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Kim HJ, Park S, Lim Y, Bang SR. Monitored Anesthesia Care in Minimally Invasive Spine Surgery-A Retrospective Case Series Study. MEDICINA (KAUNAS, LITHUANIA) 2023; 60:43. [PMID: 38256304 PMCID: PMC10821119 DOI: 10.3390/medicina60010043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 12/22/2023] [Accepted: 12/22/2023] [Indexed: 01/24/2024]
Abstract
Background and Objectives: Minimally invasive spine surgery (MISS) under monitored anesthesia care (MAC) has emerged as a treatment modality for spinal radiculopathy. It is essential to secure the airway and guarantee spontaneous respiration without endotracheal intubation during MISS in a prone position. Materials and Methods: To evaluate the feasibility and safety of MAC with dexmedetomidine during MISS, we retrospectively reviewed clinical cases. A retrospective review of medical records was conducted between September 2015 and June 2016. A total of 17 patients undergoing MISS were included. Vital signs were analyzed every 15 min. The depth of sedation was assessed using the bispectral index (BIS) and the frequency of rescue sedatives. Adverse events during anesthesia, including bradycardia, hypotension, respiratory depression, postoperative nausea, and vomiting, were evaluated. Results: All cases were completed without the occurrence of airway-related complications. None of the patients needed conversion to general anesthesia. The median maintenance dosage of dexmedetomidine for adequate sedation was 0.40 (IQR 0.40-0.60) mcg/kg/hr with a median loading dose of 0.70 (IQR 0.67-0.82) mcg/kg. The mean BIS during the main procedure was 76.46 ± 10.75. Rescue sedatives were administered in four cases (23.6%) with a mean of 1.5 mg intravenous midazolam. After dexmedetomidine administration, hypotension and bradycardia developed in six (35.3%) and three (17.6%) of the seventeen patients, respectively. Conclusions: MAC using dexmedetomidine is a feasible anesthetic method for MISS in a prone position. Hypotension and bradycardia should be monitored carefully during dexmedetomidine administration.
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Affiliation(s)
- Hyo Jin Kim
- Department of Anesthesiology and Pain Medicine, Chung-Ang University Gwangmyeong Hospital, Chung-Ang University College of Medicine, Gwangmyeong-si 14353, Republic of Korea
| | - Seongho Park
- Department of Anesthesiology and Pain Medicine, Inje University Sanggye Paik Hospital, Inje University College of Medicine, Seoul 01757, Republic of Korea
| | - Yunhee Lim
- Department of Anesthesiology and Pain Medicine, Inje University Sanggye Paik Hospital, Inje University College of Medicine, Seoul 01757, Republic of Korea
| | - Si Ra Bang
- Department of Anesthesiology and Pain Medicine, Inje University Sanggye Paik Hospital, Inje University College of Medicine, Seoul 01757, Republic of Korea
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Christensen KA, Feeling NR, Rienecke RD. Meta-Analysis and Systematic Review of Resting-State High-Frequency Heart Rate Variability in Binge-Eating Disorder. J PSYCHOPHYSIOL 2022. [DOI: 10.1027/0269-8803/a000307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract. Binge-eating disorder (BED) is associated with a greater risk for cardiac problems and co-occurring health conditions. Resting-state measures of high-frequency heart rate variability (HF-HRV), which is a physiological proxy of self-regulatory neural functioning, may aid understanding of health risks. We systematically reviewed and meta-analyzed the literature on HF-HRV in individuals with BED and without BED. Six studies were reviewed in the qualitative synthesis, and five studies assessing HRV in individuals with BED ( n = 153) and without BED ( n = 124) were included in the meta-analysis. A non-significant effect size (Hedges’ g = .08, SE = 0.36, 95% CI [−0.62, 0.78]; z = 0.23, p = .82) was found, suggesting no difference in HF-HRV between groups. Age, BMI, and BMI-matched control status were not significant covariates. Synthesizing the five studies with available data, we found no difference in resting-state HF-HRV between individuals with and without BED. There was high heterogeneity in the sample, suggesting potential moderators. We discuss potential mechanisms, methodological and demographic confounds, and future directions for study.
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Affiliation(s)
| | - Nicole R. Feeling
- Department of Physical Medicine and Rehabilitation, The Ohio State University Medical Center, Columbus, OH, USA
| | - Renee D. Rienecke
- Eating Recovery Center/Pathlight Mood and Anxiety Centers, Chicago, IL, USA
- Department of Psychiatry and Behavioral Sciences, Northwestern University, Chicago, IL, USA
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3
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Taboni A, Fagoni N, Fontolliet T, Vinetti G, Ferretti G. Dynamics of cardiovascular and baroreflex readjustments during a light-to-moderate exercise transient in humans. Eur J Appl Physiol 2022; 122:2343-2354. [PMID: 35861802 PMCID: PMC9561001 DOI: 10.1007/s00421-022-05011-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 07/07/2022] [Indexed: 12/02/2022]
Abstract
Purpose We hypothesised that, during a light-to-moderate exercise transient, compared to an equivalent rest-to-exercise transient, (1) a further baroreflex sensitivity (BRS) decrease would be slower, (2) no rapid heart rate (HR) response would occur, and (3) the rapid cardiac output (CO) response would have a smaller amplitude (A1). Hence, we analysed the dynamics of arterial baroreflexes and the HR and CO kinetics during rest-to-50 W (0–50 W) and 50-to-100 W (50–100 W) exercise transients. Methods 10 subjects performed three 0–50 W and three 50–100 W on a cycle ergometer. We recorded arterial blood pressure profiles (photo-plethysmography) and R-to-R interval (RRi, electrocardiography). The former were analysed to obtain beat-by-beat mean arterial pressure (MAP) and stroke volume (SV). CO was calculated as SV times HR. BRS was measured by modified sequence method. Results During 0–50 W, MAP transiently fell (− 9.0 ± 5.7 mmHg, p < 0.01) and BRS passed from 15.0 ± 3.7 at rest to 7.3 ± 2.4 ms mmHg−1 at 50 W (p < 0.01) promptly (first BRS sequence: 8.1 ± 4.6 ms mmHg−1, p < 0.01 vs. rest). During 50–100 W, MAP did not fall and BRS passed from 7.2 ± 2.6 at 50 W to 3.3 ± 1.3 ms mmHg−1 at 100 W (p < 0.01) slowly (first BRS sequence: 5.3 ± 3.1 ms mmHg−1, p = 0.07 vs. 50 W). A1 for HR was 9.2 ± 6.0 and 6.0 ± 4.5 min−1 in 0–50 W and 50–100 W, respectively (p = 0.19). The corresponding A1 for CO were 2.80 ± 1.54 and 0.91 ± 0.55 l∙min−1 (p < 0.01). Conclusion During 50–100 W, with respect to 0–50 W, BRS decreased more slowly, in absence of a prompt pressure decrease. BRS decrease and rapid HR response in 50–100 W were unexpected and ascribed to possible persistence of some vagal tone at 50 W. Supplementary Information The online version contains supplementary material available at 10.1007/s00421-022-05011-4.
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Affiliation(s)
- Anna Taboni
- Department of Anaesthesiology, Pharmacology, Intensive Care, and Emergencies, University of Geneva, Geneva, Switzerland
| | - Nazzareno Fagoni
- Department of Anaesthesiology, Pharmacology, Intensive Care, and Emergencies, University of Geneva, Geneva, Switzerland.,Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.,AAT Brescia, Department of Anaesthesiology, Intensive Care and Emergency Medicine, Spedali Civili University Hospital, Brescia, Italy
| | - Timothée Fontolliet
- Department of Anaesthesiology, Pharmacology, Intensive Care, and Emergencies, University of Geneva, Geneva, Switzerland
| | - Giovanni Vinetti
- Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy. .,Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy.
| | - Guido Ferretti
- Department of Anaesthesiology, Pharmacology, Intensive Care, and Emergencies, University of Geneva, Geneva, Switzerland.,Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy
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4
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Respiratory and heart rate dynamics during peripheral chemoreceptor deactivation compared to targeted sympathetic and sympathetic/parasympathetic (co-)activation. Auton Neurosci 2022; 241:103009. [PMID: 35753247 DOI: 10.1016/j.autneu.2022.103009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/29/2022] [Accepted: 06/13/2022] [Indexed: 12/15/2022]
Abstract
BACKGROUND The importance of peripheral chemoreceptors for cardiorespiratory neural control is known for decades. Pure oxygen inhalation deactivates chemoreceptors and increases parasympathetic outflow. However, the relationship between autonomic nervous system (ANS) activation and resulting respiratory as well as heart rate (HR) dynamics is still not fully understood. METHODS In young adults the impact of (1) 100 % pure oxygen inhalation (hyperoxic cardiac chemoreflex sensitivity (CHRS) testing), (2) the cold face test (CFT) and (3) the cold pressor test (CPT) on heart rate variability (HRV), hemodynamics and respiratory rate was investigated in randomized order. Baseline ANS outflow was determined assessing respiratory sinus arrhythmia via deep breathing, baroreflex sensitivity and HRV. RESULTS Baseline ANS outflow was normal in all participants (23 ± 1 years, 7 females, 3 males). Hyperoxic CHRS testing decreased HR (after 60 ± 3 vs before 63 ± 3 min-1, p = 0.004), while increasing total peripheral resistance (1053 ± 87 vs 988 ± 76 dyne*s + m2/cm5, p = 0.02) and mean arterial blood pressure (93 ± 4 vs 91 ± 4 mm Hg, p = 0.02). HRV indicated increased parasympathetic outflow after hyperoxic CHRS testing accompanied by a decrease in respiratory rate (15 ± 1vs 19 ± 1 min-1, p = 0.001). In contrast, neither CFT nor CPT altered the respiratory rate (18 ± 1 vs 18 ± 2 min-1, p = 0.38 and 18 ± 1 vs 18 ± 1 min-1, p = 0.84, respectively). CONCLUSION Changes in HR characteristics during deactivation of peripheral chemoreceptors but not during the CFT and CPT are related with a decrease in respiratory rate. This highlights the need of respiratory rate assessment when evaluating adaptations of cardiorespiratory chemoreceptor control.
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Clemson PT, Hoag JB, Cooke WH, Eckberg DL, Stefanovska A. Beyond the Baroreflex: A New Measure of Autonomic Regulation Based on the Time-Frequency Assessment of Variability, Phase Coherence and Couplings. FRONTIERS IN NETWORK PHYSIOLOGY 2022; 2:891604. [PMID: 36926062 PMCID: PMC10013010 DOI: 10.3389/fnetp.2022.891604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/03/2022] [Indexed: 11/13/2022]
Abstract
For decades the role of autonomic regulation and the baroreflex in the generation of the respiratory sinus arrhythmia (RSA) - modulation of heart rate by the frequency of breathing - has been under dispute. We hypothesized that by using autonomic blockers we can reveal which oscillations and their interactions are suppressed, elucidating their involvement in RSA as well as in cardiovascular regulation more generally. R-R intervals, end tidal CO2, finger arterial pressure, and muscle sympathetic nerve activity (MSNA) were measured simultaneously in 7 subjects during saline, atropine and propranolol infusion. The measurements were repeated during spontaneous and fixed-frequency breathing, and apnea. The power spectra, phase coherence and couplings were calculated to characterise the variability and interactions within the cardiovascular system. Atropine reduced R-R interval variability (p < 0.05) in all three breathing conditions, reduced MSNA power during apnea and removed much of the significant coherence and couplings. Propranolol had smaller effect on the power of oscillations and did not change the number of significant interactions. Most notably, atropine reduced R-R interval power in the 0.145-0.6 Hz interval during apnea, which supports the hypothesis that the RSA is modulated by a mechanism other than the baroreflex. Atropine also reduced or made negative the phase shift between the systolic and diastolic pressure, indicating the cessation of baroreflex-dependent blood pressure variability. This result suggests that coherent respiratory oscillations in the blood pressure can be used for the non-invasive assessment of autonomic regulation.
