MyMedR

Displaying publications 81 - 100 of 262 in total

Abstract:

Sort:

Perceptual and Cardiorespiratory Responses to High-Intensity Interval Exercise in Adolescents: Does Work Intensity Matter?

Malik AA, Williams CA, Weston KL, Barker AR

J Sports Sci Med, 2019 03;18(1):1-12.
PMID: 30787646

High-intensity interval exercise (HIIE) may not elicit prominent unpleasant feelings even with elevated perceived exertion and physiological stress in adolescents. However, the influence of different HIIE work intensities on the affective experience and cardiorespiratory responses is unknown. This study examined the acute affective, enjoyment, perceived exertion and cardiorespiratory responses to HIIE with different work intensities in adolescents. Participants (n = 16; 8 boys; age 12.0 ± 0.3 years) performed, on separate days, HIIE conditions consisting of 8 x 1-minute work-intervals at 70%, 85%, or 100% peak power separated by 75 seconds recovery at 20 W. Affect, enjoyment and rating of perceived exertion (RPE) were recorded before, during, and after HIIE. Heart rate (HR) and oxygen uptake were collected during HIIE. Affect declined in all conditions (p < 0.01) but 100%HIIE elicited significantly lower affect than 70%HIIE and 85%HIIE at work-interval 8 (all p < 0.02, ES > 1.74; 70%HIIE = 2.5 ± 0.8; 85%HIIE = 1.1 ± 1.5; 100%HIIE = -1.5 ± 1.4 on feeling scale). Similar enjoyment was evident during and after all conditions (all p > 0.44). RPE was significantly higher during 100%HIIE than 70%HIIE and 85%HIIE across all work-intervals (all p < 0.01, ES > 1.56). The majority of the participants attained ≥90%HRmax during 85%HIIE (87%) and 100%HIIE (100%), but not during 70%HIIE (6%). Affect responses during HIIE are dependent on the intensity of the work-interval and are not entirely negative (unpleasant feelings). Despite similar enjoyment, positive affect experienced during 70%HIIE and 85%HIIE could serve as a strategy to encourage exercise adoption and adherence in adolescents, but only 85%HIIE elicits sufficient HR stimulus to facilitate potential health benefits.

Matched MeSH terms: Heart Rate/physiology
Paroxysmal atrial fibrillation prediction method with shorter HRV sequences

Boon KH, Khalil-Hani M, Malarvili MB, Sia CW

Comput Methods Programs Biomed, 2016 Oct;134:187-96.
PMID: 27480743 DOI: 10.1016/j.cmpb.2016.07.016

This paper proposes a method that predicts the onset of paroxysmal atrial fibrillation (PAF), using heart rate variability (HRV) segments that are shorter than those applied in existing methods, while maintaining good prediction accuracy. PAF is a common cardiac arrhythmia that increases the health risk of a patient, and the development of an accurate predictor of the onset of PAF is clinical important because it increases the possibility to stabilize (electrically) and prevent the onset of atrial arrhythmias with different pacing techniques. We investigate the effect of HRV features extracted from different lengths of HRV segments prior to PAF onset with the proposed PAF prediction method. The pre-processing stage of the predictor includes QRS detection, HRV quantification and ectopic beat correction. Time-domain, frequency-domain, non-linear and bispectrum features are then extracted from the quantified HRV. In the feature selection, the HRV feature set and classifier parameters are optimized simultaneously using an optimization procedure based on genetic algorithm (GA). Both full feature set and statistically significant feature subset are optimized by GA respectively. For the statistically significant feature subset, Mann-Whitney U test is used to filter non-statistical significance features that cannot pass the statistical test at 20% significant level. The final stage of our predictor is the classifier that is based on support vector machine (SVM). A 10-fold cross-validation is applied in performance evaluation, and the proposed method achieves 79.3% prediction accuracy using 15-minutes HRV segment. This accuracy is comparable to that achieved by existing methods that use 30-minutes HRV segments, most of which achieves accuracy of around 80%. More importantly, our method significantly outperforms those that applied segments shorter than 30 minutes.

