[Coordination, an essential approach to structuring the Covid long patient pathway]. / La coordination, une démarche essentielle pour structurer le parcours patient Covid long.

To meet the care needs of "Covid long" patients, caregivers in the field, under the aegis of regional health agencies, have deployed multi-professional city-hospital collaborations to inform patients and their families and organize adapted care pathways. The clinical situation shared in this article illustrates the commitment of caregivers in the Occitanie region.

How does head position induced intracranial pressure changes impact sympathetic activity and cerebral blood flow?

PURPOSE: Acute head-down-tilt (HDT) simulates short duration hemodynamic impact of microgravity. We sought to determine whether an increase in ICP caused by acute HDT affects sympathetic nervous system activity and cerebral blood flow velocities (CBFV) in healthy male volunteers. METHODS: HDT protocol was established as follows: basal condition immediately followed by gradual negative angles (-10°, -20° and -30°) lasting 10mn and then a return to basal condition. Velocities in the MCA (CBFV) were monitored using TCD. Sympathetic activity was assessed using MSNA. Baroreflex sensitivity (BRS) was measured using the sequence method. ICP changes were assessed using ultrasonography of the optic nerve sheath diameter (ONSD). Cerebral autoregulation (CA) was evaluated by transfer function and the autoregulatory index (Mxa). RESULTS: Twelve male volunteers (age: 35 ± 2 years) were included. Neither blood pressure nor heart rate was significantly modified during HDT. ONSD increased significantly at each step of HDT and remained elevated during Recovery. MSNA burst incidence increased at -30°. A positive correlation between variations in ONSD and variations in MSNA burst incidence was observed at -20°. CBFV were significantly diminished at -20° and -30. In the LF band, the transfer function coherence was reduced at -30° and the transfer function phase was increased at -30° and during Recovery. DISCUSSION: We found that an acute though modest increase in ICP induced by HDT was associated with an increase of sympathetic activity as assessed by MSNA, and with a reduction of CBFV with preserved CA.

Effects of Resistance Exercise and Nutritional Supplementation on Dynamic Cerebral Autoregulation in Head-Down Bed Rest.

Head-down bed rest (HDBR) is commonly considered as ground-based analog to spaceflight and simulates the headward fluid shift and cardiovascular deconditioning associated with spaceflight. We investigated in healthy volunteers whether HDBR, with or without countermeasures, affect cerebral autoregulation (CA). Twelve men (at selection: 34 ± 7 years; 176 ± 7 cm; 70 ± 7 kg) underwent three interventions of a 21-day HDBR: a control condition without countermeasure (CON), a condition with resistance vibration exercise (RVE) comprising of squats, single leg heel, and bilateral heel raises and a condition using also RVE associated with nutritional supplementation (NeX). Cerebral blood flow velocity was assessed using transcranial Doppler ultrasonography. CA was evaluated by transfer function analysis and by the autoregulatory index (Mxa) in order to determine the relationship between mean cerebral blood flow velocity and mean arterial blood pressure. In RVE condition, coherence was increased after HDBR. In CON condition, Mxa index was significantly reduced after HDBR. In contrast, in RVE and NeX conditions, Mxa were increased after HBDR. Our results indicate that HDBR without countermeasures may improve dynamic CA, but this adaptation may be dampened with RVE. Furthermore, nutritional supplementation did not enhance or worsen the negative effects of RVE. These findings should be carefully considered and could not be applied in spaceflight. Indeed, the subjects spent their time in supine position during bed rest, unlike the astronauts who perform normal daily activities.

Short-term effects of a 3-week interval training program on heart rate variability in chronic heart failure. A randomised controlled trial.

