Maximum Increase In Heart Rate Research Articles

Deep abdominal breathing reduces heart rate and symptoms during orthostatic challenge in patients with postural orthostatic tachycardia syndrome.

This study investigated the effects of deep abdominal breathing on cardiovascular parameters and symptoms in patients with postural orthostatic tachycardia syndrome (POTS) during head-up tilt-table (HUT) challenge. Thirty POTS patients completed two consecutive rounds of 10-min HUT in a crossover design. One round was HUT without intervention, and one round combined the HUT with deep breathing at a rate of 6 breaths/min. Cardiovascular parameters, including mean blood pressure and maximum and mean heart rate (HR), were measured supine and standing. Symptoms were assessed using the Vanderbilt Orthostatic Symptom Score (VOSS). During the breathing technique, the mean HR increase was -7.35 bpm (95% confidence interval [CI] = -11.71 to -2.98), and the maximum HR increase was -6.27 bpm (95% CI = -11.85 to -0.68, p = 0.041), significantly lower compared to normal breathing. Additionally, improvements were observed in all absolute cardiovascular parameters during standing, with VOSS symptoms simultaneously and significantly decreasing by -5.38 (95% CI = -10.43 to -0.36). Slow deep abdominal breathing can act as a simple technique to reduce the standing HR increase upon HUT in patients with POTS. This suggests that modulation of the cardiopulmonary neurocircuits and the respiratory pump may reduce HR increase and symptoms in patients with POTS. The findings of this study highlight the use of a safe, zero-cost, and simple behavioral tool to suggest to POTS patients for symptom relief apart from standard treatment. The observed improvements in cardiovascular parameters and symptoms offer a promising therapeutic approach for patients in times of inadequate treatment options.

Quantitative autonomic testing after recovery from acute COVID-19 infection: comparison with findings in controls and individuals with neurogenic autonomic dysfunction

Abstract Background/Introduction Cardiovascular autonomic dysfunction (CvAD) is believed to contribute to the persistence of troublesome symptoms following apparent recovery from an acute COVID-19 infection. Common complaints in this setting include cognitive impairment (‘brain fog’), fatigue, and both postural and exertional intolerance with a sensation of excessive rapid heart beating. However, while the occurrence of CvAD post-acute COVID-19 has been widely recognized, its quantitative assessment remains largely unexplored. Purpose The purpose of this study was to determine whether quantitative cardiovascular autonomic testing in post-acute COVID-19 patients differ from findings in Controls and are more similar to individuals with Neurogenic CvAD, such as those with Pure Autonomic Failure. Methods Quantitative autonomic testing was prospectively undertaken in two patient groups: post-acute COVID-19 and Neurogenic CvAD patients, and in control subjects. Acute COVID-19 was documented by the nasopharyngeal PCR method and all affected patients had recovered at least 1 week prior to their autonomic study. Neurogenic CvAD patients were studied as part of their diagnostic evaluation, and none had a COVID-19 infection prior to their study. Measurements included i) heart rate (HR) and blood pressure (BP) responses during active standing (AS), ii) time to BP nadir and time to BP recovery during AS, iii) Valsalva ratio (VR), and iv) respiratory sinus arrhythmia (RSA). The unpaired student t-test and Mann Whitney U test were used to analyze normally and non-normally distributed data, respectively, between post-acute COVID patients and the Control and Neurogenic CvAD patients. All variables were continuous and presented as means with corresponding standard deviations (SD) when normally distributed or interquartile ranges (IQR) when non-normally distributed. A p-value of <0.05 was considered statistically significant. Results Post-acute COVID-19 patients (N=55, 83.6% female) and Controls (N=82, 86.6% female) were of similar age (39 [IQR 27.3, 49.2] vs. 33 [IQR 21.4, 40.0] years, respectively, p=0.034). Neurogenic CvAD patients (N=27, 51.9% female) were older (68 [IQR 62.9, 74.3], p<0.00001). The main findings (Table 1, mean [SD]) indicate that post-acute COVID-19 patients exhibited HR and BP responses during AS similar to the Control group; on the other hand, average VR, maximum systolic BP drop during AS, and maximum HR increase during AS in COVID-19 patients trended towards findings in Neurogenic CvAD patients. Conclusion Recovered post-acute COVID-19 patients referred for autonomic dysfunction evaluation due to persisting symptoms exhibit autonomic testing findings similar to control subjects but trending towards observations in neurogenic CvAD.

Comparing intraosseous computerized anaesthesia with inferior alveolar nerve block in the treatment of symptomatic irreversible pulpitis: A randomized controlled trial.