Matched MeSH terms: Heart Rate*
Over-expression of V1A receptors in PVN modulates autonomic cardiovascular control

Lozić M, Tasić T, Martin A, Greenwood M, Šarenac O, Hindmarch C, et al.

Pharmacol Res, 2016 12;114:185-195.
PMID: 27810519 DOI: 10.1016/j.phrs.2016.10.024

The hypothalamic paraventricular nucleus (PVN) is a key integrative site for the neuroendocrine control of the circulation and of the stress response. It is also a major source of the neuropeptide hormone vasopressin (VP), and co-expresses V1a receptors (V1aR). We thus sought to investigate the role of V1aR in PVN in cardiovascular control in response to stress. Experiments were performed in male Wistar rats equipped with radiotelemetric device. The right PVN was transfected with adenoviral vectors (Ads) engineered to over-express V1aR along with an enhanced green fluorescent protein (eGFP) tag. Control groups were PVN transfected with Ads expressing eGFP alone, or wild-type rats (Wt). Rats were recorded with and without selective blockade of V1aR (V1aRX) in PVN under both baseline and stressed conditions. Blood pressure (BP), heart rate (HR), their short-term variabilities, and baroreflex sensitivity (BRS) were evaluated using spectral analysis and the sequence method, respectively. Under baseline physiological conditions,V1aR rats exhibited reduced BRS and a marked increase of BP and HR variability during exposure to stress. These effects were all prevented by V1aRX pretreatment. In Wt rats, V1aRX did not modify cardiovascular parameters under baseline conditions, and prevented BP variability increase by stress. However, V1aRX pretreatment did not modify baroreflex desensitization by stress in either rat strain. It follows that increased expression of V1aR in PVN influences autonomic cardiovascular regulation and demarcates vulnerability to stress. We thus suggest a possible role of hypothalamic V1aR in cardiovascular pathology.

Matched MeSH terms: Heart Rate*
Fulltext Oral nifedipine versus intravenous labetalol for acute blood pressure control in hypertensive emergencies of pregnancy: a randomised trial

Raheem IA, Saaid R, Omar SZ, Tan PC

BJOG, 2012 Jan;119(1):78-85.
PMID: 21985500 DOI: 10.1111/j.1471-0528.2011.03151.x

To compare oral nifedipine with intravenous labetalol in their rapidity to control hypertensive emergencies of pregnancy.

Matched MeSH terms: Heart Rate/drug effects; Heart Rate, Fetal/drug effects
Fulltext Once daily felodipine monotherapy in mild to moderate hypertension

Kon SP, Tan HW, Chua CT, Ong ML, Kamsiah J, Maheendran KK, et al.

Med J Malaysia, 1992 Dec;47(4):290-6.
PMID: 1303482

In a single-blind study conducted at our centres, 78 hypertensive patients were enrolled with 58 completing the study according to the protocol. Mean supine and standing blood pressures were significantly reduced after treatment with felodipine, reductions being 27/21 mmHg (p < 0.0001) and 25/19 mmHg (p < 0.0001) respectively. Of 46 patients given felodipine 5 mg, 44 (95.7%) achieved target blood pressure defined as a diastolic blood pressure of < 90 mmHg, while all 12 patients on felodipine 10 mg did so. The 2 patients who did not achieve target pressure at the final visit did so on previous visits. There were no differences in pre and post-treatment laboratory variables. Treatment was discontinued in 6 patients because of headaches. No adverse events of clinical significance were reported in the 58 patients who completed the study. In conclusion, we found felodipine given once daily to be effective in the treatment of mild to moderate hypertension.

