Heart Rate Variability In Patients Research Articles

Neuro-vascular coupling and heart rate variability in patients with type II diabetes at different stages of diabetic retinopathy.

There is evidence that diabetes is accompanied by a break-down of functional hyperemia, an intrinsic mechanism of neural tissues to adapt blood flow to changing metabolic demands. However, to what extent functional hyperemia is altered in different stages of diabetic retinopathy (DR) in patients with type II diabetes is largely unknown. The current study set out to investigate flicker-induced retinal blood flow changes in patients with type II diabetes at different stages of DR. A total of 76 subjects were included in the present parallel-group study, of which 56 had diabetes with either no DR or different stages of non-proliferative DR (n = 29 no DR, 12 mild DR, 15 moderate to severe DR). In addition, 20 healthy subjects were included as controls. Retinal blood flow was assessed before and during visual stimulation using a combined measurement of retinal vessel calibers and blood velocity by the means of Doppler optical coherence tomography (OCT). To measure systemic autonomic nervous system function, heart rate variability (HRV) was assessed using a short-term orthostatic challenge test. In healthy controls, retinal blood flow increased by 40.4 ± 27.2% during flicker stimulation. Flicker responses in patients with DR were significantly decreased depending on the stage of the disease (no DR 37.7 ± 26.0%, mild DR 26.2 ± 28.2%, moderate to severe DR 22.3 ± 13.9%; p = 0.035, ANOVA). When assessing systemic autonomous neural function using HRV, normalized low frequency (LF) spectral power showed a significantly different response to the orthostatic maneuver in diabetic patients compared to healthy controls (p < 0.001). Our study indicates that flicker induced hyperemia is reduced in patients with DR compared to healthy subjects. Further, this impairment is more pronounced with increasing severity of DR. Further studies are needed to elucidate mechanisms behind the reduced hyperemic response in patients with type II diabetes. [https://clinicaltrials.gov/], identifier [NCT03 552562].

Evaluation of psychological stress, cortisol awakening response, and heart rate variability in patients with chronic prostatitis/chronic pelvic pain syndrome complicated by lower urinary tract symptoms and erectile dysfunction.

Mental stress and imbalance of its two neural stress systems, the autonomic nervous system (ANS) and the hypothalamic-pituitary-adrenal (HPA) axis, are associated with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) and erectile dysfunction (ED). However, the comprehensive analyses of psychological stress and stress systems are under-investigated, particularly in CP/CPPS patients complicated by lower urinary tract symptoms (LUTS) and ED. Participants were 95 patients in CP/CPPS+ED group, 290 patients in CP/CPPS group, 124 patients in ED group and 52 healthy men in control group. The National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI), the International Index of Erectile Function-5 (IIEF-5) and the International Prostate Symptom Score (IPSS) were used for assessing the disease severity of CP/CPPS, LUTS and ED. Psychometric self-report questionnaires including the Beck Anxiety Inventory (BAI), Perceived Stress Scale (PSS), Type A Personality Test (TAPT) and Symptom Checklist 90 (SCL-90) were completed for distress from physical symptoms. Twenty-five subjects per group were randomly selected for further investigating the changes of the HPA axis and ANS. Saliva samples were taken on 3 consecutive days at 8 specific times with strict reference to time of morning awakening for evaluation of free cortisol. Heart rate variability (HRV) as marker of the ANS was measured using 24 h electrocardiography, and time-and frequency-domain variables were analyzed. The BAI and SCL-90 scores were significantly higher in the CP/CPPS+ED, CP/CPPS and ED groups compared with the control group (p < 0.01). The PSS scores of both groups with ED were significantly higher than the control group (p < 0.01). Compared with the CP/CPPS group, the differences of PSS, SCL-90 and TAPT scores were statistically significant in CP/CPPS+ED patients (p < 0.01). The IPSS scores were shown to have significantly positive correlations with BAI (r = 0.32, p < 0.0001), PSS (r = 0.18, p < 0.01) and SCL-90 (r = 0.19, p < 0.01) in the CP/CPPS patients. However, in all subjects, the IIEF-5 scores were shown to have significantly negative correlations with BAI (r = -0.17，p < 0.001), PSS (r = -0.25，p < 0.0001), SCL-90 (r = -0.20，p < 0.001) and quality of life score in NIH-CPSI (r = -0.14，p = 0.0075). Cortisol awakening response (CAR) parameters and diurnal cortisol levels did not significantly vary between the four groups. Time-dependent parameters of HRV also did not differ significantly across groups. In the frequency domain analysis, low frequency (LF) was significantly lower in ED patients when compared with CP/CPPS+ED patients (p = 0.044) and healthy controls (p = 0.005), high frequency (HF) power was significantly higher in healthy controls compared to patients with ED (p < 0.001), CP/CPPS (p < 0.001) and CP/CPPS+ED (p < 0.001), and the CP/CPPS+ED group had significantly higher LF/HF ratio than the control group (p = 0.001). CP/CPPS and ED patients score exceedingly high on most psychosocial variables. The symptom scores of LUTS and ED positively correlate with the severity of psychological stress. Our findings also suggest that the ANS sympathovagal imbalance is associated with ED and LUTS in CP/CPPS, whereas HPA axis activity is not.