The aim of this study was to compare the cardiovascular effects [heart rate, oxygen saturation (SpO2 ), systolic and diastolic blood pressure] and the anaesthetic efficacy of intraosseous computerized anaesthesia (ICA) versus inferior alveolar nerve block (IANB) in Symptomatic irreversible pulpitis (SIP). The study protocol was registered with ClinicalTrials.gov (NCT03802305). In a randomized, prospective clinical trial, 72 mandibular molar teeth with SIP were randomly allocated to conventional IANB injection (n = 36) or ICA injection (n = 36), both with 1.8 mL of 4% articaine with 1:100 000 epinephrine. The primary objective was to assess the cardiovascular parameters (heart rate, oxygen saturation, blood pressure) before, during and after the anaesthesia. The secondary objectives were to compare ICA with IANB for success and postoperative outcomes for up to 3 days. The maximum increase in heart rate in the ICA group was greater than in the IANB. Other cardiovascular parameters did not show differences throughout the clinical procedure. There were no statistically significant differences (p > .05) between groups for sex, age, or anxiety. The total success rate of ICA (91.43%) was significantly higher (p = .0034) than that of IANB (69.44%). This study establishes that ICA is safe and efficient in the first intention for the treatment of SIP of the mandibular molar.

Detecting Orthostatic Intolerance in Long COVID in a Clinic Setting.

A likely mechanism of Long COVID (LC) is dysautonomia, manifesting as orthostatic intolerance (OI). In our LC service, all patients underwent a National Aeronautics and Space Administration (NASA) Lean Test (NLT), which can detect OI syndromes of Postural Tachycardia Syndrome (PoTS) or Orthostatic Hypotension (OH) in a clinic setting. Patients also completed the COVID-19 Yorkshire Rehabilitation Scale (C19-YRS), a validated LC outcome measure. Our objectives in this retrospective study were (1) to report on the findings of the NLT; and (2) to compare findings from the NLT with LC symptoms reported on the C19-YRS. NLT data, including maximum heart rate increase, blood pressure decrease, number of minutes completed and symptoms experienced during the NLT were extracted retrospectively, together with palpitation and dizziness scores from the C19-YRS. Mann-Witney U tests were used to examine for statistical difference in palpitation or dizziness scores between patients with normal NLT and those with abnormal NLT. Spearman's rank was used to examine the correlation between the degree of postural HR and BP change with C19-YRS symptom severity score. Of the 100 patients with LC recruited, 38 experienced symptoms of OI during the NLT; 13 met the haemodynamic screening criteria for PoTS and 9 for OH. On the C19-YRS, 81 reported dizziness as at least a mild problem, and 68 for palpitations being at least a mild problem. There was no significant statistical difference between reported dizziness or palpitation scores in those with normal NLT and those with abnormal NLT. The correlation between symptom severity score and NLT findings was <0.16 (poor). We have found evidence of OI, both symptomatically and haemodynamically in patients with LC. The severity of palpitations and dizziness reported on the C19-YRS does not appear to correlate with NLT findings. We would recommend using the NLT in all LC patients in a clinic setting, regardless of presenting LC symptoms, due to this inconsistency.

Effect of sympathetic auricular acupoint in orthostatic response

Objective: To elucidate the effect of auriculopuncture in Sympathetic points on autonomic function, we investigated the heart rate (HR) response to orthostatic challenge in healthy subjects. Design and setting: An experimental and cross-sectional study was conducted at Acupuncture Clinic, Universidad Autónoma Metropolitana, and México. Participants. Twenty healthy university students (twelve women) aged 22.7 ± 1.5 (mean ± SD) participated in the study. Interventions and outcomes: The study consisted of two sessions of auricular acupuncture in the Sympathetic point in the right or left ear. The data for continuous normal beat-to-beat recording to derive the statistical parameters of the normal R-R intervals of the electrocardiogram was obtained using the SphygmoCor equipment (AtCor Medical Pty Ltd, Sidney, Australia). The registration periods were computed in a supine position and then after standing. The primary outcomes were the changes in the velocities of the primary HR increase, bradycardia secondary response, and interval between the times of maximum increase in HR and minimum in secondary response. Results: Acupuncture at the Sympathetic point in the right ear raises the velocity of the initial HR increase and decreases the velocity of bradycardia secondary response and elicits a shortening of the period between the maximum increase and minimum in the secondary response in HR, in all cases significant. Otherwise, auriculopuncture in the Sympathetic point of the left ear did not produce significant changes in the outcomes studied. Conclusion: Data suggest that auriculopuncture in the Sympathetic right point elicits a vagal suppression in the initial orthostatic response to active standing.

Cardiovascular Responses to Nasal Stimulation Under Ethmoidal-Maxillary Nerve Block and Lidocaine Gel in Anesthetized Beagles.

This study aimed to compare the effect of ethmoidal-maxillary nerve block (EMBLOCK) and topical application of 2% lidocaine gel (LGEL) on cardiovascular variables (heart rate and arterial blood pressure) during mechanical stimulation of the nasal cavity. The working hypothesis was that both techniques (EMBLOCK and LGEL) similarly blunt the cardiovascular responses to the stimulation. Six beagles were anesthetized using alfaxalone and isoflurane on three occasions with each treatment (EMBLOCK, LGEL, and control) in random order. The nasal cavity from the nose tip to the medial canthus was stimulated with a standard-tip cotton swab, and cardiovascular variables were recorded before and after stimulation. The maximum increases in heart rate and blood pressure were significantly smaller in EMBLOCK and LGEL than in the control. There was no significant difference between EMBLOCK and LGEL. Therefore, although further clinical studies are required, EMBLOCK and LGEL can be used because both EMBLOCK and LGEL attenuated the cardiovascular response to mechanical stimulation of the nasal cavity in dogs.