Study site: Multicentre

Matched MeSH terms: Heart Rate/drug effects
On the binaural brain entrainment indicating lower heart rate variability

Palaniappan R, Phon-Amnuaisuk S, Eswaran C

Int J Cardiol, 2015;190:262-3.
PMID: 25932800 DOI: 10.1016/j.ijcard.2015.04.175
Matched MeSH terms: Heart Rate/physiology*
Occupational heat stress of workers in a Plastic Industry, Selangor

Goh See Ben, Zailina Hashim, Rosnan Hamzah

Journal of Occupational Safety and Health, 2004;1(2):56-63.
MyJurnal

A cross sectional study to determine the exposure of heat and its biological effects on the workers in a plastic factory located in the Shah Alam Industrial Estate, Selangor, Malaysia. Forty five respondents from the polymer section in the factory were selected as the respondents. Variables measured were the environmental temperature (WBGTin), air velocity, relative humidity, body temperature, average heart and recovery heart rate. QUESTEMP°34 Area Heat Stress Monitor was used to measure the environmental temperature in °C (WBGTin) and relative humidity (%). Velocicheck Model TSI 8830 was used to measure the air velocity in meter per second (m/s) while the OMRON Blood Pressure Monitor Model T3, was used to measure average heart rate and recovery heart rate. Body temperature (°C) was measured by the Instant Ear Thermometer-OMRON Gentle Temperature Model MC509. Interviews using questionnaires were used to determine respondents’ socioeconomic background, previous risk factors on heat exposure and other information related to heat stress. Results showed that the mean environmental temperature for the exposed group was 28.75°C, the mean air velocity was 0.15 m/s and the mean relative humidity was 58.1%. These production workers were exposed occasionally to heat when loading plastic powder into the molds as well as demolding the finished plastic products from the molds. The average time of monitoring was 2 hours for intermittent exposure and 8 hours duration for overall exposure. Maximum demand for work load was measured 1 minute after work activities were stopped at the demolding section. There was a significant difference between body temperature and average heart rate before work, after 2 hours of work and after 8 hours of work ( p < 0.001). The mean recovery heart rate after 1 min was 88.0 ± 12.0 beat per min. (bpm), indicating that there is no excessive physiological demand. Body temperature (36.8 ± 0.40°C) and average heart rate after 8 hours (78 ± 12 bpm) indicated a good body control of heat exposure. Five out of six workplaces monitored had temperatures of greater than 28°C (ACGIH TLV). The workers were exposed to moderate heat stress during the study period, however, body temperature and average heart rate measurement did not reach unacceptable level of physiologic strain.

Matched MeSH terms: Heart Rate
Obesity depresses baroreflex control of renal sympathetic nerve activity and heart rate in Sprague Dawley rats: role of the renal innervation

Khan SA, Sattar MZ, Abdullah NA, Rathore HA, Abdulla MH, Ahmad A, et al.

Acta Physiol (Oxf), 2015 Jul;214(3):390-401.
PMID: 25846561 DOI: 10.1111/apha.12499

AIM:
This study investigated the role of the renal innervation in arterial and cardiopulmonary baroreflex regulation of renal sympathetic nerve activity (RSNA) and heart rate (HR) in rats fed a high-fat diet to induce obesity.

METHODS:
Rats received either a normal (12% kcal) or high (45% kcal) fat diet for 60 days. On day 61, rats were anesthetized and prepared for recording left RSNA. In one group, the renal nerves remained intact, while in the other, both kidneys were denervated. Baroreflex gain curves for RSNA and HR were generated by increasing and decreasing blood pressure. Low-pressure baroreceptors were challenged by infusing a saline load.

RESULTS:
Mean blood pressure was 135 mmHg in the fat-fed and 105 mmHg (P < 0.05) in normal rats. Weight gain, adiposity index and creatinine clearance were 37, 82 and 55% higher (P < 0.05-0.001), but urine flow rate and fractional sodium excretions were 53 and 65% (both P < 0.001) lower, respectively, in the fat-fed compared to normal rats. In fat-fed rats with innervated kidneys, RSNA and HR arterial baroreflex sensitivities were reduced by 73 and 72% (both P < 0.05) but were normal in renally denervated rats. Volume expansion decreased RSNA by 66% (P < 0.001) in normal rats, but not in the intact fat-fed rats and by 51% (P < 0.01) in renally denervated fat-fed rats.

CONCLUSION:
Feeding a high-fat diet caused hypertension associated with dysregulation of the arterial and cardiopulmonary baroreflexes which was dependent on an intact renal innervation. This suggests that in obese states neural signals arising from the kidney contribute to a deranged autonomic control.

