Additive Value of Heart Rate Variability in Predicting Obstructive Coronary Artery Disease Beyond Framingham Risk

Symptom-limited exercise capacity is associated with long-term survival

The prognostic value of exercise capacity has been demonstrated in subjects with established cardiovascular diseases. We aim to evaluate the independence of exercise capacity measured by treadmill exercise test (TET) in predicting long-term outcomes among various comorbidities. This study was conducted from January 2003 to December 2012 in a tertiary medical center in Taiwan. Subjects referred for symptom-limited TET were recruited. Peak achieved metabolic equivalents (METs) were determined by treadmill grade and speed at peak exercise. The main outcomes were cardiovascular and all-cause mortality by linking to the National Death Registry. A total of 18,954 participants (57.8 ± 12.8 years, 62% men) achieved a mean peak METs of 9.2. Subjects in the lowest tertile of peak METs were older, had poorer renal function, lower hemoglobin, and more comorbidities. During a median follow-up of 4.3 years, there were 642 mortalities and 132 cardiovascular deaths. Peak METs significantly predicted cardiovascular death and all-cause mortality in the multivariable Cox regression models [hazard ratio (95% confidence intervals): 0.788 (0.660-0.940) and 0.835 (0.772-0.903), respectively]. The prognostic influence of peak METs consistently appeared in the subgroups, regardless of age, gender, body weight, comorbidities, use of beta-blockers, or the presence of exercise-induced ischemia. The fitness was more predictive of long-term outcomes in young or those with ischemic changes during TET (P for interaction: 0.035 and 0.018, respectively). The benefit of fitness was nonlinearly associated with long-term survival. The prognostic impacts of exercise capacity were universally observed in subjects with or without various comorbidities.

The Usefulness of Assessing Heart Rate Variability in Patients with Acute Myocardial Infarction (HeaRt-V-AMI)

BACKGROUND

Heart rate variability (HRV) could have independent and critical prognostic values in patients admitted for ST segment elevation myocardial infarction (STEMI). There are limited data in the literature regarding HRV assessment in STEMI setting. Thus, we aim to investigate the potential correlations between HRV and adverse outcomes in a contemporary cohort of patients presenting with STEMI undergoing primary percutaneous coronary intervention (PCI).

METHODS

We will perform a prospective, observational cohort study in a single healthcare center. Adult patients aged ≥18 years presenting with STEMI in sinus rhythm will be enrolled for primary PCI within 12 h from symptoms onset. Time domain, frequency domain, and nonlinear HRV parameters will be measured using a medically approved wrist-wearable device for 5 min segments during myocardial revascularization by primary PCI. Additional HRV measurements will be performed one and six months from the index event. The primary composite outcome will include all-cause mortality and major adverse cardiovascular events (during the hospital stay, one month, and one year following admission). Several secondary outcomes will be analyzed: individual components of the primary composite outcome, target lesion revascularization, hospitalizations for heart failure, ventricular arrhythmias, left ventricular ejection fraction, and left ventricular diastolic function.

CONCLUSIONS

Our study will enlighten the reliability and usefulness of HRV evaluation as a prognostic marker in contemporary patients with STEMI. The potential validation of HRV as a risk marker for adverse outcomes following STEMI will ensure a background for including HRV parameters in future risk scores and guidelines.

Role of Heart Rate Variability in Association Between Glomerular Hyperfiltration and All-Cause Mortality

Background

Glomerular hyperfiltration (GHF) is paradoxically associated with increased cardiovascular events in healthy individuals, but the pathogenesis remains unclear. We aim to investigate whether GHF is associated with mortality and whether decreased heart rate variability (HRV) is associated with GHF.

Methods and Results

We retrospectively analyzed 1615 participants (aged 66.1±17.3 years, 61.9% men) without prior cardiovascular events. The glomerular filtration rate was estimated using the Chronic Kidney Disease Epidemiology Collaboration equation. GHF was defined as glomerular filtration rate >the 95th percentile after stratification for age and sex, whereas normal filtration was defined as the 25th to 75th percentiles. HRV indexes, including time domain, frequency domain, and sample entropy, were measured using 24‐hour ambulatory electrocardiography. Clinical outcomes were defined as all‐cause mortality at 2 years. During a mean follow‐up of 16.5±8.2 months, there were 117 deaths (7.2%). GHF was associated with a higher risk of death (hazard ratio and 95% CIs, 1.97 [1.15–3.37]). Reduced HRV indexes, including time domain, frequency domain, and sample entropy (odds ratio and 95% CIs, 0.79 [0.70–0.89]) were all independently associated with the presence of GHF after accounting for age, sex, mean heart rate, morbidities, and medications. In subgroup analysis, reduced HRV was more predictive of GHF in the young than the elderly. Mediation analysis revealed a significant mediation effect between HRV and GHF in addition to their respective detrimental effects on survival.