Compact MR-compatible ergometer and its application in cardiac MR under exercise stress: A preliminary study.

PurposeTo develop a compact MR‐compatible ergometer for exercise stress and to initially evaluate the reproducibility of myocardial native T1 and myocardial blood flow (MBF) measurements during exercise stress performed on this ergometer.MethodsThe compact ergometer consists of exercise, workload, and data processing components. The exercise stress can be achieved by pedaling on a pair of cylinders at a predefined frequency with adjustable resistances. Ten healthy subjects were recruited to perform cardiac MRI scans twice in a 3.0T MR scanner, at different days to assess reproducibility. Myocardial native T1 and MBF were acquired at rest and during a moderate exercise. The reproducibility of the two tests was determined by the intra‐group correlation coefficient (ICC) and coefficient of variation (CoV).ResultsThe mean exercise intensity in this pilot study was 45 Watts (W), with an exercise duration of 5 min. Stress induced a significant increase in systolic blood pressure (from 113 ± 11 mmHg to 141 ± 12, P < 0.05) and maximal increase in heart rate by 74 ± 19%. The rate pressure product increased two‐fold (P < 0.001). Excellent reproducibility was demonstrated in native T1 during the exercise (CoV = 3.0%), whereas the reproducibility of MBF and myocardial perfusion reserve during the exercise was also good (CoV = 10.7% and 8.8%, respectively).ConclusionThis pilot study demonstrated that it is possible to acquire reproducible measurements of myocardial native T1 and MBF during the exercise stress in healthy volunteers using our new compact ergometer.

Intravenous Dexmedetomidine versus Intravenous Esmolol in Blunting the Laryngoscopy Response in Adult Normotensives Undergoing Elective Surgeries: A Randomised Clinical Trial

Introduction: A wide array of drugs are available for blunting the laryngoscopy response. Amongst them both dexmedetomidine, and esmolol belong to the non-opioid group having least interference with the recovery process without causing significant respiratory depression, thus are suitable intervention for this purpose. Dexmedetomidine a sedative highly selective α2 adrenoceptor agonist and has an anaesthetic-sparing effect at induction. It suppresses the release of catecholamine in response to a noxious stimulant because of its central sympatholytic action. Esmolol with a different pharmacokinetic profile is a water soluble, cardio-selective, an ultrashort acting beta blocker has a short t1/2 thus suited for suppressing the transient pressor reflexes following acute noxious surgical or anesthesia stimuli. Aim: To compare the degree of attenuation of the laryngoscopy response following the use of single preinduction dose (Intravenous infusion at a dose of 1 µg/kg) of dexmedetomidine with that of esmolol (intravenous bolus at a dose of 0.5 mg/kg) in adult normotensives undergoing elective intubations. Materials and Methods: The randomised clinical trial was conducted in Pondicherry Institute of Medical Sciences from September 2016 to March 2018, on 60 patients of either sex, aged between 20-60 years with American Society of Anesthesiologists (ASA) physical status I or II requiring elective intubations for general surgical procedures. The patients were randomly divided into two groups (n=30 each). Prior to induction group A received 1 µg/kg dexmedetomidine IV infusion over 10 min, and group B received 100 mL IV infusion of normal saline over 10 min. Also 2 minute before laryngoscopy group A received 10 mL of normal saline (IV) bolus, whereas, group B received esmolol 0.5 mg/kg IV diluted in 10 mL of normal saline as a bolus. Heart Rate (HR), Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP) and Mean Arterial Pressure (MAP) were recorded at baseline i.e, pre-procedure before the study drug infusion, preinduction, at laryngoscopy (0min) and 1,3,5 min after intubation. A rise of MAP and/or HR more than 20% from the baseline was considered as positive laryngoscopy response. Student’s unpaired t-test was used for analysis of inter group variables. Intra group variables were analysed using repeated measures Analysis Of Variance (ANOVA). Results: Mean age of patients in group A was 38.77±13.082 years and group B was 37.20±13.069 years (p-value=0.644). Results revealed that both the groups had an increase in HR and MAP at 1 minute after laryngoscopy and intubation. Mean readings of MAP showed a maximum rise of group A (2.15%) vs group B (7.25%) from the baseline readings at 1min following laryngoscopy which showed no statistical significance. The maximum HR increase following laryngoscopy was at 1 minute in group A (8.28%) vs group B (13.59%), which were below the positive laryngoscopy response. The mean HR, SBP, DBP and MAP recorded at preinduction, at laryngoscopy, 1, 3 and 5 mins following intubation showed no statistical difference (p-value &gt;0.05) between the two groups. Conclusion: Usage of single dose preinduction dexmedetomidine iv infusion 1 µg/kg over 10 min was found to be equally effective in blunting the pressor response to laryngoscopy and intubation when compared to bolus dose of iv esmolol 0.5 mg/kg given 2 min prior to laryngoscopy.