BACKGROUND: Exaggerated sympathetic nervous system activity associated with low heart rate variability (HRV) is considered to trigger cardiac arrhythmias and sudden death. Regular exercise training is efficient to improve autonomic balance. OBJECTIVE: We aimed to verify the superiority of high-intensity interval training (HIIT) to enhance HRV, cardiorespiratory fitness and cardiac function as compared with moderate intensity continuous training (MICT) in a short, intense cardiac rehabilitation program. METHODS: This was a prospective, monocentric, evaluator-blinded, randomised (1:1) study with a parallel two-group design. Overall, 31 individuals with voluntary chronic heart failure (CHF) (left ventricular ejection fraction [LVEF]<45%) were allocated to MICT (n=15) or HIIT (n=16) for a short rehabilitation program (mean [SD] 27 [4] days). Participants underwent 24-hr electrocardiography, echocardiography and a cardiopulmonary exercise test at entry and at the end of the study. RESULTS: High-frequency power in normalized units (HFnu%) measured as HRV increased with HIIT (from 21.2% to 26.4%, P<0.001) but remained unchanged with MICT (from 23.1% to 21.9%, P=0.444, with a significant intergroup difference, P=0.003). Resting heart rate (24-hr Holter electrocardiography) decreased significantly for both groups (from 68.2 to 64.6 bpm and 66.0 to 63.5 bpm for MICT and HIIT, respectively, with no intergroup difference, P=0.578). The 2 groups did not differ in premature ventricular contractions. Improvement in peak oxygen uptake was greater with HIIT than MICT (+21% vs. +5%, P=0.009). LVEF improved with only HIIT (from 36.2% to 39.5%, P=0.034). CONCLUSIONS: In this short rehabilitation program, HIIT was significantly superior to the classical MICT program for enhancing parasympathetic tone and peak oxygen uptake. CLINICALTRIALS. GOV IDENTIFIER: NCT03603743.

Outcome associated with prescription of cardiac rehabilitation according to predicted risk after acute myocardial infarction: Insights from the FAST-MI registries.

BACKGROUND: Cardiac rehabilitation is strongly recommended in patients after acute myocardial infarction. AIMS: To assess cardiac rehabilitation prescription after acute myocardial infarction according to predicted risk, and its association with 1-year mortality, using the FAST-MI registries. METHODS: We used data from three 1-month French nationwide registries, conducted 5 years apart from 2005 to 2015, including 13130 patients with acute myocardial infarction admitted to coronary or intensive care units. Atherothrombotic risk stratification was performed using the Thrombolysis In Myocardial Infarction Risk Score for Secondary Prevention (TRS-2P). Patients were classified into three categories: Group 1 (low risk; no or one risk indicator; score of 0 or 1); Group 2 (intermediate risk; two risk indicators; score of 2); and Group 3 (high risk; at least three risk indicators; score of≥3). RESULTS: Among the 12291 patients, cardiac rehabilitation prescription was 43.6% (49.9% in Group 1; 43.0% in Group 2; 35.2% in Group 3). Using Cox multivariable analysis, cardiac rehabilitation prescription was associated with lower mortality at 1 year in the overall population (3.8% vs. 8.2%; hazard ratio [HR] 0.72, 95% confidence interval [CI] 0.61-0.85; P<0.001). Cardiac rehabilitation was associated with improved 1-year mortality, with homogeneous relative risk reductions in low- and intermediate-risk categories (HR 0.70, 95% CI 0.51-0.94) compared with high-risk patients (HR 0.72, 95% CI 0.59-0.88). In absolute terms, however, mortality decrease associated with cardiac rehabilitation was positively correlated with risk level (Group 1, 0.9% vs. 2.4%; Group 2, 3.0% vs. 4.2%; Group 3, 10.5% vs. 17.3%). CONCLUSION: Cardiac rehabilitation prescription was inversely correlated with patient risk. A positive association between cardiac rehabilitation and 1-year survival after acute myocardial infarction was present whatever the risk level, but the greatest mortality reduction was observed in high-risk patients.

The efficacy of transcutaneous electrical nerve stimulation on the improvement of walking distance in patients with peripheral arterial disease with intermittent claudication: study protocol for a randomised controlled trial: the TENS-PAD study.

