Evaluation of myocardial work and exercise capacity in patients recovered from the severe form of COVID-19.

Background: The impact of COVID-19 goes beyond its acute form and can lead to the persistence of symptoms and the emergence of systemic disorders, defined as long-term COVID. Methods: We performed a cross-sectional study that included patients over 18 years of age who recovered from the severe form of COVID-19 at least 60 days after their discharge. Patients and controls were enrolled to undergo transthoracic echocardiography (TTE) using a more sensitive tool, myocardial work, in combination with cardiopulmonary exercise testing (CPET). Results: A total of 52 patients and 31 controls were enrolled. Significant differences were observed in ejection fraction (LVEF; 62 ± 7 vs. 66 ± 6 %; p = 0.007), global longitudinal strain (LVGLS; -18.7 ± 2.6 vs. -20.4 ± 1.4 %; p = 0.001), myocardial wasted work (GWW; 152 ± 81 vs. 101 ± 54 mmHg; p = 0.003), and myocardial work efficiency (GWE; 93 ± 3 vs. 95 ± 2 %; p = 0.002). We found a significant difference in peak VO2 (24.4 ± 5.4 vs. 33.4 ± 8.8 mL/kg/min; p < 0.001), heart rate (160 ± 14 vs. 176 ± 11 bpm; p < 0.001), ventilation (84.6 ± 22.6 vs. 104.9 ± 27.0 L/min; p < 0.001), OUES% (89 ± 16 vs. 102 ± 22 %; p = 0.002), T ½ (120.3 ± 32 vs. 97.6 ± 27 s; p = 0.002) and HRR at 2 min (-36 ± 11 vs. -43 ± 13 bpm; p = 0.010). Conclusion: Our findings revealed an increased wasted work, with lower myocardial efficiency, significantly reduced aerobic exercise capacity, and abnormal heart rate response during recovery, which may be related to previously described late symptoms. The reduction in functional capacity during physical exercise is partly associated with a decrease in resting myocardial work efficiency. These findings strongly indicate the need to determine whether these manifestations persist in the long term and their impact on cardiovascular health and quality of life in COVID-19 survivors.

Heart rate response and recovery in cycle exercise testing - normal values and association with mortality.

AIM: Chronotropic incompetence and impaired heart rate (HR) recovery are related to mortality. Guidelines lack specific reference values for HR recovery. We defined normal values and studied blunted HR response and recovery, and mortality risk. METHODS: We included 9,917 subjects (45% females) aged 18-85 years who performed a cycle exercise test. We defined normal values for peak HR, HR reserve, and HR recovery at 1 and 2 minutes (HRR1 and HRR2) based on individuals apparently healthy (N=2,242). Associations between blunted HR indices (<5th percentile) and mortality over a median follow-up of 8.6 years were analysed using Cox regression and competing risk analysis. RESULTS: All HR indices were age-dependent and independent predictors of all-cause and CV mortality. The 5th percentiles of HR reserve, HRR1, and HRR2 correlated weakly with existing reference values. HR recovery variables were the strongest predictors of all-cause mortality (HRR1, hazard ratio 1.70 [95% confidence interval, 1.49-1.94] and HRR2, 1.57 [1.37-1.79]), including in subjects with normal exercise capacity (HRR1, 1.96 [1.61-2.39] and HRR2, 1.76 [1.46-2.12]). Combining HR indices appeared to increase the risk of all-cause (HRR1 and HRR2, 1.96 [1.68-2.29] and peak HR and HRR1, 1.87 [1.56-2.23]) and CV mortality, although no specific combination was superior for predicting CV mortality. CONCLUSIONS: All HR variables were age-dependent and associated with all-cause and CV mortality. Blunted HR recovery variables were the strongest predictors of all-cause mortality, even in subjects with normal exercise capacity. Combined blunted HR indices appeared to add prognostic value.

We provide a detailed description on the physiologic HR response and recovery kinetics in a population apparently CV risk-free referred for cycle exercise testing. When assessed in a larger population, blunted HR response and recovery were associated with increased mortality. HR response and recovery are age-dependent. We provide novel reference values.All blunted HR indices (peak HR, HR reserve, HRR1 and HRR2) are strong predictors of all-cause and CV mortality, and combined HR indices appeared to add prognostic value in all the analyses.Blunted HRR1 followed by HRR2 are the strongest predictor of all-cause mortality even in subjects with normal exercise capacity, highlighting the importance of their assessment in standard exercise testing.

