Spectral analysis of the ventricular repolarisation duration in 24-hour Holter monitoring: technical requirements and early results

The study examines the feasibility of measuring RT intervals in Holter ECG recordings in order to apply spectral analysis. To obtain a resolution of 1 msec in the RT measurements an oversampling procedure was first introduced and the precision of two algorithms for the detection of the maximum and the end of the T-wave were compared as a function of noise. Following this, spectral analysis was applied on RR and RT series measured on five 24-hour Holter ECG tapes. Both RR and RT spectra were characterised by two main bands at low (LF~0.1 Hz) and high (HF~0.25 Hz) frequency. Throughout the 24 hour period RT and RR spectra showed synchronous changing in power spectral distribution but with a different balance between LF and HF bands