Normalization of RR sequences: a new approach for quantitative assessment of heart rate turbulence by abnormal post stimulation response

In our previous studies (2000, 2001), we observed different patterns of abnormal post-ectopic sinus response. In some cases, the conventional heart rate turbulence (HRT) parameter, "turbulence slope" (TS), could not be correctly used. The normalization of RR sequences allows to estimate a rate-independent parameter, TS/sub nrm/. The aim of this study was to investigate the effect of normalization of tachograms and to define new descriptors of HRT which may predict the recurrence of ventricular tachycardia (VT) and ventricular fibrillation (VF) in implantable cardioverter-defibrillator (ICD) patients.