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Affiliation(s)
- Philip T Clemson
- Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, United Kingdom.,Physics Department, Lancaster University, Lancaster, United Kingdom
| | - Jeffrey B Hoag
- Jane and Leonard Korman Respiratory Institute, Thomas Jefferson University, Philadelphia, PA, United States
| | - William H Cooke
- Kinesiology and Integrative Physiology Department, Michigan Technological University, Houghton, MI, United States
| | - Dwain L Eckberg
- Departments of Medicine and Physiology, Virginia Commonwealth University School of Medicine, Richmond, VA, United States.,Department of Veterans Affairs Medical Center, Richmond, VA, United States
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6
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Hossen A, Khriji L, Al Ghunaimi B, Al Barwani S, Jaju D. Wavelet analysis for early identification of HRV changes in offspring with genetic predisposition to hypertension in Oman. Technol Health Care 2021; 29:869-879. [PMID: 33427701 DOI: 10.3233/thc-202469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Offspring with a genetic predisposition to hypertension may have higher blood pressure (BP) at rest compared with those without a genetic predisposition to hypertension. They are also expected to have a higher sympathetic component in the heart rate variability (HRV) which could be computed with signal processing algorithms. OBJECTIVE The purpose of this study is to design a wavelet-based system to estimate the heart rate variability that can be used to detect early cardiovascular changes in offspring with a genetic predisposition to hypertension. Early detection will help in the treatment of those young people. In this work, the relation between the hypertension and the changes in HRV is investigated. METHODS The frequency domain and time domain analysis of heart rate variability (HRV) are studied to understand their relationship to the autonomic nervous system in offspring with and without a genetic predisposition to hypertension in Oman at resting state. The wavelet-based soft-decision algorithm is used as the spectral analysis tool to obtain different features from the HRV signal and to select the best performing features for detection of hypertension. The main task is to classify between three categories of subjects: 36 subjects with both normotensive parents (ONT), 22 subjects with single hypertensive parent (OHT1), and 11 subjects with both hypertensive parents (OHT2). RESULTS The summation of the power of bands B4 and B5 of the 32 bands HRV wavelet-based spectrum, which is equivalent to the frequency range (0.046875 Hz-0.078125 Hz), is used as a classification factor among OHT2, OHT1, and ONT groups. The efficiency of classification between ONT and OHT2 is 85.10%, and between OHT1 and OHT2 is 81.81%. The result of classifying between (ONT and OHT1 as one group) and OHT2 is 85.50%. CONCLUSIONS The work proves that the wavelet-based spectral analysis technique is a successful tool for classifying the three groups of subjects (ONT, OHT1, and OHT2) with different susceptibility for development of hypertension.
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Affiliation(s)
- A Hossen
- Department of Electrical & Computer Engineering, Sultan Qaboos University, Muscat, Oman
| | - L Khriji
- Department of Electrical & Computer Engineering, Sultan Qaboos University, Muscat, Oman
| | | | - S Al Barwani
- Department of Clinical Physiology, Sultan Qaboos University Hospital, Muscat, Oman
| | - D Jaju
- Department of Physiology, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman
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7
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Castro P, Ferreira ADS, Lopes AJ, Paula TD, Costa RMR, Cunha FA, Vigário PDS. Validity of the Polar V800 heart rate monitor for assessing cardiac autonomic control in individuals with spinal cord injury. MOTRIZ: REVISTA DE EDUCACAO FISICA 2021. [DOI: 10.1590/s1980-65742021003221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
| | | | | | | | | | - Felipe A. Cunha
- Universidade do Estado do Rio de Janeiro, Brazil; Universidade do Estado do Rio de Janeiro, Brazil
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8
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Peyser D, Scolnick B, Hildebrandt T, Taylor JA. Heart rate variability as a biomarker for anorexia nervosa: A review. EUROPEAN EATING DISORDERS REVIEW 2020; 29:20-31. [PMID: 32975349 DOI: 10.1002/erv.2791] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 07/17/2020] [Accepted: 08/19/2020] [Indexed: 01/13/2023]
Abstract
OBJECTIVE Anorexia nervosa (AN) typically begins in early adolescence and other than weight status has few reliable biomarkers. Early diagnosis is a critical prognostic factor, but this can be clinically challenging. Heart rate variability (HRV), the beat-by-beat variance in heart rate (HR), may provide a unique assessment for the presence of AN because it has clinical utility as a biomarker of cardiac autonomic control in various populations (e.g., athletes, the aged, those with cardiovascular diseases, etc.). We present a review of the literature examining HRV in those with AN. METHOD Relevant publications were selected from PubMed using the search terms 'anorexia nervosa AND (HR OR HRV)'. Twenty papers were selected and reviewed. RESULTS The majority of studies suggest that those with AN have markedly and consistently elevated HRV compared to controls, even greater than among young athletes. However, no studies have explored HRV as a biomarker for AN. DISCUSSION Future studies on HRV should elucidate its role as a diagnostic biomarker for AN as well as its responsiveness with serial measurement to track response rates and predict relapse.
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Affiliation(s)
- Deena Peyser
- Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Barbara Scolnick
- Department of Psychology, Boston University, Boston, Massachusetts, USA
| | - Tom Hildebrandt
- Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - J Andrew Taylor
- Spaulding Research Institute and Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, Massachusetts, USA
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Ghali MGZ, Ghali GZ. Mechanisms Contributing to the Generation of Mayer Waves. Front Neurosci 2020; 14:395. [PMID: 32765203 PMCID: PMC7381285 DOI: 10.3389/fnins.2020.00395] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 03/30/2020] [Indexed: 01/25/2023] Open
Abstract
Mayer waves may synchronize overlapping propriobulbar interneuronal microcircuits constituting the respiratory rhythm and pattern generator, sympathetic oscillators, and cardiac vagal preganglionic neurons. Initially described by Sir Sigmund Mayer in the year 1876 in the arterial pressure waveform of anesthetized rabbits, authors have since extensively observed these oscillations in recordings of hemodynamic variables, including arterial pressure waveform, peripheral resistance, and blood flow. Authors would later reveal the presence of these oscillations in sympathetic neural efferent discharge and brainstem and spinal zones corresponding with sympathetic oscillators. Mayer wave central tendency proves highly consistent within, though the specific frequency band varies extensively across, species. Striking resemblance of the Mayer wave central tendency to the species-specific baroreflex resonant frequency has led the majority of investigators to comfortably presume, and generate computational models premised upon, a baroreflex origin of these oscillations. Empirical interrogation of this conjecture has generated variable results and derivative interpretations. Sinoaortic denervation and effector sympathectomy variably reduces or abolishes spectral power contained within the Mayer wave frequency band. Refractorines of Mayer wave generation to barodeafferentation lends credence to the hypothesis these waves are chiefly generated by brainstem propriobulbar and spinal cord propriospinal interneuronal microcircuit oscillators and likely modulated by the baroreflex. The presence of these waves in unitary discharge of medullary lateral tegmental field and rostral ventrolateral medullary neurons (contemporaneously exhibiting fast sympathetic rhythms [2-6 and 10 Hz bands]) in spectral variability in vagotomized pentobarbital-anesthetized and unanesthetized midcollicular (i.e., intercollicular) decerebrate cats supports genesis of Mayer waves by supraspinal sympathetic microcircuit oscillators. Persistence of these waves following high cervical transection in vagotomized unanesthetized midcollicular decerebrate cats would seem to suggest spinal sympathetic microcircuit oscillators generate these waves. The widespread presence of Mayer waves in brainstem sympathetic-related and non-sympathetic-related cells would seem to betray a general tendency of neurons to oscillate at this frequency. We have thus presented an extensive and, hopefully cohesive, discourse evaluating, and evolving the interpretive consideration of, evidence seeking to illumine our understanding of origins of, and insight into mechanisms contributing to, the genesis of Mayer waves. We have predicated our arguments and conjectures in the substance and matter of empirical data, though we have occasionally waxed philosophical beyond these traditional confines in suggesting interpretations exceeding these limits. We believe our synthesis and interpretation of the relevant literature will fruitfully inspire future studies from the perspective of a more intimate appreciation and conceptualization of network mechanisms generating oscillatory variability in neuronal and neural outputs. Our evaluation of Mayer waves informs a novel set of disciplines we term quantum neurophysics extendable to describing subatomic reality. Beyond informing our appreciation of mechanisms generating sympathetic oscillations, Mayer waves may constitute an intrinsic property of neurons extant throughout the cerebrum, brainstem, and spinal cord or reflect an emergent property of interactions between arteriogenic and neuronal oscillations.
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Affiliation(s)
- Michael G Z Ghali
- Department of Neurological Surgery, Karolinska Institutet, Stockholm, Sweden.,Department of Neuroscience, University of Helsinki, Helsinki, Finland.,Department of Neurological Surgery, University of Oslo, Olso, Norway.,Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, United States.,Department of Neurological Surgery, Barrow Neurological Institute, Phoenix, AZ, United States.,Department of Neurological Surgery, Johns Hopkins Medical Institute, Baltimore, MD, United States
| | - George Z Ghali
- Department of Neurological Surgery, Karolinska Institutet, Stockholm, Sweden.,United States Environmental Protection Agency, Arlington, VA, United States.,Department of Toxicology, Purdue University, West Lafayette, IN, United States
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10
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La Rovere MT, Porta A, Schwartz PJ. Autonomic Control of the Heart and Its Clinical Impact. A Personal Perspective. Front Physiol 2020; 11:582. [PMID: 32670079 PMCID: PMC7328903 DOI: 10.3389/fphys.2020.00582] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 05/11/2020] [Indexed: 12/21/2022] Open
Abstract
This essay covers several aspects of the autonomic control of the heart, all relevant to cardiovascular pathophysiology with a direct impact on clinical outcomes. Ischemic heart disease, heart failure, channelopathies, and life-threatening arrhythmias are in the picture. Beginning with an overview on some of the events that marked the oscillations in the medical interest for the autonomic nervous system, our text explores specific areas, including experimental and clinical work focused on understanding the different roles of tonic and reflex sympathetic and vagal activity. The role of the baroreceptors, not just for the direct control of circulation but also because of the clinical value of interpreting alterations (spontaneous or induced) in their function, is discussed. The importance of the autonomic nervous system for gaining insights on risk stratification and for providing specific antiarrhythmic protection is also considered. Examples are the interventions to decrease sympathetic activity and/or to increase vagal activity. The non-invasive analysis of the RR and QT intervals provides additional information. The three of us have collaborated in several studies and each of us contributes with very specific and independent areas of expertise. Here, we have focused on those areas to which we have directly contributed and hence speak with personal experience. This is not an attempt to provide a neutral and general overview on the autonomic nervous system; rather, it represents our effort to share and provide the readers with our own personal views matured after many years of research in this field.