Letter to the Editor regarding 'Heart rate variability in patients with dementia or neurocognitive disorders: A systematic review and meta-analysis'.

Letter to the Editor regarding 'Heart rate variability in patients with dementia or neurocognitive disorders: A systematic review and meta-analysis'.

Heart rate variability in patients with insomnia disorder: a systematic review and meta-analysis.

Though logical inference based on small studies suggests that patients with insomnia have a blunted heart rate variability (HRV), this condition not been clearly shown. This meta-analysis aimed to determine whether or notHRV was impaired in patients withinsomnia. We conducted a comprehensive literature search for studies that examined the association of HRV with insomnia disorder. HRV measures were extracted using the SDNN (time-domain measure, i.e., standard deviation of all NN intervals,) or the HF-norm (frequency-domain measure, i.e., high-frequency power normalized using total power). The effect size estimates of R_equivalent obtained from p values and sample size were synthesized. We identified 17 studies with 921 participants. The pooled R_equivalent was 0.19 with 95% CI of 0.12 and 0.25 (p < 0.001), and there was no significant heterogeneity (I2 = 0.0%, p = 0.809). A p value of 0.075 corresponding to the R_equivalent of 0.19 was obtained, suggesting that blunted HRV was not significant in patients with insomnia disorder. The current evidence did not confirm that HRV was reliably impaired in patients with insomnia disorder. Prospective studies using standard HRV measures are needed to clarify the HRV dynamics in different insomnia subtypes.

Are changes in pain associated with changes in heart rate variability in patients treated for recurrent or persistent neck pain?

BackgroundPersistent or recurrent neck pain is associated with perturbations in the autonomic nervous system balance, and nociceptive stimulation has been seen to influence this balance. However, very few prospective studies have addressed the extent to which changes in pain associate with changes in autonomic cardiac regulation. Therefore, we investigated if changes in pain vary with changes in heart rate variability in a cohort of patients treated for persistent or recurrent neck pain.MethodThis analysis is based on data from a randomized controlled trial in which participants were given home stretching exercises with or without spinal manipulative therapy for two weeks. As the effectiveness of the intervention (home stretching exercises and spinal manipulative therapy) was found to be equal to the control (home stretching exercises alone), all 127 participants were studied as one cohort in this analysis. During the intervention, pain levels were recorded using daily text messages, and heart rate variability was measured in the clinics three times over two weeks. Two approaches were used to classify patients based on changes in pain intensity: 1) Clinically important changes in pain were categorized as either "improved" or "not improved" and, 2) Pain development was measured using pain trajectories, constructed in a data driven approach. The association of pain categories and trajectories with changes in heart rate variability indices over time were then analysed using linear mixed models.ResultsHeart rate variability did not differ significantly between improved and not-improved patients, nor were there any associations with the different pain trajectories.ConclusionsIn conclusion, changes in pain after home stretching exercises with or without spinal manipulative therapy over two weeks were not significantly associated with changes in heart rate variability for patients with persistent or recurrent neck pain. Future studies should rely on more frequent measurements of HRV during longer treatment periods.Trial registrationThe trial was registered at ClinicalTrials.gov, registration number: NCT03576846.