Does the presence and amount of epinephrine in 2% lidocaine affect its anesthetic efficacy in the management of symptomatic maxillary molars with irreversible pulpitis?

BackgroundThis was a randomized controlled clinical trial that aimed to evaluate the anesthetic efficacy of 2% lidocaine combined with different concentrations of epinephrine (plain, 1:200,000 and 1:80,000) during endodontic treatment of maxillary molars with symptomatic irreversible pulpitis.MethodsThe trial included 144 adult patients who were randomly allocated to three treatment groups. All patients received buccal-plus-palatal infiltration. After 10 min, pulp sensibility testing was performed using an electric pulp test (EPT). If a tooth responded positively, anesthesia was considered to have failed. In the case of a negative EPT response, endodontic access was initiated under rubber dam isolation. The success of anesthesia was defined as having a pain score less than 55 on the Heft Parker visual analog scale (HP VAS), which was categorized as ‘no pain’ or ‘faint/weak/mild’ pain on the HP VAS. Baseline pre-injection and post-injection maximum heart rates were recorded. The Pearson chi-square test was used to analyze the anesthetic success rates at 5% significance.ResultsPlain 2% lidocaine and 2% lidocaine with 1:200,000 epinephrine and 1:80,000 epinephrine had anesthetic success rates of 18.75%, 72.9%, and 82.3%, respectively. Statistical analysis indicated significant differences between the groups (P < 0.001, χ2 = 47.5, df = 2). The maximum heart rate increase was seen with 2% lidocaine solution with epinephrine.ConclusionAdding epinephrine to 2% lidocaine significantly improves its anesthetic success rates during the root canal treatment of maxillary molars with symptomatic irreversible pulpitis.

The effect of exercise training interventions in adult kidney transplant recipients: a systematic review and meta-analysis of randomised control trials

Background Kidney transplant recipients (KTRs) are characterised by adverse changes in physical fitness and body composition. Post-transplant management involves being physically active, although evidence for the effect of exercise is limited. Objective To assess the effects of exercise training interventions in KTRs. Methods NCBI PubMed (MEDLINE) and CENTRAL (EMBASE, WHO ICTRP) databases were searched up to March 2021 to identify eligible randomized controlled trials (RCTs) that studied exercise training in adult KTRs. Outcomes included exercise capacity, strength, blood pressure, body composition, heart rate, markers of dyslipidaemia and renal function, and health-related quality of life (QoL). Results Sixteen RCTs, containing 827 KTRs, were included. The median intervention length was 14-weeks with participants exercising between 2–7x/week. Most studies used a mixture of aerobic and resistance exercise. Significant improvements were observed in cardiorespiratory function (VO2peak) (3.21 ml/kg/min, p = 0.003), 6MWT (76.3 meters, p = 0.009), physical function (STS-60, 4.8 repetitions, p = 0.04), and high-density lipoprotein (HDL) (0.13 mg/dL, p = 0.03). A moderate increase in maximum heart rate was seen (p = 0.06). A moderate reduction in creatinine was also observed (0.14 mg/dl, p = 0.05). Isolated studies reported improvements in strength, bone health, lean mass, and QoL. Overall, studies had high risk of bias suggestive of publication bias. Conclusions Exercise training may confer several benefits in adult KTRs, particularly by increasing cardiorespiratory function and exercise capacity, strength, HDL levels, maximum heart rate, and improving QoL. Additional long-term large sampled RCTs, incorporating complex interventions requiring both exercise and dietary behaviour change, are needed to fully understand the effects of exercise in KTRs.

Comparison of the Active Sitting Test and Head-Up Tilt Test for Diagnosis of Postural Tachycardia Syndrome in Children and Adolescents.

Objectives: We aimed to compare the hemodynamic responses to the active sitting test with the passive head-up tilt test (HUTT) in children and adolescents with postural tachycardia syndrome (POTS). We hypothesized that sitting tachycardia was also present in POTS patients during sitting.Materials and methods: We tested 30 POTS patients and 31 control subjects (mean age = 12 years, range = 9–16 years) who underwent both active sitting test and HUTT successively. We measured the heart rate (HR) and blood pressure (BP) during each test.Results: For both POTS patients and control subjects, the HUTT produced significantly larger HR and BP increases from 3 to 10 min of postural change than did the sitting test. Moreover, POTS patients with excessive orthostatic tachycardia during the HUTT also had significantly larger increases in HR at all test intervals during the sitting test than did the control subjects. A maximum increase in HR ≥ 22 bpm within 10 min of the sitting test was likely suggested to predict orthostatic tachycardia, yielding a sensitivity and specificity of 83.3 and 83.9%, respectively. Only six of 30 POTS patients (20%) reached the 40-bpm criterion during the sitting test, and no one complained of sitting intolerance symptoms.Conclusions: We have shown that POTS patients also have sitting tachycardia when changing from a supine position to a sitting position. We believe that the active sitting test is a reasonable alternative maneuver in assessing POTS in population groups that cannot tolerate the standing test or HUTT.

