Higher Vagal Research Articles

Change in Performance in Response to Training Load Adjustment Based on Autonomic Activity

The primary aim of this study was to assess performance (Perf) changes in response to a new training strategy. Specifically, based on spectral analysis of heart rate variability (SA HRV) to determine autonomic nervous system (ANS) activity, training doses were adjusted to maintain vagal activity at a high and relatively stable level during training preparation. Trained athletes (5 male and 5 female) aged 23.2±4.2 years voluntarily participated in the study. ANS activity was assessed during an orthoclinostatic test, and was represented by calculating HRV variables and a total score index. Over 17 weeks, improvement (1.4-8.5%) and deterioration (0.1-8.8%) in Perf were detected in 7 and 3 athletes, respectively. A relationship (rs=0.684; P<0.05) between the change in Perf (ΔPerf) and supine PHF during season was found. Supine HRV indices (PHF, PT, and MSSD) for the last 3 weeks of the HRV-adjusting period correlated (rs=0.636; 0.648; 0.648, P<0.05) with ΔPerf. Based on the results, a high and relative stable vagal activity during preparation may indicate a readiness to train or appropriate recovery that positively affects Perf. In conclusion, daily quantification of ANS activity by SA HRV seems to be a promising tool for the enhancement of Perf.

The ECG in cardiovascular-relevant animal models of electrophysiology

The most frequently used animal species in experimental cardiac electrophysiology are mice, rabbits, and dogs. Murine and human electrocardiograms (ECGs) show salient differences, including the occurrence of a pronounced J-wave and a less distinctive T-wave in the murine ECG. Mouse models can resemble human cardiac arrhythmias, although mice differ from human in cardiac electrophysiology. Thus, arrhythmia mechanisms in mice may differ from those in humans and should be transferred to the human situation with caution. Further relevant cardiovascular animal models are rabbits, dogs, and minipigs, as they show similarities of cardiac ion channel distribution with the human heart and are suitable to study ventricular repolarization or pro- and antiarrhythmic drug effects. ECG recordings in large animals like goats and horses are feasible. Both goats and horses are a suitable animal model to study atrial fibrillation (AF) mechanisms. Horses frequently show spontaneous AF due to their high vagal tone and large atria. The zebrafish has become an important animal model. Models in "exotic" animals such as kangaroos may be suitable for particular studies.

Commentaries on Viewpoint: Is the resting bradycardia in athletes the result of remodeling of the sinoatrial node rather than high vagal tone?

Commentaries on Viewpoint: Is the resting bradycardia in athletes the result of remodeling of the sinoatrial node rather than high vagal tone?

Vocal fold medialization with tragal cartilage and perichondrium in high vagal paralysis

The goal of this pilot study was to test vocal fold medialization using autologous tragal cartilage and perichondrium by direct approach for treating high vagal paralysis. Five patients with the skull base tumors with involvement of the vagus nerve underwent concurrent vocal fold medialization with surgical excision. The patients were evaluated preoperatively, and at 14, 60 days, and 6 months later. Complete medialization with horizontal and vertical realignment was achieved. Improvement of voice and breathiness was correlated with the increase of closed quotient; the contact area of the vocal fold mucosa has increased. This advancement reduces breathiness and induced an improvement in subglottic pressure with aerodynamic parameters improvement, which led to stabilization of the vocal fold oscillation and a better voice quality recovery. This method can be considered a safe, quick, and efficient phonosurgical procedure combined with a skull-base surgical procedure.

Viewpoint: Is the resting bradycardia in athletes the result of remodeling of the sinoatrial node rather than high vagal tone?

it is well known that athletes have a low resting heart rate, i.e., a resting bradycardia and heart rates below 30 beats/min have been reported ([7][1]). For example, Wikipedia states that the Tour de France cyclist, Miguel Indurain, had a resting heart rate of 28 beats/min when race fit. The

Effects of Right Lateral Position of Body on Cardiovascular Parameters

Aim of this study was to assess the effects of right lateral position of body on cardiovascular parameters. Systolic blood pressure, diastolic blood pressure and heart rate are the main cardiovascular parameters. A total of 100 healthy male subjects were chosen for the study. Systolic blood pressure, diastolic blood pressure and heart rate were recorded after 10 minutes of rest in supine position and right lateral position. Systolic blood pressure, diastolic blood pressure and heart rate were significantly lower in right lateral position than supine state. The results suggest higher vagal activity and lower sympathetic activity in right lateral position of the body.

