Heart rate variability in myocardial infarction patients: effects of exercise training

Physical activity lowers all-cause and cardio-cerebrovascular mortality in adults with coronary heart disease

BACKGROUND

The health outcomes and their adherence to guideline-based secondary prevention physical activity in US patients with coronary heart disease (CHD), together with the association between physical activity (PA) and mortality risk, were investigated.

METHODS

Data on CHD patients (aged 18 to 85 years) was acquired from the US National Health and Nutrition Examination Survey (NHANES) 1999-2018. The patients were divided into four groups according to the level and frequency of PA, namely, a) sedentary (n = 1178), b) moderate PA (moderate, n = 270), c) vigorous PA once or twice per week (vigorous ≤2×, n = 206), and d) vigorous PA three or more times per week (vigorous >2×, n = 598). Logistic analysis was used to determine the relationship between PA and all-cause or cardio-cerebrovascular mortality in CHD patients.

RESULTS

A total of 2252 patients with CHD were enrolled, of whom 47.69% reported adequate PA. During the investigation, there were 296 (13.14%) cardio-cerebrovascular and 724 (32.15%) all-cause deaths. The incidence of all-cause or cardio-cerebrovascular death was lowest in the vigorous ≤2× group. Patients who undertook vigorous PA ≤ 2× showed the lowest risk of all-cause (odds ratio 0.32; 95% confidence interval 0.22-0.47; P < 0.01) or cardio-cerebrovascular death (odds ratio 0.43; 95% confidence interval 0.25-0.73; P < 0.01) relative to those in the sedentary group. More frequent vigorous PA did not lead to improved benefits.

CONCLUSIONS

Vigorous PA once or twice per week was more effective for reducing all-cause and cardio-cerebrovascular mortality compared with patients performing no or a moderate level of PA in US adults with CHD.

Nocturnal oxygen resaturation parameters are associated with cardiorespiratory comorbidities

BACKGROUND

There are strong associations between oxygen desaturations and cardiovascular outcomes. Additionally, oxygen resaturation rates are linked to excessive daytime sleepiness independent of oxygen desaturation severity. No studies have yet looked at the independent effects of comorbidities or medications on resaturation parameters.

METHODS

The Sleep Heart Health Study data was utilised to derive oxygen saturation parameters from 5804 participants. Participants with a history of comorbidities or medication usage were compared against healthy participants with no comorbidity/medication history.

RESULTS

4293 participants (50.4% female, median age 64 years) were included in the analysis. Females recorded significantly faster resaturation rates (mean 0.61%/s) than males (mean 0.57%/s, p < 0.001), regardless of comorbidities. After adjusting for demographics, sleep parameters, and desaturation parameters, resaturation rate was reduced with hypertension (-0.09 (95% CI -0.16, -0.03)), myocardial infarction (-0.13 (95% CI -0.21, -0.04)) and heart failure (-0.19 (95% CI -0.33, -0.05)), or when using anti-hypertensives (-0.10 (95% CI -0.17, -0.03)), mental health medications (-0.18 (95% CI -0.27, -0.08)) or anticoagulants (-0.41 (95% CI -0.56, -0.26)). Desaturation to Resaturation ratio for duration was decreased with mental health (-0.21 (95% CI -0.34, -0.08)) or diabetic medications (-0.24 (95% CI -0.41, -0.07)), and desaturation to resaturation ratio for area decreased with heart failure (-0.25 (95% CI -0.42, -0.08)).

CONCLUSIONS

Comorbidities and medications significantly affect nocturnal resaturation parameters, independent of desaturation parameters. However, the causal relationship remains unclear. Further research can enhance our knowledge and develop more precise and safer interventions for individuals affected by certain comorbidities.

Beneficial impacts of physical activity on heart rate variability: A systematic review and meta-analysis

BACKGROUND

Cardiovascular diseases (CVD) are the leading causes of morbidity and mortality. Heart rate variability (HRV) represents the modulatory capacity of the autonomous nervous system and influences mortality. By surveying this meta-analysis, we investigated the impact of physical activity on HRV.

METHODS

Databases, online journal libraries and clinical trial registries were searched for publications of randomized controlled and non-randomized controlled trials concerning adults with coronary artery disease (CAD)/ischemic heart disease (IHD), congestive heart failure (CHF), peripheral arterial disease (PAD) or after acute coronary syndrome (ACS) joining an intervention group with physical activity or a control group with usual care or no intervention. Extracted time-domain and frequency-domain parameter of HRV were analyzed in a meta-analysis using a random effect model. Subgroup analyses concerning intervention type, study design and type of heart disease and sensitivity analysis were performed.

RESULTS

Significant results were obtained for RR-Interval (p = 0.05) and standard deviation of Normal-to-Normal intervals (SDNN) (p = 0.01) for short-term assessment and for the ratio of low-frequency power (LF) to high-frequency power (HF) (p = 0.05) for 24-hour assessment. Subgroup analyses also resulted significant: root-mean-square difference of successive normal R-R intervals (RMSSD) (p = 0.01), SDNN (p = 0.02) and HF (p < 0.01) concerning CHF.

CONCLUSION

We were able to demonstrate the positive impact of physical activity on HRV, especially in patients with CHF. Cardiac rehabilitation exercise programs need to be individualized to identify the most beneficial method of training for improving the prognosis of patients with CVD.