Study on Haemodynamic Response to Laryngoscopy and Intubation using McCOY and Macintosh Laryngoscopes: A Comparative Approach

Introduction: Laryngoscopy and endotracheal intubation are known to cause increase in arterial blood pressure, heart rate and may be associated with various dysarythmias. This study is done to compare the hemodynamic changes with McCOY laryngoscope and Macintosh laryngoscope in 120 patients who were divided into 2 groups.&#x0D; Methods: A positive correlation has been demonstrated between force exerted at laryngoscopy and patient's height, weight, body mass index (BMI) and presence of maxillary incisors but it was seen that effect of these factors on force exerted with the McCOY blade is not as important as with Macintosh blade. So this study was done to compare the hemodynamic response to laryngoscopy and intubation using McCOY and Macintosh laryngoscope in stress attenuation.&#x0D; Results: Maximum increase in heart rate from the baseline after laryngoscopy in group 2 and a least rise in heart rate from base line in group 1.Group 1 has 9 % increase in heart rate from basal value. Group 2 has 22 % increases in heart rate from basal value. Group 1 has 6 % increase in Systolic BP from basal value Group 2 has 27 % increase in Systolic BP from basal value. Rise in Plasma adrenaline after laryngoscopy was not observed in Laryngoscopy with McCOY blade.&#x0D; Conclusion: McCOY laryngoscope produces significantly less in Hemodynamic parameters when compared with Macintosh blade.So this non­pharmacological intervention of McCOY blade can be utilized as a tool for obtunding hemodynamic responses to laryngoscopy and intubation

Effects of Acute-Partial Sleep Deprivation on High-Intensity Exercise Performance and Cardiac Autonomic Activity in Healthy Adolescents

Performing high-intensity exercise (HIE) in the morning under sleep deprivation may harm the health benefits related to sufficient sleep and HIE. Therefore, the aim of this study was to explore the effects of acute-partial sleep deprivation on HIE performance and cardiac autonomic activity by monitoring heart rate variability (HRV) indices. Twenty-nine healthy male adolescents in college were recruited to perform a one-time HIE session on the treadmill (Bruce protocol) after ≥7 h of normal control sleep (control) and after ≤4 h of acute-partial sleep deprivation (SD). At the beginning of control and SD periods and after exercising under the two sleep conditions, heart rate (HR), standard deviation of normal to normal (SDNN), square root of the mean squared differences of successive NN intervals (RMSSD), normalized low frequency power (LFn), normalized high frequency power (HFn), number of pairs adjacent NN intervals differing by ≥50 ms in the entire recording count divided by the total number of all NN intervals (pNN50), and short axis and long axis value in Poincaré plot (SD1 and SD2) were measured at rest in an upright sitting position. The participants slept 7.63 ± 0.52 and 3.78 ± 0.69 h during control and SD periods, respectively (p &lt; 0.001). Compared with the control participants, those suffering sleep deprivation experienced a significant decrease in exercise duration, RMSSD, HFn, SD1, and pNN50 as well as a significant increase in maximum heart rate during exercise (p &lt; 0.05). SDNN, RMSSD, HFn, SD1, and pNN50 decreased significantly after exercise (p &lt; 0.05 and 0.01 and 0.001, respectively). In summary, acute-partial sleep deprivation affected aerobic exercise performance the next morning and led to decreased cardiac vagus activity and cardiac autonomic dysfunction.

B-PO04-010 THE EFFECT OF CHRONIC NICOTINE EXPOSURE ON CARDIAC ELECTROPHYSIOLOGY IN THE RABBIT HEART

Tobacco smoke exposure is associated with increased risk for atrial and ventricular arrhythmias. However, the individual components of tobacco smoke that may promote arrhythmias and the underlying electrophysiological mechanisms responsible are unknown. Nicotine (NIC) is a major component of tobacco smoke and emerging tobacco products, including e-cigarettes. To determine the effects of chronic NIC exposure on autonomic and electrophysiological remodeling in the rabbit heart. Fully innervated hearts from rabbits exposed to NIC (21mg/day, transdermal patch, 28 days, n=7) or control (CT, n=4) rabbit hearts were optically mapped using voltage- (RH237) and calcium-sensitive (Rhod2-AM) indicators. Sympathetic nerve stimulation (SNS) was performed with electrical stimulation at the first thoracic vertebrae in which voltage was kept constant (7 V) and frequency was increased in 0.5 Hz increments until a 15% increase in heart rate (HR) was achieved. B-adrenergic (B-AR) responsiveness was evaluated with norepinephrine (500nM, NE). Baseline HR was higher in NIC vs. CT (215.8 BPM vs. 151 BPM, p<0.05). SNS stimulation thresholds necessary to produce an increase in HR were higher in NIC vs. CT (4.17 Hz vs. 1.38 Hz, p<0.05). Maximal HR increase after 40s of SNS trended lower in NIC vs. CT (19.38 vs. 54.30% increase, p=0.1). SNS also tended to produce a smaller change in action potential duration (APD80: -8.14 vs. -16.68% decrease, p=NS) and in calcium transient duration (CaTD80: -7.80 vs. - 20.74% decrease, p=NS) in NIC vs. CT. B-AR responsiveness was decreased in NIC vs. CT (33.38 vs. 75.77% increase in HR with NE, p=0.12). These results suggest that chronic NIC exposure may cause baseline sympathetic hyperactivity reduced B-AR sensitivity. Findings from this study will have significant implications for youth and young adults who represent the fastest growing group of nicotine users and the cardiac effects of nicotine on this potentially vulnerable population is unknown. Thus, data from this study may have implications for tobacco products and other nicotine containing products.

