Effects of respiratory time ratio on heart rate variability and spontaneous baroreflex sensitivity

2013 ◽  
Vol 115 (11) ◽  
pp. 1648-1655 ◽  
Author(s):  
Yong-Ping Wang ◽  
Terry B. J. Kuo ◽  
Chun-Ting Lai ◽  
Jui-Wen Chu ◽  
Cheryl C. H. Yang
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Baroreflex Sensitivity ◽  
Sitting Position ◽  
Relative Timing ◽  
Paced Breathing ◽  
Time Ratio ◽  
Rate Asymmetry ◽  
Heart Rate Asymmetry ◽  
Spontaneous Baroreflex

Paced breathing is a frequently performed technique for cardiovascular autonomic studies. The relative timing of inspiration and expiration during paced breathing, however, is not consistent. We, therefore, examined whether indexes of heart rate variability and spontaneous baroreflex sensitivity would be affected by the respiratory time ratio that is set. We studied 14 healthy young adults who controlled their breathing rates to either 0.1 or 0.25 Hz in the supine and sitting positions. Four different inspiratory-to-expiratory time ratios (I/E) (uncontrolled, 1:1, 1:2, and 1:3) were examined for each condition in a randomized order. The results showed spectral indexes of heart rate variability and spontaneous baroreflex sensitivity were not influenced by the I/E that was set during paced breathing under supine and sitting positions. Porta's and Guzik's indexes of heart rate asymmetry were also not different at various I/E during 0.1-Hz breathing, but had larger values at 1:1 during 0.25-Hz breathing, although significant change was found in the sitting position only. At the same time, Porta's and Guzik's indexes obtained during 0.1-Hz breathing were greater than during 0.25-Hz breathing in both positions. The authors suggest that setting the I/E during paced breathing is not necessary when measuring spectral indexes of heart rate variability and spontaneous baroreflex sensitivity under the conditions used in this study. The necessity of paced breathing for the measurement of heart rate asymmetry, however, requires further investigation.

Spontaneous baroreflex sensitivity after coronary artery bypass graft surgery as a function of gender and age

2003 ◽  
Vol 81 (9) ◽  
pp. 894-902 ◽  
Author(s):  
C Ann Brown ◽  
Larry A Wolfe ◽  
Sylvia Hains ◽  
Glorianne Ropchan ◽  
Joel Parlow
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Analysis ◽  
Baroreflex Sensitivity ◽  
Artery Bypass ◽  
Bypass Graft ◽  
Artery Bypass Graft ◽  
Standing Posture ◽  
Cabg Surgery ◽  
Spontaneous Baroreflex

The effects of coronary artery bypass graft (CABG) surgery on spontaneous baroreflex (SBR) sensitivity and heart rate variability were examined in 11 women and 23 men preoperatively and 5 days postoperatively. Electrocardiograph R–R interval and beat-by-beat arterial blood pressure data were collected continuously for 20 min in the supine and standing postures. Coarse graining spectral analysis was performed on the heart rate variability data. Spontaneous baroreflex sensitivity declined after surgery with a differential influence of gender. Men showed a decrease in SBR slope following surgery, with a greater decrease in the standing posture; the parasympathetic (PNS) indicator was lower postoperatively and in the standing posture; the reduction in low-frequency (LF) power was greater for the younger men. In women, the PNS indicator was lower in the standing posture. Both men and women showed a decrease in high-frequency power following CABG surgery, which decreased the sensitivity of the short-term cardiac control mechanisms that modulate heart rate, with the greater effects occurring in men. The reduction in SBR sensitivity indicates that the ability of the cardiovascular system to respond rapidly to changing stimuli was compromised. The decline in the PNS indicator implies that patients were vulnerable to the risks of myocardial ischemia, sympathetically mediated cardiac dysrhythmias, and sudden cardiac death.Key words: spectral analysis, spontaneous baroreflex sensitivity, CABG surgery, gender, age, posture.