Comparison of autonomic nervous system dysfunction, arterial stiffness, and heart rate recovery according to spinal cord injury level.

OBJECTIVE: To investigate the differences in autonomic nervous system (ANS) dysfunction, arterial stiffness, and the degree of delay in post-exercise heart rate recovery (HRR) according to the level of spinal cord injury (SCI), and propose preventive measures against cardiovascular diseases after SCI. METHODS: This retrospective study included 51 patients with SCI. Based on the neurological level of injury (NLI), patients were divided into two groups: Group A (NLI at and above T6) and Group B (NLI below T6). To assess ANS dysfunction, the head-up tilt test and 24-hour ambulatory blood pressure monitoring were conducted. Arterial stiffness was measured using the pulse wave velocity test. The exercise tolerance test was conducted to measure post-exercise HRR. RESULTS: Group A had significantly higher values in the head-up tilt test and 24-hour ambulatory blood pressure monitoring. In the pulse wave velocity test, both sides (left and right) had significantly higher values in Group B. One minute after the exercise tolerance test, Group A had significantly slower HRR (18.8 ± 11.1 beats/minute) than Group B. CONCLUSION: Understanding the impact of ANS dysfunction and arterial stiffness on HRR in SCI according to NLI may provide insights for clinical management and preventative strategies for cardiovascular diseases.

Recovery of heart rate and heart rate variability after a maximal cardiopulmonary exercise test in novice female runners.

PURPOSE: Previous studies have shown delayed cardiac vagal reactivation after high-intensity endurance exercise when estimated with heart rate variability (HRV). However, the recovery dynamics of RR intervals (RRI) and HRV after a maximal incremental exercise test have been studied less in non-athletic population and especially in females. The main aim of the study was to examine the recovery dynamics of RRI and HRV immediately after a maximal cardiopulmonary exercise test (CPET) in adult females. METHODS: Twenty-eight healthy, novice recreational female runners (33.7 ± 4.2 years) were selected to participate in this study from a larger group of participants (Run RCT). RRIs were collected continuously during a controlled rest, a CPET on a treadmill and a 15-min controlled, passive recovery. Minute-by-minute recovery dynamics were analyzed. RESULTS: The dynamic phase of RRI and heart rate recovery (HRR) (from 192.2 ± 9.9 to 111.4 ± 2.4, P < 0.001) occurred during the first 4.5 min with HRR of 36 ± 10 beats during the first minute of the recovery. Resting heart rate was negatively associated (r = - 0.53, P = 0.016) with HRR during the recovery. No recovery of root mean square of successive RRIs (RMSSD) was detected during the 15-min recovery. RMSSD was 15.0 ± 9.2% of resting values at the end of the recovery. CONCLUSION: No recovery of vagal-derived HRV was detected immediately after a CPET in novice recreational female runners despite marked changes in sympathovagal balance, detected by rapid recovery of RRI during the first 5 min after exercise cessation.

Joint association of sedentary time and physical activity with abnormal heart rate recovery in young and middle-aged adults.

BACKGROUND: Abnormal heart rate recovery (HRR), representing cardiac autonomic dysfunction, is an important predictor of cardiovascular disease. Prolonged sedentary time (ST) is associated with a slower HRR. However, it is not clear how much moderate-to-vigorous physical activity (MVPA) is required to mitigate the adverse effects of sedentary behavior on HRR in young and middle-aged adults. This study aimed to examine the joint association of ST and MVPA with abnormal HRR in this population. METHODS: A cross-sectional analysis was conducted on 1253 participants (aged 20-50 years, 67.8% male) from an observational study assessing cardiopulmonary fitness in Fujian Province, China. HRR measured via cardiopulmonary exercise tests on a treadmill was calculated as the difference between heart rate at peak exercise and 2 min after exercise. When the HRR was ≤ 42 beats·minute-1 within this time, it was considered abnormal. ST and MVPA were assessed by the IPAQ-LF. Individuals were classified as having a low sedentary time (LST [< 6 h·day-1]) or high sedentary time (HST [≥ 6 h·day-1]) and according to their MVPA level (low MVPA [0-149 min·week-1], medium MVPA [150-299 min·week-1], high MVPA [≥ 300 min·week-1]). Finally, six ST-MVPA groups were derived. Associations between ST-MVPA groups with abnormal HRR incidence were examined using logistic regression models. RESULTS: 53.1% of the young and middle-aged adults had less than 300 min of MVPA per week. In model 2, adjusted for possible confounders (e.g. age, sex, current smoking status, current alcohol consumption, sleep status, body mass index), HST was associated with higher odds of an abnormal HRR compared to LST (odds ratio (OR) = 1.473, 95% confidence interval (CI) = 1.172-1.852). Compared with the reference group (HST and low MVPA), the HST and high MVPA groups have a lower chance of abnormal HRR (OR, 95% CI = 0.553, 0.385-0.795). Compared with individuals with HST and low MVPA, regardless of whether MVPA is low, medium, or high, the odds of abnormal HRR in individuals with LST is significantly reduced (OR, 95% CI = 0.515, 0.308-0.857 for LST and low MVPA; OR, 95% CI = 0.558, 0.345-0.902 for LST and medium MVPA; OR, 95% CI = 0.476, 0.326-0.668 for LST and high MVPA). CONCLUSION: Higher amounts of MVPA appears to mitigate the increased odds of an abnormal HRR associated with HST for healthy young and middle-aged adults.

