Accuracy boundary in heart rate variability analysis from solid state ambulatory recordings

Solid-state (SS) Holter recorders, being free from electromechanical noise sources, are expected to allow accurate estimates of heart rate variability (HRV) parameters. To verify this expectation, the authors evaluated four commercial SS systems: HP 43420B (HP), Marquette SEER (MRQ), Oxford 6000FD2 (OXF), and Reynolds ERAM (REY). Computer generated electrocardiogram (ECG) sequences having a different degree of RR variability were fed into each recorder and a set of time and frequency domain HRV parameters were estimated on annotated RR lists created by their respective processing units. Descriptive statistics of the estimation error of all parameters were computed for each system. The data show that for HP, MRQ, and OXF the accuracy of HRV measurements is essentially bounded by the error caused by the sampling frequency of the ECG signal. The REY system shows lower accuracy indicating that some extra noise sources affect RR measurements