Conclusions

Reduced HRV was independently associated with the presence of GHF. Autonomic dysfunction may be involved in the pathogenesis of adverse outcomes of GHF in individuals without prior cardiovascular events.

Respiratory Sinus Arrhythmia in Children-Predictable or Random?

Background: Respiratory sinus arrhythmia (RSA) is associated with better health in children.

Aim: The study was conducted to analyze the trajectory of RSA in 10-year-olds.

Methods: A follow-up study on 120 healthy children (62 boys) aged 10.7 ± 0.5 years consisted of a standard 12-lead electrocardiogram, measurements of height, weight and blood pressure. The protocol was repeated after 3 years. Assessment of RSA based on semi-automatic measurements of RR intervals included: the difference between the longest and shortest RR interval duration (pvRSA), the root mean square of differences between successive RR intervals (RMSSD), the standard deviation of the RR interval length (SDNN) and their equivalents corrected for heart rate (RMSSDc and SDNNc).

Results: A the first visit 61.7% of children presented with RSA; 51.7% 3 years later. 23.3% of them had RSA only on the first examination; 13.3% only on the second one. The pvRSA, RMSSD, and SDNN measured in 2019 did not differ significantly from their 2016 equivalents (p > 0.05). The decline in RSA defined by RMSSD was noted in 52.5% of children and in 54.2% when defined by SDNN. The corrected values decreased in 68.3 and 64.2% of the participants for RMSSDc and SDNNc, respectively. The students with RSA at both visits had lower heart rate (p < 0.001) and systolic blood pressure (p = 0.010) compared to those with rhythmic electrocardiograms.

Conclusions: RSA in children is changeable, though its measurable indices should be adjusted to heart rate.

Cardiovascular Risk and Quality of Life in Autosomal Dominant Polycystic Kidney Disease Patients on Therapy With Tolvaptan: A Pilot Study

INTRODUCTION

Cardiovascular (CV) complications are the most frequent cause of morbidity and mortality in autosomal dominant polycystic kidney disease (ADPKD) patients. In 2017, the Italian Medicines Agency authorised tolvaptan, a vasopressin V2 receptor antagonist, for the treatment of ADPKD, based on the Tolvaptan Phase 3 Efficacy and Safety Study in ADPKD (TEMPO 3: 4), TEMPO 4: 4 and Replicating Evidence of Preserved Renal Function: An Investigation of Tolvaptan Safety and Efficacy (REPRISE) studies.

AIM OF THE STUDY

The aim of the study was to assess the impact of tolvaptan on CV risk and quality of life, evaluated by nutritional, inflammatory, metabolic, instrumental parameters and psychocognitive tests on ADPKD patients.

METHODS AND MATERIALS

We evaluated 36 patients with ADPKD; 10 patients (7 males, mean age 42.5±7.0 years) treated with tolvaptan and 26 controls (11 males, mean age 36.7±9.1 years). They underwent, at T0, monthly, and at T1 (1 year) clinical, laboratory and instrumental evaluation, in addition to psychocognitive tests.

RESULTS

In ADPKD patients treated with tolvaptan, we found at T1, a decrease in carotid intima-- media thickness (p=0.048), epicardial adipose tissue thickness (p=0.002), C-reactive protein (p=0.026), sympathovagal balance during night (p=0.045) and increased flow-mediated dilation (p=0.023) with a reduction in depression (Hamilton and Beck tests, p=0.008 and p=0.002, respectively) compared with controls.

CONCLUSION

These preliminary results suggest that treatment with tolvaptan could improve early atherosclerosis and endothelial dysfunction markers and improve mood in ADPKD patients (probably by acting on endothelial cell and adipocyte V2 receptors).