Heart Rate Recovery: Up to Date in Heart Failure-A Literature Review.

The rising prevalence of cardiovascular disease underscores the growing significance of heart failure (HF). Pathophysiological insights into HF highlight the dysregulation of the autonomic nervous system (ANS), characterized by sympathetic overactivity and diminished vagal tone, impacting cardiovascular function. Heart rate recovery (HRR), a metric measuring the heart's ability to return to its baseline rate post-exertion, plays a crucial role in assessing cardiovascular health. Widely applied across various cardiovascular conditions including HF, coronary artery disease (CAD), and arterial hypertension (HTN), HRR quantifies the difference between peak and recovery heart rates. Given its association with elevated sympathetic tone and exercise, HRR provides valuable insights into the perspective of HF, beyond effort tolerance, reaching toward prognostic and mortality indicators. Incorporating HRR into cardiovascular evaluations enhances our understanding of autonomic regulation in HF, offering potential implications for prognostication and patient management. This review addresses the significance of HRR in HF assessment, analyzing recently conducted studies, and providing a foundation for further research and clinical application.

Abnormal Heart Rate Recovery and Chronotropic Incompetence With Exercise in Patients With Interstitial Lung Disease With and Without Pulmonary Hypertension.

Introduction Chronotropic incompetence (CI) and heart rate (HR) recovery at one minute post-exercise (HRR1) have been proposed as indicators of autonomic imbalance. We retrospectively studied the presence of CI and HRR1 attained on cardiopulmonary exercise testing (CPET) in patients with interstitial lung disease (ILD) and those with interstitial lung disease with pulmonary hypertension (ILD-PHTN). Methods A total of 32 patients (21 had ILD alone; 11 had ILD-PHTN) underwent CPET performed per American Thoracic Society protocol on a manually-braked bicycle. HRR1 was defined as the difference between peak HR and HR after one minute post-exercise. The utilization of HR reserve recovery at peak exercise was expressed as Chronotropic Response Index (CRI) and was calculated as (peak HR-resting HR)/(220-age-resting HR). CI was defined by failure to reach 85% of the age-predicted maximum heart rate (APMHR = 200-Age) and CRI<0.80 (80%). Results VO2max was lower in patients with ILD-PHTN compared to ILD alone (14.15± 5.00 vs. 18.11± 4.48, p<0.05). Mean CRI (0.468± 0.179 versus 0.691± 0.210, p<0.05) and HRR1 (10± 7 versus 18± 9, p<0.05) were lower in patients with ILD-PHTN compared to ILD alone. Twenty out of a total of 32 patients (62.5%) met the criteria for CI. In the ILD group, 10 out of 21 patients (47.62%) and in the ILD-PHTN group 10 of 11 patients (90.90%) had CI. Conclusion Chronotropic Incompetence and abnormal heart rate recovery at one minute post-exercise are notable in patients with ILD and are more severe in patients with ILD-PHTN. These findings may contribute to our understanding of dyspnea due to these conditions.

Physical Activity, Fitness, and Cardiac Autonomic Function among Adults Born Postterm.