Lessons From India: A Narrative Review of Integrating Yoga Within the US Healthcare System

The ancient practice of yoga has gained worldwide popularity as a way for people to improve their overall health and well-being. This manuscript reviews and examines the history of yoga, its physical and mental health benefits, its incorporation into the Indian healthcare system, and the public perception of yoga in India. Many initiatives for yoga exist, including promoting research on yoga, providing education and information on its benefits, and developing evidence-based standardized yoga therapy guidelines. With this in mind, this narrative review article explores the potential benefits of incorporating yoga into the United States (US) healthcare system and the possible challenges of doing so. It also provides valuable insights for policymakers and healthcare professionals.

Response and Adaptation of the Cardiac Autonomic System to Functional High-intensity Interval Training with Respiratory Facemasks: Impacts of the Training Period and Facemask Modality During a COVID-19 Pandemic

Background: Following the SARS-CoV-2 pandemic in 2019, medical face masks were widely recommended for large numbers of people and for long periods of time. The effect of wearing surgical and N95 face masks during long-term high-intensity interval training on the cardiac autonomic system has not been reported. Methods: Eighteen healthy men were randomly divided into three groups (surgical mask, N95 mask, and no mask) and performed high-intensity interval training with (80-90%-heart rate max) intensity three times a week, three repetitions in a session for four weeks. Heart rate variability parameters were evaluated with an electrocardiogram device and Kubius software. The R-R interval was recorded for 5 minutes in a sitting position in the pre-and post-modified Bruce test before and after four weeks of interval training to extract parasympathetic (RMSSD, HF, SD1), sympathetic indices (LF, LF/HF) and RR mean. We used the two-way ANOVA test and the Bonferroni post hoc test. Results: In all groups, four-week functional HIIT exercises increased the resting parasympathetic indices (RMSSD, SD1) compared to baseline levels. This increase was more evident in the N95 mask group than in the surgical mask group. In addition, the five-minute recovery of the cardiac autonomic system after a modified Bruce test following functional HIIT exercise increased parasympathetic tone (RMSSD, HFn.u) in all groups compared to baseline levels. Therefore, a four-week adaptation to HIIT exercises leads to faster recovery of sympathetic indices (LFn.u, LF/HF) in the Nomask group, as compared to the surgical and N95 groups. Despite the above, there was no significant difference in the recovery and resting values of cardiac autonomic system indices between the two types of surgical masks and N95 compared to the control group (No mask). Conclusions: Four weeks of high-intensity interval training using surgical and N95 face masks improved the cardiac autonomic nervous system. This data is important for recommending the use of face masks during physical activity.

Effects of Exercise on Heart Failure with Preserved Ejection Fraction: An Updated Review of Literature

Heart failure with preserved ejection fraction (HFpEF) represents the most common HF phenotype of patients aged > 65 years, with an incidence and a prevalence that are constantly growing. The HFpEF cardinal symptom is exercise intolerance (EI), defined as the impaired ability to perform physical activity and to reach the predicted age-related level of exercise duration in the absence of symptoms—such as fatigue or dyspnea—and is associated with a poor quality of life, a higher number of hospitalizations, and poor outcomes. The evidence of the protective effect between exercise and adverse cardiovascular outcomes is numerous and long-established. Regular exercise is known to reduce cardiovascular events and overall mortality both in apparently healthy individuals and in patients with established cardiovascular disease, representing a cornerstone in the prevention and treatment of many cardio-metabolic conditions. Several studies have investigated the role of exercise in HFpEF patients. The present review aims to dwell upon the effects of exercise on HFpEF. For this purpose, the relevant data from a literature search (PubMed, EMBASE, and Medline) were reviewed. The analysis of these studies underlines the fact that exercise training programs improve the cardiorespiratory performance of HFpEF patients in terms of the increase in peak oxygen uptake, the 6 min walk test distance, and the ventilatory threshold; on the other hand, diastolic or systolic functions are generally unchanged or only partially modified by exercise, suggesting that multiple mechanisms contribute to the improvement of exercise tolerance in HFpEF patients. In conclusion, considering that exercise training programs are able to improve the cardiorespiratory performance of HFpEF patients, the prescription of exercise training programs should be encouraged in stable HFpEF patients, and further research is needed to better elucidate the pathophysiological mechanisms underpinning the beneficial effects described.

Harnessing the benefits of yoga for myositis, muscle dystrophies, and other musculoskeletal disorders

The recent global increase in popularity of home-based yoga, an ancient Indian technique practiced for thousands of years, has translated into its use as a complementary therapy for a multitude of ailments. This review aims to examine the published literature regarding the effects of yoga therapy on systemic chronic diseases; in particular on the inflammatory myopathies (IMs) and other muscle disorders.

Despite the fact that the evidence base for yoga in inflammatory myositis is in its infancy, collateral results in other disorders such as muscular dystrophies are promising. A beneficial effect of yoga in chronic pain has been shown alongside an improvement in motor function and muscle strength. Patients with Duchenne muscular dystrophy with respiratory involvement may find improvement in lung function. Elderly patients may experience reduction in falls secondary to an improvement in balance while practicing long-term yoga therapy.

Further benefits are improving disorders of mental health such as depression and anxiety. A reported improvement in overall quality of life further suggests its efficacy in reducing morbidity in patients with chronic diseases, who often suffer co-existent psychological comorbidities.

Cardiac Autonomic Modulation in Response to Three Types of Exercise in Patients with Type 2 Diabetic Neuropathy

Purpose

Physical exercise is necessary in the handling DM, but it is not distinct which kind of physical exercise can improve cardiac autonomic modulation in T2DM. The purpose of this study was to compare the effects of three different modalities of exercise (aerobic, resistant, and combined) on cardiac autonomic modulation as measured by HRV in patients with type 2 diabetic neuropathy.

