Heart Rate Response To Deep Breathing Research Articles

Concurrent chemoradiation therapy is associated with an accelerated risk of cardiovascular autonomic dysfunction in patients with nasopharyngeal carcinoma: A 9-year prospective follow-up study

BackgroundConcurrent chemoradiation therapy (CCRT) is the mainstay treatment for patients with nasopharyngeal carcinoma (NPC). Baroreflex impairment can be a late sequela in patients after neck radiotherapy. We hypothesized that cardiovascular autonomic dysfunction is a progressive process that can begin after CCRT and persists for a longer period. MethodsCardiovascular autonomic function was assessed in 29 newly diagnosed patients with NPC using standardized measures including heart rate response to deep breathing (HRDB), Valsalva ratio (VR), baroreflex sensitivity (BRS), and analyses of heart rate variability (HRV), biomarkers of oxidative stress, and inflammation at three different time points (baseline, immediately after CCRT, and 9 years after enrollment). A healthy control group was recruited for the comparison. ResultsAlthough there was an aging effect on autonomic parameters in both groups during the 9 years of follow-up, the between-group comparison showed that there was a significant decrease in HRDB, VR, and HRV at the 9th year of follow-up in the NPC group. Repeated measures ANOVA after controlling for age and sex showed that both HRDB and triangle index of HRV had statistically significant differences between the two groups. ConclusionBased on our results, cardiovascular autonomic dysfunction after CCRT is a progressive and dynamic process. Cardiovagal impairment occurs in the early phase and persists in decline, while adrenergic dysfunction is significant only after a 9-year follow-up. In contrast to the current opinion, our study showed that both afferent and efferent baroreflex pathways can be involved after CCRT.

Detraining Effect on Pulmonary and Cardiovascular Autonomic Function and Functional Outcomes in Patients With Parkinson's Disease After Respiratory Muscle Training: An 18-Month Follow-Up Study.

Background: The effect of 3-month respiratory muscle training (RMT) on pulmonary and autonomic function and functional outcomes has been demonstrated in patients with Parkinson's disease (PD); however, there is a paucity of information on the durability of the training effect. In this study, we monitored the pulmonary and cardiovascular autonomic function and clinical severity scales until 18 months after the cessation of RMT to elucidate the detraining effect after RMT.Methods: All patients with PD receiving RMT were assessed with clinical severity scales as well as pulmonary and autonomic function tests at four different stages (baseline on enrollment, immediately after 3 months of RMT, and 6 and 18 months after cessation of RMT). A control group of PD patients who did not receive RMT was also recruited for comparison. Pulmonary function parameters, including forced vital capacity (FVC), forced expiratory volume in one second (FEV1), maximum inspiratory pressure (MIP), and maximum expiratory pressure (MEP), were assessed. Cardiovascular autonomic function was assessed using measures including heart rate response to deep breathing (HRDB), Valsalva ratio, and baroreflex sensitivity. Clinical severity scores were also measured using the Hoehn and Yahr staging and the Unified Parkinson's Disease Rating Scale (UPDRS).Results: The results showed significant improvements in MIP, MEP, HRDB, and UPDRS immediately after RMT. Despite some decay, the improvements in pulmonary function (MIP and MEP) and functional outcomes (UPDRS) remained significant until 6 months of detraining (9 months after enrollment). However, the improvement in cardiovascular autonomic function (HRDB) was reversed after 6 months of detraining.Conclusions: Based on these findings, we recommend that RMT may be repeated after at least 6 months after previous session (9 months after enrollment) for patients with PD to maintain optimal therapeutic effects.

Simultaneously Improved Pulmonary and Cardiovascular Autonomic Function and Short-Term Functional Outcomes in Patients with Parkinson’s Disease after Respiratory Muscle Training