Recent studies have suggested that adverse outcomes of postterm birth (≥42 completed weeks of gestation), including increased cardiometabolic risk factors, impaired glucose metabolism, and obesity, may extend into adulthood. We studied interconnected determinants of cardiovascular health, including physical activity (based on accelerometry for two weeks), muscular strength (handgrip strength), cardiorespiratory fitness (4-min step test), and cardiac autonomic function (heart rate recovery, heart rate variability, and baroreflex sensitivity) among 46-year-old adults from the Northern Finland Birth Cohort (NFBC) born postterm (n = 805) and at term (n = 2,645). Adults born postterm undertook vigorous-intensity physical activity 2.0 min/day (95% CI 0.4, 3.7) less than term-born adults when adjusted for sex, age, and maternal- and pregnancy-related covariates in multiple linear regression. Postterm birth was associated with reduced cardiorespiratory fitness based on a higher peak heart rate (2.1 bpm, 95% CI 0.9, 3.4) and slower heart rate recovery 30 s after the step test (-0.7 bpm, 95% CI -1.3, -0.1). Postterm birth was associated with lower vigorous-intensity physical activity and cardiorespiratory fitness and slower heart rate recovery in middle age. Our findings reinforce previous suggestions that postterm birth should be included as a perinatal risk factor for adult cardiometabolic disease.

Assessing criterion and longitudinal validity of submaximal heart rate indices as measures of cardiorespiratory fitness: A preliminary study in football.

OBJECTIVES: To evaluate the criterion and longitudinal validity of field- and laboratory-derived heart rate (HR) indices of resting and submaximal fitness tests (SMFTs) as measures of cardiorespiratory fitness. DESIGN: Observational, repeated measures. METHODS: Twenty-nine semi-professional footballers participated. Laboratory assessments took place at the start and end of a preseason training period, whereby resting, SMFT HR-derived indices, and criterion measures of cardiorespiratory fitness (running economy [RE], maximal oxygen uptake [V̇O2 max] and aerobic speed [MAS]) were collected. Throughout this training period, two field-based SMFT protocols, prescribed at different intensities, were administered weekly. Individual slopes were calculated from the analysis of within-athlete change scores. Associations between laboratory and field measures were assessed via Pearson's correlation coefficient (r) and linear regression models. RESULTS: Relationships between SMFT HR-derived indices from laboratory and field were very-large for exercise HR (r = 0.74 to 0.87) and moderate to very-large for HR recovery (0.43 to 0.76). Moderate to very-large inverse relationships were observed between exercise HR and HR recovery with V̇O2 max and MAS (-0.41 to -0.78), whereas resting HR showed no substantial relationships. Changes in exercise HR showed large and very-large inverse correlations with preseason changes in V̇O2 max (-0.54 to -0.60) and MAS (-0.64 to -0.83). Relationships between changes in HR recovery and maximal cardiorespiratory criterion measures were moderate to large (-0.32 to -0.63). CONCLUSION: SMFT exercise HR is a valid proxy measure of cardiorespiratory fitness irrespective of test setting, whereas the validity of HRR remains elusive and appears to vary between exercise intensities.

Unraveling the Mechanisms Behind Exercise Intolerance and Recovery in Long COVID.

BACKGROUND: Patients suffering from long COVID may exhibit autonomic dysregulation. However, the association between autonomic dysregulation and exercise intolerance and the impact of therapeutic interventions on its modulation remains unclear. This study investigated the relationship between heart rate recovery at the first minute (HRR1), a proxy for autonomic imbalance, and exercise intolerance in patients with long COVID. Additionally, the study aimed to assess the effects of a 12-week home-based inspiratory muscle training program on autonomic modulation in this patient population. METHODS: This study is a post hoc subanalysis of a randomized trial in which 26 patients with long COVID were randomly assigned to receive either a 12-week inspiratory muscle training program or usual care alone (NCT05279430). The data were analyzed using Pearson's correlation and linear mixed regression analysis. RESULTS: The mean age was 50.4 ± 12.2 years, and 11 (42.3%) were women. Baseline HRR1 was significantly correlated with maximal functional capacity (peakVO2) (r = 0.402, P = .041). Patients with lower baseline HRR1 (≤22 bpm) exhibited higher resting heart rates and lower peakVO2. Inspiratory muscle training led to a more substantial increase in peakVO2 in patients with lower HRR1 at baseline (P = .019). Additionally, a significant improvement in HRR1 was observed in the IMT group compared to the usual care group after 12-week (Δ +9.39, 95% CI = 2.4-16.4, P = .010). CONCLUSION: Lower baseline HRR1 is associated with exercise intolerance in long COVID patients and may serve as a valuable criterion for identifying individuals likely to benefit more from a home-based inspiratory muscle training program.

Association between serum uric acid and cardiovascular fitness among US adults: A cross-sectional study.

