Comparison of Polar 810 s and an Ambulatory ECG System for RR Interval Measurement During Progressive Exercise

Abstract

Ambulatory heart rate monitors and clinical electrocardiographic (ECG) devices are capable of measuring the length of consecutive cardiac periods (RR intervals). The aim of the study was to assess the agreement between the Polar 810 s heart rate monitor (Polar) and the Reynolds digital ambulatory ECG using Pathfinder software version 8.4 (Reynolds v8.4) during cycle ergometry. For this purpose, eight subjects completed incremental cycling exercise that began at 60 W and increased by 30 W each 2-minute period until volitional fatigue. Simultaneous recording of the ECG (Reynolds Pathfinder), RR interval (Polar), and respiratory parameters (Metamax 3B) were undertaken at rest and throughout the exercise period. No significant differences were found in RR intervals measured by Polar and Reynolds v8.4 at any relative intensity. Polar and Reynolds v8.4 displayed strong linear relationships at all relative intensities (r² = 0.927 to 0.998). Bland and Altman analyses between Polar and Reynolds v8.4 consistently demonstrated minimal bias in absolute RR interval (< 0.10 ms) and the limits of agreement for group differences in RR interval and heart rate were less than ± 10 ms and ± 2 beats · min^-1 for all relative intensities, respectively. Power spectral analysis provided similar results for both systems in all bandwidths studied during rest and low intensity exercise. However, significant differences and large relative limits of agreement (> 100 % of mean of paired means) were identified in UF at intensities > 40 % V·O_2max, HF at intensities > 60 % V·O_2max and LF during exercise at 80 - 100 % V·O_2max. These findings demonstrate that RR intervals and heart rate measurements obtained using Polar and Reynolds v8.4 are in good agreement. However, caution should be exercised when interpreting spectral analysis of RR interval data derived from different acquisition systems during physical activity.

Key words

Heart rate monitor - power spectral analysis - ambulatory - ECG - agreement

References

• 2 Anosov O, Patzak A, Kononovich Y, Persson P B. High-frequency oscillations of the heart rate during ramp load reflect the human anaerobic threshold.  J Appl Physiol. 2000;  83 388-394
• 3 Bland J M, Altman D G. Statistical methods for assessing agreement between two methods of clinical measurement.  Lancet. 1986;  1 307-310
• 4 Bland J M, Altman D G. Measuring agreement in method comparison studies.  Stat Methods Med Res. 1999;  8 135-160
• 5 Godsen R, Carroll T, Stone S. How well does Polar Vantage XL heart rate monitor estimate actual heart rate?.  Med Sci Sports Exerc. 1991;  23 14
• 6 Hedelin R, Wiklund U, Bjerle P, Henriksson-Larsen R. Cardiac autonomic imbalance in an overtrained athlete.  Med Sci Sports Exerc. 2000;  32 1531-1533
• 7 Karvonen J, Chwalbinska-Moneta J, Säynäjäkangas S. Comparison of heart rates measured by ECG and microcomputer.  Phys Sportsmed. 1984;  12 65-69
• 8 Laukkanen R MT, Virtanen P K. Heart rate monitors: State of the art.  J Sports Sci. 1998;  16 3-7
• 9 Malliani A, Lombardi F, Pagani M. Power spectrum analysis of heart rate variability: a tool to explore neural regulatory mechanisms.  Br Heart J. 1994;  71 1-2
• 10 Ruha A, Sallinen S, Nissila S. A real-time microprocessor QRS detector system with a 1-ms timing accuracy for the measurement of ambulatory HRV.  IEEE Trans Biomed Eng. 1997;  44 159-167
• 1 Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology . Heart rate variability. Standards of measurement, physiological interpretation, and clinical use.  Eur Heart J. 1996;  17 354-381
• 11 Thakor N V, Zhu Y-S. Applications of adaptive filtering to ECG analysis: Noise cancellation an arrhythmia detection.  IEEE Trans Biomed Eng. 1991;  38 785-794
• 12 Treiber F A, Musante L, Hartdagen S, Davis H, Levy M, Strong W B. Validation of a heart rate monitor with children in laboratory and field settings.  Med Sci Sports Exerc. 1989;  21 338-342
• 13 Yamamoto Y, Hughson Rl, Peterson J C. Autonomic control of heart rate during exercise studied by heart rate variability spectral analysis.  J Appl Physiol. 1991;  71 1136-1142