ИЗМЕНЕНИЕ ЧАСТОТЫ СЕРДЕЧНЫХ СОКРАЩЕНИЙ И САТУРАЦИИ КРОВИ У ЮНЫХ СПОРТСМЕНОВ-ОРИЕНТИРОВЩИКОВ ПРИ ПРОХОЖДЕНИИ СПОРТИВНЫХ ДИСТАНЦИЙ РАЗНОЙ СЛОЖНОСТИ

Nowadays, youth sport, on a par with professional sport, imposes stringent requirements for physical and emotional preparation of athletes [1]. Orienteering is no exception, where in the system of preparation of young athletes an important task is to control the formation of adequate adaptive reactions to intensive muscular activity [2]. Running orienteering is characterized by performing maximum and even excessive physical loads during different time intervals, which is associated with significant mobilization of energy systems of young athletes’ organism – cardiovascular, respiratory, humoral and metabolic, etc. [2, 3]. Due to the fact that for ethical reasons invasive methods (blood lactate control) of functional diagnostics, as well as some stress tests (load testing «to failure») are often not applicable to school-age children, including orienteering athletes, the search for simple noninvasive, applicable in the field methods of functional state control during and after passing sports distances of different complexity in order to monitor adequacy of training process and prognosis is actual. We think that assessment of blood oxygen saturation degree (SpO2 %), which, according to literature data, reflects real efficiency of cardiorespiratory system operation, is one of such methods along with heart rate (HR) recording [4–9]. SpO2 % determination by direct oximetry has been introduced into clinical practice for quite a long time. However, recently it has become possible to monitor blood oxygen saturation out of clinical control due to the development of portable pulse oximeters for indirect transdermal determination of SpO2 %. However, to date in the scientific literature there are virtually no studies of functional changes in the degree of blood saturation, as well as HR, in young orienteering athletes. Therefore, the aim of our study was to assess the changes in heart rate and peripheral saturation in young orienteering athletes when passing sport distances of different difficulty. After athletic distance the HR values in young athletes increased on average by 130–170 % (boys) and 140–150 % (girls) relative to the values recorded at rest in these subjects. The maximum increase in heart rate was recorded in both groups of test athletes after cross sprint distances – by 177.4 % (p&lt;0.05) and 147.05 % (p&lt;0.05)) cross-long – by 251.6 % (p&lt;0.05) and 141.2 % (p&lt;0.05) for boys and girls respectively, indicating the greatest changes in functional state, particularly tension of energy supply mechanisms during these distances. After cross-sprint and cross-long distances the reliable decrease of peripheral blood saturation ≈ on 1,8 % (p&lt;0,05) at boys and ≈ on 2,6 % (p&lt;0,05) at girls has been registered in young orienteering athletes. The data obtained by us testify to the fact that the passage of distances cross-sprint and cross-long caused the greatest change in blood saturation and tension of mechanisms of their energy supply in young orienteering athletes associated with the development of hypoxic states, caused by lactate acidosis. Significant differences in the dynamics of changes in the studied parameters between the groups of boys and girls 13–14 were recorded only for the saturation index: on the distances cross-sprint and cross-long SpO2 values for both distances for girls were ≈1.03 % (p&lt;0,05) lower than for boys. This indicates that young men have an advantage in adapting to physical loads associated with cross-country sport distances compared to girls of the same age.

Comparison of incidence of oculocardiac reflex between hang-back and conventional rectus recession in horizontal strabismus surgery

To compare the incidence of oculocardiac reflex(OCR) between hang-back and conventional method of rectus muscle recession in horizontal strabismus.In this prospective, randomized, double blind study, 40 consecutive patients of horizontal strabismus were evaluated. The patients were randomized into two groups based on the type of surgical recession technique employed for squint correction. Twenty patients were operated by Hang-back technique (group-1) and 20 by conventional rectus muscle recession where the muscle tendon was sutured directly to the globe (group-2). All patients underwent pre-operative evaluation which included refraction, keratometry and assessment of angle of deviation etc. ECG was monitored before surgery. During surgery heart rate (HR) was recorded as heart rate baseline (HRB), after 5 minutes of intubation (HR5), during muscle traction (HRT), Minimum heart rate during traction of muscle (HRMin), Maximum increase in heart rate (HRMax). OCR was defined as &amp;#62; 20% reduction in HR during muscle traction as compared to baseline HR. Out of total 40 patients 17(42.50%) were having exotropia and 23 (57.50%) had esotropia. The overall incidence of OCR in conventional recession was found to be greater than that in hang-back recession. The mean baseline HR was 72.00± 7.391 beat/min in conventional recession group and 77.55± 7.494 beat/min in hang-back recession group. The mean HR reduction in conventional procedure was 56.05± 8.787 beat/min. and that in hang-back procedure 61.80 ± 9.317 beat/min., which was statistically significant (p&amp;#60;0.01). This was probably attributed to the shorter duration of surgery and lesser manipulation during surgery in hang-back as compared to conventional procedure. OCR is a common complication encountered during manipulation of muscle during strabismus surgery. Hang-back recession is a safe and effective method of muscle recession as it offers a shorter surgical time and better exposure along with lesser incidence of OCR with similar success rates when compared to conventional muscle recession.