Cardiac autonomic profile during rest and working memory load in essential hypotensive women

To our knowledge, no previous study has provided reliable data supporting a different modulation of the Neurovegetative system in essential hypotension. Our purpose was to provide, in essential hypotensive women compared to normotensives, evidence of a distinct sympathetic and parasympathetic cardiac control. Cardiovascular and autonomic indexes derived by impedance cardiography (heart rate, HR; pre-ejection period, PEP), photoplethysmographic technique (blood pressure, BP) and heart rate variability analysis (high and low frequencies power, HF and LF) were continuously collected during rest and mental stress condition. Hypotensives, compared to normotensives, exhibited prolonged PEP (low sympathetic tone) and elevated HF (high vagal involvement) during rest. In addition, they showed cardiovascular (reduced increases in BP and HR) and sympathetic (lower reductions of PEP) hypo-reactivity to the task. Furthermore, a lower sympathetic reactivity in hypotensives was associated to a poorer task performance. Essential hypotension was characterized by a low sympathetic and high parasympathetic tone. In addition, a reduced sympathetic nervous system reactivity suggests the main role of the Neurovegetative system in mediating the relationship between blood pressure and cognitive performance in hypotensives.

Cardiac vagal tone predicts inhibited attention to fearful faces.

The neurovisceral integration model (Thayer, J. F., & Lane, R. D., 2000, A model of neurovisceral integration in emotion regulation and dysregulation. Journal of Affective Disorders, 61, 201-216. doi:10.1016/S0165-0327(00)00338-4) proposes that individual differences in heart rate variability (HRV)-an index of cardiac vagal tone-are associated with attentional and emotional self-regulation. In this article, we demonstrate that individual differences in resting HRV predict the functioning of the inhibition of return (IOR), an inhibitory attentional mechanism highly adaptive to novelty search, in response to affectively significant face cues. As predicted, participants with lower HRV exhibited a smaller IOR effect to fearful versus neutral face cues than participants with higher HRV, which shows a failure to inhibit attention from affectively significant cues and instigate novelty search. In contrast, participants with higher HRV exhibited similar IOR effects to fearful and neutral face cues, which shows an ability to inhibit attention from cues and instigate novelty search. Their ability to inhibit attention was most pronounced to high spatial frequency fearful face cues, suggesting that this effect may be mediated by cortical mechanisms. The current research demonstrates that individual differences in HRV predict attentional inhibition and suggests that successful inhibition and novelty search may be mediated by cortical inhibitory mechanisms among people with high cardiac vagal tone.

Food Deprivation Sensitizes Pain Perception

While food deprivation has known effects on sympathovagal balance, little is known about hunger’s influence on the perception of pain. Since autonomic activities influence many cognitive and emotional processes, this suggests that food deprivation should interact with the perception of pain. This study analyzed the possible effects of short-term food deprivation on pain sensitivity in healthy female participants. This study was comprised of 32 healthy female participants who underwent a 48-hr inpatient hospital investigation. Prior to testing, heart rate and heart rate variability were assessed. After a standardized breakfast, day 1 measurements were taken. Food intake was then not allowed again until the following evening for 22 participants (experimental group), while 12 participants were served standard meals (control group). Pain threshold and tolerance were assessed at 10:00 a.m. on both days using a pressure algometer. Additionally pain experience was examined. Food deprivation significantly reduced pain thresholds and tolerance scores in the experimental group. Additionally, the sympathovagal balance changed, characterized by a decrease in parasympathetic activation. Higher vagal withdrawal after food deprivation was associated with higher pain sensitivity in the experimental group. Furthermore, perceived unpleasantness and pain intensity increased for threshold and tolerance stimuli in the experimental group. We conclude that short-term food deprivation sensitized pain perception in healthy females. An imbalance in sympathovagal activation evoked by food deprivation accounted for this effect. Our results might be a pathogenic mechanism for the development of emotional difficulties associated with disturbed eating behavior.