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Affiliation(s)
- Maria Teresa La Rovere
- Department of Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Montescano (Pavia), Italy
| | - Alberto Porta
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.,Department of Cardiothoracic, Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, Milan, Italy
| | - Peter J Schwartz
- Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Istituto Auxologico Italiano, IRCCS, Milan, Italy
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Stewart JM, Medow MS, Visintainer P, Sutton R. When Sinus Tachycardia Becomes Too Much: Negative Effects of Excessive Upright Tachycardia on Cardiac Output in Vasovagal Syncope, Postural Tachycardia Syndrome, and Inappropriate Sinus Tachycardia. Circ Arrhythm Electrophysiol 2020; 13:e007744. [PMID: 31941353 PMCID: PMC7068217 DOI: 10.1161/circep.119.007744] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 12/13/2019] [Indexed: 11/16/2022]
Abstract
BACKGROUND Upright posture reduces venous return, stroke volume, and cardiac output (CO) while causing reflex sinus rate (heart rate [HR]) increase. Yet, in inappropriate sinus tachycardia (IST), postural tachycardia syndrome (POTS), and vasovagal syncope (VVS), symptomatic excessive HR occurs. We hypothesized that CO reaches maximum as function of HR in all. METHODS We recruited 12 healthy controls, 9 IST, 30 VVS, and 30 POTS patients (13-23years) selected randomly by disorder not by HR, each fulfilled appropriate diagnostic criteria. Subjects were instrumented for electrocardiography, beat-to-beat blood pressure, respiratory rate, CO-Modelflow algorithm, and central blood volume from impedance cardiography; 10-minute data were collected supine; subjects were tilted head-up for ≤10 minutes. We computed phase differences, ΔΦ, between fluctuations of HR (ΔHR) and CO (ΔCO) tabulating data when phases were synchronized, determined by a squared nonlinear phase synchronization index >0.5, describing extent/validity of CO/HR coupling. We graphed results supine, 1-minute post-tilt-up, mid-tilt, and pre-tilt-down using polar coordinates (HR-radius, ΔΦ-angle) plotting cos(ΔΦ) versus HR to determine if transition HR exists at which in-phase shifts to antiphase above which CO decreases when HR further increases. RESULTS At baseline HR, diastolic and mean arterial pressures in IST and POTS were higher versus controls. Upright HR increased most in POTS then IST and VVS, with diverse changes in CO, SVR, and central blood volume. Each patient grouping was separately and collectively analyzed for HR change showing transition from in-phase to anti-phase (ΔΦ) as HR increased: HRtransition=115±6 (IST), 123±8 (POTS), 124±7 (VVS), P=ns. Controls never reached transitional HR. CONCLUSIONS Excessive HR independently and equivalently reduces upright CO, in IST, POTS, and VVS.
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Affiliation(s)
- Julian M. Stewart
- Department of Pediatrics and Physiology, New York Medical College, Valhalla, NY
| | - Marvin S. Medow
- Department of Pediatrics and Physiology, New York Medical College, Valhalla, NY
| | - Paul Visintainer
- Baystate Medical Center, Springfield & University of Massachusetts School of Medicine, Worcester, MA
| | - Richard Sutton
- National Heart & Lung institute, Imperial College, London, United Kingdom
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12
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Abstract
Variability in cardiovascular spectra was first described by Stephan Hales in 1733. Traube and Hering initially noted respirophasic variation of the arterial pressure waveform in 1865 and Sigmund Mayer noted a lower frequency oscillation of the same in anesthetized rabbits in 1876. Very low frequency oscillations were noted by Barcroft and Nisimaru in 1932, likely representing vasogenic autorhythmicity. While the origins of Traube Hering and very low frequency oscillatory variability in cardiovascular spectra are well described, genesis mechanisms and functional significance of Mayer waves remain in controversy. Various theories have posited baroreflex and central supraspinal mechanisms for genesis of Mayer waves. Several studies have demonstrated the persistence of Mayer waves following high cervical transection, indicating a spinal capacity for genesis of these oscillations. We suggest a general tendency for central sympathetic neurons to oscillate at the Mayer wave frequency, the presence of multiple Mayer wave oscillators throughout the brainstem and spinal cord, and possible contemporaneous genesis by baroreflex and vasomotor mechanisms.
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Affiliation(s)
- George Zaki Ghali
- United States Environmental Protection Agency, Arlington, VA; Department of Toxicology, Purdue University, West Lafayette, IN, USA
| | - Michael George Zaki Ghali
- Department of Neurological Surgery, Houston Methodist Hospital, Houston, TX; Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Emil Zaki Ghali
- Department of Medicine, Inova Alexandria Hospital, Alexandria, VA, USA; Department of Cardiothoracic Surgery, El Gomhoureya General Hospital, Alexandria, Egypt
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13
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Herry CL, Burns P, Desrochers A, Fecteau G, Durosier LD, Cao M, Seely AJE, Frasch MG. Vagal contributions to fetal heart rate variability: an omics approach. Physiol Meas 2019; 40:065004. [PMID: 31091517 DOI: 10.1088/1361-6579/ab21ae] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Fetal heart rate variability (fHRV) is an important indicator of health and disease, yet its physiological origins, neural contributions, in particular, are not well understood. We aimed to develop novel experimental and data analytical approaches to identify fHRV measures reflecting the vagus nerve contributions to fHRV. APPROACH In near-term ovine fetuses, a comprehensive set of 46 fHRV measures was computed from fetal pre-cordial electrocardiogram recorded during surgery and 72 h later without (n = 24) and with intra-surgical bilateral cervical vagotomy (n = 15). MAIN RESULTS The fetal heart rate did not change due to vagotomy. We identify fHRV measures specific to the vagal modulation of fHRV: multiscale time irreversibility asymmetry index (AsymI), detrended fluctuation analysis (DFA) α 1, Kullback-Leibler permutation entropy (KLPE) and scale-dependent Lyapunov exponent slope (SDLE α). SIGNIFICANCE We provide a systematic delineation of vagal contributions to fHRV across signal-analytical domains which should be relevant for the emerging field of bioelectronic medicine and the deciphering of the 'vagus code'. Our findings also have clinical significance for in utero monitoring of fetal health during surgery. Key points •Fetal surgery causes a complex pattern of changes in heart rate variability measures with an overall reduction of complexity or variability. •At 72 h after surgery, many of the HRV measures recover and this recovery is delayed by an intrasurgical cervical bilateral vagotomy. •We identify HRV pattern representing complete vagal withdrawal that can be understood as part of 'HRV code', rather than any single HRV measure. •We identify HRV biomarkers of recovery from fetal surgery and discuss the effect of anticholinergic medication on this recovery.
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Affiliation(s)
- Christophe L Herry
- Ottawa Hospital Research Institute, University of Ottawa, ON, Canada. PB and CH contributed equally to this manuscript
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Fontolliet T, Pichot V, Bringard A, Fagoni N, Adami A, Tam E, Furlan R, Barthélémy JC, Ferretti G. TESTING THE VAGAL WITHDRAWAL HYPOTHESIS DURING LIGHT EXERCISE UNDER AUTONOMIC BLOCKADE: A HEART RATE VARIABILITY STUDY. J Appl Physiol (1985) 2018; 125:1804-1811. [PMID: 30307822 DOI: 10.1152/japplphysiol.00619.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
INTRODUCTION We performed the first analysis of heart rate variability (HRV) at rest and exercise under full autonomic blockade on the same subjects, to test the conjecture that vagal tone withdrawal occurs at exercise onset. We hypothesized that, between rest and exercise: i) no differences in total power (PTOT) under parasympathetic blockade; ii) a PTOT fall under β1-sympathetic blockade; iii) no differences in Ptot under blockade of both ANS branches. METHODS 7 males (24±3 years) performed 5-min cycling (80W) supine, preceded by 5-min rest during control and with administration of atropine, metoprolol and atropine+metoprolol (double blockade). Heart rate and arterial blood pressure were continuously recorded. HRV and blood pressure variability were determined by power spectral analysis, and baroreflex sensitivity (BRS) by the sequence method. RESULTS At rest, PTOT and the powers of low (LF) and high (HF) frequency components of HRV were dramatically decreased in atropine and double blockade compared to control and metoprolol, with no effects on LF/HF ratio and on the normalised LF (LFnu) and HF (HFnu). At exercise, patterns were the same as at rest. Comparing exercise to rest, PTOT varied as hypothesized. For SAP and DAP, resting PTOT was the same in all conditions. At exercise, in all conditions, PTOT was lower than in control. BRS decreased under atropine and double blockade at rest, under control and metoprolol during exercise. CONCLUSIONS The results support the hypothesis that vagal suppression determined disappearance of HRV during exercise.
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Affiliation(s)
| | | | - Aurélien Bringard
- Department of Basic Neurosciences, University of Geneva, Switzerland, Switzerland
| | - Nazzareno Fagoni
- Dipartment of Kinesiology, College of Health Sciences, Universita di Brescia, Italy
| | - Alessandra Adami
- Department of Kinesiology, University of Rhode Island, Kingston, RI, USA, United States
| | - Enrico Tam
- Dipartimento di Scienze Neurologiche e del Movimento, Università di Verona, Italy
| | - Raffaello Furlan
- Division of Internal Medicine, Humanitas Clinical and Research Center, Rozzano Humanitas University, Italy
| | | | - Guido Ferretti
- University of Geneva, Switzerland, and of Brescia, Italy, Switzerland
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Cepeda FX, Lapointe M, Tan CO, Andrew Taylor J. Inconsistent relation of nonlinear heart rate variability indices to increasing vagal tone in healthy humans. Auton Neurosci 2018; 213:1-7. [PMID: 30005735 DOI: 10.1016/j.autneu.2018.04.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 04/05/2018] [Accepted: 04/30/2018] [Indexed: 11/17/2022]
Abstract
BACKGROUND Prior work has found that linear heart rate variability (HRV) indices do not accurately reflect cardiac vagal control, and nonlinear indices of HRV have been proposed as alternative tools that may better capture cardiac vagal effects. We used progressive low dose atropine to induce changes in cardiac vagal tone to test the hypotheses that nonlinear HRV indices accurately reflect cardiac vagal control, and that their changes in response to low dose atropine correlate with those in RR interval. METHODS Changes in RR interval and HRV indices during intravenous injections of saline (control) and 6 cumulative doses of atropine (from 1.4 to 7.2 μg/kg) during controlled breathing at 15 breaths per minute were assessed in 14 young healthy individuals. RESULTS As expected, low dose atropine increased average RR interval (vagotonic effect). There was no strong association between vagotonic changes in RR interval and the majority of nonlinear HRV indices, either within or among subjects. CONCLUSIONS These data suggest an inconsistent relationship between responses of nonlinear HRV indices and RR interval to changes in cardiac vagal tone. Therefore, nonlinear HRV indices may not be reliable indices of cardiac vagal control in healthy humans.
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Affiliation(s)
- Felipe X Cepeda
- Heart Institute (InCor-HCFMUSP) do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; Cardiovascular Research Laboratory, Spaulding Rehabilitation Hospital, Cambridge, MA, United States
| | - Matthew Lapointe
- Cardiovascular Research Laboratory, Spaulding Rehabilitation Hospital, Cambridge, MA, United States
| | - Can Ozan Tan
- Cardiovascular Research Laboratory, Spaulding Rehabilitation Hospital, Cambridge, MA, United States; Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA, United States
| | - J Andrew Taylor
- Cardiovascular Research Laboratory, Spaulding Rehabilitation Hospital, Cambridge, MA, United States; Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA, United States.