Both pulmonary function and autonomic function are impaired in patients with Parkinson’s diseases (PD). This study tested the hypothesis that respiratory muscle training (RMT) can not only improve pulmonary function, but also simultaneously improve cardiovascular autonomic function and short-term functional outcomes in patients with PD. Pulmonary function was measured by the forced vital capacity (FVC), forced expiratory volume in one second (FEV1), maximum inspiratory pressures (MIP), and maximum expiratory pressures (MEP). Cardiovascular autonomic function was measured by the heart rate response to deep breathing (HRDB), Valsalva ratio, baroreflex sensitivity, and spectral analysis. The functional and severity scores were measured by the Hoehn and Yahr stage and Unified Parkinson’s Disease Rating Scale (UPDRS). These measures were evaluated in patients with PD before and after 3 months of RMT, compared with a control group of PD patients without RMT. The results showed significant improvement of clinical scores (total UPDRS and UPDRS I, II and III) after RMT (p < 0.0001). Concerning pulmonary function, the parameters of MIP and MEP improved significantly. The parameters of cardiovascular function also improved after RMT, although only HRDB reached statistical significance. Based on the results of our study, RMT can not only improve both pulmonary and cardiovascular autonomic function, but can also improve short-term functional outcomes in patients with PD.

The Effect of Stroke Subtypes on Baroreceptor Sensitivity, a Predict for Acute Stroke Outcome.

Background Reduced baroreflex sensitivity (BRS) has been reported in patients with acute cardiovascular events. We tested the hypothesis that BRS varies in different subtypes of acute ischemic stroke (AIS) and that BRS is a predictor of clinical outcomes. Methods We examined autonomic parameters in 34 patients with AIS, including the small deep hemisphere infarction, the large hemisphere infarction, and the brainstem infarction groups on Day 1, Day 7, and Day 30 after AIS. Autonomic parameters were also evaluated in 18 age- and sex-matched healthy volunteers as a control group. The clinical outcomes were analyzed using the modified Rankin scale at 30 days after stroke. Results The BRS, Valsalva ratio, and heart rate response to deep breathing (HR-DB) were significantly lower in patients after AIS on admission than in controls (p<0.01). The frequency domain of HRV (LF/HF ratio) was significantly increased in patients after AIS compared to controls (p<0.05). BRS was significantly reduced in patients with large hemisphere infarction or brainstem infarction compared to patients with small deep hemisphere infarction on Day 1 after AIS (p<0.01). Stepwise logistic regression showed that the levels of BRS and NIHSS are prognostic factors of 1-month outcomes in patients with AIS. Conclusion Beside NIHSS score on admission, BRS is a potential prognostic factor of 1-month outcomes in patients with AIS. Patients with large hemisphere infarction or brainstem infarction have more blunting BRS than do those with lacunar infarction, which provides some insight into which patients may be expected to have a poor outcome.

Utility of Time and Frequency Domain Parameters of Heart Rate Variability in the Context of Autonomic Disorders Characterized by Orthostatic Dysfunction.

The clinical significance of heart rate variability in the context of autonomic dysfunction continues to be a matter of debate. A consensus is lacking on the best heart rate variability measures for clinical purposes. Therefore, the purpose of this study was to investigate the utility of heart rate variability parameters in healthy versus autonomic dysfunction. Healthy young (n = 134), healthy older (n = 32), and patients with mild (postural tachycardia syndrome; n = 25) and severe (neurogenic orthostatic hypotension; n = 34) autonomic dysfunction were included. Time and frequency parameters during baseline, head-up tilt (HUT), and heart rate response to deep breathing (HRDB) were compared. Cardiovagal time parameters were significantly reduced during HUT in healthy young and postural tachycardia syndrome (P < 0.001). Healthy young had significantly higher time parameters during baseline, HUT, and HRDB (P < 0.01). This was reflected by a significantly lower resting heart rate (HR) (61.4 ± 9.0 bpm vs. 76.8 ± 13.6 bpm; P < 0.001) and a smaller [INCREMENT]HR during HUT (32.8 ± 10.5 bpm vs. 44.4 ± 13.3 bpm; P < 0.001). Time parameters increased in young and postural tachycardia syndrome during HRDB, which was characterized by a nonsignificant difference in [INCREMENT]HR between both groups. Time parameters were significantly higher in healthy old versus neurogenic orthostatic hypotension at rest and during HRDB (P < 0.05). During HUT, only the SD of all normal RR intervals remained significantly higher. Heart rate changes corroborated these findings. Resting HR was significantly lower in healthy older (62.6 ± 11.0 bpm vs. 70.7 ± 12.4 bpm), and [INCREMENT]HR during HRDB was significantly higher (15.9 ± 9.2 bpm vs. 3.9 ± 4.2 bpm; P < 0.001). During HUT, [INCREMENT]HR showed no significant differences. Time domain parameters of heart rate variability have a greater utility than frequency parameters in clinical autonomic disorders.