Young footballers, assessed by deep breathing test, have a higher vagal response

Parasympathetic function can be assessed by the deep breathing test (DB) as a simple and reproducible cardiovascular reflex. The aim of this study is to use this test to compare the vagal response of a young footballers group to of age-matched untrained normal subjects. Deep breathing test was performed in 2 groups: one of 20 adult young footballers (average age of 19.3 ± 0.6 years), and a second age-matched group of 20 untrained subjects (average age of 19.6 ± 0.6 years). Subjects underwent the DB test after 30 min resting in supine position, and responses were expressed as a percentage of variation of heart rate during the stimulation. Student’s t-test was used to evaluate statistical differences among the two groups for all parameters (vagal response, heart rate, VO2max….) and considering p < 0.05 as a significant difference. The results showed that vagal response to deep breathing test was significantly higher in the young footballers when compared to the untrained controls (72.6% ± 16.2% vs 55.0% ± 12.8%, respectively, p = 0.03). The basal heart rate was significantly lower in footballers than in the controls group (52.1 ± 7.4 bat/min vs 69.8 ± 14.3 bat/min, p < 0.01). The use of the simple test of deep breathing allowed us to demonstrate that adult young footballers have a significantly lower basal HR and higher parasympathetic response in comparison to untrained subjects.

Cricothyroid approximation for voice and swallowing rehabilitation of high vagal paralysis secondary to skull base neoplasms

This study documents the speech and swallowing outcomes of isolated ipsilateral cricothyroid approximation (aka tensioning thyroplasty; Type IV thyroplasty) for the treatment of high vagal paralysis (combined superior laryngeal nerve and recurrent laryngeal nerve paralysis). This is a pilot study of five cases with high vagal paralysis consequent to skull base neoplasms. Unilateral cricothyroid tensioning sutures were used. In all cases, vocal fold tensioning and vertical realignment of lax vocal folds were achieved. A partial, but acceptable medialization of vocal cord position was achieved. In all cases, aspiration was minimized and normal swallow function was restored by 6 weeks. The voice outcome was excellent in four cases and acceptable in one. Cricothyroid approximation restores vocal fold tension; in addition, it restores vertical vocal fold position and partially restores horizontal vocal fold position. Good voice and swallowing outcomes have been achieved. The procedure is quick, safe, and convenient when combined with a skull-base excision procedure. Further evaluation is merited.

Benefits of achieving vigorous as well as moderate physical activity recommendations: Evidence from heart rate complexity and cardiac vagal modulation

The aim of this study was to examine differences in traditional heart rate variability measurements and heart rate complexity (sample entropy) in young adults grouped by objectively measured achievement of either moderate or both moderate and vigorous physical activity recommendations. Of 168 young adults tested (86 females, 82 males; age 20.5 ± 1.2 years), 119 achieved only recommendations for moderate physical activity (moderate group) and 49 achieved recommendations for both moderate and vigorous physical activity (vigorous group). Analysis of covariance controlling for sex, weekly minutes of moderate physical activity, and percentage of body fat was used to assess between-group differences in heart rate variability and heart rate complexity. Logistic regression analysis was used to determine the group characteristics that best predicted high heart rate complexity and vagal indices of heart rate variability. The majority of the autonomic measures were higher (P < 0.05) in the vigorous group, and regression analysis showed that vigorous physical activity was the only multivariate predictor of higher heart rate complexity and higher heart rate variability. Young adults engaged in regular vigorous physical activity were more than twice as likely to have high heart rate complexity than those involved in predominantly moderate exercise. These findings suggest that vigorous physical activity is more closely associated with high heart rate complexity than moderate physical activity in young adults.

Sport Modality and Training Period Determines the Bradycardia Magnitude and their Mechanisms in Elite Athletes

Exercise training (ET) leads to marked resting bradycardia in elite athletes. However, some factors could influence the magnitude of resting bradycardia and its mechanisms of control. PURPOSE: evaluate the influence of sport modality and annual ET period (begging of annual ET - BET and competitive period - CP) on the level of resting heart rate (HR), HR response to head-up tilt test and their mechanisms of control in elite athletes. METHODS: 13 cyclists, 13 runners and 11 rowers (males; 26±3; 29±4 and 24±5years old, respectively, p=0.01 runners vs. rowers) were evaluated. HR was recorded on beat-to-beat basis (ECG) at rest and during head-up tilt test. Intrinsic HR was measured by atropine (0.04µg/kg) and esmolol (500µg/kg) infusions and vagal effect after atropine infusion. The responses to tilt test were expressed as percentage in relation to rest. HR variability was evaluated by time and frequency domains. Non parametric tests were performed (data are shown as median and interquartile range). RESULTS: At rest, runners showed lower HR compared with cyclists at CP [cyclists=50(45/55), runners=44(43/47), rowers=44(43/53)bpm, p<0.03]. Runners and rowers, showed higher vagal effect [cyclists=41(36/46), runners=55(48/59), rowers=50(42/66)bpm, p=0.03] and higher intrinsic HR [cyclists=84(82/87), runners=92(87/94), rowers=96(85/101)bpm, p=0.03] compared with cyclists at CP. Rowers showed higher intrinsic HR than cyclists at BET [cyclists=88(86/92), runners=91(82/99), rowers=95(90/101)bpm, p=0.03]. CP compared with BET decreased vagal effect [41(36/46) vs. 48(43/51)bpm, p<0.05] and intrinsic HR [84(82/87) vs. 88(86/92)bpm, p<0.05] of cyclists. At head-up tilt test, runners showed a lower increase on HR compared with cyclists at BET [cyclists=64(49/73), runners=46(43/55), rowers=53(42/77)%, p<0.05]. Neither sport modality nor ET period influenced HR variability indices (SDNN, rMSSD, pNN50, variance, LF, HF and LF/HF) at rest or tilt test. CONCLUSIONS: Run provokes higher resting bradycardia, mainly mediated by high vagal activity and leads to lower sympathetic activation at head-up tilt test. The bradycardia caused by rowing seems also to be mediated by vagal activity. However, cycling leads to resting bradycardia mainly by decreased intrinsic HR that is exacerbated at CP. Supported by Fapesp

