RR*QT coherence discriminates within situation-dependent, dual sympathetic drive to the heart in healthy young

The authors document, by opening regulatory loops using invasive manipulation, that the THM spectral fraction of beat-by-beat variability of the QT interval reflects in part sympathetic control to ventricles that can be separated from Bazell-like RR effects using RR^*QT coherence analysis. This finding holds promise for more pertinent evaluation of RR and QT spectra derived form Holter high resolution ECG, in terms of arrhythmia risk stratification in both myocardial infarction patients and non-cardiac subjects with stress-dependent sporadic rhythm disturbances