Multi-Domain Assessment of Autonomic Function in Spinal Cord Injury Using a Modified Autonomic Reflex Screen.

The aim of this study was to characterize autonomic lesions in participants with spinal cord injury (SCI; n = 10) using an autonomic reflex screen, incorporating sudomotor, cardiovagal, and sympathetic adrenergic tests, as well as hemodynamic responses to head-up tilt (HUT). Hemodynamic responses were compared to healthy controls (n = 20) and previously published normative cutoffs in order better identify autonomic impairments. Sympathetic skin responses (SSRs), heart rate response to deep breathing (HRDB), and heart rate and beat-to-beat blood pressure responses to Valsalva maneuver (VM) and HUT were measured. SCI participants demonstrated impairment in at least one domain, with 7 of 10 demonstrating autonomic impairment across all domains. No single test was concordant with orthostatic hypotension on HUT, in all participants. Measures of cardiovagal function, including HRDB (SCI = 7.7 ± 3.8 beats/min vs. controls = 17.6 ± 8.1 beats/min) and Valsalva ratio (SCI = 1.53 ± 0.29 vs. controls = 1.85 ± 0.37), were significantly reduced in SCI participants, compared to controls (p < 0.05). These findings suggest that an autonomic reflex screen, which includes standardized testing protocol and normative data for comparison, is useful for determining the autonomic domains affected by the neurological injury in SCI. We also demonstrated significant cardiovagal impairment in SCI participants compared to controls, which warrants further investigation to determine whether cardiovagal dysfunction is associated with the negative cardiovascular outcomes, which are known to occur in SCI.

Assessment of autonomic symptoms in a medically complex, urban patient population.

Urban, minority communities are disproportionately affected by the chronic diseases associated with autonomic neuropathy; however validated measures of autonomic symptoms have not been studied in these complex populations. We sought to validate the Autonomic Symptom Profile (ASP) in a low income, medically complex, urban patient population. Ninety-seven adults were recruited from the outpatient neurology clinic of an academic medical center serving the East Harlem neighborhood of New York City. Participants completed the ASP, and underwent a comprehensive neurologic examination, and a standardized battery of autonomic function tests (quantitative sweat testing, heart rate response to deep breathing (HRDB), Valsalva maneuver, and tilt table). Burden of chronic disease was summarized using the Charlson co-morbidity index (CCI), and detailed medication history was obtained. The ASP displayed good internal consistency (Cronbach's α=.88), even among lower literacy participants. In univariate analyses, the ASP was correlated with HRDB (r=-.301, p=.002), a marker of cardiac autonomic neuropathy, with the CCI (r=.37, p<.001), and with use of medications with autonomic effects [t(95)=-2.13, p=.036]. However, in multivariate analysis, only the CCI remained significant. In this urban, predominantly minority patient population, the symptoms captured by the ASP were more closely associated with burden of medical disease than with autonomic dysfunction. Due to this lack of specificity, it is essential that results from autonomic questionnaires be interpreted in the context of the neurologic history and exam, burden of co-morbid illness and medications, and most importantly autonomic function tests.

Headache of neurally mediated syncope.

Neurally mediated syncope and migraine have a complex relationship. The aim of this study was to investigate whether patients developing syncope in the laboratory would experience migraine. Thirty-one consecutive patients were evaluated for precipitation of headache during head-up tilt (HUT)-induced syncope (reduction of systolic blood pressure [SBP] >20 mmHg and prodromal symptoms with or without loss of consciousness). Autonomic functions were assessed using heart rate response to deep breathing (HRDB), Valsalva maneuver and HUT. Blood pressure and heart rate (via electrocardiography) were continuously monitored. Headache diagnosis was based on ICHD-3 criteria. Eighteen patients (58%) experienced syncope without headache and 13 (42%) had syncope and headache (SH). No difference was observed in time of syncope onset, reduction in SBP, Valsalva ratio, HRDB or tachycardia during initial 10 minutes of HUT. Of the 13 SH patients, 11 (85%) had a past history of migraine. Two reported headache just before tilt, eight developed headache during tilt and three developed headache only after tilt. Headache resolved within 1-15 minutes in 10 out of 13 patients. No patient experienced migraine. Syncope did not precipitate migraine. Headache during syncope may be due to cerebral hypoperfusion, and cerebral hyperperfusion may cause post-syncopal headache.