Unilateral high vagal paralysis: Relationship of the severity of swallowing disturbance and types of injuries

To evaluate the prognoses of high vagal lesions and their association with their clinical presentation, and seek to determine the best strategy of management for each patient. Retrospective case series with chart review. Patients following laryngoplasty from 2001 to 2008 at a tertiary referral voice and swallowing center in Taiwan were reviewed. They were divided into two groups according to the etiologies of high vagal trauma. The pre- and posttreatment voice and swallowing functions were reviewed; swallowing status was compared between patient groups. Of 186 consecutive patients who underwent laryngoplasty, 8 females and 9 males were diagnosed of unilateral high vagal damage. One group of 11 patients suffered vagal damaging suddenly from skull base trauma, cerebrovascular accidents, and surgical complications; symptoms of vagal paralysis occurred immediately after those events. The second group was comprised of six patients who lost their high vagal functions gradually from a skull base tumor or mass compression. Feeding tube status was significantly different between the groups. All except one patient in group 2 recovered their voice and swallowing abilities after appropriate laryngoplasty. High vagal nerve damage from skull base surgery or trauma leads to a higher incidence of feeding tube dependency than that from skull base tumor compression. Patients can be treated successfully with an appropriate injection or medialization thyroplasty. Immediate laryngoplasty is suggested for cases right after skull base surgery or trauma.

Dynamic Conduction Defects

Scenario: As a part of a screening regimen, a 24-hour ECG Holter was obtained on a 28-year-old healthy male firefighter. Three different time periods are shown below. The overall recording revealed a normal sinus rhythm with a heart rate range of 37–146/min. Baseline measurements included a blood pressure of 135/60 mm Hg and a body mass index of 31 kg/m2. The firefighter also successfully completed a graded exercise treadmill test using a Bruce protocol, achieving 100% of his maximum heart rate. Other than a previous history of smoking, he had no significant personal or familial medical history of cardiovascular diseases and does not take any medicine.Second degree heart block, Type 1 (T1 and T2), Type II (T3).The first ECG strip (T1) shows regularly irregular sinus bradycardia at rate of 42/min with second degree atrioventricular (AV) heart block Type 1 (also called Mobitz I or Wenchebach). It shows a progressive PR interval prolongation that eventually results in a dropped QRS complex before the cycle starts again. This condition is considered benign and always resembles a conduction defect of the AV node (70%) or His-Purkinje system (30%). Most are asymptomatic and the condition does not warrant further investigations. At T2 the same pattern is observed but the rhythm starts to show irregularly irregular sinus bradycardia (mixed 3:2 and 4:3 patterns). However, at T3 the rhythm shows a new onset first degree AV block with a fixed prolonged PR interval (400/ms) that is followed by a dropped QRS complex, referred to as second degree AV block Type 2 or Mobitz II: a conduction defect that occurs below the AV node. Those with Mobitz II are more likely to experience dizziness and syncope; the AV block is usually associated with right bundle branch block and is more likely to progress to third degree heart block. The prevalence of second degree heart blocks in young adults is as low as 0.003%; these are more prevalent in athletes, children with structural heart diseases, and postmyocardial infarctions. Sometimes they are due to certain medications (eg, beta-blockers).Whereas Mobitz I is not associated with increased risk of morbidity or mortality, Mobitz II is associated with an increased risk of mortality.These abnormalities seen in an asymptomatic firefighter may be related to the high vagal tone (athlete status); however, other etiologies need to be ruled out because cardiovascular diseases and sudden cardiac death account for 45% of on-duty deaths among firefighters. Although the recording was predominantly in normal sinus rhythm, the primary care provider should do a complete history and physical evaluation and refer the firefighter for a cardiology workup, even though he is asymptomatic.

