Implication of heart rate variability on cerebral small vessel disease: A potential therapeutic target

The Roles of Heart Rate Variability in Cerebral Stroke

Heart rate variability (HRV), as a safe and noninvasive marker of autonomic activity, is becoming a prescreening tool for the prediction of cardiovascular complications such as myocardial infarction and heart failure after cerebral stroke. With good reproducibility and quantitative assessment of autonomic nervous system function, the association of some HRV parameters with neurological functional prognosis and stroke recurrence has been widely reported. However, current studies on the relationship between HRV and the clinical outcomes of stroke remain controversial. Previous studies on HRV have mainly focused on stroke prognosis or its role as a clinical biomarker, whereas other roles have rarely been explored. In this article, we review recent advances in the role of HRV in cerebral stroke according to current progress. Specifically, we summarized the role of HRV in the outcomes, complications, treatments, and mechanisms of stroke, based on the latest research. Further, in-depth implications of HRV in stroke are discussed.

Cognitive implications of white matter microstructural changes in individuals with low heart rate variability: a NODDI study

Objective

This study aimed to investigated the microstructural integrity of WM and the relationship with the cognitive domains and cognition-related plasma biomarkers in low heart rate variability (HRV).

Methods

Our study recruited 44 high HRV and 44 low HRV (Grouping by median of HF). Diffusion Magnetic resonance imaging (MRI) was utilized for the calculation of neurite orientation dispersion and density imaging (NODDI) parameters, and tract-based spatial statistics (TBSS) were employed to explore differential clusters. The fibers covered by these clusters were defined as regions of interest (ROI) for the extraction of NODDI parameter values and the analysis of their correlation with cognitive domains and cognition-related plasma biomarkers.

Results

The TBSS analysis unveiled specific cerebral regions exhibiting disparities within the low HRV group high HRV group. These differences were evident in fractional isotropy (FISO; p < 0.05). The extracted values from these ROIs (p < 0.05) were mainly manifested in the anterior regions of the brain and corpus callosum. Further analysis showed that the abnormal white matter (WM) showed significant correlations with CDR, RCFT-I, RCFT-D, attention, memory, language, and cognition-related plasma biomarkers to varying degrees.

Conclusion

Patients with low HRV exhibit distinctive patterns of microstructural changes in the WM as revealed by the FISO which indicate a decline in white matter integrity, and the relationship between low HRV-related and worse cognitive performance may be attributed to damage of the frontal-corpus callosum pathways.

Heart Rate Variability Applications in Medical Specialties: A Narrative Review

HRV is clinically considered to be a surrogate measure of the asymmetrical interplay of the sympathetic and parasympathetic nervous system. While HRV has become an increasingly measured variable through commercially-available wearable devices, HRV is not routinely monitored or utilized in healthcare settings at this time. The purpose of this narrative review is to discuss and evaluate the current research and potential future applications of HRV in several medical specialties, including critical care, cardiology, pulmonology, nephrology, gastroenterology, endocrinology, infectious disease, hematology and oncology, neurology and rehabilitation, sports medicine, surgery and anesthesiology, rheumatology and chronic pain, obstetrics and gynecology, pediatrics, and psychiatry/psychology. A narrative literature review was conducted with search terms including HRV and relevant terminology to the medical specialty in question. While HRV has demonstrated promise for some diagnoses as a non-invasive, easy to use, and cost-effective metric for early disease detection, prognosis and mortality prediction, disease monitoring, and biofeedback therapy, several issues plague the current literature. Substantial heterogeneity exists in the current HRV literature which limits its applicability in clinical practice. However, applications of HRV in psychiatry, critical care, and in specific chronic diseases demonstrate sufficient evidence to warrant clinical application regardless of the surmountable research issues. More data is needed to understand the exact impact of standardizing HRV monitoring and treatment protocols on patient outcomes in each of the clinical contexts discussed in this paper.