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Perera RK, Fischer TH, Wagner M, Dewenter M, Vettel C, Bork NI, Maier LS, Conti M, Wess J, El-Armouche A, Hasenfuß G, Nikolaev VO. Atropine augments cardiac contractility by inhibiting cAMP-specific phosphodiesterase type 4. Sci Rep 2017; 7:15222. [PMID: 29123207 PMCID: PMC5680190 DOI: 10.1038/s41598-017-15632-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 10/31/2017] [Indexed: 01/21/2023] Open
Abstract
Atropine is a clinically relevant anticholinergic drug, which blocks inhibitory effects of the parasympathetic neurotransmitter acetylcholine on heart rate leading to tachycardia. However, many cardiac effects of atropine cannot be adequately explained solely by its antagonism at muscarinic receptors. In isolated mouse ventricular cardiomyocytes expressing a Förster resonance energy transfer (FRET)-based cAMP biosensor, we confirmed that atropine inhibited acetylcholine-induced decreases in cAMP. Unexpectedly, even in the absence of acetylcholine, after G-protein inactivation with pertussis toxin or in myocytes from M2- or M1/3-muscarinic receptor knockout mice, atropine increased cAMP levels that were pre-elevated with the β-adrenergic agonist isoproterenol. Using the FRET approach and in vitro phosphodiesterase (PDE) activity assays, we show that atropine acts as an allosteric PDE type 4 (PDE4) inhibitor. In human atrial myocardium and in both intact wildtype and M2 or M1/3-receptor knockout mouse Langendorff hearts, atropine led to increased contractility and heart rates, respectively. In vivo, the atropine-dependent prolongation of heart rate increase was blunted in PDE4D but not in wildtype or PDE4B knockout mice. We propose that inhibition of PDE4 by atropine accounts, at least in part, for the induction of tachycardia and the arrhythmogenic potency of this drug.
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Affiliation(s)
- Ruwan K Perera
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Clinic of Cardiology and Pulmonology, Heart Research Center Göttingen, Georg August University Medical Center, Göttingen, Germany
| | - Thomas H Fischer
- Clinic of Cardiology and Pulmonology, Heart Research Center Göttingen, Georg August University Medical Center, Göttingen, Germany
| | - Michael Wagner
- Institute of Pharmacology and Toxicology, Technical University of Dresden, Dresden, Germany
| | - Matthias Dewenter
- Institute of Pharmacology and Toxicology, Technical University of Dresden, Dresden, Germany
| | - Christiane Vettel
- Institute of Experimental and Clinical Pharmacology and Toxicology, Mannheim Medical Faculty, Heidelberg University, Mannheim, Germany
| | - Nadja I Bork
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,DZHK, German Center for Cardiovascular Research, partner sites Hamburg/Kiel/Lübeck and Göttingen, Hamburg, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Marco Conti
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, United States
| | - Juergen Wess
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Bethesda, Maryland, USA
| | - Ali El-Armouche
- Institute of Pharmacology and Toxicology, Technical University of Dresden, Dresden, Germany
| | - Gerd Hasenfuß
- Clinic of Cardiology and Pulmonology, Heart Research Center Göttingen, Georg August University Medical Center, Göttingen, Germany.,DZHK, German Center for Cardiovascular Research, partner sites Hamburg/Kiel/Lübeck and Göttingen, Hamburg, Germany
| | - Viacheslav O Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. .,DZHK, German Center for Cardiovascular Research, partner sites Hamburg/Kiel/Lübeck and Göttingen, Hamburg, Germany.
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Draghici AE, Taylor JA. The physiological basis and measurement of heart rate variability in humans. J Physiol Anthropol 2016; 35:22. [PMID: 27680542 PMCID: PMC5039876 DOI: 10.1186/s40101-016-0113-7] [Citation(s) in RCA: 152] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 09/15/2016] [Indexed: 11/10/2022] Open
Abstract
Cardiovascular variabilities were recognized over 250 years ago, but only in the past 20 years has their apparent utility come to be appreciated. Technological advancement has allowed precise measurement and quantification of short-term cardiovascular fluctuations; however, our understanding of the integrated mechanisms which underlie these oscillations is inadequate for their widespread application. Both autonomic branches, the parasympathetic and sympathetic nervous system, are key determinants of the magnitude of these spontaneous cardiovascular fluctuations. Heart rate variability can be an indicator of an individual cardiovascular condition. In this review, we will discuss the two primary rhythmic oscillations that underlie the complexity of the heart rate waveform. The first oscillation occurs over several cardiac cycles, is respiratory related, and termed respiratory sinus arrhythmia. The second oscillation occurs at an approximate 10 s cycle. Due to the closed-loop nature of the control system of cardiovascular oscillations, it is difficult to define specific relations among cardiovascular variables. In this review, we will present the feedforward and feedback mechanism that underlie both oscillations and their implication as quantitative measures of autonomic circulatory control. We will also review the various methodologies to assess them.
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Affiliation(s)
- Adina E Draghici
- Department of Bioengineering, Northeastern University, Boston, MA, USA
| | - J Andrew Taylor
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA, USA. .,Cardiovascular Research Laboratory, Spaulding Rehabilitation Hospital, 1575 Cambridge St, Cambridge, 02138, MA, USA.
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Choi WJ, Lee K, Kim YK, Song KJ, Jeong SM, Hwang GS. Vagolytic atropine attenuates cerebral vasodilation response during acute orthostatic hypotension. Korean J Anesthesiol 2015; 68:594-602. [PMID: 26634084 PMCID: PMC4667146 DOI: 10.4097/kjae.2015.68.6.594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 04/29/2015] [Accepted: 06/05/2015] [Indexed: 12/02/2022] Open
Abstract
Background Atropine is an anticholinergic drug which is commonly used in clinical practice. The effect of parasympathetic block with atropine on dynamic cerebrovascular regulation remains unclear. This study was aimed to identify effects of vagolytic atropine on cerebrovascular response during acute orthostatic hypotension in humans. Methods Continuous middle cerebral blood flow velocity (CBFV, transcranial Doppler) and arterial blood pressure (ABP, Finometer) were measured during a sit-to-stand procedure in 10 healthy subjects with placebo and vagolytic (10 µg/kg) doses of atropine. Cerebral vascular tone was assessed by cerebrovascular resistance (CVR = ABP / CBFV). Dynamic cerebral autoregulation was also assessed by transfer function analysis of ABP and CBFV. Results During the standing session, ABP fell to a similar extent in both groups by an average of 23 to 25 mmHg (26% to 29%). CBFV also fell in all subjects but significantly more in vagolytic atropine (-15.0 ± 7.0 cm/s) compared with placebo (-12.0 ± 5.8 cm/s, P < 0.05). CVR was decreased significantly in the placebo group during posture change (1.56 ± 0.44 vs. 1.38 ± 0.38, P < 0.05), in contrast, lesser decreased in the atropine group (1.60 ± 0.50 vs. 1.53 ± 0.42, P = 0.193). Transfer function coherence in the very-low-frequency range was significantly increased in the atropine group during the standing session (0.55 ± 0.14), compared with the sitting session (0.45 ± 0.14, P = 0.006). Conclusions These data present that vagolytic atropine attenuates cerebral vasodilation response to acute orthostatic hypotension, suggesting the use of atropine may need care in patients with cerebrovascular disease with vagal impairment.
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Affiliation(s)
- Woo-Jong Choi
- Department of Anesthesiology and Pain Medicine, Laboratory for Cardiovascular Dynamics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Kichang Lee
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, MA, USA
| | - Young-Kug Kim
- Department of Anesthesiology and Pain Medicine, Laboratory for Cardiovascular Dynamics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Kyo-Joon Song
- Department of Anesthesiology and Pain Medicine, VHS Medical Center, Seoul, Korea
| | - Sung-Moon Jeong
- Department of Anesthesiology and Pain Medicine, Laboratory for Cardiovascular Dynamics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Gyu-Sam Hwang
- Department of Anesthesiology and Pain Medicine, Laboratory for Cardiovascular Dynamics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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Seeman S, Sims R. Comparison of Psychophysiological and Dual-Task Measures of Listening Effort. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2015; 58:1781-92. [PMID: 26363285 DOI: 10.1044/2015_jslhr-h-14-0180] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 08/07/2015] [Indexed: 05/24/2023]
Abstract
PURPOSE We wished to make a comparison of psychophysiological measures of listening effort with subjective and dual-task measures of listening effort for a diotic-dichotic-digits and a sentences-in-noise task. METHOD Three groups of young adults (18-38 years old) with normal hearing participated in three experiments: two psychophysiological studies for two different listening tasks and a dual-task measure for a sentences-in-noise task. Psychophysiological variables included skin conductance, heart-rate variability, and heart rate; the dual-task measure was a letter-identification task. Heart-rate variability was quantified with the difference from baseline for the normalized standard deviation of R to R. RESULTS Heart-rate variability differences from baseline were greater for increased task complexity and for poorer signal-to-noise ratios (SNRs). The dual-task measure of listening effort also increased for sentences presented at a +5 dB SNR compared with a +15 dB SNR. Skin conductance was elevated for greater task complexity only, and similar across noise conditions. None of these measures were significantly correlated with subjective measures of listening effort. CONCLUSIONS Heart-rate variability appears to be a robust psychophysiological indicator of listening effort, sensitive to both task complexity and SNR. This sensitivity to SNR was similar to a dual-task measure of listening effort.
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20
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Halim MA, Gillberg L, Boghus S, Sundbom M, Karlbom U, Webb DL, Hellström PM. Nitric oxide regulation of migrating motor complex: randomized trial of N(G)-monomethyl-L-arginine effects in relation to muscarinic and serotonergic receptor blockade. Acta Physiol (Oxf) 2015; 215:105-18. [PMID: 26176347 DOI: 10.1111/apha.12554] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Revised: 05/28/2015] [Accepted: 07/08/2015] [Indexed: 12/13/2022]
Abstract
AIM The migrating motor complex (MMC) propels contents through the gastrointestinal tract during fasting. Nitric oxide (NO) is an inhibitory neurotransmitter in the gastrointestinal tract. Little is known about how NO regulates the MMC. In this study, the aim was to examine nitrergic inhibition of the MMC in man using N(G)-monomethyl-L-arginine (L-NMMA) in combination with muscarinic receptor antagonist atropine and 5-HT3 receptor antagonist ondansetron. METHODS Twenty-six healthy volunteers underwent antroduodenojejunal manometry for 8 h with saline or NO synthase (NOS) inhibitor L-NMMA randomly injected I.V. at 4 h with or without atropine or ondansetron. Plasma ghrelin, motilin and somatostatin were measured by ELISA. Intestinal muscle strip contractions were investigated for NO-dependent mechanisms using L-NMMA and tetrodotoxin. NOS expression was localized by immunohistochemistry. RESULTS L-NMMA elicited premature duodenojejunal phase III in all subjects but one, irrespective of atropine or ondansetron. L-NMMA shortened MMC cycle length, suppressed phase I and shifted motility towards phase II. Pre-treatment with atropine extended phase II, while ondansetron had no effect. L-NMMA did not change circulating ghrelin, motilin or somatostatin. Intestinal contractions were stimulated by L-NMMA, insensitive to tetrodotoxin. NOS immunoreactivity was detected in the myenteric plexus but not in smooth muscle cells. CONCLUSION Nitric oxide suppresses phase III of MMC independent of muscarinic and 5-HT3 receptors as shown by nitrergic blockade, and acts through a neurocrine disinhibition step resulting in stimulated phase III of MMC independent of cholinergic or 5-HT3 -ergic mechanisms. Furthermore, phase II of MMC is governed by inhibitory nitrergic and excitatory cholinergic, but not 5-HT3 -ergic mechanisms.