BACKGROUND: In patients with peripheral arterial disease (PAD), walking improvements are often limited by early pain onset due to vascular claudication. It would thus appear interesting to develop noninvasive therapeutic strategies, such as transcutaneous electrical nerve stimulation (TENS), to improve the participation of PAD patients in rehabilitation programmes, and thus improve their quality of life. Our team recently tested the efficacy of a single 45-min session of 10-Hz TENS prior to walking. TENS significantly delayed pain onset and increased the pain-free walking distance in patients with class-II PAD. We now seek to assess the efficacy of a chronic intervention that includes the daily use of TENS for 3 weeks (5 days a week) on walking distance in Leriche-Fontaine stage-II PAD patients. METHODS/DESIGN: This is a prospective, double-blind, multicentre, randomised, placebo-controlled trial. One hundred subjects with unilateral PAD (Leriche-Fontaine stage II) will be randomised into two groups (1:1). For the experimental group (TENS group): the treatment will consist of stimulation of the affected leg (at a biphasic frequency of 10 Hz, with a pulse width of 200 µs, maximal intensity below the motor threshold) for 45 min per day, in the morning before the exercise rehabilitation programme, for 3 weeks, 5 days per week. For the control group (SHAM group): the placebo stimulation will be delivered according to the same modalities as for the TENS group but with a voltage level automatically falling to zero after 10 s of stimulation. First outcome: walking distance without pain. SECONDARY OUTCOMES: transcutaneous oxygen pressure (TcPO2) measured during a Strandness exercise test, peak oxygen uptake (VO2 peak), endothelial function (EndoPAT®), Ankle-brachial Pressure Index, Body Mass Index, lipid profile (LDL-C, HDL-C, triglycerides), fasting glycaemia, HbA1c level, and the WELCH questionnaire. DISCUSSION: TENS-PAD is the first randomised controlled trial that uses transcutaneous electrical therapy as an adjuvant technique to improve vascular function in the treatment of PAD. If the results are confirmed, this technique could be incorporated into the routine care in cardiovascular rehabilitation centers and used in the long term by patients to improve their walking capacity. TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT02678403 . Registered on 9 February 2016. SPONSOR: Toulouse University Hospital.

Vitamin D deficiency related to physical capacity during cardiac rehabilitation.

BACKGROUND: Vitamin D deficiency is a frequent pathology associated with cardiovascular diseases and physical performance. OBJECTIVE: To study the link between 25-hydroxyvitamin D (25OHD) level and physical performance and gain in physical performance after cardiovascular rehabilitation (CVR) with vitamin D deficiency. METHODS: 25OHD level was assessed in a retrospective cohort of patients admitted for CVR. Data were collected on physical fitness [6-min walk test distance (6MWD) in percentage of predicted, maximal power (Pmax)]. The threshold of vitamin D deficiency was 20ng/ml chosen according to the literature. RESULTS: Among the 131 patients included, as compared with those with nondeficiency (n=83; 63%), patients with vitamin D deficiency (n=48, 37%) had lower initial 6MWD (82±18 vs 89±12% predicted, P=0.009) and Pmax (100±58 vs 120±39W, P=0.006). After CVR, this difference was maintained. The improvement in 6MWD and Pmax was significantly lower with deficiency than nondeficiency, for an increase of 11±8% versus 14±9% predicted (P=0.048) and 10±30 versus 32±30W (P=0.00001), respectively. CONCLUSION: Vitamin D deficiency may be associated with impaired physical fitness before CVR and a smaller gain in physical fitness with CVR, probably related to the action of vitamin D on the muscle.

Exercise training-induced modification in autonomic nervous system: An update for cardiac patients.

Patients with cardiovascular disease show autonomic dysfunction, including sympathetic activation and vagal withdrawal, which leads to fatal events. This review aims to place sympathovagal balance as an essential element to be considered in management for cardiovascular disease patients who benefit from a cardiac rehabilitation program. Many studies showed that exercise training, as non-pharmacologic treatment, plays an important role in enhancing sympathovagal balance and could normalize levels of markers of sympathetic flow measured by microneurography, heart rate variability or plasma catecholamine levels. This alteration positively affects prognosis with cardiovascular disease. In general, cardiac rehabilitation programs include moderate-intensity and continuous aerobic exercise. Other forms of activities such as high-intensity interval training, breathing exercises, relaxation and transcutaneous electrical stimulation can improve sympathovagal balance and should be implemented in cardiac rehabilitation programs. Currently, the exercise training programs in cardiac rehabilitation are individualized to optimize health outcomes. The sports science concept of the heart rate variability (HRV)-vagal index used to manage exercise sessions (for a goal of performance) could be implemented in cardiac rehabilitation to improve cardiovascular fitness and autonomic nervous system function.

Whole-body strength training with Huber Motion Lab and traditional strength training in cardiac rehabilitation: A randomized controlled study.