Methods

The participants were 45 men (age: 55.24 ± 8.11 years, weight: 89.5 ± 13.4 kg, height: 171.85 ± 6.98 cm, duration of diabetes: 12.51 ± 6.46 years) with type 2 diabetic neuropathy who were clinically free from signs and symptoms of cardiovascular disease. Participants were randomly assigned to one of four groups: aerobic-training (n = 11), dynamic resistant-training (n = 11), Combined-training (n = 11), or a non-exercise control group (n = 12). The exercise groups performed aerobic and resistant exercise for 25-45 min per day, 3-5 times per week for 12 weeks. Anthropometrics, biochemical markers (FBS, HbA1c, Lipid Profile, and Insulin), and heart rate variability in the exercise laboratory and under ambulatory conditions by 3-channel ECG digital Holter recorder were examined.

Results

All time and frequency-domain HRV parameters (except LF power) were significantly improved in the exercise groups, compared with the control group (p < 0.05). SDNN, rMSSD, and HF power were boosted, LF power was not different, and the LF/HF ratio decreased after versus before exercise training, independent of exercise modality. HbA1c in aerobic and resistant-training groups, and insulin and LDL in the resistant-training group were decreased after exercise training (p < 0.05).

Conclusions

Exercise training, independent of modality, in patients with type 2 diabetic neuropathy who were clinically free of the cardiovascular disease cause to significant progress in cardiovascular autonomic function assessed by HRV via enhancing cardio-vagal and reducing cardio-sympathetic tone.

Rehabilitation Programs for Bedridden Patients with Prolonged Immobility: A Scoping Review Protocol

Bedridden patients usually stay in bed for long periods, presenting several motor problems caused by immobility, such as reductions in muscle mass, bone mineral density and physical impairment, resulting in a long recovery process. Thus, identifying physical rehabilitation programs for bedridden patients with prolonged immobility is a matter of urgent research for a solution that will help health professionals and stakeholders to develop more adjusted programs and identify possible gaps. To date, no previous scoping reviews addressing this purpose have been found. This scoping review will be guided by the Joanna Briggs Institute (JBI) methodology, will focus on physical rehabilitation programs for bedridden patients with prolonged immobility and aims to map the programs, the devices used, and the parameters assessed. A relevant set of electronic databases and grey literature will be searched. Data extraction will be conducted using a tool developed by the research team that will address the review objectives and questions. Data synthesis will be presented in tabular form and a narrative summary aligned with the review's objective. This scoping review will contribute to the improvement of clinical practice, identifying key challenges that might justify the need to develop new programs suitable in clinical and organizational contexts.

Acute effects of exercise on cardiac autonomic function and arterial stiffness in patients with stable coronary artery disease

Objectives. To examine the acute effect of a maximal aerobic exercise effort on aortic, peripheral arterial stiffness and cardiovagal modulation of trained and untrained patients with coronary artery disease (CAD). Design. Cross-sectional study. Methods. Eighteen untrained patients with CAD, 18 trained patients with CAD, and 18 apparently healthy trained subjects were sampled and matched for age and body mass index. Aortic and peripheral stiffness were measured by applanation tonometry estimates of carotid-femoral (cfPWV), carotid-radial (crPWV), and carotid-dorsalis pedis pulse wave velocity (cdPWV), respectively. Cardiovagal modulation was assessed by heart-rate variability (HRV) indices including the standard deviation of normal-to-normal RR intervals (SDNN), root-mean-square of successive differences (RMSSD), and the high-frequency power band (HF). cfPWV, crPWV, cdPWV, and HRV indices were measured at rest, 10 and 30 min following a maximal cardiopulmonary exercise test on a cycle ergometer. Results. No differences were observed between groups at rest nor over time in indices of HRV, cfPWV and cdPWV. Still, main effects of time were observed in cfPWV (p < .001; ɳ² = 0.313) and cdPWV (p = .003, ɳ² = 0.111), RMSSD (p < .001, ɳ² = 0.352), HF (p < .001, ɳ² = 0.265) and LF/HF (p = .001, ɳ² = 0.239), as cdPWV, RMSSD, and HF were reduced 10 min following exercise, whereas cfPWV and LF/HF were increased. Changes in cPP were associated with changes in HRV from rest to min 10 (HF, r = 0.302), and to min 30 (HF, r = 0.377; SDNN, r = 0.357; RMSSD, r = 0.429). Conclusion. Training level and CAD do not seem to influence arterial stiffness and cardiac autonomic responses to maximal exercise.

Reduced sympatho-vagal responses to orthostatic stress in drug-naïve idiopathic restless legs syndrome

STUDY OBJECTIVES

Restless legs syndrome (RLS) is known to be a risk factor for cardiovascular disease. However, there are no electrophysiological biomarkers to assess this risk. This study aimed to evaluate heart rate variability (HRV) and cardiovascular reflexes in the supine and standing positions during wakefulness in patients with RLS.

METHODS

Fourteen drug-naïve patients with RLS (12 women and 2 men, mean age, 42.14 ± 7.81 years) and 10 healthy control patients underwent tests for blood pressure, heart rate when in the supine and standing positions, and deep breathing and handgrip tests in controlled laboratory conditions. Data on 5-minute R-R intervals at each position were collected and analyzed for HRV.

RESULTS

Expected cardiovascular reflexes were within the normal range and were similar between the 2 groups. In HRV analysis, the normalized unit of the low-frequency component and the low-frequency/high-frequency ratio during standing were lower in patients with RLS than in the control patients. The low-frequency/high-frequency ratio responses during the change from the supine to the standing position were significantly reduced in patients with RLS (mean ± standard deviation, 2.94 ± 3.11; control patients: 7.51 ± 5.58; P = .042.) On Spearman rank correlation, questionnaires related to sleep problems were associated with the parameters of HRV.