The effect of passive lower limb training on heart rate asymmetry

2021 ◽  
Author(s):  
Ping Shi ◽  
Anan Li ◽  
Liang Wu ◽  
Hongliu Yu
Keyword(s):  
Heart Rate ◽  
Time Series ◽  
Heart Rate Variability ◽  
Sinus Rhythm ◽  
Lower Limb ◽  
Automatic Regulation ◽  
Training Methods ◽  
Rate Asymmetry ◽  
Heart Rate Asymmetry ◽  
Healthy Participants

Abstract Objective: Heart rate asymmetry (HRA) is an approach for quantitatively assessing the uneven distribution of heart rate accelerations and decelerations for sinus rhythm. We aimed to investigate whether automatic regulation led to HRA alternation during passive lower limb training. Methods: Thirty healthy participants were recruited in this study. The protocol included a baseline (Pre-E) and three passive lower limb training trials (E1, E2 and E3) with a randomized order. Several variance-based HRA variables were established. Heart rate variability (HRV) parameters, i.e., mean RR, SDNN, RMSSD, LF (n.u.), HF (n.u.) and VLF (ms2), and HRA variables, i.e., SD1a, SD1d, SD2a, SD2d, SDNNa and SDNNd, were calculated by using 5-min RR time series, as well as the normalized HRA variables, i.e., C1a, C1d, C2a, C2d, Ca and Cd. Results: Our results showed that the performance of HRA was distinguished. The normalized HRA was observed with significant changes in E1, E2 and E3 compared to Pre -E. Moreover, parts of non-normalized HRA variables correlated with HRV parameters, which indicated that HRA might benefit in assessing cardiovascular modulation in passive lower limb training. Conclusions: In summary, this study suggested that passive training led to significant HRA alternation and the application of HRA gave us the possibility for autonomic assessment.

Sugar-Sweetened Soft Drink Consumption Acutely Decreases Spontaneous Baroreflex Sensitivity and Heart Rate Variability

2021 ◽  
Author(s):  
Christopher L. Chapman ◽  
Emma L Reed ◽  
Morgan L Worley ◽  
Leonard D Pietrafesa ◽  
Paul J Kueck ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Baroreflex Sensitivity ◽  
Soft Drink ◽  
Soft Drinks ◽  
Paced Breathing ◽  
Soft Drink Consumption ◽  
Healthy Humans ◽  
Sequence Method

In healthy humans, fructose-sweetened water consumption increases blood pressure variability (BPV) and decreases spontaneous cardiovagal baroreflex sensitivity (cBRS) and heart rate variability (HRV). However, if consuming commercially available soft drinks containing high levels of fructose elicits similar responses is unknown. We hypothesized that high-fructose corn syrup (HFCS) sweetened soft drink consumption increases BPV and decreases cBRS and HRV to a greater extent compared to artificially-sweetened (Diet) and sucrose-sweetened (Sucrose) soft drinks and water. Twelve subjects completed four randomized, double-blinded trials in which they drank 500 mL of water or commercially available soft drinks matched for taste and caffeine content. We continuously measured beat-to-beat blood pressure (photoplethysmography) and R-R interval (ECG) before and 30 minutes after drink consumption during supine rest for 5 minutes during spontaneous and paced breathing. BPV was evaluated using standard deviation (SD), average real variability (ARV), and successive variation (SV) methods for systolic and diastolic blood pressure. cBRS was assessed using the sequence method. HRV was evaluated using the root mean square of successive differences in R-R interval (RMSSD). There were no differences between conditions in the magnitude of change from baseline in SD, ARV, and SV (P≥0.07). There were greater reductions in cBRS during spontaneous breathing in the HFCS (-3±5 ms/mmHg) and Sucrose (-3±5 ms/mmHg) trials compared to Water (+1±5 ms/mmHg, P<0.03). During paced breathing, HFCS evoked greater reductions in RMSSD compared to Water (-26±34 vs. +2±26 ms, P<0.01). These findings suggest that sugar-sweetened soft drink consumption alters cBRS and HRV but not BPV.