The state of systolic and diastolic functions of the left ventricle and heart rate variability in patients with atrial fibrillation after infection of COVID-19

Abstract Introduction It is known that atrial fibrillation (AF) is one of the most common arrhythmias in patients (pts) who have had a COVID-19 infection (CI). The aim of our study was to evaluate systolic and diastolic functions of the left ventricle (LV) and heart rate variability (HRV) in pts with AF depending on the past CI. Research material and methods 131 pts with paroxysmal or persistent forms of AF in sinus rhythm were studied. 93 people had a history of an average of 6.2±0.5 months ago of COVID-19 infection. They made up the 1st group of examined pts. The remaining 38 patients did not have a history of this infection. They constituted the 2nd group of the study group, which was the control group. Transthoracic echocardiography and Holter monitoring ECG were performed according to the standard technique. Results of the study We did not find any difference in hemodynamic parameters characterizing the systolic function of LV. So, the values of the end-diastolic volume (117.0±7.6 mm and 116.0±7.2 mm), end-systolic volume (55.7±4.9 mm and 55.2±4.7 mm) and ejection fractions (55.0±2.1% and 54.4±2.0%) in the groups did not differ significantly. However, statistical significance was obtained in indicators characterizing LV diastolic function. So, significantly different flow rates in the 1st and 2nd groups of pts – E (60.8±1.63 sm/s and 94.6±2.97 sm/s, p&amp;lt;0.001), A (61.8±0.83 sm/s and 73.1±1.03 sm/s, p&amp;lt;0.001), their E/A ratios (0.98±0.02 and 1.39 + 0.03, p&amp;lt;0.001) and DE score (175.9±2.20 ms and 202.5±4.03 ms, p&amp;lt;0.001). A more significant violation of LV diastolic function after CI led to an increase in the diameter of the left atrium (LA) (4.99±0.14 cm in the 1st group compared with 4.40±0.004 sm in the 2nd group, p&amp;lt;0.001) and LA index (46.4±0.011 sm in the 1st group compared with 42.93±0.08 in the 2nd group, p&amp;lt;0.001). We also found a significant difference in such indicators of HRV between groups “1” and “2” as – SDANN (102.7±2.33 and 151.7±1.23 ms, p&amp;lt;0.001), SDNN (124, 3±4.06 and 181.3±4.83 ms, p&amp;lt;0.001), and RMSSD (100.4±4.57 and 173.2±13.51 ms, p&amp;lt;0.001). Conclusion In pts with AF, after undergoing CI, the LV diastolic function begins to suffer first, which leads to an increase in the size of the LA. Pts after CI also had a change in the autonomic regulation of the heart rhythm, and as a result, an increase in the electrical instability of the atria. Funding Acknowledgement Type of funding sources: None.

ЗНАЧЕНИЯ ВАРИАБЕЛЬНОСТИ СЕРДЕЧНОГО РИТМА В ОТДАЛЕННОМ ПЕРИОДЕ У БОЛЬНЫХ С ФИБРИЛЛЯЦИЕЙ ПРЕДСЕРДИЙ, ПОЛУЧАЮЩИХ АЛЛАПИНИН

Abstract. The study shows the values of heart rate variability in patients with paroxysmal atrial fibrillation treated with allapinin monotherapy and a combination of allapinin with metoprolol, allapinin with sotahexal and allapinin with diltiazem with preventive antiarrhythmic therapy. Analysis of heart rate variability allows you to determine the state of the autonomic nervous system. A high probability of an unfavorable outcome of diseases of the cardiovascular system is observed with the predominance of the tone of the sympathetic nervous system and a decrease in the tone of the parasympathetic nervous system. A decrease in heart rate variability and a predominance of sympathetic nervous system tone are predictors of the occurrence of another paroxysm in patients with paroxysmal atrial fibrillation. Indicators of heart rate variability are of great importance in the selection of antiarrhythmic therapy. The initial predominance of the tone of the parasympathetic nervous system in comparison with healthy ones and the absence of negative dynamics after 1 year was recorded in patients with paroxysmal atrial fibrillation with allapinin monotherapy. Patients treated with a combination of allapinin and metoprolol had a predominance of the tone of the parasympathetic nervous system initially compared with the healthy group and a transition to sympathicotonia after 1 year compared with healthy, control and their own baseline values. Patients receiving allapinin and sotahexal had no significant differences either at the beginning of the study or after 1 year. Predominance of sympathetic nervous system tone was registered in patients treated with allapinin and diltiazem by the end of 1 year of the study in comparison with a group of healthy.

