DYNAMIC ANALYSIS OF VENTRICULAR REPOLARIZATION DURATION FROM 24-HOUR HOLTER RECORDINGS

Evaluation of the influence of the autonomic nervous system on the ven tricular repolarization duration was carried out using beat-to-beat an alysis of the time intervals between the peaks of the R and T waves (R Tm). After pre-processing of digitized Holter ECG's, auto and cross sp ectrum analyses were applied to heart rate and repolarization duration variability signals. Coherence analysis was used to assess the existe nce of common spectral contributions. The heart rate variability signa l was used as reference of the sympatho-vagal balance at the sinus nod e. It was found that, in normal individuals, the autonomic nervous sys tem directly influences the ventricular repolarization duration and th at this influence is qualitatively very similar to the one that modula tes the heart rate. Pathological alteration of these parallel autonomi c activities to the heart (on the sinus node and on the ventricle) mig ht cause uncoupling between depolarization and repolarization.