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Affiliation(s)
- M A Halim
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - L Gillberg
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - S Boghus
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - M Sundbom
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - U Karlbom
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - D-L Webb
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - P M Hellström
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
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Gonçalves TR, Farinatti PDTV, Gurgel JL, da Silva Soares PP. Correlation Between Cardiac Autonomic Modulation in Response to Orthostatic Stress and Indicators of Quality of Life, Physical Capacity, and Physical Activity in Healthy Individuals. J Strength Cond Res 2015; 29:1415-21. [DOI: 10.1519/jsc.0000000000000769] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Botha C, Farmer AD, Nilsson M, Brock C, Gavrila AD, Drewes AM, Knowles CH, Aziz Q. Preliminary report: modulation of parasympathetic nervous system tone influences oesophageal pain hypersensitivity. Gut 2015; 64:611-7. [PMID: 24870622 DOI: 10.1136/gutjnl-2013-306698] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Autonomic nervous system dysfunction has been implicated in visceral hypersensitivity. However, the specific contribution of the parasympathetic nervous system (PNS) is unclear. We aimed to determine whether physiological and pharmacological manipulation of parasympathetic tone influences the development of hypersensitivity in a validated model of acid-induced oesophageal pain. DESIGN Prior to, and following, a 30-min distal oesophageal infusion of 0.15 M hydrochloric acid, pain thresholds to electrical stimulation were determined in the proximal non-acid exposed oesophagus in healthy subjects. Validated sympathetic (skin conductance response) and parasympathetic (cardiac vagal tone) parameters were measured at baseline and continuously thereafter. In study 1, 55 subjects were randomised in a pragmatic blinded crossover design to receive deep breathing or un-paced breathing during acid infusion. In study 2, 32 subjects were randomised in a blinded, crossover design to receive intravenous atropine or placebo (saline) with deep breathing during acid infusion. RESULTS Study 1: Deep breathing increased cardiac vagal tone (2.1±2.3 vs -0.3±2.3, p=0.0006) with concomitant withdrawal of skin conductance response (-0.6±4.9 vs 3±4.8, p=0.03) in comparison with un-paced breathing. Deep breathing prevented the development of acid-induced oesophageal hypersensitivity in comparison with sham breathing (p=0.0001). Study 2: Atropine, in comparison with placebo, blocked the attenuating effect of deep breathing on the development of acid-induced oesophageal hypersensitivity (p=0.046). CONCLUSIONS The development of oesophageal hyperalgesia is prevented by physiologically increasing parasympathetic tone. This effect is pharmacologically blocked with atropine, providing evidence that the PNS influences the development of oesophageal pain hypersensitivity.
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Affiliation(s)
- Claude Botha
- Centre for Digestive Diseases, Blizard Institute of Cell & Molecular Science, Wingate Institute of Neurogastroenterology, Barts and the London School of Medicine & Dentistry, Queen Mary University of London, London, UK
| | - Adam D Farmer
- Centre for Digestive Diseases, Blizard Institute of Cell & Molecular Science, Wingate Institute of Neurogastroenterology, Barts and the London School of Medicine & Dentistry, Queen Mary University of London, London, UK
| | - Matias Nilsson
- Mech-Sense, Department of Gastroenterology, Aalborg University Hospital, Aalborg, Denmark
| | - Christina Brock
- Mech-Sense, Department of Gastroenterology, Aalborg University Hospital, Aalborg, Denmark
| | - Ana D Gavrila
- Centre for Digestive Diseases, Blizard Institute of Cell & Molecular Science, Wingate Institute of Neurogastroenterology, Barts and the London School of Medicine & Dentistry, Queen Mary University of London, London, UK
| | - Asbjørn Mohr Drewes
- Mech-Sense, Department of Gastroenterology, Aalborg University Hospital, Aalborg, Denmark
| | - Charles H Knowles
- Centre for Digestive Diseases, Blizard Institute of Cell & Molecular Science, Wingate Institute of Neurogastroenterology, Barts and the London School of Medicine & Dentistry, Queen Mary University of London, London, UK
| | - Qasim Aziz
- Centre for Digestive Diseases, Blizard Institute of Cell & Molecular Science, Wingate Institute of Neurogastroenterology, Barts and the London School of Medicine & Dentistry, Queen Mary University of London, London, UK
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Cysarz D, Van Leeuwen P, Edelhäuser F, Montano N, Somers VK, Porta A. Symbolic transformations of heart rate variability preserve information about cardiac autonomic control. Physiol Meas 2015; 36:643-57. [PMID: 25798889 DOI: 10.1088/0967-3334/36/4/643] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Traditional measures of heart rate variability (HRV) in the time or frequency domain (e.g. standard deviation of normal-to-normal intervals, SDNN, or the high frequency component of spectral analysis, HF) may be used to track vagal and sympathetic modulation directed to the sinus node. In this study, we assess the ability of symbolic analysis to monitor cardiac autonomic regulation during two autonomic challenges (phenylephrine and nitroprusside; low and high dose of atropine). To assess the effect of the coarse graining procedure, symbolic series obtained from four different transformations over the original series and the series of successive differences of the original values. The analysis focused on patterns of length 3 and exploited a redundancy reduction strategy to group patterns into a small number of families. It turns out that each symbolic series created by the four transformations still contained sufficient dynamical features to quantify differences of cardiovascular changes during the pharmacological challenges. The symbolic series created by transformations of the beat-to-beat interview, i.e RR interval series, showed that patterns without variations (0V) appear more often during a high dose of atropine compared to rest or to a low dose of atropine. Furthermore, patterns with two unlike variations (2UV) appear more often during a low dose of atropine and less often during a high dose of atropine. Differences of nitroprusside and phenylephrine could also be assessed by patterns with these variations. In conclusion, the changes of cardiovascular regulation during pharmacological challenges can be assessed by the analysis of symbolic dynamics derived from the RR interval series independently of the specific symbolic transformation.
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Affiliation(s)
- Dirk Cysarz
- Integrated Curriculum for Anthroposophic Medicine, University of Witten/Herdecke, Germany. Institute for Integrative Medicine, University of Witten/Herdecke, Germany
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Cunha FA, Midgley AW, Gonçalves T, Soares PP, Farinatti P. Parasympathetic reactivation after maximal CPET depends on exercise modality and resting vagal activity in healthy men. SPRINGERPLUS 2015; 4:100. [PMID: 25793148 PMCID: PMC4359698 DOI: 10.1186/s40064-015-0882-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 02/10/2015] [Indexed: 12/19/2022]
Abstract
Purpose The main purpose of this study was to investigate parasympathetic reactivation of the heart [evaluated through heart rate recovery (HRR) and HR variability (HRV)] after maximal cardiopulmonary exercise testing (CPET) using three different exercise modalities. Methods Twenty healthy men, aged 17 to 28 yr, performed three maximal CPETs (cycling, walking, and running) separated by 72 h and in a randomized, counter-balanced order. HRR was determined from the absolute differences between HRpeak and HR at 1–3 min after exercise. The root mean square of successive R-R differences calculated for consecutive 30-s windows (rMSSD30s) was calculated to assess the parasympathetic reactivation after maximal CPET. Results Lower HRpeak, VO2peak and energy expenditure were observed after the cycling CPET than the walking and running CPETs (P < 0.001). Both HRR and rMSSD30s were significantly greater during recovery from the cycling CPET compared to the walking and running CPETs (P < 0.001). Furthermore, Δ rMSSD (i.e. resting minus postexercise rMSSD every 30 s into the recovery period) was positively related to the resting high-frequency component (HF), rMSSD, and standard deviation of all normal R-R intervals (SDNN) (rs = 0.89 to 0.98; P < 0.001), and negatively related to the resting low-frequency component (LF) and sympathovagal balance (LF:HF ratio) after all exercise conditions (rs = −0.73 to −0.79 and −0.86 to −0.90, respectively; P < 0.001). Conclusions These findings support that parasympathetic reactivation after maximal CPET (as assessed by HRR and rMSSD30s) depends on exercise modality and cardiac autonomic control at rest.
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Affiliation(s)
- Felipe A Cunha
- Medical Sciences Graduate Program, Faculty of Medical Sciences, University of Rio de Janeiro State, Rio de Janeiro, Brazil ; Institute of Physical Education and Sports, Laboratory of Physical Activity and Health Promotion, University of Rio de Janeiro State, Rio de Janeiro, Brazil
| | - Adrian W Midgley
- Department of Sport and Physical Activity, Edge Hill University, Ormskirk, Lancashire, UK
| | - Thiago Gonçalves
- Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil
| | - Pedro P Soares
- Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil
| | - Paulo Farinatti
- Institute of Physical Education and Sports, Laboratory of Physical Activity and Health Promotion, University of Rio de Janeiro State, Rio de Janeiro, Brazil ; Physical Activity Sciences Graduate Program, Salgado de Oliveira University, Niterói, Brazil
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Carron M, Veronese S. Atropine sulfate for treatment of bradycardia in a patient with morbid obesity: what may happen when you least expect it. BMJ Case Rep 2015; 2015:bcr2014207596. [PMID: 25634857 PMCID: PMC4322279 DOI: 10.1136/bcr-2014-207596] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2015] [Indexed: 11/03/2022] Open
Abstract
A 74-year-old morbidly obese man was scheduled for surgical repair of an incisional ventral hernia. Anaesthesia was induced with propofol and fentanyl, and maintained with desflurane. A second dose of fentanyl 0.2 mg, given before starting surgery, resulted in sinus bradycardia and mild decrease of arterial blood pressure. Atropine sulfate 0.5 mg was administered. One minute later, the ECG rhythm on the monitor changed to third degree atrioventricular block with a ventricular response rate of 40 beats/min associated with marked hypotension. Isoproterenol 0.02 mg reverted the atrioventricular block to sinus rhythm. Cardiac enzymes and ECG ruled out acute myocardial ischaemia. The surgical procedure and the recovery from anaesthesia were uneventful. The patient was discharged from the hospital on the fifth postoperative day. For the treatment of bradycardia atropine sulfate should be adjusted at least to lean body weight in order to avoid paradoxical heart rate response in patients with obesity.