Predictive value of heart rate deceleration capacity on coronary artery lesion in acute phase of Kawasaki disease

This study was to investigate the correlation of vagal activity with coronary artery lesion (CAL) in Kawasaki disease (KD) children, and assess the predictive value of heart rate deceleration capacity (DC) for CAL in acute phase of KD.50 KD children with CAL, 130 KD children without CAL, 30 children with acute upper respiratory infection and 100 healthy children were recruited and indicators reflecting vagal activity including DC were measstuogram. KD children with CAL showed decreased vagal activity with significantly lower values of DC. DC was negatively correlated with levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) and C-reactive protein (CRP) in KD children. DC was a usable cardiac electrophysiological index to predict CAL in children with KD, with an area under the receiver operating characteristic curve (AUC) of 0.741. The cut-off value of DC for predicting CAL in KD children was 4.37 ms. DC was an independent predictor of CAL in children with KD, evaluated by multiple logistic regression analysis, KD children with DC ≤ 4.37 ms had an increased risk of CAL, with odds ratios (OR) of 5.94. Our study illustrates DC could be used to predict CAL in acute phase of KD.

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.

Reduction in Heart Rate Variability in Autosomal Dominant Polycystic Kidney Disease

INTRODUCTION

Cardiovascular disease is one of the main causes of morbidity and mortality in patients with autosomal dominant polycystic kidney disease (ADPKD). Autonomic dysfunction is associated with an increased risk for all cardiovascular events in the general population and can be evaluated with heart rate variability (HRV).

OBJECTIVE

To evaluate HRV in ADPKD patients with mild hypertension versus hypertensive patients with organ damage and healthy controls (HC).

MATERIALS AND METHODS

We have enrolled 65 patients: 21 ADPKD patients (10 males), 20 patients with hypertension (14 males), and 24 HC (10 males). Biochemical analysis, clinical evaluation, anthropometric data, intima-media thickness, 24-h ECG Holter recording, and echocardiography were investigated at the time of enrollment.

RESULTS

No significant differences in HRV parameters were found between ADPKD with mild hypertension and hypertensive patients with organ damage. The median of HRV variables in time domain as SDNN (global autonomic activity) was significantly lower in ADPKD and hypertensive patients than HC (p < 0.05). In the frequency domain analysis, low frequency (LF), which mainly reflects the sympathetic component, showed higher values in ADPKD and hypertensive patients than HC during the night (p < 0.01). During the night, the sympathovagal balance, LF/high frequency (HF), showed higher values in ADPKD and hypertensive patients than HC (p < 0.0001). Conversely, LF day was lower in ADPKD and hypertensive patients than HC (p < 0.01). HF, which mainly reflects the parasympathetic component, was lower in ADPKD and hypertensive patients during the night than HC (p < 0.0001).

CONCLUSIONS

HRV reduction is present in ADPKD patients with mild hypertension in the absence of organ damage. The evaluation of sympathovagal balance can provide novel information on the cardiovascular risk in ADPKD patients in addition to classical risk factors.

Psychological Traits, Heart Rate Variability, and Risk of Coronary Heart Disease in Healthy Aging Women-The Women's Health Initiative

OBJECTIVE

Psychological traits such as optimism and hostility affect coronary heart disease (CHD) risk, but mechanisms for this association are unclear. We hypothesized that optimism and hostility may affect CHD risk via changes in heart rate variability (HRV).

METHODS

We conducted a longitudinal analysis using data from the Women's Health Initiative Myocardial Ischemia and Migraine Study. Participants underwent 24-hour ambulatory electrocardiogram monitoring 3 years after enrollment. Optimism (Life Orientation Test-Revised), cynical hostility (Cook-Medley), demographics, and coronary risk factors were assessed at baseline. HRV measures included standard deviation of average N-N intervals (SDNN); standard deviation of average N-N intervals for 5 minutes (SDANN); and average heart rate (HR). CHD was defined as the first occurrence of myocardial infarction, angina, coronary angioplasty, and bypass grafting. Linear and Cox regression models adjusted for CHD risk factors were used to examine, respectively, associations between optimism, hostility, and HRV and between HRV and CHD risk.

RESULTS

Final analyses included 2655 women. Although optimism was not associated with HRV, hostility was inversely associated with HRV 3 years later (SDANN: adjusted β = -0.54; 95% CI = -0.97 to -0.11; SDNN: -0.49; 95% CI = -0.93 to -0.05). HRV was inversely associated with CHD risk; for each 10-millisecond increase in SDNN or SDANN, there was a decrease in CHD risk of 9% (p = .023) and 12% (p = .006), respectively.

CONCLUSIONS

HRV did not play a major role in explaining why more optimistic women seem to be somewhat protected from CHD risk. Although hostility was inversely associated with HRV, its role in explaining the association between hostility and CHD risk remains to be established.

WITHDRAWN: Are high heart rate variability and parasympathetic activity a key for wellness?