KEYWORDS:
baroreflex gain curves; cardiopulmonary reflex; high-fat diet

Matched MeSH terms: Heart Rate*
Numerical optimization studies of cardiovascular-rotary blood pump interaction

Lim E, Dokos S, Salamonsen RF, Rosenfeldt FL, Ayre PJ, Lovell NH

Artif Organs, 2012 May;36(5):E110-24.
PMID: 22489799 DOI: 10.1111/j.1525-1594.2012.01449.x

A heart-pump interaction model has been developed based on animal experimental measurements obtained with a rotary blood pump in situ. Five canine experiments were performed to investigate the interaction between the cardiovascular system and the implantable rotary blood pump over a wide range of operating conditions, including variations in cardiac contractility and heart rate, systemic vascular resistance (SVR), and total blood volume (V(total) ). It was observed in our experiments that SVR decreased with increasing mean pump speed under the healthy condition, but was relatively constant during the speed ramp study under reduced cardiac contractility conditions. Furthermore, we also found a significant increase in pulmonary vascular resistance with increasing mean pump speed and decreasing total blood volume, despite a relatively constant SVR. Least squares parameter estimation methods were utilized to fit a subset of model parameters in order to achieve better agreement with the experimental data and to evaluate the robustness and validity of the model under various operating conditions. The fitted model produced reasonable agreement with the experimental measurements, both in terms of mean values and steady-state waveforms. In addition, all the optimized parameters were within physiological limits.

Matched MeSH terms: Heart Rate*
Non-invasive parameters of autonomic function using beat-to-beat cardiovascular variations and arterial stiffness in hypertensive individuals: a systematic review

Ooi JH, Lim R, Seng H, Tan MP, Goh CH, Lovell NH, et al.

Biomed Eng Online, 2024 Feb 20;23(1):23.
PMID: 38378540 DOI: 10.1186/s12938-024-01202-6

PURPOSE: Non-invasive, beat-to-beat variations in physiological indices provide an opportunity for more accessible assessment of autonomic dysfunction. The potential association between the changes in these parameters and arterial stiffness in hypertension remains poorly understood. This systematic review aims to investigate the association between non-invasive indicators of autonomic function based on beat-to-beat cardiovascular signals with arterial stiffness in individuals with hypertension.
METHODS: Four electronic databases were searched from inception to June 2022. Studies that investigated non-invasive parameters of arterial stiffness and autonomic function using beat-to-beat cardiovascular signals over a period of > 5min were included. Study quality was assessed using the STROBE criteria. Two authors screened the titles, abstracts, and full texts independently.
RESULTS: Nineteen studies met the inclusion criteria. A comprehensive overview of experimental design for assessing autonomic function in terms of baroreflex sensitivity and beat-to-beat cardiovascular variabilities, as well as arterial stiffness, was presented. Alterations in non-invasive indicators of autonomic function, which included baroreflex sensitivity, beat-to-beat cardiovascular variabilities and hemodynamic changes in response to autonomic challenges, as well as arterial stiffness, were identified in individuals with hypertension. A mixed result was found in terms of the association between non-invasive quantitative autonomic indices and arterial stiffness in hypertensive individuals. Nine out of 12 studies which quantified baroreflex sensitivity revealed a significant association with arterial stiffness parameters. Three studies estimated beat-to-beat heart rate variability and only one study reported a significant relationship with arterial stiffness indices. Three out of five studies which studied beat-to-beat blood pressure variability showed a significant association with arterial structural changes. One study revealed that hemodynamic changes in response to autonomic challenges were significantly correlated with arterial stiffness parameters.
CONCLUSIONS: The current review demonstrated alteration in autonomic function, which encompasses both the sympathetic and parasympathetic modulation of sinus node function and vasomotor tone (derived from beat-to-beat cardiovascular signals) in hypertension, and a significant association between some of these parameters with arterial stiffness. By employing non-invasive measurements to monitor changes in autonomic function and arterial remodeling in individuals with hypertension, we would be able to enhance our ability to identify individuals at high risk of cardiovascular disease. Understanding the intricate relationships among these cardiovascular variability measures and arterial stiffness could contribute toward better individualized treatment for hypertension in the future.
SYSTEMATIC REVIEW REGISTRATION: PROSPERO ID: CRD42022336703. Date of registration: 12/06/2022.