Background: While serum uric acid (SUA) is known as a cardiovascular disease risk factor and is associated with increased cardiovascular mortality, the relationship between SUA and cardiovascular adaptability under exercise stress remains unclear. Aims: This study aims to elucidate the relationship between SUA levels and cardiovascular fitness, particularly as manifested during cardiopulmonary exercise testing. Methods: Utilizing data from the National Health and Nutrition Examination Survey (NHANES) 1999-2004, this study included 5765 participants aged 12-49 years. Heart rate recovery (HRR) during cardiopulmonary exercise testing was measured as an indicator of cardiovascular fitness. Multivariate linear regression analysis was used to explore the association between SUA levels and heart rate recovery at 1 min (HRR1) and 2 min (HRR2) post-exercise. Results: After adjusting for potential confounders, an inverse relationship was found between SUA levels and both HRR1 and HRR2. Multivariate adjusted smoothing spline plots demonstrated a decrease in HRR1 and HRR2 with increasing SUA levels. This negative correlation was observed across nearly all subgroups. Conclusions: Elevated SUA levels are indicative of poorer cardiovascular adaptability in the adult US population.

Association between arterial stiffness and autonomic dysfunction in participants underwent treadmill exercise testing: a cross-sectional analysis.

Data on the impact of arterial stiffness on autonomic function are limited. We sought to investigate whether heart rate recovery (HRR), a predictor of autonomic function, is impaired in patients with increased arterial stiffness. A total of 475 participants (mean age 55.8 ± 11.1 years, 34.3% women) who underwent a treadmill exercise test (TET) for the evaluation of chest pain were retrospectively analyzed. All patients underwent brachial-ankle pulse wave velocity (baPWV) measurement on the same day. HRR was defined as the difference in heart rate from maximal exercise to 1 min of recovery. Participants with the lowest HRR tertile were older and had more cardiovascular risk factors than those with the highest HRR tertile. Simple correlation analysis showed that baPWV was negatively correlated with HRR (r = - 0.327, P < 0.001). In multiple linear regression analysis, there was a significant association between baPWV and HRR, even after adjusting for potential confounders (ß = - 0.181, P < 0.001). In participants who underwent TET, baPWV was negatively correlated with HRR. The results of our study indicate a potential relationship between arterial stiffness and the autonomic nervous system.

High-level competition exercise and related fatigue are associated with stride and jumping characteristics in eventing horses.

BACKGROUND: Fatigue and related injuries to the musculoskeletal system are among the most frequent reasons for the withdrawal of high-level eventing horses from the sport. The safety of both horse and rider is very important, and early detection of fatigue is crucial. OBJECTIVES: To investigate elite eventing horses in competitive events focusing on biomechanical, cardiovascular and metabolic variables across the cross-country test and to identify their potential associations with fatigue. STUDY DESIGN: Prospective observational exploratory field study. METHODS: Observations on 54 cross-country tests of 33 horses at five competitive, high-level events were evaluated using sternal accelerometric analysis of stride parameters between and at the jumps. Blood lactate concentration and heart rate were determined 10 min after finishing. The differences in kinematic parameters between the course start and end were analysed with mixed models for repeated measures. Associations between blood lactate and heart rate recovery with the kinematic variables were quantified with Pearson correlation coefficients. RESULTS: We observed numerous stride characteristics between the jumps and the jumps changing over time during the courses. Blood lactate concentrations were positively correlated with the mean maximal strike power at the jumps in the last minute of the course (r = 0.41; p < 0.001), and the latter was negatively correlated with the mean stride height over the jumps (r = -0.41; p = 0.003). MAIN LIMITATIONS: The sample contained horses of varying breeds, sexes and ages, and different horses participated in different events. CONCLUSIONS: We identified several kinematic changes during a cross-country test depending on event, speed and fatigue.

Attenuated peripheral oxygen extraction and greater cardiac output in women with posttraumatic stress disorder during exercise.