Analysis of Factors Relevant to the Severity of Symptoms in Children and Adolescents with Postural Orthostatic Tachycardia Syndrome

Objectives: The current study aims to investigate the factors associated with the severity of conditions for pediatric cases with postural orthostatic tachycardia syndrome (POTS). Methods: Patients hospitalized and first diagnosed with POTS were retrospectively included and reviewed. The severity of symptoms was evaluated by symptom scores (SSs). Multiple Spearman correlation analyses and multiple linear regression analyses were used to determine factors independently associated with SS. Patients were divided into the mild (SS ≤ P25) and severe (SS ≥ P75) groups to test the distinguishing efficiency of the candidate factors. The efficiency of each independently correlated factor in indicating the condition of children with POTS was assessed by the receiver operating characteristic (ROC) curve. Results: A series of 296 pediatric patients aged 5-17 years suffering from POTS were included. Multiple Spearman correlation analyses and multiple linear regression analyses showed that corrected QT interval dispersion (QTcd) was independently correlated with SS (p < 0.05). QTcd can be used to suggest the severity of POTS symptoms, and the area under the curve (AUC) was 0.986 (95% CI 0.976-0.997). At a threshold of QTcd = 45 ms, the sensitivity and specificity were, respectively, 94.0% and 91.8% for symptom severity indication. Conclusions: In pediatric cases with POTS, QTcd was positively correlated with their symptom severity and exhibited a strong indicative value. A QTcd of 45 ms was a valid cut-off value for indicating symptom severity.

Relationship between heart rate variability traits and stroke: A Mendelian randomization study

BACKGROUND

Previous observational studies have suggested a potential association between heart rate variability (HRV) and cerebrovascular disease. However, a causal relationship between the two has not yet been established.

AIMS

The objective of this study was to determine the causal relationship between heart rate variability (HRV) and stroke through a two-sample Mendelian randomization analysis.

METHODS

Three genetic predictive traits of heart rate variability standard deviation of the normal-to-normal interbeat intervals (SDNN), the root mean square of the successive differences of interbeat intervals (RMSSD), and the peak-valley respiratory sinus arrhythmia or high-frequency power (pvRSA/HF) were collected from publicly available genome-wide association studies (IEU Open GWAS). Additionally, stroke (STROKE) and its sub-types: ischemic stroke (IS), cardioembolic stroke (CES), small vessel stroke (SVS), large artery stroke (LAS), lacunar stroke (LS), and intracerebral hemorrhage (ICH)were also from this database. Two-sample Mendelian randomization and various sensitivity analyses were employed to explore the causal relationship between HRV and stroke and its sub-types. Inverse-variance weighted (IVW) was the primary method via which Mendelian randomization (MR) was conducted, and for the causal estimates determined by IVW, a series of sensitivity analyses were performed to assess the reliability of the results. (i) Four additional MR methods that complement IVW were utilized; (ii) Cochran's Q-test was employed for assessing heterogeneity; (iii) the MR-Egger's intercept test and MR-PRESSO global test were applied to assess the level of multivariate validity, and (iv) the "leave-one-out" method was utilized to assess stability.

RESULTS

Two of the genetically predictive traits of HRV (standard deviation of the normal-to-normal interbeat intervals [SDNN]) and (the peak-valley respiratory sinus arrhythmia or high-frequency power [pvRSA/HF]) were associated with IS (OR 0.63,95 %CI 0.42-0.95, P = 0.03), (OR 0.84, 95 %CI: 0.72-1.00; P = 0.04), and LAS (OR 135.93, 95 %CI: 7.19-2569.22; P = 0.05), (OR 1.42, 95 %CI: 1.02-1.98; P = 0.04) were significantly correlated in addition to (pvRSA/HF) and LS (OR 0.84, 95 %CI: 0.72-1.00; P = 0.04) were also causally associated. Neither was causally associated with other sub-types of stroke or hemorrhagic stroke. Another genetically predictive trait of HRV (the root mean square of the successive differences of interbeat intervals [RMSSD]) was not found to be significantly associated with stroke, its subtypes, or Intracerebral hemorrhage.

CONCLUSION

This study provides genetic evidence supporting the causal effects of HRV (SDNN) on ischemic stroke (IS) and large artery stroke (LAS), as well as (pvRSA/HF) on ischemic stroke (IS), large artery stroke (LAS), and lacunar stroke (LS).

Bathing-Related Ischemic Stroke: Association between Stroke Subtype and Cerebral Small Vessel Disease

AIMS

Bathing-related ischemic stroke (BIS) is sometimes fatal. However, its mechanisms and risk factors remain unclear. We aimed to identify the incidence of stroke subtypes in BIS, and clarify the impact of cerebral small vessel disease (CSVD) on BIS.