Matched MeSH terms: Heart Rate/physiology
Newborn seizure detection based on heart rate variability

Malarvili MB, Mesbah M

IEEE Trans Biomed Eng, 2009 Nov;56(11):2594-603.
PMID: 19628449 DOI: 10.1109/TBME.2009.2026908

In this paper, we investigate the use of heart rate variability (HRV) for automatic newborn seizure detection. The proposed method consists of a sequence of processing steps, namely, obtaining HRV from the ECG, extracting a discriminating HRV feature set, selecting an optimal subset from the full feature set, and, finally, classifying the HRV into seizure/nonseizure using a supervised statistical classifier. Due to the fact that HRV signals are nonstationary, a set of time-frequency features from the newborn HRV is proposed and extracted. In order to achieve efficient HRV-based automatic newborn seizure detection, a two-phase wrapper-based feature selection technique is used to select the feature subset with minimum redundancy and maximum class discriminability. Tested on ECG recordings obtained from eight newborns with identified EEG seizure, the proposed HRV-based neonatal seizure detection algorithm achieved 85.7% sensitivity and 84.6% specificity. These results suggest that the HRV is sensitive to changes in the cardioregulatory system induced by the seizure, and therefore, can be used as a basis for an automatic seizure detection.

Matched MeSH terms: Heart Rate/physiology*
Fulltext Minimal Agreement between Internal and External Training Load Metrics across a 2-wk Training Microcycle in Elite Squash

James C, Dhawan A, Jones T, Pok C, Yeo V, Girard O

J Sports Sci Med, 2021 03;20(1):101-109.
PMID: 33707993 DOI: 10.52082/jssm.2021.101

This study investigated the relationships between internal and external training load metrics across a 2-week 'in-season' microcycle in squash. 134 on-court and 32 off-court 'conditioning' sessions were completed by fifteen elite squash players with an average (±SD) of 11 ± 3 per player. During every session, external load was captured using a tri-axial accelerometer to calculate Playerload; i.e., the instantaneous rate of change of acceleration across 3-dimensional planes. Internal load was measured using heart rate (HR), global (sRPE) and differential RPE (dRPE-Legs, dRPE-Breathing). Additionally, HR was used to calculate Banister's, Edward's and TEAM TRIMPs. Across 166 training sessions, Playerload was moderately correlated with TRIMP-Banister (r = 0.43 [95% CI: 0.29-0.55], p < 0.001) and TRIMP-Edwards (r = 0.50 [0.37-0.61], p < 0.001). Association of Playerload with TRIMP-TEAM (r = 0.24 [0.09-0.38], p = 0.001) was small. There was a moderate correlation between sRPE and Playerload (r = 0.46 [0.33-0.57], p < 0.001). Association of sRPE was large with TRIMP-Banister (r = 0.68 [0.59-0.76], p = 0.001), very large with TRIMP-Edwards (r = 0.79 [0.72-0.84], p < 0.001) and moderate with TRIMP-TEAM (r = 0.44 [0.31-0.56], p < 0.001). Both dRPE-Legs (r = 0.95 [0.93-0.96], p < 0.001) and dRPE-Breathing (r = 0.92 [0.89-0.94], p < 0.001) demonstrated nearly perfect correlations with sRPE and with each other (r = 0.91 [0.88-0.93], p < 0.001). Collection of both internal and external training load data is recommended to fully appreciate the physical demands of squash training. During a training microcycle containing a variety of training sessions, interpreting internal or external metrics in isolation may underestimate or overestimate the training stress a player is experiencing.