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Association between cardiac autonomic nervous dysfunction and the severity of coronary lesions in patients with stable coronary artery disease

Objective

Autonomic dysfunction is recognized in patients with coronary artery disease (CAD) and is related to worse cardiovascular outcome. This study aimed to evaluate cardiac autonomic nervous function by heart rate recovery (HRR) and heart rate variability (HRV), and demonstrate their relationship with the severity of coronary lesions in patients with stable CAD (SCAD).

Methods

Consecutive patients without CAD (controls, n = 65) and those with SCAD (n = 63) were included in this study. Patients with SCAD were further divided into single- or two-/three-vessel disease, as well as <70% or ≥70% stenosis subgroups. The association between HRR/HRV and coronary lesions was analysed.

Results

HRR and HRV values were significantly lower in the SCAD group compared with the control group. Multivariate logistic regression analysis showed that abnormal HRR and HRV were risk factors of SCAD. Moreover, delayed HRR was a risk factor of the severity of coronary lesions.

Conclusions

Our results show that autonomic function is impaired in patients with SCAD and delayed HRR is closely related to the severity of coronary lesions.

A novel heart rate variability based risk prediction model for septic patients presenting to the emergency department

A quick, objective, non-invasive means of identifying high-risk septic patients in the emergency department (ED) can improve hospital outcomes through early, appropriate management. Heart rate variability (HRV) analysis has been correlated with mortality in critically ill patients. We aimed to develop a Singapore ED sepsis (SEDS) predictive model to assess the risk of 30-day in-hospital mortality in septic patients presenting to the ED. We used demographics, vital signs, and HRV parameters in model building and compared it with the modified early warning score (MEWS), national early warning score (NEWS), and quick sequential organ failure assessment (qSOFA) score.Adult patients clinically suspected to have sepsis in the ED and who met the systemic inflammatory response syndrome (SIRS) criteria were included. Routine triage electrocardiogram segments were used to obtain HRV variables. The primary endpoint was 30-day in-hospital mortality. Multivariate logistic regression was used to derive the SEDS model. MEWS, NEWS, and qSOFA (initial and worst measurements) scores were computed. Receiver operating characteristic (ROC) analysis was used to evaluate their predictive performances.Of the 214 patients included in this study, 40 (18.7%) met the primary endpoint. The SEDS model comprises of 5 components (age, respiratory rate, systolic blood pressure, mean RR interval, and detrended fluctuation analysis α2) and performed with an area under the ROC curve (AUC) of 0.78 (95% confidence interval [CI]: 0.72-0.86), compared with 0.65 (95% CI: 0.56-0.74), 0.70 (95% CI: 0.61-0.79), 0.70 (95% CI: 0.62-0.79), 0.56 (95% CI: 0.46-0.66) by qSOFA (initial), qSOFA (worst), NEWS, and MEWS, respectively.HRV analysis is a useful component in mortality risk prediction for septic patients presenting to the ED.

Ultra-short-term heart rate variability during resistance exercise in the elderly

Despite the appeal of ultra-short-term heart rate variability (HRV) methods of analysis applied in the clinical and research settings, the number of studies that have investigated HRV by analyzing R-R interval (RRi) recordings shorter than 5 min is still limited. Moreover, ultra-short-term HRV analysis has not been extensively validated during exercise and, currently, no indications exist for its applicability during resistance exercise. The aim of the present study was to compare ultra-short-term HRV analysis with standard short-term HRV analysis during low-intensity, dynamic, lower limb resistance exercise in healthy elderly subjects. Heart rate (HR) and RRi signals were collected from 9 healthy elderly men during discontinuous incremental resistance exercise consisting of 4-min intervals at low intensities (10, 20, 30, and 35% of 1-repetition maximum). The original RRi signals were segmented into 1-, 2-, and 3-min sections. HRV was analyzed in the time domain (root mean square of the of differences between adjacent RRi, divided by the number of RRi, minus one [RMSSD]), RRi mean value and standard deviation [SDNN] (percentage of differences between adjacent NN intervals that are greater than 50 ms [pNN50]), and by non-linear analysis (short-term RRi standard deviation [SD1] and long-term RRi standard deviation [SD2]). No significant difference was found at any exercise intensity between the results of ultra-short-term HRV analysis and the results of standard short-term HRV analysis. Furthermore, we observed excellent (0.70 to 0.89) to near-perfect (0.90 to 1.00) concordance between linear and non-linear parameters calculated over 1- and 2-min signal sections and parameters calculated over 3-min signal sections. Ultra-short-term HRV analysis appears to be a reliable surrogate of standard short-term HRV analysis during resistance exercise in healthy elderly subjects.