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Affiliation(s)
- Michele Carron
- Department of Medicine, Anaesthesiology and Intensive Care, University of Padova, Padova, Italy
| | - Stefano Veronese
- Department of Medicine, Anaesthesiology and Intensive Care, University of Padova, Padova, Italy
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Evans JM, Jenkins RA, Ilgner RH, Knapp CF, Zhang Q, Patwardhan AR. Acute cardiovascular autonomic responses to inhaled particulates. Eur J Appl Physiol 2014; 115:257-68. [DOI: 10.1007/s00421-014-2998-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 09/10/2014] [Indexed: 11/24/2022]
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Karam M, Kossaify A. Concealed Sinus Node Dysfunction and Paradoxical Effect of Atropine during Arrhythmia Diagnostic Pharmacological Testing. CLINICAL MEDICINE INSIGHTS-CASE REPORTS 2014; 7:99-102. [PMID: 25232283 PMCID: PMC4159371 DOI: 10.4137/ccrep.s18122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 07/21/2014] [Accepted: 07/24/2014] [Indexed: 11/16/2022]
Abstract
A 78-year-old male patient presented with repetitive fainting episodes. His electrocardiogram showed sinus rhythm with persistent ventricular bigeminy. Concealed sinus node dysfunction (SND) with consecutive bradycardia-induced ventricular hyperexcitability was suspected. Pharmacological testing with atropine resulted in accelerated junctional rhythm along with nearly total disappearance of the ventricular ectopy. The diagnosis of SND was retained, a dual chamber pacemaker was implanted, and consequently, ventricular hyperexcitability disappeared. The junctional rhythm was a paradoxical effect of atropine, and many explanations were provided. Discussion was made accordingly taking into account relevant data from the literature.
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Affiliation(s)
- Myriam Karam
- Anesthesia and Critical care Department, University Hospital Notre Dame de Secours, St Charbel street, Byblos, Lebanon
| | - Antoine Kossaify
- Electrophysiology Unit, Cardiology Department, University Hospital Notre Dame de Secours, St Charbel Street, Byblos, Lebanon
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Comparison of the Surgical Pleth Index with autonomic nervous system modulation on cardiac activity during general anaesthesia: A randomised cross-over study. Eur J Anaesthesiol 2014; 31:76-84. [PMID: 24284309 DOI: 10.1097/01.eja.0000436116.06728.b3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Surgical plethysmographic index (SPI) has been proposed as a tool to measure the nociception/antinociception balance during general anaesthesia. Untreated nociception may increase sympathetic tone, but the relationship between SPI and the autonomic nervous system (ANS) is poorly understood. OBJECTIVE We hypothesised that two different levels of SPI might be associated with differences in ANS modulation, measured by the frequency domain analysis of heart rate variability (HRV). DESIGN A randomised, cross-over group study, conducted between February and November 2009. SETTING University tertiary referral hospital in Milan, Italy. PATIENTS Forty-two adult patients undergoing scheduled laparoscopic abdominal surgery. INTERVENTIONS ECG, noninvasive arterial blood pressure and SPI were recorded during balanced general anaesthesia with inhaled sevoflurane and intravenous remifentanil. After pneumoperitoneum induction, the remifentanil infusion rate was set to obtain two different levels of SPI (>50, HI-SPI, and <50, LO-SPI) for each patient. MAIN OUTCOME MEASURES Arterial pressure, heart rate (HR), low-frequency and high-frequency spectral components, the low frequency/high frequency ratio (measure of sympathovagal balance) and whole power spectrum density of HRV were measured at the two different levels of SPI. RESULTS Thirty-nine patients were included in the final analysis. During LO-SPI, HR and systolic and mean blood pressures were significantly lower than HI-SPI. The median low frequency/high frequency ratio was reduced during LO-SPI [1.29 interquartile range (IQR) 0.66 to 2.05) vs. 2.36 (1.30 to 3.62), P = 0.008]. The sensitivity analysis revealed a significant correlation between SPI changes and changes of all ANS indices, arterial pressure and HR, with a slightly better correlation for low frequency/high frequency (Spearman ρ = 0.70, IQR 0.484 to 0.834, P < 0.001). CONCLUSION In the context of a balanced general anaesthesia in healthy patients undergoing laparoscopic abdominal surgery, ANS modulation seems to correlate with changes in SPI. Further studies are warranted to assess whether this may reflect a change in nociception/antinociception balance or a pharmacodynamic effect of remifentanil.
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Sympathetic nerve activity and simulated diving in healthy humans. Auton Neurosci 2013; 181:74-8. [PMID: 24368150 DOI: 10.1016/j.autneu.2013.12.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 11/27/2013] [Accepted: 12/03/2013] [Indexed: 11/21/2022]
Abstract
The goal of our study was to develop a simple and practical method for simulating diving in humans using facial cold exposure and apnea stimuli to measure neural and circulatory responses during the stimulated diving reflex. We hypothesized that responses to simultaneous facial cold exposure and apnea (simulated diving) would be synergistic, exceeding the sum of responses to individual stimuli. We studied 56 volunteers (24 female and 32 male), average age of 39 years. All subjects were healthy, free of cardiovascular and other diseases, and on no medications. Although muscle sympathetic nerve activity (MSNA), blood pressure, and vascular resistance increased markedly during both early and late phases of simulated diving, significant reductions in heart rate were observed only during the late phase. Total MSNA during simulated diving was greater than combined MSNA responses to the individual stimuli. We found that simulated diving is a powerful stimulus to sympathetic nerve traffic with significant bradycardia evident in the late phase of diving and eliciting synergistic sympathetic and parasympathetic responses. Our data provide insight into autonomic triggers that could help explain catastrophic cardiovascular events that may occur during asphyxia or swimming, such as in patients with obstructive sleep apnea or congenital long QT syndrome.
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Borgers AJ, van den Born BJH, Alkemade A, Eeftinck Schattenkerk DW, van Lieshout JJ, Wesseling KH, Bisschop PH, Westerhof BE. Determinants of vascular and cardiac baroreflex sensitivity values in a random population sample. Med Biol Eng Comput 2013; 52:65-73. [DOI: 10.1007/s11517-013-1111-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 09/01/2013] [Indexed: 10/26/2022]
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Tan CO. Heart rate variability: are there complex patterns? Front Physiol 2013; 4:165. [PMID: 23847544 PMCID: PMC3701329 DOI: 10.3389/fphys.2013.00165] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 06/14/2013] [Indexed: 11/13/2022] Open
Affiliation(s)
- Can Ozan Tan
- Department of Physical Medicine and Rehabilitation, Harvard Medical School Boston, MA, USA ; Cardiovascular Research Laboratory, Spaulding Rehabilitation Hospital Boston, MA, USA
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Champeroux P, Martel E, Jude S, Laigot C, Laveissière A, Weyn-Marotte AA, Fowler JSL, Maurin A, Richard S, Babuty D. Power spectral analysis of heart rate variability in cynomolgus monkeys in safety pharmacology studies: comparative study with beagle dogs. J Pharmacol Toxicol Methods 2013; 68:166-74. [PMID: 23435316 DOI: 10.1016/j.vascn.2013.02.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 01/22/2013] [Accepted: 02/05/2013] [Indexed: 11/18/2022]
Abstract
INTRODUCTION Power spectral analysis of heart rate variability is a tool known to provide information of interest on the autonomic control of heart rate in human. However, its use and its conditions of application and interpretation for safety purposes are not well defined for cardiovascular safety pharmacology studies. Likewise, data of power spectral analysis of heart rate variability in cynomolgus monkeys, a species often appropriate for use as second non rodent species in preclinical safety programmes, are not available. This study was designed to evaluate the relevance of this biomarker in this non human primate species, and to compare results with those from beagle dogs under the conditions of safety evaluation studies. METHODS Power spectral analysis of heart rate variability was performed on data collected in both species by telemetry following a standard design for cardiovascular safety pharmacology studies. Various pharmacological agents were tested in order to compare the profile of responses in both species after modifying the autonomic nervous balance. RESULTS Heart rate variability in cynomolgus monkeys is mainly driven by the parasympathetic nervous system as in beagle dogs although vagal tone is less than in dogs. Power spectral analysis of heart rate variability allows detection of interaction with the autonomic nervous system in both species in all investigated situations, i.e. sympatholytic/sympathomimetic and parasympatholytic/parasympathomimetic drug induced effects. However, due to species difference in the autonomic control of heart rate, cynomolgus monkeys are likely to be more sensitive than beagle dogs for assessment of sympatholytic properties. DISCUSSION This study confirms that power spectral analysis of heart rate variability from data derived from ECG recordings in telemetry studies is applicable in cardiovascular safety pharmacology studies and may provide relevant information about possible interaction with the autonomic nervous system when new drug entities are evaluated in either species. However, interspecies differences in autonomic control must be taken into account when interpreting possible drug effects.
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Affiliation(s)
- Pascal Champeroux
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800 Baugy, France.
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Riganello F, Garbarino S, Sannita WG. Heart Rate Variability, Homeostasis, and Brain Function. J PSYCHOPHYSIOL 2012. [DOI: 10.1027/0269-8803/a000080] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Measures of heart rate variability (HRV) are major indices of the sympathovagal balance in cardiovascular research. These measures are thought to reflect complex patterns of brain activation as well and HRV is now emerging as a descriptor thought to provide information on the nervous system organization of homeostatic responses in accordance with the situational requirements. Current models of integration equate HRV to the affective states as parallel outputs of the central autonomic network, with HRV reflecting its organization of affective, physiological, “cognitive,” and behavioral elements into a homeostatic response. Clinical application is in the study of patients with psychiatric disorders, traumatic brain injury, impaired emotion-specific processing, personality, and communication disorders. HRV responses to highly emotional sensory inputs have been identified in subjects in vegetative state and in healthy or brain injured subjects processing complex sensory stimuli. In this respect, HRV measurements can provide additional information on the brain functional setup in the severely brain damaged and would provide researchers with a suitable approach in the absence of conscious behavior or whenever complex experimental conditions and data collection are impracticable, as it is the case, for example, in intensive care units.
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Affiliation(s)
- Francesco Riganello
- S. Anna Institute and RAN – Research in Advanced Neurorehabilitation, Crotone, Italy
| | - Sergio Garbarino
- Department of Neuroscience, Ophthalmology and Genetics, University of Genova, Italy
| | - Walter G. Sannita
- Department of Neuroscience, Ophthalmology and Genetics, University of Genova, Italy
- Department of Psychiatry, State University of New York, Stony Brook, NY, USA
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Abstract
OBJECTIVE To review indications, procedures, and prognosis for common cardiovascular emergencies requiring intervention in small animals. ETIOLOGY Pericardial effusion, symptomatic bradycardia, and heartworm-induced caval syndrome are examples of clinical scenarios commonly requiring intervention. Pericardial effusion in small animals occurs most frequently from cardiac neoplasia, idiopathic pericarditis, or congestive heart failure. Indications for temporary pacing include transient bradyarrhythmias, ingestions resulting in chronotropic incompetence, and emergency stabilization of critical bradyarrhythmias. Caval syndrome results from a large dirofilarial worm burden, pulmonary hypertension, and mechanical obstruction of right-sided cardiac output with resultant hemolysis and organ dysfunction. DIAGNOSIS The diagnosis of pericardial effusion is suspected from signalment and physical findings and confirmed with cardiac ultrasound. Symptomatic bradycardias often present for syncope and definitive diagnosis derives from an ECG. Caval syndrome is diagnosed upon clinical, hematologic, and ultrasonographic evidence of severe heartworm infestation, cardiovascular compromise, and/or mechanical hemolysis. THERAPY Pericardial effusion is alleviated by pericardiocentesis in the emergency setting, though may require further intervention for long-term palliation. Temporary transvenous pacing can be performed emergently to stabilize the symptomatic patient with a bradyarrhythmia. Dirofilariasis leading to caval syndrome requires urgent heartworm extraction. PROGNOSIS The prognosis for pericardial effusion is dependent upon the underlying etiology; the prognosis for cardiac pacing is favorable, and the prognosis for caval syndrome is grave if untreated and guarded to fair if heartworm extraction is performed.