Matched MeSH terms: Heart Rate
Method optimization to assess endothelial function in females-duration of glyceryl trinitrate effect

Ibrahim NN, Rasool AH, Wong AR, Rahman AR

Methods Find Exp Clin Pharmacol, 2007 Jun;29(5):349-52.
PMID: 17805437

Pulse-wave analysis (PWA) combined with pharmacological challenges has recently been used as a method to measure endothelial function. This involved administration of glyceryl trinitrate (GTN), followed by salbutamol as endothelium-independent and -dependent vasodilators, respectively. The duration of GTN effect needs to be established before the administration of salbutamol. Baseline augmentation index (AIx) and pulse-wave velocity (PWV) measurements were taken in 11 healthy female subjects (mean age 23.27 +/- 3.66 years). Sublingual GTN 0.5 mg was administered for 3 min, followed by AIx and PWV measurements every 5 min till 20 min and then every 10 min until 40 min post-GTN. Maximum change in AIx post-GTN was at 3 min with a mean change from the baseline of -17.86% +/- 4.40% (p < 0.001). There were no significant changes noted after 30 and 40 min with mean change being -0.82% +/- 2.61% and 0.14% +/- 3.20%, respectively (p > 0.05). Significant changes in PWV were noted at 5 and 10 min with the mean change of -0.33 +/- 0.36 m/s and -0.33 +/- 0.35 m/s, respectively (p = 0.01). There were no further changes noted at 15 min and thereafter (p > 0.05). A duration of at least 30 min after GTN is required for AIx and PWV values to reach their baseline. Thus, the administration of salbutamol should be given only after 30 min of sublingual GTN for the assessment of endothelial function.

Matched MeSH terms: Heart Rate/drug effects
Fulltext Method optimization on the process of Iontophoresis with laser doppler fluximetry in the assessment of microvascular endothelial function

Belqes Abdullah, A. T., Yvonne, T. G. B., Ahmad, S. H., Abdul Aziz, A. S. I., Aida, H. G. R.

Malaysian Journal of Medicine and Health Sciences, 2011;7(1):35-40.
MyJurnal

Introduction: Iontophoresis of vasoactive substances such as acetylcholine (ACh) and sodium nitroprusside (SNP) combined with Laser Doppler fluximetry (LDF) is a non-invasive tool used to determine microvascular endothelial function. This study aims to test the effect of sodium chloride on
non-specific vasodilatation when used as a vehicle in the process of iontophoresis. This study also aims to define the number of current pulses needed to get the maximum effect during iontophoresis with ACh and SNP using low current strength. Methods: The experiment was conducted in five healthy females. Baseline skin perfusion was taken before administration of seven current pulses. Current strength of 0.007 mA and current density of 0.01 mA/cm2 were used. Acetylcholine was used to assess endothelial dependent vasodilatation, while SNP was used to assess endothelial independent vasodilatation. The mean skin perfusion (AU) responses to the iontophoresis of ACh at the anodal and SNP at the cathode leads were recorded. Sodium chloride (0.9%) was used as a vehicle to obtain concentration of 1% for both ACh and SNP. Iontophoresis of pure vehicle (NaCl) was conducted on a separate day to observe the effect of vehicle only on the iontophoresis process at both anode and cathode. Results: Iontophoresis of NaCl showed no significant increase in perfusion compared to baseline at both anode and cathode. Significant increases in skin perfusion were observed with SNP and ACh; a plateau of ACh was reached from the 3rd pulse onwards; while the plateau of SNP was reached from the 4th pulse onwards. Conclusion: NaCl could be used as a vehicle for Ach and SNP during iontophoresis as it did not cause non-specific vasodilatation. Using five current pulses are adequate for iontophoresis of ACh and SNP to assess microvascular endothelial function.

Matched MeSH terms: Heart Rate
Fulltext Mechanisms underpinning sympathetic nervous activity and its modulation using transcutaneous vagus nerve stimulation

Deuchars SA, Lall VK, Clancy J, Mahadi M, Murray A, Peers L, et al.