CONCLUSIONS

Patients with RLS showed reduced sympatho-vagal responses during the change from the supine to the upright position during wakefulness, and RLS-related sleep disturbance was a contributing factor for autonomic nervous system dysfunction. This case-control study showed a difference in HRV response to position change in a considerably small group of patients with RLS. The relevance of this finding is uncertain, but it may be worthy of further investigation in longitudinal studies on RLS and cardiovascular disease.

Improvement of Cardiac Function in Rats With Myocardial Infarction by Low-Intensity to Moderate-Intensity Endurance Exercise Is Associated With Normalization of Klotho and SIRT1

ABSTRACT

Exercise training (Ex) has beneficial effects on cardiovascular diseases by increasing Klotho and SIRT1. This study aimed to investigate whether the beneficial impact of Ex on myocardial infarction (MI) is mediated through Klotho and SIRT1. Fifty-six Wistar rats were divided into 4 main groups of Sham, MI, Ex, and MI + Ex. MI was induced by the closure of the left anterior descending. Animals were trained by endurance exercise for 4 weeks. In the end, hemodynamic and heart contractility indices were assessed. The levels of Klotho and SIRT1 in the serum and heart were measured by enzyme-linked immunosorbent assay and Western blot, respectively. The ADAM17 level in the heart and kidneys was assessed by enzyme-linked immunosorbent assay. The infarct size and fibrosis area were assessed by triphenyltetrazolium chloride and Masson trichrome staining, respectively. Ex recovered the reduction of dp/dt max and dp/dt min and decreased myocardial infarct size and fibrotic area in the MI group. Ex normalized the increase in heart rate, systolic blood pressure, left ventricular systolic pressure, and left ventricular end diastolic pressure in the MI group. Ex also normalized the reduction of the levels of Klotho and SIRT1 in serum and heart in the MI group. The changes of Klotho and SIRT1 in serum were positively correlated. Ex also restored ADAM17 levels in the MI group. Ex improved cardiac function in the MI group and is associated with reduction of the infarct size and normalization of Klotho and SIRT1 levels. Regarding unidirectional changes in Klotho and SIRT1, these proteins may play a role in beneficial effects of Ex on MI recovery.

Different physiotherapy protocols after coronary artery bypass graft surgery: A randomized controlled trial

BACKGROUND AND PURPOSE

The aim of this study was to investigate the influence of different physiotherapy protocols on heart rate variability (HRV) and hospital length of stay in older adults undergoing coronary artery bypass graft (CABG).

METHODS

Randomized controlled trial with allocation and researcher blinding and intention-to-treat analysis. Forty-eight patients undergoing CABG were randomly assigned to a control group (CG), early mobilization group (EMG), or virtual reality group (VRG). CG performed respiratory physiotherapy and metabolic exercises, the EMG performed cycle ergometer exercises and ambulation, and the VRG performed the same activities as the EMG, with the addition of two Nintendo Wii games during 3 postoperative days. The variables of heart rate variability on preoperative and fourth postoperative day, and time of discharge of hospital was analyzed.

RESULTS

The VRG presented a shorter hospital length of stay (p = 0.03). The CG showed a decline in HRV from the preoperative period to fourth postoperative day on square root of the mean of the squared differences between successive RR intervals (33.18 ± 9.89-9.74 ± 6.88, p < 0.05), standard deviation of all RR intervals (25.48 ± 7.50-15.23 ± 11.27, p < 0.05), and dispersion of points perpendicular to identity line (28.26 ± 21.6-2.73 ± 1.31, p < 0.05). The EMG and VRG presented a higher cardiac autonomic modulation compared to the CG (p < 0.05), with improved parasympathetic activity.

CONCLUSIONS

Different protocols of physiotherapy intervention affected autonomic modulation of the heart rate and hospital length of stay in patients undergoing CABG.

Sleep heart rate variability assists the automatic prediction of long-term cardiovascular outcomes

OBJECTIVE

We aimed to investigate the association between sleep HRV and long-term cardiovascular disease (CVD) outcomes, and further explore whether HRV features can assist the automatic CVD prediction.

METHODS

We retrospectively analyzed polysomnography (PSG) data obtained from 2111 participants in the Sleep Heart Health Study, who were followed up for a median of 11.8 years after PSG acquisition. During follow-up, 1252 participants suffered CVD events (CVD group) and 859 participants remained CVD-free (non-CVD group). HRV measures, derived from time-domain and frequency-domain, were calculated. Regression models were created to determine the independent predictor for long-term CVD outcomes, and to explore the association between HRV and CVD latency. Furthermore, based on HRV and other clinical features, a model was trained to automatically predict CVD outcomes using the eXtreme Gradient Boosting algorithm.

RESULTS

Compared with the non-CVD group, decreased HRV during sleep was found in the CVD group. HRV, particularly its component of high frequency (HF), was demonstrated to be independent predictor of CVD outcomes. Moreover, normalized HF was positively correlated with CVD latency. The proposed prediction model achieved a total accuracy of 75.3%, in which sleep HRV features served as a supplement to the well-recognized CVD risk factors, such as aging, adiposity and sleep disorders.

CONCLUSIONS

Association between sleep HRV and long-term CVD outcomes was demonstrated here, suggesting that altered HRV during sleep might occur many years prior to the onset of CVD. Machine learning models, combining sleep HRV and other clinical characteristics, should be promising in the early prediction of CVD outcomes.