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Affiliation(s)
- Brian A Scansen
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA.
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Tripathi KK. Very low frequency oscillations in the power spectra of heart rate variability during dry supine immersion and exposure to non-hypoxic hypobaria. Physiol Meas 2011; 32:717-29. [PMID: 21606562 DOI: 10.1088/0967-3334/32/6/008] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The origin of very low frequency (VLF) oscillations in the power spectra of heart rate variability (HRV) is controversial with possible mechanisms involving thermoregulation and/or renin-angiotensin-aldosterone system. Recently, a major contribution from vagal influences has been suggested. The present study investigated the behaviour of VLF (0.004-0.040 Hz) components of HRV power spectra in a group of healthy male volunteers during their exposure to (1) dry, supine, immersion in thermo-neutral water for 6 h (n = 7) and (2) non-hypoxic hypobaria (breathing 40-60% oxygen at 15,000' simulated in a decompression chamber) for 5 h (n = 15). The two manoeuvres are established to increase vagal outflow. During both the manoeuvres, all the frequency domain indices of HRV exhibited a significant increase. Increase in HRV was much more than that in the R-R interval. At 6 h of immersion, the R-R interval increased by ∼ 15% but the total power increased ∼ fourfold. Similarly, at 5 h of exposure to hypobaria, total power increased ∼ twofold with a very modest increase in an R-R of ∼ 9%. Increase in spectral power was appreciable even after normalization with mean R-R(2). Increase in VLF during immersion was more than reported during enalaprilat blockade of angiotensin convertase enzyme. Plasma renin activity did not vary during hypobaria. There was a significant increase in pNN50, an established marker of cardiac vagal activity. Centre frequencies of the spectra and slope (β) of the relation between log(PSD) and log(frequency) did not change. Results were supportive of the notion that the parasympathetic system is pre-potent to influence slower (than respiratory) frequency components in HRV spectrum. Additionally, such an effect was without a change in the time constant of effector responses or pacemaker frequencies of VLF and LF periodicities and HRV was not a simple linear surrogate for cardiac vagal effects. An invariance of spectral exponent (β) ruled out contamination of VLF and LF spectra from fractal power as an alternate explanation.
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Affiliation(s)
- K K Tripathi
- Air Force Station, Jamnagar-361 003, Gujarat, India.
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Wang SZ, Li S, Xu XY, Lin GP, Shao L, Zhao Y, Wang TH. Effect of slow abdominal breathing combined with biofeedback on blood pressure and heart rate variability in prehypertension. J Altern Complement Med 2011; 16:1039-45. [PMID: 20954960 DOI: 10.1089/acm.2009.0577] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVE Prehypertension is a new category designated by the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7) in 2003. Managing prehypertension with nonpharmacological intervention is possibly beneficial to the prevention of hypertension. In this study, we observed the effect of slow abdominal breathing combined with electromyographic (EMG) biofeedback training on blood pressure (BP) in prehypertensives and assessed the changes of heart rate variability (HRV) in order to find an optional intervention to prevent hypertension and acquire some experimental data to clarify the underlying neural mechanism. METHODS Twenty-two (22) postmenopausal women with prehypertension were randomly assigned to either the experiment group or the control group. The experiment group performed 10 sessions of slow abdominal breathing (six cycles/min) combined with frontal electromyographic (EMG) biofeedback training and daily home practice, while the control group only performed slow abdominal breathing and daily home practice. BP and HRV (including R-R interval and standard deviation of the normal-normal intervals [SDNN]) were measured. RESULTS Participants with prehypertension could lower their systolic blood pressure (SBP) 8.4 mm Hg (p < 0.001) and diastolic blood pressure (DBP) 3.9 mm Hg (p < 0.05) using slow abdominal breathing combined with EMG biofeedback. The slow abdominal breathing also significantly decreased the SBP 4.3 mm Hg (p < 0.05), while it had no effect on the DBP (p > 0.05). Repeated-measures analyses showed that the biofeedback group + abdominal respiratory group (AB+BF) training was more effective in lowering the BP than the slow breathing (p < 0.05). Compared with the control group, the R-R interval increased significantly during the training in the AB+BF group (p < 0.05). The SDNN increased remarkably in both groups during the training (p < 0.05). CONCLUSIONS Slow abdominal breathing combined with EMG biofeedback is an effective intervention to manage prehypertension. The possible mechanism is that slow abdominal breathing combined with EMG biofeedback could reduce sympathetic activity and meanwhile could enhance vagal activity.
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Affiliation(s)
- Shu-Zhen Wang
- Department of Physiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
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Affiliation(s)
- Terje Alraek
- The National Research Center in Complementary and Alternative Medicine, University of Tromsø, Tromsø, Norway
| | - Can Ozan Tan
- Cardiovascular Research Laboratory, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, Massachusetts, USA
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Low-frequency oscillations in R–R interval and blood pressure across the continuum of cardiovascular risk. Auton Neurosci 2010; 158:92-9. [DOI: 10.1016/j.autneu.2010.05.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Revised: 05/04/2010] [Accepted: 05/25/2010] [Indexed: 11/18/2022]
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Frequency of slow oscillations in arterial pressure and R–R intervals during muscle metaboreflex activation. Auton Neurosci 2010; 152:88-95. [DOI: 10.1016/j.autneu.2009.08.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Revised: 08/17/2009] [Accepted: 08/31/2009] [Indexed: 01/27/2023]
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Huovinen J, Tulppo M, Nissilä J, Linnamo V, Häkkinen K, Kyrolainen H. Relationship between heart rate variability and the serum testosterone-to-cortisol ratio during military service. Eur J Sport Sci 2009. [DOI: 10.1080/17461390902874040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Montano N, Furlan R, Guzzetti S, McAllen RM, Julien C. Analysis of sympathetic neural discharge in rats and humans. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2009; 367:1265-1282. [PMID: 19324708 DOI: 10.1098/rsta.2008.0285] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Neural signals convey information through two different modalities: intensity and discharge pattern. The intensity code is based on the number of action potentials per unit time, which is then easily translated into neurotransmitter release. This kind of information may be assessed simply by counting the number of spikes or bursts over a time unit. However, the discharge pattern is a further, efficient means of neural information transfer. Rhythmic patterns (i.e. oscillations) can support highly structured, temporal codes based on correlation and synchronization. It is therefore clear that applying frequency domain analysis to sympathetic activity recorded in animals and humans may provide additional information about the neural control of the circulation. Over the last century, data obtained by the analysis of sympathetic activity in experimental animals, and recently also in humans, have provided fundamental contributions to our understanding of the physiological mechanisms involved in the neural control of circulation, as well as how these are altered in cardiovascular and non-cardiovascular diseases. The aim of this paper is to address some aspects related to the recording, analysis and interpretation of sympathetic activity in rats and humans, with special emphasis on analysis in the frequency domain.
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Affiliation(s)
- Nicola Montano
- Internal Medicine II, Department of Clinical Sciences, L. Sacco Hospital, University of Milan, 20157 Milano, Italy.
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Chang YJ, Jung WS, Byun JS, Kim HS, Lee KC. Effects of pneumoperitoneum and position changes on blood pressure variability and heart rate variability during laparoscopy-assisted vaginal hysterectomy. Korean J Anesthesiol 2009; 57:314-319. [DOI: 10.4097/kjae.2009.57.3.314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Yong Jin Chang
- Department of Anesthesiology and Pain Medicine, Gil Medical Center, Gachon University of Medicine and Science, Incheon, Korea
| | - Wol Seon Jung
- Department of Anesthesiology and Pain Medicine, Gil Medical Center, Gachon University of Medicine and Science, Incheon, Korea
| | - Jong Soon Byun
- Department of Anesthesiology and Pain Medicine, Seoul Medical Center, Seoul, Korea
| | - Hong Sun Kim
- Department of Anesthesiology and Pain Medicine, Gil Medical Center, Gachon University of Medicine and Science, Incheon, Korea
| | - Kyung Cheon Lee
- Department of Anesthesiology and Pain Medicine, Gil Medical Center, Gachon University of Medicine and Science, Incheon, Korea
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Montano N, Porta A, Cogliati C, Costantino G, Tobaldini E, Casali KR, Iellamo F. Heart rate variability explored in the frequency domain: a tool to investigate the link between heart and behavior. Neurosci Biobehav Rev 2008; 33:71-80. [PMID: 18706440 DOI: 10.1016/j.neubiorev.2008.07.006] [Citation(s) in RCA: 275] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2008] [Revised: 07/17/2008] [Accepted: 07/22/2008] [Indexed: 11/28/2022]
Abstract
The neural regulation of circulatory function is mainly effected through the interplay of the sympathetic and vagal outflows. This interaction can be explored by assessing cardiovascular rhythmicity with appropriate spectral methodologies. Spectral analysis of cardiovascular signal variability, and in particular of RR period (heart rate variability, HRV), is a widely used procedure to investigate autonomic cardiovascular control and/or target function impairment. The oscillatory pattern which characterizes the spectral profile of heart rate and arterial pressure short-term variability consists of two major components, at low (LF, 0.04-0.15Hz) and high (HF, synchronous with respiratory rate) frequency, respectively, related to vasomotor and respiratory activity. With this procedure the state of sympathovagal balance modulating sinus node pacemaker activity can be quantified in a variety of physiological and pathophysiological conditions. Changes in sympathovagal balance can be often detected in basal conditions, however a reduced responsiveness to an excitatory stimulus is the most common feature that characterizes numerous pathophysiological states. Moreover the attenuation of an oscillatory pattern or its impaired responsiveness to a given stimulus can also reflect an altered target function and thus can furnish interesting prognostic markers. The dynamic assessment of these autonomic changes may provide crucial diagnostic, therapeutic and prognostic information, not only in relation to cardiovascular, but also non-cardiovascular disease. As linear methodologies fail to provide significant information in conditions of extremely reduced variability (e.g. strenuous exercise, heart failure) and in presence of rapid and transients changes or coactivation of the two branches of autonomic nervous system, the development of new non-linear approaches seems to provide a new perspective in investigating neural control of cardiovascular system.
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Affiliation(s)
- Nicola Montano
- Department of Clinical Science, Luigi Sacco Hospital, University of Milan, Milan, Italy.
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Bai Y, Siu KL, Ashraf S, Faes L, Nollo G, Chon KH. Nonlinear coupling is absent in acute myocardial patients but not healthy subjects. Am J Physiol Heart Circ Physiol 2008; 295:H578-86. [PMID: 18539759 DOI: 10.1152/ajpheart.00247.2008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated whether autonomic nervous system imbalance imposed by pharmacological blockades and associated with acute myocardial infarction (AMI) is manifested as modifications of the nonlinear interactions in heart rate variability signal using a statistically based bispectrum method. The statistically based bispectrum method is an ideal approach for identifying nonlinear couplings in a system and overcomes the previous limitation of determining in an ad hoc way the presence of such interactions. Using the improved bispectrum method, we found significant nonlinear interactions in healthy young subjects, which were abolished by the administration of atropine but were still present after propranolol administration. The complete decoupling of nonlinear interactions was obtained with double pharmacological blockades. Nonlinear couplings were found to be the strongest for healthy young subjects followed by degradation with old age and a complete absence of such couplings for the old age-matched AMI subjects. Our results suggest that the presence of nonlinear couplings is largely driven by the parasympathetic nervous system regulation and that the often-reported autonomic nervous system imbalance seen in AMI subjects is manifested as the absence of nonlinear interactions between the sympathetic and parasympathetic nervous regulations.