Exp Physiol, 2018 Mar 01;103(3):326-331.
PMID: 29205954 DOI: 10.1113/EP086433

What is the topic of this review? This review briefly considers what modulates sympathetic nerve activity and how it may change as we age or in pathological conditions. It then focuses on transcutaneous vagus nerve stimulation, a method of neuromodulation in autonomic cardiovascular control. What advances does it highlight? The review considers the pathways involved in eliciting the changes in autonomic balance seen with transcutaneous vagus nerve stimulation in relationship to other neuromodulatory techniques. The autonomic nervous system, consisting of the sympathetic and parasympathetic branches, is a major contributor to the maintenance of cardiovascular variables within homeostatic limits. As we age or in certain pathological conditions, the balance between the two branches changes such that sympathetic activity is more dominant, and this change in dominance is negatively correlated with prognosis in conditions such as heart failure. We have shown that non-invasive stimulation of the tragus of the ear increases parasympathetic activity and reduces sympathetic activity and that the extent of this effect is correlated with the baseline cardiovascular parameters of different subjects. The effects could be attributable to activation of the afferent branch of the vagus and, potentially, other sensory nerves in that region. This indicates that tragus stimulation may be a viable treatment in disorders where autonomic activity to the heart is compromised.

Matched MeSH terms: Heart Rate/physiology
Making collapsing pulse user-friendly

Puthiaparampil T

Med J Malaysia, 2020 07;75(4):406-408.
PMID: 32724004

Collapsing pulse is generally elicited by elevating the patient's arm. However, the pulse becoming stronger on arm elevation is a physiological phenomenon, which is bound to create confusion, if routine lifting of the arm in search of collapsing pulse is practiced. The name 'collapsing pulse' represents only the second component of this sign. It masks the more important first component - the slapping, bounding upstroke, characterised by its other name 'water-hammer pulse'. It is possible to elicit this sign by appreciating the slapping character on routine pulse examination. The insistence on arm lifting in medical school teaching is better avoided.

Matched MeSH terms: Heart Rate/physiology*
Fulltext Magnetic Non-invasive Auricular Acupuncture During Eye-Exam for Retinopathy of Prematurity in Preterm Infants: A Multicentre Randomized Controlled Trial

Gan KML, Oei JL, Quah-Smith I, Kamar AA, Lordudass AAD, Liem KD, et al.

Front Pediatr, 2020;8:615008.
PMID: 33425820 DOI: 10.3389/fped.2020.615008

Background: Eye exam for Retinopathy of prematurity (ROP) is a painful procedure and pharmacological analgesia might be ineffective. We hypothesized that magnetic auricular acupuncture (MAA) compared to placebo will decrease pain during ROP exam in preterm infants. Methods: Multicentre randomized controlled trial conducted in three hospitals (Australia, Canada, and Malaysia). Eligibility: >32 weeks, ROP exam, not sedated, and parental consent. A total of 100 infants were randomized (1:1) to MAA (n = 50) or placebo (n = 50). MAA stickers or placebo were placed on both ears by an unblinded investigator. Pain was assessed using the Premature Infant Pain Profile. Primary analyses were by intention-to-treat. ClinicalTrials.gov:NCT03650621. Findings: The mean (standard deviation, SD) gestation, birthweight, and postnatal age were (MAA 28(3) vs. placebo 28(2) weeks; MAA 1,057(455) vs. placebo 952(273) g; MAA 7(3) vs. placebo 7(3) weeks. Placebo infants had significantly higher PIPP scores during [mean difference 1.6 points (95%CI 0.1-3.1)] and 1 h mean difference 1.5 points (95%CI 0.7-2.2) after the procedure (p < 0.03). Heart rate was lower (173(22) vs. 184(18)/min) and oxygen saturations were higher (93.8(6.2) vs. 91.7(6.1)%, p = 0.05) in MAA infants. No adverse effects. Interpretation: MAA may reduce physiological pain responses during and after ROP exam in preterm infants. Assessment of long-term effects are warranted. Clinical trial registration: www.ClinicalTrials.gov, identifier: NCT03650621.

Matched MeSH terms: Heart Rate
Linear and nonlinear analysis of normal and CAD-affected heart rate signals

Acharya UR, Faust O, Sree V, Swapna G, Martis RJ, Kadri NA, et al.