Modeling of Heart Rate Variability and Respiratory Muscle Activity in Organophosphate Poisoned Patients

We propose an extended model of cardiovascular regulation to assess heart rate variability in patients poisoned with organophosphate during their treatment with mechanical ventilation. The model was modified to fit a population of 21 patients poisoned with organophosphorus compounds and undergoing mechanical ventilation. The extended model incorporated the respiratory muscle activity measured by surface electromyography for quantifying the vagal-sympathetic engagement during spontaneous breathing test. The order and structure of the parasympathetic and the sympathetic transfer function with respect to the original model were modified to a second-order system. In this extended model, the parameters related to the vagal-sympathetic response (corner frequency and constant gain) were correlated with respiratory muscle activity. When the diaphragm's contractions were stronger, the sympathetic corner frequency increased while the parasympathetic corner frequency and gain decreased. Thus, the proposed model could be useful to improve the ventilatory support and pharmacological treatment for patients poisoned with organophosphorus compounds considering the vagal-sympathetic response inferred from the respiratory muscle activity.

Effect of Yoga as an Add-on Therapy in the Modulation of Heart Rate Variability in Children with Duchenne Muscular Dystrophy

Background:

Duchene muscular dystrophy (DMD) is a progressive muscular disorder. Cardiac disorder is the second-most common cause of death in children with DMD, with 10%–20% of them dying of cardiac failure. Heart rate variability (HRV) is shown to be a predictor of cardio-autonomic function. Physiotherapy (PT) is advised for these children as a regular treatment for maintaining their functional status. The effect of yogic practices on the cardio-autonomic functions has been demonstrated in various neurological conditions and may prove beneficial in DMD.

Materials and Methods:

In this study, 124 patients with DMD were randomized to PT alone or PT with yoga intervention. Home-based PT and yoga were advised. Adherence was serially assessed at a follow-up interval of 3 months. Error-free, electrocardiogram was recorded in all patients at rest in the supine position. HRV parameters were computed in time and frequency domains. HRV was recorded at baseline and at an interval of 3 months up to 1 year. Repeated-measures ANOVA was used to analyze longitudinal follow-up and least significant difference for post hoc analysis and P < 0.05 was considered statistically significant.

Results:

In our study, with PT protocol, standard deviation of NN, root of square mean of successive NN, total power, low frequency, high-frequency normalized units (HFnu), and sympathovagal balance improved at varying time points and the improvement lasted up for 6–9 months, whereas PT and yoga protocol showed an improvement in HFnu during the last 3 months of the study period and all the other parameters were stable up to 1 year. Thus, it is evident that both the groups improved cardiac functions in DMD. However, no significant difference was noted in the changes observed between the groups.

Conclusion:

The intense PT and PT with yoga, particularly home-based program, is indeed beneficial as a therapeutic strategy in DMD children to maintain and/or to sustain HRV in DMD.

Need for Systematic Efforts to Modify Health-Related Behaviors After Acute Myocardial Infarction in Korea

BACKGROUND

Modification of health-related behaviors may improve clinical outcomes after acute myocardial infarction (AMI), but the need for systematic efforts to modify such behaviors and the estimated effect have not been investigated, especially in Asian populations. The aim of the study was to investigate changes in smoking and physical activity after AMI and their associations with death and recurrent revascularization. Methods and Results: Using the Korean National Insurance Health Service database, we included 13,452 patients with AMI in 2011, who were stable until 1.5 years on average after onset. Patients were grouped according to their smoking status and physical activity before and after AMI. After AMI, 44.6% of smokers continued smoking and only 11.0% of inactive patients increased their physical activity to a sufficient level. The 'smoker/smoker' group and 'non-smoker/smoker' group showed higher mortality (hazard ratio (HR): 1.566, 95% confidence interval (CI): 1.192-2.035; HR: 1.785, 95% CI: 1.061-2.815, respectively). On the other hand, the 'active/active' group and 'inactive/active' group showed less mortality (HR: 0.625, 95% CI: 0.460-0.832; HR: 0.681, 95% CI: 0.438-1.009, respectively) and the 'inactive/active' group showed less recurrent revascularization (HR: 0.761, 95% CI: 0.599-0.952).

CONCLUSIONS

Smoking cessation and maintaining sufficient physical activity after AMI remain challenging for many Korean patients, and are associated with higher rates of mortality and recurrent revascularization. Systematic nationwide efforts such as cardiac rehabilitation (CR) to change health-related behaviors after AMI are required in Korea.

Neural mechanism of angiotensin-converting enzyme inhibitors in improving heart rate variability and sleep disturbance after myocardial infarction

BACKGROUND

Sympathetic hyperactivity and poor sleep quality are reported in myocardial infarction (MI) patients and angiotensin-converting enzyme inhibitors (ACEI) can improve long-term survival in these patients. We aimed to evaluate ACEI effects on cardiac autonomic activity (CAA) and disordered sleep patterns in ambulatory rats after MI.

METHODS

Polysomnographic recording was performed in sham (n = 8) and MI (n = 9) male rats during normal daytime sleep before and after captopril treatment. Spectral analyses of the electroencephalogram and electromyogram were evaluated to define active waking (AW), quiet sleep (QS), and paradoxical sleep (PS). Central sleep apnea (CSA) events were measured by analyzing the electromyogram of the diaphragm. CAA was measured by power spectrum analyses of heart rate variability (HRV).