METHODS

Consecutive patients with ischemic stroke between October 2012 and February 2022 were retrospectively screened. The inclusion criteria were: 1) onset-to-door time within 7 days; and 2) availability of the results of MRI evaluation of CSVD markers during hospitalization. BIS was defined as an ischemic stroke that occurred while or shortly after bathing. We investigated the incidence of the stroke subtype and the correlation between CSVD markers and BIS.

RESULTS

1,753 ischemic stroke patients (1,241 [71%] male, median age 69 years) were included. 57 patients (3%) were included in the BIS group. A higher frequency of large artery atherosclerosis (LAA) (prevalence ratio [PR] 2.069, 95% confidence interval [CI] 1.089 to 3.931, p=0.026) and lower frequency of cardio-embolism (CES) (PR 0.362, 95% CI 0.132 to 0.991, p=0.048) in BIS cases were identified. Moreover, lower periventricular hyperintensity (PVH) Fazekas grade (PR 0.671, 95% CI 0.472 to 0.956, p=0.027) and fewer cerebral microbleeds (CMBs) in deep brain region (PR 0.810, 95%CI 0.657 to 0.999, p=0.049) were associated with BIS cases.

CONCLUSIONS

The BIS group was more likely to develop LAA and less likely to develop CES. Lower PVH grade and fewer CMBs in deep brain region were associated with the development of BIS.

Different implications of daytime and nighttime heart rate variability on total burden of cerebral small vascular disease in patients with nondisabling ischemic cerebrovascular events

Objective

This study aimed to explore the relationship between total burden of cerebral small vessel disease (CSVD) and daytime and nighttime heart rate variability (HRV) parameters.

Method

Consecutive patients with nondisabling ischemic cerebrovascular events were recruited from the cerebrovascular disease clinic of Changzhou Second People's Hospital between January 2022 and June 2023. A total of 144 enrolled participants were divided into a mild CSVD group (74 patients) and a moderate-to-severe CSVD group (70 patients) based on total burden of CSVD. Various HRV parameters measured during 24-h, 4-h daytime, and 4-h nighttime periods (including natural log-transformed [ln] root mean square of successive RR interval differences [RMSSD], ln absolute power of the high-frequency band [0.15-0.4 Hz] [HF], ln absolute power of the low-frequency band [0.04-0.15 Hz][LF], and LF-to-HF ratio [LF/HF]) were then assessed in the 2 groups. Spearman correlation analysis was used to assess the correlation between total burden of CSVD and HRV parameters. HRV parameters with P-value < 0.05 in correlation analysis were included in the multivariable logistic regression analysis, and restricted cubic spline analysis was performed to assess dose-response relationships.

Results

Daytime 4-h lnRMSSD (r = -0.221; P = 0.008) and 4-h lnHF (r = -0.232; P = 0.005) were negatively correlated with total burden of CSVD, and daytime 4-h lnLF/HF (r = 0.187; P = 0.025) was positively correlated with total burden of CSVD. There was no correlation between nighttime HRV parameters and total burden of CSVD. After adjustments were made for potential confounders, daytime 4-h lnRMSSD (OR = 0.34; 95% CI: 0.16-0.76), 4-h lnHF (OR = 0.57; 95% CI: 0.39-0.84), and 4-h lnLF/HF (OR = 2.12; 95% CI: 1.18-3.82) were independent predictors of total burden of CSVD (all P < 0.05). S-shaped linear associations with moderate-to-severe total burden of CSVD were seen for daytime 4h-lnRMSSD (P for nonlinearity = 0.543), 4-h lnHF (P for nonlinearity = 0.31), and 4-h lnLF/HF (P for nonlinearity = 0.502).

Conclusion

Daytime parasympathetic HRV parameters are independent influencing factors of total burden of CSVD and may serve as potential therapeutic observation indicators for CSVD.