218 High and Low Affinity Vagal CCK-a Receptors Activate Different Signal Transduction Cascades and Ion Channels to Stimulate Nodose Ganglia: Implication in Pancreatic Enzyme Secretion and Satitey Regulation

218 High and Low Affinity Vagal CCK-a Receptors Activate Different Signal Transduction Cascades and Ion Channels to Stimulate Nodose Ganglia: Implication in Pancreatic Enzyme Secretion and Satitey Regulation

Exploring the relationship between vagal tone and event-related potentials in response to an affective picture task

The present study is the first to investigate the relationship between vagal tone level and event-related potentials (ERPs) in adults. Numerous studies have shown a relationship between vagal tone and the individual differences between a variety of psychophysiological, affective, and social outcomes. This suggests that vagal tone can be related to how people process relevant affective social information at the brain level. This study aimed to assess whether the ERP response varies between high and low vagal tone groups, in the face of salient affective information. In the experimental cohort, two groups were separated according to their vagal tone level. ERPs were recorded while individuals performed an affective picture task that included positive, neutral, and negative emotional stimuli. Differences between the high and low vagal tone groups were observed at the early posterior negativity for both positive and negative valences, and at the late positive potential for all the categories. It can be concluded that differences between high and low vagal tone levels are related to differences in the ERPs at early, middle, and late latencies. The results are discussed with respect to the effect of differences between the vagal tone conditions on various stages of information-processing.

Autonomic regulation of the heart during digestion and aerobic swimming in the European sea bass (Dicentrarchus labrax)

The autonomic regulation of the heart was studied in European sea bass (Dicentrarchus labrax) during digestion and aerobic exercise by measuring cardiac output (Q), heart rate (fH), stroke volume (Vs) and oxygen consumption (MO2) before and after pharmacological blockade by intraperitoneal injections of atropine and propranolol. The significant rise in MO2 (134±14 to 174±14mgkg−1h−1) 6h after feeding (3% body mass) caused a significant tachycardia (47.7±10.9 to 72.6±7.2beatsmin−1), but only a small elevation of Q. MO2 of fasting fish increased progressively with swimming speed (0.7–2.1BLs−1) causing a significant tachycardia (43±6 to 61±4mLmin−1kg−1) and increased Q but Vs did not change. Inactive fish were characterized by a high vagal tone (98.3±21.7%), and the tachycardia during digestion and exercise was exclusively due to a reduction of vagal tone, while the adrenergic tone remained low during all conditions. Intrinsic fH, revealed after double autonomic blockade, was not affected by digestion (71±4 and 70±6min−1, respectively), indicating that non-adrenergic, non-cholinergic (NANC) factors do not contribute to the tachycardia during digestion in sea bass.

Recovery of heart rate following intense dynamic exercise

The Olympic biathlon is a very demanding physical event that requires high oxygen delivery, good cross-country skiing skills and skilful use of a rifle. Like all high-performance endurance athletes, high cardiac vagal tone is a characteristic and extends the range over which cardiac output can increase. In the biathlete, however, the enhanced vagal control of the heart also allows a strategy for better control of stability needed for accurately firing a rifle at the end of each lap of the race. The role of endurance training, central command, reflexes from muscle, and of the carotid-cardiac baroreceptor reflex in changing vagal tone during intense exercise and recovery is discussed.

Complete Atrioventricular Block With Bradycardia After Craniotomy

We report an 82-year-old male patient who developed complete atrioventricular block (CAVB) with severe bradycardia 1 hour after craniotomy. After emergency placement of a transvenous pacemaker, the patient's heart rate was restored. Serial assays of serum cardiac enzymes, echocardiography and serum digoxin concentration did not show evidence of myocardial infarction, myocardial injury, or drug toxicity. Tracing back past history, neither syncope nor arrhythmia of any form was noted. A neurogenic heart disorder, high vagal tone, and aging possibly contributed to this cardiac event in this patient. CAVB, although uncommon, is a disastrous complication following craniotomy, and needs aggressive and instantaneous management.