RESULTS

In the MI group, there was a higher low frequency/high frequency ratio during sleep, which reduced significantly after captopril treatment, especially at the QS stage compared to that before captopril treatment. The frequency of sleep interruption was higher in the MI group than the sham group. Increased AW and PS, and decreased QS times were noted in the MI group compared to the sham group. These changes were restored to baseline after captopril treatment in the MI group. CSA events were significantly increased in the MI group, and were restored to the normal level after captopril treatment.

CONCLUSIONS

Our results demonstrate significant sleep fragmentation with sympathetic hyperactivity after MI, and that captopril restores the autonomic dysfunction and sleep disorder. These findings suggest that ACEI improved sleep-related respiration disorder after MI by restoring autonomic homeostasis, and provide a hypothesis generating for future studies in humans.

Water exercise in coronary artery disease patients, effects on heart rate variability, and body composition: A randomized controlled trial

BACKGROUND AND PURPOSE

It is important to assess the effectiveness and efficiency of water-based training programs in order to prescribe it as an alternative in cardiac rehabilitation for patients who have coronary artery disease (CAD). In these patients, autonomic dysfunction is an important physiological change strongly associated with adverse outcomes, morbidity, and mortality. Given that the beneficial effects of physical training in CAD patients have been traditionally evidenced with programs involving land-based aerobic exercises, this study aims to evaluate the effects of water aerobic exercise training (WAET) on the autonomic modulation of heart rate (HR) and body composition, in the rehabilitation of CAD patients.

METHODS

Twenty-six male subjects with CAD were randomly divided into a training group (n = 14), submitted to the WAET, and a control group (n = 12). The WAET consisted of 3 weekly sessions on alternate days, totalling 48 sessions. The analysis of HR variability was used to evaluate the autonomic modulation of HR, from the recording of R-R intervals for 15 min, at rest in the supine position, and the body composition was evaluated through the bioelectrical impedance analysis.

RESULTS

Only the training group participants had improvement in the HR variability indices; patterns without variation decreased (0V, p = .005) and an increase of patterns of two different variations (p < .001), Shannon entropy (p = .02), and normalized conditional entropy (p = .03), whereas the control group had an increase of 0V (p = .04) and a decrease of normalized conditional entropy (p = .01). All body composition variables remained unchanged.

CONCLUSIONS

The WAET protocol improved the cardiac autonomic modulation of patients with CAD and can be considered as exercise training strategy in cardiac rehabilitation programs.

Physical Exercise Improves Heart Rate Variability in Patients with Type 2 Diabetes: A Systematic Review

PURPOSE OF REVIEW

The aim of the present systematic review is to provide an up-to-date analysis of the research on the effects of exercise programs on heart rate variability (HRV) in individuals with type 2 diabetes mellitus (T2DM). An electronic search of the literature (PubMed, PEDro and Web of Science) was performed. "HRV", "heart rate variability", "exercise", "physical" and "diabetes" were the terms used for article retrieval. Lastly, 15 articles were selected. PRISMA methodology was employed and data were extracted according to the PICOS approach.

RECENT FINDINGS

Although HRV is not routinely measured in the management of T2DM, it is an important measure due to its relation with mortality and diabetic neuropathy. Physical exercise has become a therapy for T2DM, because it improves physical fitness and functional capacity, enhances metabolic control and insulin sensitivity, reduces inflammatory markers and neuropathy symptoms and can increase the regenerative capacity of cutaneous axons, slowing or preventing neuropathy progression. However, it is not clear to what extent physical exercise can improve HRV in this population. Participation in the 15 selected studies was similar in men and women (48.01% men and 51.99% women). All the intervention programs included aerobic training, and it was complemented by strength training in four studies. Duration of physical exercise sessions ranged between 30 and 75 min, the frequency being between 2 and 7 days/week. Statistically significant improvements in groups with diabetes, relative to baseline, were observed in nine studies. More than 3 days per week of aerobic training, complemented by strength training, during at least 3 months seems to improve HRV in T2DM. Weekly frequency might be the most important factor to improve HRV. These aspects could help to design better programs based in scientific evidence, incorporating HRV as an important variable associated with diabetic neuropathy and mortality.

Heart rate variability based on risk stratification for type 2 diabetes mellitus

Objective

To evaluate heart rate variability among adults with different risk levels for type 2 diabetes mellitus.

Methods

The risk for type 2 diabetes mellitus was assessed in 130 participants (89 females) based on the questionnaire Finnish Diabetes Risk Score and was classified as low risk (n=26), slightly elevated risk (n=41), moderate risk (n=27) and high risk (n=32). To measure heart rate variability, a heart-rate monitor Polar S810i^® was employed to obtain RR series for each individual, at rest, for 5 minutes, followed by analysis of linear and nonlinear indexes.

Results

The groups at higher risk of type 2 diabetes mellitus had significantly lower linear and nonlinear heart rate variability indexes.

Conclusion

The individuals at high risk for type 2 diabetes mellitus have lower heart rate variability.

Physical activity in primary and secondary prevention of cardiovascular disease: Overview updated

Although the observed progress in the cardiovascular disease treatment, the incidence of new and recurrent coronary artery disease remains elevated and constitutes the leading cause of death in the developed countries. Three-quarters of deaths due to cardiovascular diseases could be prevented with adequate changes in lifestyle, including increased daily physical activity. New evidence confirms that there is an inverse dose-response relationship between physical activity and cardiovascular disease and mortality risk. However, participation in moderate to vigorous physical activity may not fully attenuate the independent effect of sedentary activities on increased risk for cardiovascular diseases. Physical activity also plays an important role in secondary prevention of cardiovascular diseases by reducing the impact of the disease, slowing its progress and preventing recurrence. Nonetheless, most of eligible cardiovascular patients still do not benefit from secondary prevention/cardiac rehabilitation programs. The present review draws attention to the importance of physical activity in the primary and secondary prevention of cardiovascular diseases. It also addresses the mechanisms by which physical activity and regular exercise can improve cardiovascular health and reduce the burden of the disease.

