A comparison of photoplethysmography and ECG recording to analyse heart rate variability in healthy subjects

Abstract

Measures of heart rate variability (HRV) are widely used to assess autonomic nervous system (ANS) function. The signal from which they are derived requires accurate determination of the interval between successive heartbeats; it can be recorded via electrocardiography (ECG), which is both non-invasive and widely available. However, methodological problems inherent in the recording and analysis of ECG traces have motivated a search for alternatives. Photoplethysmography (PPG) constitutes another means of determining the timing of cardiac cycles via continuous monitoring of changes in blood volume in a portion of the peripheral microvasculature. This technique measures pulse waveforms, which in some instances may prove a practical basis for HRV analysis. We investigated the feasibility of using earlobe PPG to analyse HRV by applying the same analytic process to PPG and ECG recordings made simultaneously. Comparison of 5-minute recordings demonstrated a very high degree of correlation in the temporal and frequency domains and in nonlinear dynamic analyses between HRV measures derived from PPG and ECG. Our results confirm that PPG provides accurate interpulse intervals from which HRV measures can be accurately derived in healthy subjects under ideal conditions, suggesting this technique may prove a practical alternative to ECG for HRV analysis. This finding is of particular relevance to the care of patients suffering from peripheral hyperkinesia or tremor, which make fingertip PPG recording impractical, and following clinical interventions known to introduce electrical artefacts into the electrocardiogram.

Brain hypoactivation, autonomic nervous system dysregulation, and gonadal hormones in depression: A preliminary study

“…We also had a set of a priori ROIs and controlled for menstrual status (which significantly affects RRV [26]), thus increasing the power of our tests. Further, although using pulse oximetry to measure HF-RRV is not as sensitive or direct as acquisition via electrocardiogram, recent data support its use as a valid means of measuring HRV compared to ECG [24]. Also, our results are remarkably consistent with previous studies reporting activation in our ROIs, several of which are in the central autonomic network [23].…”

Brain structural thickness and resting state autonomic function in adolescents with major depression

“…A segment of 5 min was selected for analysis of HR and HRV, discarding 30 s each at the beginning and end of the recoding. Pulse-to-pulse intervals are a sufficient proxy for cardiac inter-beat-intervals (IBIs) and suitable for analysis of HR and HRV (Selvaraj et al , 2008; Lu et al , 2009; Gil et al , 2010). Readout of pulse oximetry data was automated in MATLAB to determine IBIs based on the built-in Siemens peak detection algorithm, as described in Gaebler et al (2013).…”

Resting-state high-frequency heart rate variability is related to respiratory frequency in individuals with severe mental illness but not healthy controls

“…Approximately seven minutes of data were collected in total, however, the first two minutes of data were removed to account for habituation to the imaging procedure. Pulse oximetry data offers an especially accurate approximation of interbeat intervals4950. Consistent with recommendations10, the raw pulse data was upsampled to 1000 Hz using spline interpolation to refine the pulse peak point to calculate HRV in ARTiiFACT51.…”