BACKGROUND: Isometric strengthening has been rarely studied in patients with coronary heart disease (CHD), mainly because of possible potential side effects and lack of appropriate and reliable devices. OBJECTIVE: We aimed to compare 2 different modes of resistance training, an isometric mode with the Huber Motion Lab (HML) and traditional strength training (TST), in CHD patients undergoing a cardiac rehabilitation program. DESIGN: We randomly assigned 50 patients to HML or TST. Patients underwent complete blinded evaluation before and after the rehabilitation program, including testing for cardiopulmonary exercise, maximal isometric voluntary contraction, endothelial function and body composition. RESULTS: After 4 weeks of training (16 sessions), the groups did not differ in body composition, anthropometric characteristics, or endothelial function. With HML, peak power output (P=0.035), maximal heart rate (P<0.01) and gain of force measured in the chest press position (P<0.02) were greater after versus before training. CONCLUSION: Both protocols appeared to be well tolerated, safe and feasible for these CHD patients. A training protocol involving 6s phases of isometric contractions with 10s of passive recovery on an HML device could be safely implemented in rehabilitation programs for patients with CHD and improve functional outcomes.

Reliability and concurrent validity of the Acti'MET calculator: A new tool to assess physical activity in cardiac rehabilitation.

OBJECTIVE: We created a tool for assessing physical activity (PA), the Acti'MET calculator, to quickly estimate weekly energy expenditure. This study aimed to assess the metrological properties of the tool in cardiac rehabilitation (CR). METHODS: Two examiners evaluated the reliability and concurrent validity of the tool with cardiac patients. The validity of the tool was assessed by comparison with other classical methods for measurement of PA such as the Dijon Physical Activity Score (PAS) and the International Physical Activity Questionnaire (IPAQ) score, the 6-min walk test (6MWT) and the cardiopulmonary maximal exercise test. Correlation was assessed by Pearson or Spearman correlation analysis. RESULTS: For the 36 cardiac patients (mean age 55±11 years, 24 men), inter-rater and intra-rater reliabilities were strong: r=0.87 and r=0.98, respectively, both P<0.0001. We found a strong correlation of the Acti'MET score with the IPAQ score (r=0.88, P<0.0001), moderate correlation with the PAS (r=0.39, P<0.05) and 6MWT (r=0.54, P<0.01), and no correlation with peak power output. CONCLUSION: The Acti'MET calculator is reliable, valid and easy to use for assessing PA in CR. This tool seems to well reflect the weekly PA, unlike the PAS, which evaluates PA on a yearly basis.

Improved Walking Claudication Distance with Transcutaneous Electrical Nerve Stimulation: An Old Treatment with a New Indication in Patients with Peripheral Artery Disease.

OBJECTIVE: The aim of this study was to determine whether 45 mins of transcutaneous electrical nerve stimulation before exercise could delay pain onset and increase walking distance in peripheral artery disease patients. DESIGN: After a baseline assessment of the walking velocity that led to pain after 300 m, 15 peripheral artery disease patients underwent four exercise sessions in a random order. The patients had a 45-min transcutaneous electrical nerve stimulation session with different experimental conditions: 80 Hz, 10 Hz, sham (presence of electrodes without stimulation), or control with no electrodes, immediately followed by five walking bouts on a treadmill until pain occurred. The patients were allowed to rest for 10 mins between each bout and had no feedback concerning the walking distance achieved. RESULTS: Total walking distance was significantly different between T10, T80, sham, and control (P < 0.0003). No difference was observed between T10 and T80, but T10 was different from sham and control. Sham, T10, and T80 were all different from control (P < 0.001). There was no difference between each condition for heart rate and blood pressure. CONCLUSIONS: Transcutaneous electrical nerve stimulation immediately before walking can delay pain onset and increase walking distance in patients with class II peripheral artery disease, with transcutaneous electrical nerve stimulation of 10 Hz being the most effective.

Whole-body strength training using a Huber Motion Lab in coronary heart disease patients: safety, tolerance, fuel selection, and energy expenditure aspects and optimization.