Tracking Restoration of Park and Urban Street Settings in Coronary Artery Disease Patients

The physiological effects of natural and urban environments on the cardiovascular system of coronary artery disease (CAD) patients are not fully understood. This controlled field study examines the effects of restorative walking in a park vs. in an urban street environment on CAD patients’ stress parameters and cardiac function. Methods: Twenty stable CAD patients were randomly allocated to 7 days controlled walking in a city park or in an urban street environment group. The relationship between different environmental exposures and health effects was analyzed using Wilcoxon signed-rank test and exact Mann-Whitney U test. Results: The mean reduction in cortisol levels and negative effects after the walk on the first day was greater in the city park than in the urban street exposed group, while a reduction in negative effects in the urban group were greater after seven days. The reduction in diastolic blood pressure (DBP) in the park group was evident on the seventh day before the walk (−4 mm Hg, p = 0.031) and 60 min after the walk (−6.00 mm Hg, p = 0.002). The cortisol slope was negatively associated with the DBP changes (r = −0.514, p < 0.05). Conclusions: Physical activity in a green environment with noise and air pollution levels lower than in an urban environment has a greater positive effect on CAD patients’ stress level and hemodynamic parameters. Mitigating green environmental influences may allow urban residents to maintain health and reduce disability.

Pilot Randomized Study of a Gratitude Journaling Intervention on Heart Rate Variability and Inflammatory Biomarkers in Patients With Stage B Heart Failure

OBJECTIVE

Stage B, asymptomatic heart failure (HF) presents a therapeutic window for attenuating disease progression and development of HF symptoms, and improving quality of life. Gratitude, the practice of appreciating positive life features, is highly related to quality of life, leading to development of promising clinical interventions. However, few gratitude studies have investigated objective measures of physical health; most relied on self-report measures. We conducted a pilot study in Stage B HF patients to examine whether gratitude journaling improved biomarkers related to HF prognosis.

METHODS

Patients (n = 70; mean [standard deviation] age = 66.2 [7.6] years) were randomized to an 8-week gratitude journaling intervention or treatment as usual. Baseline (T1) assessments included the six-item Gratitude Questionnaire, resting heart rate variability (HRV), and an inflammatory biomarker index. At T2 (midintervention), the six-item Gratitude Questionnaire was measured. At T3 (postintervention), T1 measures were repeated but also included a gratitude journaling task.

RESULTS

The gratitude intervention was associated with improved trait gratitude scores (F = 6.0, p = .017, η = 0.10), reduced inflammatory biomarker index score over time (F = 9.7, p = .004, η = 0.21), and increased parasympathetic HRV responses during the gratitude journaling task (F = 4.2, p = .036, η = 0.15), compared with treatment as usual. However, there were no resting preintervention to postintervention group differences in HRV (p values > .10).

CONCLUSIONS

Gratitude journaling may improve biomarkers related to HF morbidity, such as reduced inflammation; large-scale studies with active control conditions are needed to confirm these findings.

TRIAL REGISTRATION

Clinicaltrials.govidentifier:NCT01615094.

Whole body periodic acceleration (pGz) preserves heart rate variability after cardiac arrest

AIMS

Heart rate variability (HRV) is a measure of the balance between the sympathetic and parasympathetic autonomic nervous system and lack thereof an ominous sign in many cardiac and neurological conditions including post-cardiac arrest syndrome. Whole body periodic acceleration (pGz) has been shown to be cardio protective when applied prior to during and after cardiac arrest (CA). Here, we investigate whether or not pGz pre or post treatment after CA preserves HRV.

METHODS

Eight min of unsupported ventricular fibrillation followed by CPR and defibrillation was carried out in 32 anesthetized and paralyzed male swine who were randomized to pretreatment (1h pGz prior to CA, pre-pGz [n=8]) or post-treatment (pGz beginning at 30min after return of spontaneous circulation ([ROSC], post-pGz [n=8]) or none (CONT [n=8]). pGz was applied together with conventional mechanical ventilation. In a separate group (n=8), infusion of TRIM (nNOS inhibitor) was used to determine the effects of nNOS inhibition on HRV.

RESULTS

Time and frequency domain measures of HRV were determined along with measurements of blood gases and hemodynamics, obtained at baseline and at 30, 60, 120 and 180min after ROSC. All animals had ROSC and there were no significant differences for arterial blood gases, mean blood pressure and coronary perfusion pressure after ROSC among the groups. HRV was significantly depressed after cardiac arrest and remained depressed in CONT group. In contrast, both pre and post pGz treated groups had significantly higher and preserved time domain measures of HRV (RMSSD and SDNN) from 60 to 180min after ROSC, and nNOS inhibition markedly reduced HRV. The frequency domain of HRV did not show changes.

CONCLUSIONS

In a pig model of CA, pre or post treatment with pGz preserves HRV. Inhibition of nNOS markedly reduced HRV. Post-treatment with pGz is a novel therapeutic strategy that might serve as an adjunct to current pharmacological or hypothermia modalities to potentially improve outcomes from post-cardiac arrest syndrome.