Resting heart rate causally affects the brain cortical structure: Mendelian randomization study

Resting heart rate (RHR) has been linked to impaired cortical structure in observational studies. However, the extent to which this association is potentially causal has not been determined. Using genetic data, this study aimed to reveal the causal effect of RHR on brain cortical structure. A Two-Sample Mendelian randomization (MR) analysis was conducted. Sensitivity analyses, weighted median, MR Pleiotropy residual sum and outlier, and MR-Egger regression were conducted to evaluate heterogeneity and pleiotropy. A causal relationship between RHR and cortical structures was identified by MR analysis. On the global scale, elevated RHR was found to decrease global surface area (SA; P < 0.0125). On a regional scale, the elevated RHR significantly decreased the SA of pars triangularis without global weighted (P = 1.58 × 10-4) and the thickness (TH) of the paracentral with global weighted (P = 3.56 × 10-5), whereas it increased the TH of banks of the superior temporal sulcus in the presence of global weighted (P = 1.04 × 10-4). MR study provided evidence that RHR might be causally linked to brain cortical structure, which offers a different way to understand the heart-brain axis theory.

Spatiotemporal gait characteristics during single- and dual-task walking are associated with the burden of cerebral small vessel disease

Introduction

Gait impairment is a common symptom among individuals with cerebral small vessel disease (CSVD). However, performance differences between single-task walking (STW) and dual-task walking (DTW) among individuals with CSVD remain unclear. Therefore, we aimed to examine differences in gait characteristics during STW and DTW as well as the association between gait performance and neuroimaging markers.

Methods

We enrolled 126 older individuals with CSVD. The speed, cadence, stride length, stride time, and their dual-task cost (DTC) or variability were measured under the STW, motor-cognitive DTW (cognitive DTW), and motor-motor DTW (motor DTW) conditions. We examined neuroimaging features such as white matter hyperintensities (WMHs), lacunes, microbleeds, and total burden. Further, we analysed the association of neuroimaging markers with gait performance, including gait variability and DTC.

Results

Almost all spatiotemporal characteristics, as well as their DTCs or variabilities, showed significant among-group differences according to disease severity in the cognitive DTW condition; however, relatively lesser differences were observed in the STW and motor DTW conditions. The total CSVD burden score was moderately correlated with all the spatial parameters, as well as their DTCs or variabilities, in the cognitive DTW condition. Moreover, WMHs showed a correlation with speed, stride time, and cadence, as well as their DTCs, in the cognitive DTW condition. Furthermore, lacunes showed a moderate correlation with speed, stride length, and the DTC of speed, whilst microbleeds were only related to the DTC of stride length in the cognitive DTW condition. Neuroimaging biomarkers were not correlated with spatiotemporal parameters in STW and motor DTW conditions after Bonferroni correction. Moreover, the correlation coefficient between the total CSVD burden score and gait parameters was greater than those of other biomarkers.

Discussion

Parameters in the cognitive DTW condition are more appropriate than those in the motor DTW condition for the evaluation of gait abnormalities in patients with CSVD. Moreover, the total CSVD burden score might have better predictive utility than any single neuroimaging marker. Patients with CSVD, especially those with moderate-to-severe disease, should concentrate more on their gait patterns and reduce the load of secondary cognitive tasks whilst walking in daily life.

Type A personality, sleep quality, and cerebral small vessel disease: investigating the mediating role of sleep in a community-based study

Purpose

Type A behavior pattern (TABP) is a personality type characterized by rapid speech, impatience, competition, and hostility. Asymptomatic cerebral small vessel disease (CSVD) is often endemic in older adults. Individuals with TABP commonly experience suboptimal sleep quality, and a correlation exists between sleep disturbances and CSVD. We investigated the relationship between TABP and CSVD markers and further explored the mediating role of sleep quality in the relationship between TABP and CSVD.

Methods

A cross-sectional survey included 764 community-dwelling adults aged 55-85 years. The TABP Scale and the Pittsburgh Sleep Quality Index (PSQI) were used to assess personality and sleep quality, respectively. Linear and logistic regression analyses were used to examine relationships between variables of interest. In addition, mediation analyses with bootstrapping were used to test whether sleep quality mediated the relationship between TABP and CSVD.

Results

Of the 764 participants [median age 65 (61-69) years, 59.9% female], the population with type A personality accounted for 44.8%. After adjusting for covariates, TABP scores (p = 0.03) and PSQI scores (p < 0.001) were significantly correlated with CSVD. In addition, sleep quality partially mediated the association between type A behavior and CSVD, and the mediating effect was 10.67%.

Conclusion

This study showed that type A behavior was a risk factor for CSVD among older community-dwelling adults and that sleep quality mediated the relationship between type A behavior and CSVD. Changing type A behavior may help improve sleep quality, which may in turn reduce the prevalence of CSVD.