OBJECTIVE: The aim of this study was to investigate safety, tolerance, relative exercise intensity, and muscle substrate oxidation during sessions performed on a Huber Motion Lab in coronary heart disease patients. DESIGN: After an assessment of Vo2 peak, 20 coronary heart disease patients participated in two different exercises performed in random order at 40% and 70% (W40 and W70) of the maximal isometric voluntary contraction. RESULTS: No significant arrhythmia or abnormal blood pressure responses occurred during either session, and no muscle soreness was reported within 48 hrs posttest. The authors found a difference between W40 and W70 sessions for mean (standard deviation) ventilation (25.1% [8%] and 32.1% [9%] of maximal ventilation, respectively; P = 0.04) and a small difference for mean (standard deviation) heart rate (73 [7] and 79 [8] beats/min, respectively; P < 0.01). When compared with the W40, the W70 was associated with higher active energy expenditure (2.4 [0.6] and 3.1 [0.9] Kcal/min, respectively; P < 0.0001) and a similar mean (standard deviation) oxygen uptake (5.5 [1] and 6.6 [1] ml/min per kilogram, respectively; P = 0.07). The qualitative percentages of carbohydrates and lipids oxidized were 71% and 29%, respectively, at W40 and 91% and 9%, respectively, at W70. CONCLUSIONS: Both protocols, which consisted of repeating 6-sec phases of contractions with 10 secs of passive recovery on the Huber Motion Lab, seemed to be well tolerated, safe, and feasible in this group of coronary heart disease patients.

Direct evidences for sympathetic hyperactivity and baroreflex impairment in Tako Tsubo cardiopathy.

BACKGROUND: The exact pathophysiology of Tako-Tsubo cardiomyopathy (TTC) remains unknown but a role for sympathetic hyperactivity has been suggested. Up to now, no direct evidence of sympathetic nerve hyperactivity has been established nor involvement of sympathetic baroreflex identified. The aim of our study was to determine, by direct sympathetic nerve activity (SNS) recording if sympathetic nervous system activity is increased and spontaneous baroreflex control of sympathetic activity reduced in patients with TTC. METHODS: We included 13 patients who presented with TTC and compared their SNS activity and spontaneous baroreflex control of sympathetic activity with that of 13 control patients with acutely decompensated chronic heart failure. SNS activity was evaluated by microneurography, a technique assessing muscle sympathetic nerve activity (MSNA). Spontaneous baroreflex control of sympathetic activity was evaluated as the absolute value of the slope of the regression line representing the relationship between spontaneous diastolic blood pressure values and concomitant SNS activity. Control patients were matched for age, sex, left ventricular ejection fraction and creatinine clearance. RESULTS: The mean age of the patients with TTC was 80 years, all patients were women. There were no significant differences between the two groups of patients for blood pressure, heart rate or oxygen saturation level. TTC patients presented a significant increase in sympathetic nerve activity (MSNA median 63.3 bursts/min [interquartile range 61.3 to 66.0] vs median 55.7 bursts/min [interquartile range 51.0 to 61.7]; p = 0.0089) and a decrease in spontaneous baroreflex control of sympathetic activity compared to matched control patients (spontaneous baroreflex control of sympathetic activity median 0.7%burst/mmHg [interquartile range 0.4 to 1.9] vs median 2.4%burst/mmHg [interquartile range 1.8 to 2.9]; p = 0.005). CONCLUSIONS: We report for the first time, through direct measurement of sympathetic nerve activity, that patients with TTC exhibit elevated SNS activity associated with a decrease in spontaneous baroreflex control of sympathetic activity. These data may explain the pathophysiology and clinical presentation of patient with TTC.

Between-day reliability of centre of pressure measures for balance assessment in hemiplegic stroke patients.