Comput Methods Programs Biomed, 2014;113(1):55-68.
PMID: 24119391 DOI: 10.1016/j.cmpb.2013.08.017

Coronary artery disease (CAD) is one of the dangerous cardiac disease, often may lead to sudden cardiac death. It is difficult to diagnose CAD by manual inspection of electrocardiogram (ECG) signals. To automate this detection task, in this study, we extracted the heart rate (HR) from the ECG signals and used them as base signal for further analysis. We then analyzed the HR signals of both normal and CAD subjects using (i) time domain, (ii) frequency domain and (iii) nonlinear techniques. The following are the nonlinear methods that were used in this work: Poincare plots, Recurrence Quantification Analysis (RQA) parameters, Shannon entropy, Approximate Entropy (ApEn), Sample Entropy (SampEn), Higher Order Spectra (HOS) methods, Detrended Fluctuation Analysis (DFA), Empirical Mode Decomposition (EMD), Cumulants, and Correlation Dimension. As a result of the analysis, we present unique recurrence, Poincare and HOS plots for normal and CAD subjects. We have also observed significant variations in the range of these features with respect to normal and CAD classes, and have presented the same in this paper. We found that the RQA parameters were higher for CAD subjects indicating more rhythm. Since the activity of CAD subjects is less, similar signal patterns repeat more frequently compared to the normal subjects. The entropy based parameters, ApEn and SampEn, are lower for CAD subjects indicating lower entropy (less activity due to impairment) for CAD. Almost all HOS parameters showed higher values for the CAD group, indicating the presence of higher frequency content in the CAD signals. Thus, our study provides a deep insight into how such nonlinear features could be exploited to effectively and reliably detect the presence of CAD.

Matched MeSH terms: Heart Rate*
Ketamine and xylazine combinations for short-term immobilization of wild variable flying foxes (Pteropus hypomelanus)

Sohayati AR, Zaini CM, Hassan L, Epstein J, Siti Suri A, Daszak P, et al.

J. Zoo Wildl. Med., 2008 Dec;39(4):674-6.
PMID: 19110718

Collection of biological samples from pteropid bats requires chemical restraint of the bats to minimize risks to humans and stress to the bat. The effectiveness of an intravenous combination of ketamine and xylazine for short-term restraint of wild-caught variable flying foxes (Pteropus hypomelanus) in a field situation was evaluated. Eight adult male variable flying foxes were injected intravenously with 0.1 ml of ketamine and xylaxine containing 5 mg of ketamine and 1 mg of xylazine. The mean induction time was 80 +/- 20 sec, and mean immobilization time was 26 +/- 10 min. The ketamine-xylazine combination used in this study produced effective short-term immobilization of wild variable flying foxes for the collection of biological samples.

Matched MeSH terms: Heart Rate/drug effects
Fulltext Is Heart Rate a Confounding Factor for Photoplethysmography Markers? A Systematic Review

Md Lazin Md Lazim MR, Aminuddin A, Chellappan K, Ugusman A, Hamid AA, Wan Ahmad WAN, et al.

Int J Environ Res Public Health, 2020 04 10;17(7).
PMID: 32290168 DOI: 10.3390/ijerph17072591

Finger photoplethysmography (PPG) waveform is blood volume change of finger microcirculation that reflects vascular function. Reflection index (RI), stiffness index (SI) and second derivative of photoplethysmogram (SDPPG) are derived from PPG waveforms proposed as cardiovascular disease (CVD) markers. Heart rate (HR) is a known factor that affects vascular function. Individual resting HR variation may affect RI, SI and SDPPG. This review aims to identify studies about the relationship between HR with RI, SI and SDPPG among humans. A literature search was conducted in Medline via the Ebscohost and Scopus databases to find relevant articles published within 11 years. The main inclusion criteria were articles in the English language that discuss the relationship between HR with RI, SI and SDPPG using PPG among humans. The search found 1960 relevant articles but only six articles that met the inclusion criteria. SI and RI showed an association with HR. SDPPG (SDPPG-b/SDPPG-a ratio, SDPPG-d/SDPPG-a ratio, aging index (AGI) and revised aging index (RAGI)) also had an association with HR. Only RI had a considerable association with HR, the association between SI and HR was non-considerable and the association between HR and SDPPG was inconclusive. Further interventional studies should be conducted to investigate this issue, as a variation in resting HR may challenge the validity of PPG-based CVD markers.

Matched MeSH terms: Heart Rate/physiology*

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links