Cardiovagal and somatic sensory nerve functions in healthy subjects.

Heart rate response to deep breathing (HRDB), which depends on the integrity of cardiac vagal preganglionic neurons and efferent fibers, and the function of sural nerve fibers are both associated with an age-related decline process. The aim of this study was to determine whether the effects attributed to aging on cardiovagal and sural nerve function decline are associated. HRDB and sural sensory nerve action potential (SNAP) amplitude, latency, and conduction velocity (SCV) were measured in one hundred healthy asymptomatic subjects (aged 14-92 years, 41 women). Multiple and simple linear regressions were used to analyze the relationships between the variables. There were significant linear relationships between sural SNAP amplitude and HRDB with age. There was also a significant linear relationship between sural SNAP amplitude and HRDB (correlation coefficient 0.46, p<0.0001), but the model explained only 21.5% of the variability in HRDB. Cardiovagal function assessed by HRDB is associated with sural SNAP amplitude in healthy subjects. Age-related decline only partially explained the variability seen in the association. Other genetic and environmental factors may also play a role.

Utility of corrected QT interval in orthostatic intolerance.

We performed this study to determine whether electrocardiographic corrected QT (QTc) interval predicts alterations in sympathovagal balance during orthostatic intolerance (OI). We reviewed 1,368 patients presenting with symptoms suggestive of OI who underwent electrocardiography and composite autonomic function tests (AFTs). Patients with a positive response to the head-up tilt test were classified into orthostatic hypotension (OH), neurocardiogenic syncope (NCS), or postural orthostatic tachycardia syndrome (POTS) groups. A total of 275 patients (159 OH, 54 NCS, and 62 POTS) were included in the final analysis. Between-group comparisons of OI symptom grade, QTc interval, QTc dispersion, and each AFT measure were performed. QTc interval and dispersion were correlated with AFT measures. OH Patients had the most severe OI symptom grade and NCS patients the mildest. Patients with OH showed the longest QTc interval (448.8±33.6 msec), QTc dispersion (59.5±30.3 msec) and the lowest values in heart rate response to deep breathing (HRDB) (10.3±6.0 beats/min) and Valsalva ratio (1.3±0.2). Patients with POTS showed the shortest QTc interval (421.7±28.6 msec), the highest HRDB values (24.5±9.2 beats/min), Valsalva ratio (1.8±0.3), and proximal and distal leg sweat volumes in the quantitative sudomotor axon reflex test. QTc interval correlated negatively with HRDB (r = −0.443, p<0.001) and Valsalva ratio (r = −0.425, p<0.001). We found negative correlations between QTc interval and AFT values representing cardiovagal function in patients with OI. Our findings suggest that prolonged QTc interval may be considered to be a biomarker for detecting alterations in sympathovagal balance, especially cardiovagal dysfunction in OH.

The Autonomic Reflex Screen in Healthy Participants from Southwestern Ontario

The autonomic reflex screen (ARS) is a composite of well-defined tests of various autonomic domains and is an essential part of the diagnosis of autonomic disorders. Institutional and regional differences exist and necessitate the ongoing development of control values for the ARS. Here we present data obtained from healthy participants from Southwestern Ontario. A total of 121 healthy individuals underwent quantitative sudomotor axon reflex testing (QSART), heart rate response to deep breathing (HRDB), and Valsalva maneuver using standard protocols as part of the ARS. Sweat volumes obtained during QSART are presented by site (forearm, proximal leg, distal leg and foot) and by gender. Data is expressed as the mean sweat volume per site with the associated 2.5th, 5th and 95th percentiles. Data for males and females is also stratified by age group (14-25, 26-40 and 41-76 years). Measurements of cardiovagal parasympathetic function including HRDB and Valsalva ratio are stratified by age group (14-25, 26- 40 and 41-76 years). Data is expressed as the mean with associated percentiles (2.5, 5, 95 and 97.5 percentiles). The current manuscript provides control data for the various components of the ARS to aid in the diagnosis of autonomic disorders.