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Affiliation(s)
- Yan Bai
- Dept. of Biomedical Engineering, SUNY at Stony Brook, HSC T18, Rm. 030, Stony Brook, NY 11794-8181, USA
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Zhong Y, Bai Y, Yang B, Ju K, Shin K, Lee M, Jan KM, Chon KH. Autonomic nervous nonlinear interactions lead to frequency modulation between low- and high-frequency bands of the heart rate variability spectrum. Am J Physiol Regul Integr Comp Physiol 2007; 293:R1961-8. [PMID: 17715181 DOI: 10.1152/ajpregu.00362.2007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiac sympathetic and parasympathetic neural activities have been found to interact with each other to efficiently regulate the heart rate and maintain homeostasis. Quantitative and noninvasive methods used to detect the presence of interactions have been lacking, however. This may be because interactions among autonomic nervous systems are nonlinear and nonstationary. The goal of this work was to identify nonlinear interactions between the sympathetic and parasympathetic nervous systems in the form of frequency and amplitude modulations in human heart rate data. To this end, wavelet analysis was performed, followed by frequency analysis of the resultant wavelet decomposed signals in several frequency brackets defined as very low frequency ( f < 0.04 Hz), low frequency (LF; 0.04–0.15 Hz), and high frequency (HF; 0.15–0.4 Hz). Our analysis suggests that the HF band is significantly modulated by the LF band in the heart rate data obtained in both supine and upright body positions. The strength of modulations is stronger in the upright than supine position, which is consistent with elevated sympathetic nervous activities in the upright position. Furthermore, significantly stronger frequency modulation than in the control condition was also observed with the cold pressor test. The results with the cold pressor test, as well as the body position experiments, further demonstrate that the frequency modulation between LF and HF is most likely due to sympathetic and parasympathetic nervous interactions during sympathetic activations. The modulation phenomenon suggests that the parasympathetic nervous system is frequency modulated by the sympathetic nervous system. In this study, there was no evidence of amplitude modulation among these frequencies.
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Affiliation(s)
- Yuru Zhong
- Dept of Biomedical Engineering, State University of New York at Stony Brook, Stony Brook, NY 11794-8181, USA
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Tankersley CG, Bierman A, Rabold R. Variation in heart rate regulation and the effects of particle exposure in inbred mice. Inhal Toxicol 2007; 19:621-9. [PMID: 17510835 DOI: 10.1080/08958370701353049] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Altered autonomic control of heart rate (HR) rhythm during exposure to particulate matter (PM) has been suggested in human and animal studies. Our lab has shown strain variation in HR regulation between quiescent C3H/HeJ (C3) and C57BL/6J (B6) mice: that is, C3 mice show a consistently higher HR by approximately 80 bpm compared with B6 mice during a normal 24-h circadian cycle. In the current study, we hypothesize that the balance between sympathetic and parasympathetic control of HR during PM exposure varies between C3 and B6 mice. Radiotelemeters were implanted in C3 and B6 mice to measure HR responses and HR variability (HRV) parameters during successive 3-h exposures to filtered air (FA) or carbon black (CB, < 300 mug/m3). Exposures were repeated following administration of saline or parasympathetic (PS; atropine, 0.5 mg/kg i.p.) and sympathetic (S; propranolol, 1 mg/kg i.p.) blockade to study the autonomic regulation of HR during CB exposure. During FA exposure with saline, a significantly (p < .05) greater 3-h average HR response (bpm +/- SEM) occurred in C3 compared with B6 mice (496 +/- 22 vs. 427 +/- 3). With PS blockade, the strain difference between C3 and B6 mice was not evident (485 +/- 23 vs. 503 +/- 61). With S blockade, the 3-h average HR responses for C3 mice were significantly (p < .05) reduced compared with saline (413 +/- 18 vs. 392 +/- 15 for B6). During CB exposure with saline, HR responses were again significantly (p < 0.05) elevated in C3 compared with B6 mice, but these HR responses were not different relative to FA exposure. With S blockade, HR was significantly (p < .05) elevated in B6 mice during CB relative to FA, but was unchanged in C3 mice. Collectively, these results suggest that strain variation in HR regulation is due to a robust PS tone evident in B6 mice and a predominant S tone in C3 mice. Furthermore, CB exposure alters HR regulation in B6 mice by modulating a withdrawal of PS tone. Finally, strain variation in HR between B6 and C3 mice in responding to acute PM exposure implies that robust genetic determinants modulate altered autonomic regulation in susceptible individuals.
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Affiliation(s)
- Clarke G Tankersley
- Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA.
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Ayer A, Antic V, Dulloo AG, Van Vliet BN, Montani JP. Hemodynamic consequences of chronic parasympathetic blockade with a peripheral muscarinic antagonist. Am J Physiol Heart Circ Physiol 2007; 293:H1265-72. [PMID: 17496215 DOI: 10.1152/ajpheart.00326.2007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Whereas the sympathetic nervous system has a well-established role in blood pressure (BP) regulation, it is not clear whether long-term levels of BP are affected by parasympathetic function or dysfunction. We tested the hypothesis that chronic blockade of the parasympathetic nervous system has sustained effects on BP, heart rate (HR), and BP variability (BPV). Sprague-Dawley rats were instrumented for monitoring of BP 22-h per day by telemetry and housed in metabolic cages. After the rats healed from surgery and a baseline control period, scopolamine methyl bromide (SMB), a peripheral muscarinic antagonist, was infused intravenously for 12 days. This was followed by a 10-day recovery period. SMB induced a rapid increase in mean BP from 98 ± 2 mmHg to a peak value of 108 ± 2 mmHg on day 2 of the SMB infusion and then stabilized at a plateau value of +3 ± 1 mmHg above control ( P < 0.05). After cessation of the infusion, the mean BP fell by 6 ± 1 mmHg. There was an immediate elevation in HR that remained significantly above control on the last day of SMB infusion. SMB also induced a decrease in short-term (within 30-min periods) HR variability and an increase in both short-term and long-term (between 30-min periods) BPV. The data suggest that chronic peripheral muscarinic blockade leads to modest, but sustained, increases in BP, HR, and BPV, which are known risk factors for cardiovascular morbidity.
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Affiliation(s)
- Antoine Ayer
- Department of Medicine/Division of Physiology, University of Fribourg, Rue du Musée 5, CH-1700 Fribourg, Switzerland
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Kaufman CL, Kaiser DR, Steinberger J, Kelly AS, Dengel DR. Relationships of cardiac autonomic function with metabolic abnormalities in childhood obesity. Obesity (Silver Spring) 2007; 15:1164-71. [PMID: 17495192 DOI: 10.1038/oby.2007.619] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
OBJECTIVE The objective was to examine cardiovascular autonomic (cANS) function and its potential relationships with leptin resistance, insulin resistance, oxidative stress, and inflammation in a pediatric sample with varying levels of obesity. RESEARCH METHODS AND PROCEDURES Participants were normal-weight (NW; BMI <85th percentile, 6 male, 4 female), overweight (OW; 85th percentile < BMI <95th percentile, 6 male, 4 female), and obese children (OB; BMI >95th percentile, 6 male, 10 female) who had cANS function assessed via heart rate variability (HRV) methods during resting conditions. Standard time-domain and frequency-domain measures [high-frequency normalized units (HFnu; measure of parasympathetic nervous system activity) and low frequency:high-frequency ratio (LF:HF; overall sympathovagal balance)] of HRV were calculated. Fasting blood samples were drawn for measurement of glucose, insulin, lipids, 8-isoprostane, leptin, soluble leptin-receptor (sOB-R), C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha). Results were reported as mean +/- standard error of the mean. RESULTS OB had significantly elevated LF:HF and decreased HFnu when compared with NW (p < 0.05), but no differences between OW and NW were observed. Measures of HRV were significantly related to leptin, insulin resistance, 8-isoprostane, and CRP (p < 0.05), but these relationships were not significant after adjustment for fat mass. DISCUSSION When compared with NW, OB but not OW children are characterized by cANS dysfunction and increased leptin, insulin resistance, oxidative stress, and inflammation (CRP). The relationships between these factors seem to be dependent on quantity of fat mass and/or other factors associated with being obese.
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Gamboa A, Diedrich A, Biaggioni I. Pharmacological probes to measure the importance of the autonomic nervous system. Clin Auton Res 2007; 17:65-8. [PMID: 17401762 DOI: 10.1007/s10286-007-0406-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Porta A, Guzzetti S, Furlan R, Gnecchi-Ruscone T, Montano N, Malliani A. Complexity and nonlinearity in short-term heart period variability: comparison of methods based on local nonlinear prediction. IEEE Trans Biomed Eng 2007; 54:94-106. [PMID: 17260860 DOI: 10.1109/tbme.2006.883789] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This paper evaluates the paradigm that proposes to quantify short-term complexity and detect nonlinear dynamics by exploiting local nonlinear prediction. Local nonlinear prediction methods are classified according to how they judge similarity among patterns of L samples (i.e., according to different definitions of the cells utilized to discretize the phase space) and examined in connection with different types of surrogate data: 1) phase-randomized or Fourier transform based, FT; 2) amplitude-adjusted FT, AAFT; 3) iteratively-refined AAFT, IAAFT, preserving distribution IAAFT-1; 4) IAAFT preserving power spectrum, IAAFT-2. The methods were applied on ad-hoc simulations and on a large database of short heart period variability series (approximately 300 cardiac beats) recorded in healthy young subjects during experimental conditions inducing a sympathetic activation (head-up tilt, infusion of nitroprusside, or handgrip), a parasympathetic activation (low dose administration of atropine or infusion of phenylephrine), a complete parasympathetic blockade (high dose administration of atropine), or during controlled respiration at different breathing rates. As to complexity analysis we found that: 1) although complexity indexes derived from different methods were different in terms of absolute values, changes due to experimental conditions were consistently detected; 2) complexity was significantly decreased by all the experimental conditions provoking a sympathetic activation and by controlled respiration at slow breathing rates. As to detection of nonlinearities we found that: 1) IAAFT-1 and IAAFT-2 surrogates performed similarly in all protocols; 2) FT and IAAFT surrogates detected about the same percentage of nonlinear dynamics in all protocols; 3) AAFT surrogates were inappropriate with all the methods and should be dismissed in future applications; 4) methods based on overlapping cells with variable size were characterized by a larger rate of false detections of nonlinear dynamics; 5) short-term heart period variability at rest was mostly linear; 6) controlled respiration at slow breathing rates increased nonlinear components, while the separate activation of the two branches of the autonomic nervous system (i.e., sympathetic or parasympathetic) was ineffective at this regard.
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Affiliation(s)
- Alberto Porta
- Dipartimento di Scienze Precliniche LITA di Vialba, Laboratorio di Modellistica di Sistemi Complessi, Universita' degli Studi di Milano, Milan 20157, Italy.
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