Posttraumatic stress disorder (PTSD) is associated with an increased risk of developing cardiovascular disease, especially in women. Evidence indicates that men with PTSD exhibit lower maximal oxygen uptake (V̇o2max) relative to controls; however, whether V̇o2max is blunted in women with PTSD remains unknown. Furthermore, it is unclear what determinants (i.e., central and/or peripheral) of V̇o2max are impacted by PTSD. Therefore, we evaluated the central (i.e., cardiac output; Q̇c) and peripheral (i.e., arteriovenous oxygen difference) determinants of V̇o2max in women with PTSD; hypothesizing that V̇o2max would be lower in women with PTSD compared with women without PTSD (controls), primarily due to smaller increases in stroke volume (SV), and therefore Q̇c. Oxygen uptake (V̇o2), heart rate (HR), Q̇c, SV, and arteriovenous oxygen difference were measured in women with PTSD (n = 14; mean [SD]: 43 [11] yr,) and controls (n = 17; 45 [11] yr) at rest, and during an incremental maximal treadmill exercise test, and the Q̇c/V̇o2 slope was calculated. V̇o2max was not different between women with and without PTSD (24.3 [5.6] vs. 26.4 [5.0] mL/kg/min; P = 0.265). However, women with PTSD had higher Q̇c [P = 0.002; primarily due to greater SV (P = 0.069), not HR (P = 0.285)], and lower arteriovenous oxygen difference (P = 0.002) throughout exercise compared with controls. Furthermore, the Q̇c/V̇o2 slope was steeper in women with PTSD relative to controls (6.6 [1.4] vs. 5.7 [1.0] AU; P = 0.033). Following maximal exercise, women with PTSD exhibited slower HR recovery than controls (P = 0.046). Thus, despite attenuated peripheral oxygen extraction, V̇o2max is not reduced in women with PTSD, likely due to larger increases in Q̇c.NEW & NOTEWORTHY The current study indicates that V̇o2max is not different between women with and without PTSD; however, women with PTSD exhibit blunted peripheral extraction of oxygen, thus requiring an increase in Q̇c to meet metabolic demand during exercise. Furthermore, following exercise, women with PTSD demonstrate impaired autonomic cardiovascular control relative to sedentary controls. We interpret these data to indicate that women with PTSD demonstrate aberrant cardiovascular responses during and immediately following fatiguing exercise.

The effects of a music intervention on the autonomic nervous system during recovery from strenuous exercise.

OBJECTIVE: To investigate the effect of music on heart rate recovery (HRR) and heart rate variability (HRV) after intense exertion. METHODS: Five hundred male students enrolled at Yongin University, Korea, underwent a cycling test to assess aerobic capacity; 180 students with equal scores were selected for a music intervention, which was conducted after vigorous exercise. The 180 participants were randomized into three music groups and a control group; the participants in each music group listened to music at three different tempos: slow (lento) (n = 45), moderate (moderato) (n = 45), and fast (allegretto) (n = 45). The control group did not listen to music (n = 45). After the test, data on cardiac recovery and HRV were gathered and modeled. RESULTS: The results revealed no significant variation in HRR and HRV indexes between the four cohorts (p > .05), and no significant differences were observed in the anaerobic power cycling indexes during strenuous exercise (p > .05). The music intervention had a significant impact on HR, low-frequency power (LF), high-frequency power (HF), normalized LF (LFnorm ), normalized HF (HFnorm ), and the LF/HF ratio during recovery (p < .05). CONCLUSION: After rigorous activity, listening to allegretto music improved HRR and restored HRV equilibrium, which is critical to preventing and minimizing arrhythmias and sudden cardiac death.

Association of Postexercise Vagal Dysfunction With Protein-Energy Wasting and Noncardiovascular Outcomes in Patients Receiving Hemodialysis: A Retrospective Cohort Study.

OBJECTIVE: Postexercise vagal dysfunction is linked to noncardiovascular mortality in hemodialysis patients, but the mechanism is unknown. This study aimed to determine the association of cardiovagal neuropathy with systemic inflammation, protein-energy wasting, and noncardiovascular hospitalization. METHODS: This 2-center retrospective cohort study analyzed data from 280 hemodialysis patients who underwent exercise test. Patients were assessed for heart rate (HR) recovery (bpm) for 1 minute after exercise, a marker of vagal function, and were divided into 3 categories (Low: ≤ 6, Mid: 7-11, High: ≥ 12 bpm). We followed 1-year changes in the systemic inflammation-based prognostic score (Glasgow Prognostic Score [GPS]), body weight, and creatinine generation rate (CGR), an indicator of muscle mass, as well as 2-year hospitalization. RESULTS: The HR recovery category was associated with serum C-reactive protein and albumin levels and GPS. After 1 year, the low HR recovery category was associated with worsening in GPS (low, 0 [0-0.5]; mid, 0 [0-1]; high, 0 [0-0]), weight (low, 100.0 [96.1-102.5]; mid, 101.3 [98.9-105.0]; high, 100.5 [98.2-102.9]%), and CGR (low, 97.0 [88.5-111.4]; mid, 110.2 [90.9-124.8]; high, 106.2 [95.5-115.5]%), and the correlations with GPS and CGR remained consistent after adjusting for confounders such as exercise capacity and hospitalization during the follow-up period. There were 117 patients hospitalized. Compared to the high HR recovery category, the mid (hazard ratio: 1.8, 95% confidence interval [CI]: 1.1-3.1, P = .02) and low (hazard ratio: 2.4, 95% CI: 1.5-4.0, P = .001) categories were independently associated with an increased risk of all-cause hospitalization. For noncardiovascular disease hospitalization, the low HR recovery category was independently associated with increased risk of hospitalization (hazard ratio: 2.1, 95% CI: 1.2-3.7, P = .007). CONCLUSIONS: Vagal neuropathy in this population can contribute to adverse outcomes associated with systemic inflammation and protein-energy wasting.