Coat-Hanger Ache of Orthostatic Hypotension? (P05.207)

Objective: To compare the frequency and clinical aspects of coat-hanger ache (CHA) in patients with orthostatic hypotension (OH) (SBP↓ >20 mmHg within 3 minutes of standing) during daily activities versus during head-up tilt (HUT). Background Questionnaires administered to OH patients reveal frequent CHA occurrence (∼90%), but its precipitation during HUT has not been investigated. Design/Methods: Retrospective IRB-approved review of prospectively collected data on 18 dysautonomic patients. Heart rate response to deep breathing (HRDB), Valsalva maneuver (VM), HUT, and thermoregulatory sweat test (TST) evaluated cardiovagal, adrenergic, and sudomotor functions. Occurrence and clinical features of CHA during daily activities and during HUT were recorded. Data were analyzed with descriptive statistics and expressed as mean ± SE. Results: Nine of 18 patients reported precipitation of dull ache or pressure affecting the posterolateral neck and shoulders within 3-10 minutes of standing or after a variable duration of sitting that was relieved within 5-20 minutes of recumbency. During HUT, 3/9 patients developed CHA. The other nine patients were without CHA during daily activities or during HUT. One of three patients who developed CHA during HUT reported amelioration during presyncopal phase. All patients had OH with SBP↓ 57.05 ± 6.02 within 1 minute of HUT. HUT duration tolerated was 5.28 ± 0.83 minutes. Autonomic tests demonstrated severe adrenergic (OH), cardiovagal (HRDB 3.07 ± 0.48 [normal, ≥ 11 bpm] and VR 1.22 ± 0.05 [normal, 1.76 ± 0.03]), and sudomotor (partial or complete anhidrosis) impairment. Conclusions: CHA was reported by 50% of OH patients during daily activities and by only 16.7% during HUT. These observations suggest a lack of direct association between OH and CHA and a complex pathophysiology. Disclosure: Dr. Khurana has nothing to disclose.

Changes in the Autonomic Function after Thoracic Sympathicotomy by Clipping

Background: A thoracic sympathicotomy with cauterization has been reported to decrease cardiac sympathetic activity. The purpose of this study was to investigate immediate changes in autonomic function after thoracic sympathicotomy by clipping. Methods: Autonomic function test such as heart rate response to deep breathing (HRDB), Valsalva ratio (VR), 30/15 ratio and systolic blood pressure change response to standing (SBP) were measured before (baseline) and 2 hr after the T3-4 sympathicotomy by clipping in 12 patients with palmar hyperhidrosis. Baseline data were also compared with data obtained from 18 matched patients who were planned to take minor surgery. Anesthesia was induced with 5 mg/kg thiopental sodium and 0.6 mg/kg rocuronium. The anesthesia was maintained with 2.0-2.5 vol% sevoflurane, 2 L/min nitrous oxide and 2 L/min oxygen. Results: There were no significant differences of the autonomic test results between control and clip group before operation. In the clip group, there were no significant differences of autonomic test results between before and after clipping. Conclusions: This study showed that the response to sympathetic stimulation was not changed after thoracic sympathicotomy by clipping.

Autonomic evaluation by means of standard tests and power spectral analysis in multiple sclerosis.

Standard autonomic tests [heart rate response to deep breathing (HRDB), change in systolic blood pressure due to tilt], and spectral analysis of heart rate (HR), arterial blood pressure (ABP), and the associated transfer function analysis (gains and phases) were performed in 20 patients with multiple sclerosis to determine their diagnostic value. Transfer function analysis suggested impairment of baroreflex function in 7 patients and an alteration of cardiorespiratory coupling on a brain stem level in 4 patients. In addition, sympathetic vasomotor outflow was reduced in 2 patients (spectral ABP measures in the mid frequency band) and a decrease of vagal outflow was suggested by abnormal respiratory HR parameters in another 2 patients. An abnormal HRDB was present in 5 patients and was probably due to a central alteration (cardiorespiratory coupling) in 2 patients and due to diminished respiratory effort in 1 patient. Spectral analysis of both HR and ABP oscillations and their transfer function may considerably improve the pathophysiological interpretation of cardiovascular autonomic dysfunction in patients with central nervous system disease.