BACKGROUND: Stroke patients have impaired postural balance that increases the risk of falls and impairs their mobility. Assessment of postural balance is commonly carried out by recording centre of pressure (CoP) displacements, but the lack of data concerning reliability of these measures compromises their interpretation. The purpose of this study was to investigate the between-day reliability of six CoP-based variables, in order to provide i) reliability data for monitoring postural sway and weight-bearing asymmetry of stroke patients in clinical practice and ii) consistent assessment method of measurement error for applications in physical medicine and rehabilitation. METHODS: Postural balance of 20 stroke patients was assessed in quiet standing on a force platform, in two sessions, 7 days apart. Six CoP-based variables were collected in eyes open and eyes closed conditions: postural sway was assessed with mean and standart deviation of CoP-velocity, CoP-velocity along the mediolateral and anteroposterior axes, and confidence ellipse area (CE(AREA)); weight-bearing asymmetry was assessed with mean CoP position along the mediolateral axis (CoP(ML)). The intraclass correlation coefficient (ICC) was used to determine the level of agreement between test-retest. Small real difference (SRD), corresponding to the smallest change that indicates a real improvement for a single individual, was used to determine the extent of measurement error. RESULTS: ICCs were satisfactory (>0.9) for all CoP-based variables, except for CE(AREA) in eyes open condition and CoP(ML) (<0.8). The SRDs (eyes open/closed conditions) were: 6.1/9.5 mm.s(-1) for mean velocity; 12.3/12.2 mm.s(-1) for standard deviation of CoP-velocity; 3.6/5.5 mm.s(-1) and 4.9/7.3 mm.s(-1) for CoP-velocity in mediolateral and anteroposterior axes, respectively; 17.4/21.4 mm for CoP(ML). Because CE(AREA) showed heteroscedasticity of measurement error distribution, SRD (eyes open/closed conditions) was expressed as a percentage (121/75%) and a ratio (3.68/2.16) obtained after log-antilog procedure. CONCLUSIONS: In clinical practice, the CoP-based velocity variables should be prefer to CE(AREA) to assess and monitor postural sway over time in hemiplegic stroke patients. The poor reliability of CoP(ML) compromises its use to assess weight-bearing asymmetry. The procedure we used could be applied in reliability studies concerning other CoP-based variables or other biological variables in the field of physical medicine and rehabilitation.

Acute electromyostimulation decreases muscle sympathetic nerve activity in patients with advanced chronic heart failure (EMSICA Study).

BACKGROUND: Muscle passive contraction of lower limb by neuromuscular electrostimulation (NMES) is frequently used in chronic heart failure (CHF) patients but no data are available concerning its action on sympathetic activity. However, Transcutaneous Electrical Nerve Stimulation (TENS) is able to improve baroreflex in CHF. The primary aim of the present study was to investigate the acute effect of TENS and NMES compared to Sham stimulation on sympathetic overactivity as assessed by Muscle Sympathetic Nerve Activity (MSNA). METHODS: We performed a serie of two parallel, randomized, double blinded and sham controlled protocols in twenty-two CHF patients in New York Heart Association (NYHA) Class III. Half of them performed stimulation by TENS, and the others tested NMES. RESULTS: Compare to Sham stimulation, both TENS and NMES are able to reduce MSNA (63.5 ± 3.5 vs 69.7 ± 3.1 bursts / min, p < 0.01 after TENS and 51.6 ± 3.3 vs 56.7 ± 3.3 bursts / min, p < 0, 01 after NMES). No variation of blood pressure, heart rate or respiratory parameters was observed after stimulation. CONCLUSION: The results suggest that sensory stimulation of lower limbs by electrical device, either TENS or NMES, could inhibit sympathetic outflow directed to legs in CHF patients. These properties could benefits CHF patients and pave the way for a new non-pharmacological approach of CHF.

Transcatheter aortic valve implantation reduces sympathetic activity and normalizes arterial spontaneous baroreflex in patients with aortic stenosis.

OBJECTIVES: This study sought to measure muscle sympathetic nerve activity (MSNA) in patients with aortic stenosis (AS) before and after transcatheter aortic valve implantation (TAVI) and to compare MSNA with that of control patients. BACKGROUND: TAVI is an emerging therapeutic option in patients with severe AS at high risk of open heart surgery. Whether patients with AS have increased sympathetic activity remains to be established, and the effects of TAVI on the sympathetic nervous system are also unknown. METHODS: We prospectively enrolled 14 patients with severe symptomatic AS treated by TAVI. Fourteen control patients matched for age, body mass index, and unscathed of AS were also included. All patients underwent MSNA and arterial baroreflex gain assessment at baseline and 1 week after TAVI for AS patients. RESULTS: Patients with AS had lower blood pressure (BP) levels, a significant increase in MSNA (61.0 ± 1.7 burst/min vs. 55.4 ± 1.4 burst/min; p < 0.05), and a decrease in arterial baroreflex gain (2.13 ± 0.14% burst/mm Hg vs. 3.32 ± 0.19% burst/mm Hg; p < 0.01) compared with matched control patients. The TAVI procedures induced an increase in BP associated with a significant decrease in MSNA (from 61.0 ± 1.7 burst/min to 54.1 ± 1.0 burst/min; p < 0.01) and was associated with a significant increase in arterial baroreflex gain (from 2.13 ± 0.14% burst/mm Hg to 3.49 ± 0.33% burst/mm Hg; p < 0.01). CONCLUSIONS: We report for the first time, through direct measurement of nerve activity, that patients with AS have increased sympathetic nervous system activity associated with a decrease in sympathetic baroreflex gain and that TAVI normalizes these parameters. This study provides evidence of a new beneficial effect of TAVI, namely, normalization of sympathetic nervous system hyperactivity.