scholarly journals Short-term recovery of heart rate variability and its relationship with blood pressure after different intensity treadmill exercise

2020 ◽  
Author(s):  
Liang Wu ◽  
Ping Shi ◽  
Jiang Shao ◽  
Anan Li ◽  
Hongliu Yu ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Treadmill Exercise ◽  
Recovery Period ◽  
Short Term ◽  
Poincaré Plot ◽  
Time Frequency ◽  
Rate Asymmetry ◽  
Heart Rate Asymmetry

Abstract Background : Heart rate variability (HRV) provides an opportunity to capture the tiny but early signs that may predict the future cardiovascular risk in healthy individuals and further, helps understand how well the cardiovascular autonomic system works. Aims of this study were to elucidate short-term recovery of HRV and its relationship with blood pressure recovery after different intensity treadmill exercise. Methods : Fifteen healthy participants performed four different conditions (REST; speed 6km/h; speed 8km/h; speed 10km/h), systolic and diastolic blood pressure per 30s (SBP, DBP) and 5-mins consecutive heart beats intervals were measured after each trial. Autonomic nervous regulation was evaluated using HRV time-frequency domain indices and heart rate asymmetry (HRA) indices. Each index was calculated using 5 mins electrocardiogram (ECG) series and consecutive 30-s windows in 5 mins. Results : the vagally related indices (RMSSD, pNN50 and HF) decreased and the indices representing overall variability (SDNN, LF) had different trends as intensity increasing. The sympathetic-vagal balance parameter LF/HF increased, too. HRV indices had strong correlations with DBP but weak with SBP. Meanwhile, heart rate asymmetry vanished after each trial. Conclusions : The findings suggested a vagal withdrawal as soon as the end of treadmill exercise. It could be concluded that sympathetic modulation was stronger as intensity increasing. During recovery period, DBP was mediated by vagal activation and sympathetic withdrawal. The diminished asymmetry in Poincaré plot was the result of sympathetic acceleration and vagal reduction.

Heart rate variability following coronary artery bypass graft surgery as a function of recovery time, posture, and exercise

2004 ◽  
Vol 82 (7) ◽  
pp. 457-464 ◽  
Author(s):  
C Ann Brown ◽  
Larry A Wolfe ◽  
Sylvia Hains ◽  
Glorianne Ropchan ◽  
Joel Parlow
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Baroreflex Sensitivity ◽  
Artery Bypass ◽  
Bypass Graft ◽  
Interval Data ◽  
Artery Bypass Graft ◽  
Low Intensity ◽  
Spontaneous Baroreflex ◽  
Low Intensity Exercise

This study examined the claim made by Niemela et al. (1992) that the decline in heart rate variability after coronary artery bypass graft surgery is irreversible. We tested six women and 16 men six and 12 weeks postoperative in three postures: in the supine position, in the standing position, and during low-intensity steady-state exercise. Beat-by-beat arterial blood pressure and electrocardiographic R–R interval data were collected continuously for 10 min in each condition. R–R interval data were analyzed with spectral analysis; baroreflex data were analyzed using the sequence method. Our results show that the indices of parasympathetic modulation improved over time, as seen by an | increased spontaneous baroreflex sensitivity and parasympathetic indicator, that both indices were affected by posture, and that spontaneous baroreflex sensitivity was also affected by low-intensity exercise. The effects of posture are consistent with attenuated responses of healthy older subjects to orthostatic stress. Similarly, the effects of low-intensity exercise are consistent with findings in healthy subjects. We found that spontaneous baroreflex sensitivity declined during exercise, whereas, in healthy subjects, this is maintained during low-intensity steady-state exercise. Our results of significant functional recovery between six and 12 weeks postoperative suggest that at least some of the autonomic dysfunction following surgery is temporary. Previously, no such duration of study has lasted longer than four or six weeks following cardiac surgery, which may not have been long enough to show significant functional restoration in heart rate variability.Key words: heart rate variability, spontaneous baroreflex sensitivity, CABG surgery, posture, exercise.

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