Heart rate recovery after orthostatic challenge and cardiopulmonary exercise testing in older individuals: prospective multicentre observational cohort study.

Background: Impaired vagal function in older individuals, quantified by the 'gold standard' delayed heart rate recovery after maximal exercise (HRRexercise), is an independent predictor of cardiorespiratory capacity and mortality (particularly when HRR ≤12 beats min-1). Heart rate also often declines after orthostatic challenge (HRRorthostatic), but the mechanism remains unclear. We tested whether HRRorthostatic reflects similar vagal autonomic characteristics as HRRexercise. Methods: Prospective multicentre cohort study of subjects scheduled for cardiopulmonary exercise testing (CPET) as part of routine care. Before undergoing CPET, heart rate was measured with participants seated for 3 min, before standing for 3 min (HRRorthostatic). HRRexercise 1 min after the end of CPET was recorded. The primary outcome was the correlation between mean heart rate change every 10 s for 1 min after peak heart rate was attained on standing and after exercise for each participant. Secondary outcomes were HRRorthostatic and peak VO2 compared between individuals with HRRexercise <12 beats min-1. Results: A total of 87 participants (mean age: 64 yr [95%CI: 61-66]; 48 (55%) females) completed both tests. Mean heart rate change every 10 s for 1 min after peak heart rate after standing and exercise was significantly correlated (R2=0.81; P<0.0001). HRRorthostatic was unchanged in individuals with HRRexercise ≤12 beats min-1 (n=27), but was lower when HRRexercise >12 beats min-1 (n=60; mean difference: 3 beats min-1 [95% confidence interval 1-5 beats min-1]; P<0.0001). Slower HRRorthostatic was associated with lower peak VO2 (mean difference: 3.7 ml kg-1 min-1 [95% confidence interval 0.7-6.8 ml kg-1 min-1]; P=0.039). Conclusion: Prognostically significant heart rate recovery after exhaustive exercise is characterised by quantitative differences in heart rate recovery after orthostatic challenge. These data suggest that orthostatic challenge is a valid, simple test indicating vagal impairment. Clinical trial registration: researchregistry6550.

N terminal prohormone of brain natriuretic peptide is associated with improved heart rate recovery after treadmill exercise test.

Background: Heart rate recovery (HRR) and N terminal-pro B type natriuretic peptide (NT-proBNP) are markers for survival and cardiac function; however, Little is known about their association. Method: We examined 2540 healthy subjects aged 12-49 years with data from National Health and Nutrition Examination Survey(NHANES) 1999-2002. HRR parameters 1-3 min after exercise were calculated from exercise test results. Baseline characteristics, anthropometric and NT-proBNP, and other risk covariates were obtained. Result: The results showed that NT-proBNP was positively correlated with HRR2(correlation coefficient (cc) = 0.042 [0.029-0.054], P < 0.001) and HRR3(cc = 0.046 [0.029-0.064], P = 0.001); with further adjustment, the associations remained significant between NT-proBNP and HRR2(cc = 0.030 [0.010-0.049], P = 0.004)/HRR3(cc = 0.029[0.004-0.054], P = 0.025). Our study also found significant correlations between NT-pro BNP and SBP(cc = -0.026 [-0.046∼-0.005], P = 0.017), DBP(cc = -0.037 [-0.062∼-0.012], P = 0.005), and total cholesterol(cc = -0.065 [-0.12∼-0.018], P = 0.009). Conclusions: Our results suggest that BNP might reduce heart rate after exercise by inhibiting the sympathetic nervous system (SNS), reducing HRR2 and HRR3, as these phases involve the reduction of heart rate through cardiac sympathetic withdrawal. Moreover, the interaction of BNP on the SNS might be related to the effect of BNP on cardiovascular risks.