Pharmacological stress test for myocardial ischemia when Adenosine is contraindicated: prospective documentation of side effects in over 700 patients with COPD or bronchial asthma

Abstract Background In the face of an increasingly elder population, physical exercise tests become less feasible with an increasing need for pharmacological stress tests, preferably with imaging techniques. For myocardial stress tests provoking myocardial ischemia, vasodilator stress is most frequently used. Whereas Dipyridamole should be obsolete, the predominant drug applied within this context is Adenosine for myocardial scintigraphy, magnetic resonance imaging and FFR. Adenosine, however, is contraindicated in patients with COPD or bronchial asthma, predominantly due to a possible exacerbation of bronchospasm or other pulmonary side effects. In contrast, Regadenoson, was especially developed as a highly selective A2A receptor agonist to circumvent these problems. Methods Regadenoson was applied with the standard injection dose of 400 μg in 780 consecutive patients with a history of COPD or bronchial asthma for SPECT myocardial perfusion scintigraphy. 12% of the patients had a preexisting first degree AV-block. Blood pressure, heart rate and possible side effects were prospectively monitored and documented for 10 minutes after the injection. Results The mean age was 70.8±8.9 years, 52% of the patients were female, 48% were male. 69% had a history of COPD and 31% of bronchial asthma. The maximum increase in heart rate was significant from 66.1±8.1 to 98.3±17.4 bpm. The maximum decrease in systolic blood pressure was significant from 124.3±12.9 to 117.3±24.7 mmHg. Most frequent side effects were a feeling if increased breathing (73%), headache (22%), feeling of warmth (22%), pressure in the stomach (17%) and pressure in the chest (16%). Complications: only 1 patient (without preexisting first degree AV-block) developed a systolic drop in blood pressure from 107 to 60 mmHg with transient severe dyspnoea. No induction of bronchospasm or other pulmonary side effects were observed. Conclusion In patients with COPD or bronchial asthma undergoing a pharmacological stress test, Adenosine is contraindicated due to its – potentially severe – pulmonary side effects, Regadenoson is the vasodilator of choice in these patients. In our series, no severe complication was observed – even not in patients with a preexisting first degree AV-block. Funding Acknowledgement Type of funding source: None

Abstract 491: E-cigarette Aerosol Elevates Cardiovascular Oxidative Stress in Mice With Aldehyde Dehydrogenase 2 Deficiency

Introduction: E-cigarette aerosol contains reactive aldehydes including acetaldehyde, formaldehyde, and acrolein when e-cigarette is heated. Approximately 560 million people worldwide cannot efficiently metabolize aldehydes present in e-cigarette aerosol, due to a genetic deficiency in aldehyde dehydrogenase 2 enzyme (ALDH2), known as ALDH2*2. Little is known how aldehyde exposure from e-cigarettes, coupled with genetic differences in aldehyde metabolism, affects cardiovascular oxidative stress both at a physiological and cellular level. Hypothesis: E-cigarette aerosol exposure will elevate heart rate and cellular oxidative stress more substantially in ALDH2*2 knock-in mice versus wild type ALDH2 mice. Methods: To measure aldehyde levels, e-cigarette Juul aerosols were collected and quantified by selective ion flow gas mass spectrometry. Further, age-matched male wild type and homozygous ALDH2*2 mice (8-10 weeks old, ~25g) were implanted with EKG telemeters. After surgical recovery, mice were paired by genotype (one wild type ALDH2 and one ALDH2*2 mice) and exposed to either Juul aerosol or room air 4 sessions per day for 10 days. For each session, 7 puffs/min were drawn for the first two minutes (a total of 14 puffs), and the whole body exposure to Juul aerosol lasted 7 minutes, continued with 23 minutes smoking-free intervals in each session. Mice EKG waveforms were recorded daily. After 10 days of exposure, heart homogenates were subjected to biochemical assays including lipid peroxidation, 4-HNE protein adduct formation, and protein carbonylation. Results: Quantification of reactive aldehyde levels in e-cigarettes revealed that Juul aerosol contained acetaldehyde (5.3±0.32 ppm), formaldehyde (0.20±0.02 ppm), and acrolein (0.09±0.01 ppm). When exposed to Juul aerosol, ALDH2*2 mice showed a maximal increase in heart rate unlike ALDH2 wild type mice (774.6±29.5 bpm versus 678.9±32.8 bpm respectively, * p &lt;0.01, n=8) at day 6. Furthermore, heart homogenates from ALDH2*2 mice demonstrated exacerbated oxidative stress, including higher level of 4-HNE adducts (1.5-fold), protein carbonyls (1.5-fold) and lipid peroxides (2-fold) relative to hearts from wild type ALDH2 mice, when both genotype mice were exposed to Juul e-cigarette aerosol (n=4/group). Conclusions: These findings indicate e-cigarette aerosols contain reactive aldehydes, primarily acetaldehyde. A deficiency in reactive aldehyde metabolism by having an ALDH2*2 deficiency may contribute to increases in heart rate and oxidative stress within the cardiovascular system while smoking e-cigarettes.

