Journal: Sensors (Basel, Switzerland)

Article Title: Investigation of Possible Sources of Electrodermal Activity in Surgical Personnel to Assess Workplace Stress Levels

doi: 10.3390/s24227172

Figure Lengend Snippet: Changes in EDA and ECG data during mental and physical exertion compared to the resting measurements.

Article Snippet: ECG data were analyzed using the Signal Processing Toolbox in MATLAB, specifically through the detection of peak values from which the heart rate was determined.

Techniques:

Journal: Nature Communications

Article Title: Distinct circadian mechanisms govern cardiac rhythms and susceptibility to arrhythmia

doi: 10.1038/s41467-021-22788-8

Figure Lengend Snippet: A . Schematic of 4-day laboratory session , with total sleep deprivation (TSD) and recovery nap on day 3 ( n = 14 individuals). B – F HR ( B ), HRV ( C ), and z-scored ECG parameter profiles under baseline (black) and TSD (orange) days (shading indicates + /−SEM), highlighting the profound impact of mistimed sleep on RR ( D ) and QT ( E ), but not PR seg ( F ). HR has been derived from the RR interval and is shown for clarity. At baseline, all parameters were rhythmic based on cosinor analysis ( P < 0.001). Individual traces were excluded from waveform analysis where data coverage fell <70% of the 5-min time bins; n (baseline/TSD) = 13/14 ( B ), 12/14 ( C ), 13/14 ( D ), 11/12 ( E ), 12/14 ( F ). Mean ECG parameters were quantified across a 4 h mid-night and mid-day (equivalent to the nap window on day 3) analysis windows on the baseline and TSD days (two-way RM ANOVA/Mixed model; n = 14 ( B , C , D , F ), 12 ( E )). G , H Under baseline conditions, LOWESS fit of ECG profiles ( G ) and cross-correlation ( H ; yellow: RR vs RR, blue: QT vs RR, orange: PR seg vs RR) revealed a significant phase delay in PR seg rhythm relative to that of RR (Gaussian fit with one-sample T test; n = 13, 11, 12, respectively). I Acute changes in RR were mirrored by a concordant change in QT, but not PR seg duration (ΔRR reflects z-scored difference in RR between sequential 5-min analysis bins; Δparam reflects the concurrent change in QT or PR). All data presented as group mean ± SEM; ns P > 0.05, ** P < 0.01, *** P < 0.001. bpm = beats per minute; std = standard deviation. See Supplementary Fig. for additional information; source data and statistical details are provided as a Source Data File.

Article Snippet: All ECG data were processed in MATLAB (R2018a; Mathworks, USA) using custom-written algorithms as described below.

Techniques: Derivative Assay, Standard Deviation

Journal: Nature Communications

Article Title: Distinct circadian mechanisms govern cardiac rhythms and susceptibility to arrhythmia

doi: 10.1038/s41467-021-22788-8

Figure Lengend Snippet: A Schematic of 6-day laboratory session with simulated day-shift (left) and night-shift (right) routines ( n = 7 individuals/group ). B , C ECG parameters recorded during mid-day (pink) and mid-night (green) showed a rapid reversal of RR and QT interval rhythms, but not that of PR seg in response to the switch to night-shift behavioral routine. Two-way ANOVA with repeated measures, colored asterisks indicate the difference from day 1. D Hourly binned z-scored group data and sinusoid fits from day- (orange) and night-shift (blue) conditions. Data presented as group mean ± SEM. E , F Timing (acrophase) of individual rhythm peaks relative to lights on (i.e., start of constant routine) ( E ) or external clock time ( F ). Asterisks indicate differences between groups (Watson–Williams test). * P < 0.05, ** P < 0.01, *** P < 0.001. Source data and statistical details are provided as a Source Data File.

Article Snippet: All ECG data were processed in MATLAB (R2018a; Mathworks, USA) using custom-written algorithms as described below.

Techniques:

Journal: Nature Communications

Article Title: Distinct circadian mechanisms govern cardiac rhythms and susceptibility to arrhythmia

doi: 10.1038/s41467-021-22788-8

Figure Lengend Snippet: A Rhythms in locomotor activity (LA, arbitrary units) and ECG-derived heart rate (HR), HRV, RR, QT, and PR seg parameters in mice (based on 5 days of recording; shading reflects + /− SEM; x axis black bar indicates dark phase; n = 10 mice). B – E Impact of LA and HR on ECG parameters. B Decreased LA during mid-night siesta (marked by an arrow in A ) was accompanied by a significant decrease in RR and QT intervals, but not in PR seg duration (2-h siesta period (black) vs preceding 2 h of activity (blue); two-way RM ANOVA). C Periods of LA followed by >45 min of complete inactivity were isolated and aligned to the cessation of activity (time 0). RR (yellow), QT (blue), and to a lesser extent PR seg (orange) showed a significant response to the activity which decreased over subsequent inactivity (two-way RM ANOVA, Dunnet’s post hoc, difference from t = 40). D Transient bouts of LA (preceded and followed by inactivity) caused a significant response in RR and QT interval lengths, but not PR seg (two-way RM ANOVA, Dunnet’s post hoc, difference from t = −5). E Acute change in RR (across 5-min analysis bins) was mirrored by concordant changes in QT, but not PR seg . F Representative body temperature profile recorded across a 9-h advance of the LD cycle (data are double plotted; shaded regions indicate periods of darkness). G The 9-h phase advance led to profound separation in RR (black) and PR seg (orange) interval rhythms. H Mean RR and PR seg intervals measured across dark (green) and light (pink) phases the day prior to shift (day 0) and equivalent times on the day of the shift (day 1; two-way RM ANOVA, n = 11 mice). I Misalignment of RR and PR seg rhythms in response to the shift in LD cycles disrupts the normal temporal relationship of the two parameters. Data reflect group mean PR seg /RR on the day prior to shift (black) and the shift day (blue). All data presented as mean ± SEM. ns P > 0.05, * P < 0.05, ** P < 0.01, *** P < 0.001. Source data and statistical details are provided as a Source Data File.

Article Snippet: All ECG data were processed in MATLAB (R2018a; Mathworks, USA) using custom-written algorithms as described below.

Techniques: Activity Assay, Derivative Assay, Isolation

Journal: Nature Communications

Article Title: Distinct circadian mechanisms govern cardiac rhythms and susceptibility to arrhythmia

doi: 10.1038/s41467-021-22788-8

Figure Lengend Snippet: A Typical ECG traces before (baseline) and after injection of caffeine and adrenaline. Animals displayed rapid tachycardia, typically followed by bradycardia and sinus pauses and/or premature complexes, with some progressing into bidirectional VT (bottom right). Vertical scale bars represent 0.5 mV and inset times are time from returning to the cage after injection. B Proportion of animals that display evidence of each stage of VT progression. At ZT12, all control animals (six of six mice tested) displayed robust evidence of bidirectional VT, compared to only one of six mice tested at ZT0. Only two of five αMHC CRE Bmal1 Fl/Fl mice displayed bidirectional VT at ZT12. * P < 0.05, ** P < 0.01, Chi-square. Source data and statistical details are provided as a Source Data File.

Article Snippet: All ECG data were processed in MATLAB (R2018a; Mathworks, USA) using custom-written algorithms as described below.

Techniques: Injection, Control