Effect of Physical Exercise on Cardiac Autonomic Modulation in Hypertensive Individuals: A Systematic Review and Meta-analysis.

BACKGROUND: Cardiac autonomic dysfunction is associated with hypertension and exercise training (ET) in healthy individuals is found to improve cardiac autonomic modulation (CAM). However, the effects of physical exercise on CAM in hypertensive individuals are under debate. OBJECTIVE: The aim of the review is to systematically evaluate the literature on the effects of physical exercise on CAM in hypertensive individuals and analyse comparative differences in the effects of exercise between hypertensive and normotensive individuals. METHODS: Electronic databases, such as Pubmed, PEDro, Scopus, and Web of Science, were systematically searched from inception up to February, 2022, evaluating the effect of ET on CAM either by heart rate variability (HRV), baroreflex sensitivity or heart rate recovery. Fifteen studies were included in the review. The risk of bias was assessed using the Cochrane risk of bias tool version 2 and the risk of bias in studies of intervention (ROBINS-I) tool. The overall quality of evidence was assessed using the grading of recommendations, assessment, development, and evaluation approach. Ten studies were included in the quantitative analysis. The meta-analysis and sensitivity analysis were performed using review manager 5.4.1; publication bias was assessed using Jamovi 2.2.5 software. RESULTS: The qualitative analysis revealed low to moderate certainty of evidence for ET and moderate for aerobic training. For the effect of overall ET, the analysis revealed that the standardized mean differences (SMD) showed a significant effect of ET on HF (SMD 1.76, p = 0.04) and RMSSD (SMD 1.19, p < 0.0001) and a significant decrease in LF (SMD -1.78, p = 0.04). Aerobic training revealed nonsignificant improvement in HRV parameters. In the comparative analysis, ET did not show a significant difference in improvement between hypertensive and normotensive individuals. CONCLUSION: This review suggests an improvement in CAM with physical exercise in hypertensive individuals, but the overall effect of ET in hypertensive individuals must be interpreted with caution as the robustness of the data is compromised in the sensitivity analysis of the trials. High-quality future trials focusing on different modes of ET interventions are needed to strengthen the findings of the present review.

[Heart rate recovery and presence of coronary lesions in case of ischemic heart disease at the Abidjan Cardiology Institute in Côte d'Ivoire]. / Fréquence cardiaque de récupération et présence de lésions coronaires au cours des cardiopathies ischémiques à l'Institut de cardiologie d'Abidjan en Côte d'Ivoire.

Introduction: Heart rate recovery (HRR) measured during stress tests, assesses the vago-sympathetic balance. It is a known prognostic and predictive parameter of cardiovascular mortality that is believed to be correlated with the presence and severity of coronary artery disease. The aim of this work was to assess the predictive value of heart rate recovery in the diagnostic and severity of coronary lesions in a major metropolis of sub-Saharan Africa where access to specialist care is unevenly distributed. Patients and method: We conducted a retrospective observational study from January 2010 to February 2020 at the Abidjan Cardiology Institute, including patients who performed a diagnostic coronary angiography after a positive exercise test. Clinical, angiographic and exercise parameters were analyzed and compared in patients with abnormal heart rate recovery (HRR) and those with normal one. Results: The main study limitation is small sampling due to the cost of the angiographic procedure which limits its realization. We recorded 41 subjects whose mean age was 53.4 ± 9.6 years with a male predominance (sex ratio of 3.6). The predominant age group was between 50 and 60 years. Males were older than females with no significant difference. The predominant cardiovascular risk factors were overweight/obesity (68.29%) and hypertension (61%). Eight patients (19.5%) presenting an abnormal HRR (≤12 bpm) had more significant coronary disease (p=0.02) and more severe ones (p=0.003). Patients with abnormal HRR tended to be older without statistical significance (p=0.081), and had lower chronotropic reserve and maximum heart rate (p=0.008 and p=0.042, respectively). The positive predictive value of HHR was 87.5% and its negative predictive value was 60.6%. Conclusion: Abnormal HRR can predict the presence of coronary artery disease and its severity. Evaluating HRR during stress tests could help in the detection, evaluation, and monitoring of ischemic heart disease in our resource-limited countries.