High-intensity interval exercise improves vagal tone and decreases arrhythmias in chronic heart failure.

PURPOSE: Autonomic dysfunction including sympathetic activation and vagal withdrawal has been reported in patients with chronic heart failure (CHF). We tested the hypotheses that high-intensity interval exercise (HIIE) in CHF patients would enhance vagal modulation and thus decrease arrhythmic events. METHODS: Eighteen CHF patients underwent a baseline assessment (CON) and were then randomized to a single session of HIIE and to an isocaloric moderate-intensity continuous exercise (MICE). We evaluated the HR, HR variability parameters, and arrhythmic events by 24-h Holter ECG recordings after HIIE, MICE, and CON sessions. RESULTS: We found that HR was significantly decreased after HIIE (68 ± 3 bpm, P < 0.01) when compared with CON and MICE values (71.1 ± 2 and 69 ± 3 bpm, respectively). HIIE led to a significant increase in normalized high-frequency power (35.95% ± 2.83% vs 31.56% ± 1.93% and 24.61% ± 2.62% for CON and MICE, respectively, P < 0.01). Both exercise conditions were associated with an increase in very low frequency power comparative to CON. After HIIE, premature ventricular contractions were significantly decreased (531 ± 338 vs 1007 ± 693 and 1671 ± 1604 for CON and MICE, respectively, P < 0.01). An association was found between the changes in premature ventricular contraction and the changes in low-frequency/high-frequency ratio (r = 0.66, P < 0.01) in patients exposed to HIIE. CONCLUSION: We demonstrate that a single session of HIIE improves autonomic profile of CHF patients, leading to significant reductions of HR and arrhythmic events in a 24-h posttraining period. Cardioprotective effects of HIIE in CHF patients need to be confirmed in a larger study population and on a long-term basis.

Cardiorenal anemia syndrome in chronic heart failure contributes to increased sympathetic nerve activity.

BACKGROUND: We sought to assess whether cardiorenal anemia syndrome (CRAS) in chronic heart failure (CHF) patients contributes to sympathetic overactivity through modulation of sympathetic reflexes. METHODS AND RESULTS: We prospectively studied 15 patients with CRAS and CHF and 15 control CHF patients, matched for age, gender distribution, type of cardiomyopathy, left ventricular ejection fraction (LVEF) and BMI. We compared muscle sympathetic nerve activity (MSNA) and the effect of peripheral chemoreflex deactivation on MSNA in both groups. We also compared sympathetic baroreflex function, assessed by the slope of the relationship between MSNA and diastolic blood pressure in both groups and while peripheral chemoreflexes were (by breathing 100% oxygen for 15 min) or not deactivated. Baseline MSNA was significantly elevated in CHF patients with CRAS compared with control CHF patients (83.1 ± 4.6 versus 64.9 ± 2.9 bursts/100 heart beats; P<0.05) and sympathetic baroreflex impaired (2.69 ± 0.44 vs 5.25 ± 0.60%bursts/mmHg; P<0.01). Chemoreflex deactivation with administration of 100% oxygen led to a significant decrease in muscle sympathetic nerve activity (77.8 ± 4.7 versus 82.1 ± 4.9 bursts/100 heart beats; P<0.01) and to an increase in sympathetic baroreflex function (2.77 ± 0.45 vs 5.63 ± 0.73%bursts/mmHg; P<0.01) in patients with CRAS and CHF. In contrast, neither room air nor 100% oxygen changed MSNA, hemodynamic or sympathetic baroreflex function in control CHF patients. CONCLUSIONS: CRAS in CHF patients is associated with elevated sympathetic activity mediated by both tonic activation of peripheral chemoreflex and baroreflex impairment.