Dipeptidyl peptidase-4 inhibitor improves cardiac function by attenuating adverse cardiac remodelling in rats with chronic myocardial infarction

NEW FINDINGS

What is the central question of this study? Although cardioprotective effects of dipeptidyl peptidase-4 (DPP-4) inhibitors have been demonstrated, their cardiac effects in chronic myocardial infarction (MI) are unclear. We determined the effects of a DPP-4 inhibitor on cardiac function and remodelling in rats with chronic MI. What is the main finding and its importance? We demonstrated, for the first time, that DPP-4 inhibitor, but not metformin, exerted similar efficacy in improving cardiac function and attenuating cardiac fibrosis compared with enalapril in rats with chronic MI. These findings reveal benefits additional to the glycaemic control by the DPP-4 inhibitor in chronic MI, and it might become the new drug of choice for MI in patients with diabetes mellitus. Adverse cardiac remodelling after myocardial infarction (MI) leads to progressive heart failure. Dipeptidyl peptidase-4 (DPP-4) inhibitors are new antidiabetic drugs that exert cardioprotection. However, their role in cardiac function and remodelling in chronic MI is unclear. We hypothesized that the DPP-4 inhibitor vildagliptin reduces adverse cardiac remodelling and improves cardiac function in rats with chronic MI. These effects were also compared with enalapril and metformin. Male Wistar rats (n = 36) with chronic MI induced by ligation of the left anterior descending coronary artery were divided into six groups to receive vehicle, vildagliptin (3 mg kg(-1)  day(-1) ), metformin (30 mg kg(-1)  day(-1) ), enalapril (10 mg kg(-1)  day(-1) ), combined metformin and enalapril or combined vildagliptin and enalapril for 8 weeks. At the end of the study, plasma malondialdehyde (MDA), heart rate variability (HRV), left ventricular (LV) function, pathological and biochemical studies of cardiac remodelling were investigated. Our study demonstrated that rats with chronic MI had increased oxidative stress levels, depressed HRV, adverse cardiac remodelling, indicated by cardiac fibrosis, and LV dysfunction. Treatment with vildagliptin or enalapril significantly decreased oxidative stress, attenuated cardiac fibrosis and improved HRV and LV function. We conclude that vildagliptin exerts similar cardioprotective effects to enalapril in attenuating oxidative stress and cardiac fibrosis and improving cardiac function in rats with chronic MI. Metformin does not provide these benefits in this model. Moreover, addition of either metformin or vildagliptin to enalapril does not provide additional benefit in attenuating cardiac remodelling or improving LV function compared with enalapril alone.

Exercise training in the management of patients with resistant hypertension

Hypertension is a very prevalent risk factor for cardiovascular disease. The prevalence of resistant hypertension, i.e., uncontrolled hypertension with 3 or more antihypertensive agents including 1 diuretic, is between 5% and 30% in the hypertensive population. The causes of resistant hypertension are multifactorial and include behavioral and biological factors, such as non-adherence to pharmacological treatment. All current treatment guidelines highlight the positive role of physical exercise as a non-pharmacological tool in the treatment of hypertension. This paper draws attention to the possible role of physical exercise as an adjunct non-pharmacological tool in the management of resistant hypertension. A few studies have investigated it, employing different methodologies, and taken together they have shown promising results. In summary, the available evidence suggests that aerobic physical exercise could be a valuable addition to the optimal pharmacological treatment of patients with resistant hypertension.

Interaction between selenium and mercury in biological samples of Pakistani myocardial infarction patients at different stages as related to controls

It has been speculated that trace elements may a play role in the pathogenesis of heart diseases. In the present study, we aimed to assess the levels of selenium (Se) and mercury (Hg) in biological samples (whole blood, urine, and scalp hair) of myocardial infarction (MI) patients of both genders (age range 45-60 years) at the first, second, and third heart attack (n = 130), hospitalized in a cardiac ward of a civil hospital of Hyderabad City (Pakistan). For comparison, healthy age-matched referent subjects (n = 61) of both genders were also selected. Se and Hg in biological samples were measured by electrothermal atomic absorption spectrometry and cold vapor atomic absorption spectrometry, prior to microwave acid digestion, respectively. The validity of the methodology was checked by biological certified reference materials. During this study, 78 % of the 32 registered patients of third MI attack (aged >50 years) died. The concentration of Se was decreased in scalp hair and blood samples of MI patients, while Hg was higher in all biological samples as compared to referent subjects. Se concentration was inversely associated with the risk of MI attacks in both genders. These results add to an increasing body of evidence that Se is a protective element for cardiovascular health.

Impaired signaling intrinsic to sinoatrial node pacemaker cells affects heart rate variability during cardiac disease

The normal heart beat intervals are neither strictly stationary nor completely random, and continuously shift from one period to another. Decoding the ECG identifies this "hidden" information that imparts inherent complexity to the heart-beating interval time series. Loss of this complexity in cardiovascular disease is manifested as a reduction in heart rate variability (HRV) and this reduction correlates with an increase in both morbidity and mortality. Because HRV measurements are noninvasive and easy to perform, they have emerged as an important tool in cardiology. However, the identities of specific mechanisms that underline the changes in HRV that occur in cardiovascular diseases remain largely unknown. Changes in HRV have mainly been interpreted on a neural basis, ie due to changes in autonomic impulses to the heart: sympathetic activity decreases both the average heart beat interval and HRV, and parasympathetic activity increases both. It has now become clear, however, that the heart rate and HRV are also determined by intrinsic properties of the pacemaker cells that comprise the sinoatrial node, and the responses of these properties to autonomic receptor stimulation. Here we review how changes in the properties of coupled-clock mechanisms intrinsic to pacemaker cells that comprise the sinoatrial node and their impaired response to autonomic receptor stimulation are implicated in the changes of HRV observed in heart diseases.