem be a risk factors for cardiovascular mortality.