Chronotropic incompetence and myocardial injury after noncardiac surgery: planned secondary analysis of a prospective observational international cohort study

BackgroundPhysiological measures of heart failure are common in surgical patients, despite the absence of a diagnosis. Heart rate (HR) increases during exercise are frequently blunted in heart failure (termed chronotropic incompetence), which primarily reflects beta-adrenoreceptor dysfunction. We examined whether chronotropic incompetence was associated with myocardial injury after noncardiac surgery. MethodsThis was a predefined analysis of an international cohort study where participants aged ≥40 yr underwent symptom-limited cardiopulmonary exercise testing before noncardiac surgery. Chronotropic incompetence was defined as the ratio of increase in HR during exercise to age-predicted maximal increase in HR <0.6. The primary outcome was myocardial injury within 3 days after surgery, defined by high-sensitivity troponin assays >99th centile. Explanatory variables were biomarkers for heart failure (ventilatory efficiency slope [minute ventilation/carbon dioxide production] ≥34; peak oxygen consumption ≤14 ml kg−1 min−1; HR recovery ≤6 beats min−1 decrease 1 min post-exercise; preoperative N-terminal pro-B-type natriuretic peptide [NT pro-BNP] >300 pg ml−1). Myocardial injury was compared in the presence or absence of sympathetic (i.e. chronotropic incompetence) or parasympathetic (i.e. impaired HR recovery after exercise) thresholds indicative of dysfunction. Data are presented as odds ratios (ORs) (95% confidence intervals). ResultsChronotropic incompetence occurred in 396/1325 (29.9%) participants; only 16/1325 (1.2%) had a heart failure diagnosis. Myocardial injury was sustained by 162/1325 (12.2%) patients. Raised preoperative NT pro-BNP was more common when chronotropic incompetence was <0.6 (OR: 1.57 [1.11–2.23]; P=0.011). Chronotropic incompetence was not significantly associated with myocardial injury (OR: 1.05 [0.74–1.50]; P=0.78), independent of rate-limiting therapy. HR recovery <12 beats min−1 decrease after exercise was associated with myocardial injury in the presence (OR: 1.62 [1.05–2.51]; P=0.03) or absence (OR: 1.60 [1.06–2.39]; P=0.02) of chronotropic incompetence. ConclusionsChronotropic incompetence is common in surgical patients. In contrast to parasympathetic dysfunction which was associated with myocardial injury, preoperative chronotropic incompetence (suggestive of sympathetic dysfunction) was not associated with postoperative myocardial injury.

Hemodiafiltración intermitente en línea como terapia de reemplazo renal en paciente crítico: Experiencia en un centro de diálisis de agudo

In critical patients with acute renal failure, intermittent diffusive renal replacement techniques cause hemodynamic problems due to their high depurative efficiency. This situation is avoided using continuous low efficiency therapies, which are expensive, prevent patient mobilization and add hemorrhagic risk due to systemic anticoagulation. Intermittent and prolonged hemodiafiltration (HDF) has the depurative benefits of diffusion, plus the positive attributes of convection in a less expensive therapy. To report our experience with intermittent and prolonged on-line HDF in critically ill patients. During 2016, HDF therapies performed on critical patients with indication of renal replacement therapy were characterized. The hemodynamic profile was evaluated (doses of noradrenaline, blood pressure, heart rate and perfusion parameters). Fifty-one therapies were performed in 25 critical patients, aged 58 ± 11 years (28% women), with an APACHE II score of 22.1 ±10. The average time of the therapies was 4.15 hours (range 3-8 hours), the replacement volume was 75 ± 18 mL/kg/h and ultrafiltration rate was 226 ± 207 mL/h. The mean initial, maximum and final noradrenaline doses were 0.07 ± 0.1, 0.13 ±0.18 and 0.09 ±0.16 μg/kg/min respectively. No differences between patients with low, medium and high doses of noradrenaline or dose increases during therapy, were observed. The greatest decrease in mean arterial pressure was 15.3% and the maximum increase in heart rate was 12.8%. Anticoagulation was not required in 88% of therapies. High-volume intermittent or prolonged HDF is an effective therapy in critical patients, with good hemodynamic tolerability, lower costs and avoidance of systemic anticoagulation risks.