COMPARATIVE EVALUATION OF THE EFFECTIVENESS OF CLASS III ANTIARRHYTHMIC DRUGS IN ELDERLY PATIENTS WITH PAROXYSMAL ATRIAL FIBRILLATION

Abstract. The article presents the results of the effectiveness of preventive antiarrhythmic monotherapy with sotahexal and cordarone based on heart rate variability and examination of patients at intervals of every 3 months for one year. The relevance of studying heart rate variability indicators is beyond doubt. The simplicity and non-invasiveness of this procedure dictates its increasing use. As a result of the study, the mechanism of occurrence of paroxysms of atrial fibrillation was shown both in patients with the existing paroxysmal form of atrial fibrillation, and in comparison, groups, where the debuts of this disease were recorded as a result of the study. It is known that with age there is an increase in diseases of the cardiovascular system, including atrial fibrillation. Elderly patients make up the bulk. Therefore, properly selected antiarrhythmic therapy based on heart rate variability indicators can help reduce morbidity in this group of patients. When studying the effectiveness of antiarrhythmic therapy on the example of representatives of the III class of antiarrhythmic drugs sotahexal and cordarone, it was found that the effectiveness of monotherapy with sotahexal and cordarone by the end of 1 year of the study was 74 and 71%, respectively. Indicators of heart rate variability in patients receiving sotahexal after 1 year did not significantly differ from each other, and at the initial stage of treatment, indicators characterizing the tone of the parasympathetic nervous system prevailed over the same indicators of patients receiving cordarone, over the tone differed from the initial ones in the downward direction. In patients receiving cordarone, a year later, there was a shift in the vegetative balance towards sympathicotonia compared with baseline indicators.

The short-term effect of weather variables on heart rate variability in patients after open-heart surgery

The short-term effect of weather variables on heart rate variability in patients after open-heart surgery

The effect of CPAP therapy on heart rate variability in patients with obstructive sleep apnea

The aim of this study was to analyze the relationship between the initiation of CPAP therapy and HRV in patients with OSA. The study group consisted of 37 patients, aged 34–79 (mean 54.95 years) with OSA treated with CPAP. Two subgroups of patients were distinguished: less than severe (AHI < 30, n = 16) and severe OSA (AHI ≥ 30, n = 21). The second study was carried out around a month after the initiation of therapy. CPAP therapy caused the improvement in polysomnographic parameters, however, in most parameters in time and frequency analysis, there were no significant positive changes in parasympathetic tone. Moreover, in HRV time analysis, the reduced rMSSD and pNN50 parameters in the hours of night rest and rMSSD and SDSD during the 15-min N3 sleep period were noted. Especially, in the group with AHI ≥ 30, we observed significant decreases in rMSSD and pNN50 for the entire time. The changes were mainly for the night periods including the N3 sleep period, which is especially connected with sleep apnea (parameters: rMSSD, SDSD, and pNN50). In spectral analysis, the decrease in HF from the 15-min daily activity period and the N3 sleep period was observed. Inverse correlations were seen between the maximum, median, and mean positive airway pressure (PAP) and the change in rMSSD, SDNN, and SDSD, mainly during night hours and the N3 sleep period. Only in patients with AHI < 30 the increase in SDNN was observed in 15-min N3 sleep period. The beneficial increase in SDNN parameter from time analysis was observed only in one sleep period in less ill patients with OSA. The lack of significant changes was observed in the majority of the parameters of heart rate variability after initiation of CPAP therapy in a short observational time; however, the shift towards reduced HRV was observed in patients with AHI > 30, so the response to CPAP therapy may depends on the severity of the apnea. The results may suggest that a longer observational period is needed in such studies, and the problem is still not fully elucidated.

Comparison of the autonomic nervous system dysfunction between different chronic spine disorders: neck pain versus low back pain.

SUMMARYOBJECTIVE:This study aims to compare heart rate variability (HRV) between patients with chronic neck pain and patients with chronic low back pain and to correlate the chronic pain variables with heart rate variability indices.METHODS:This is a cross-sectional study. We divided the sample into two groups: neck pain (n=30) and low back pain (n=30). We used the Numeric Pain Rating Scale, Neck Disability Index, Roland-Morris Disability Questionnaire, Pain-Related Catastrophizing Thoughts Scale, Tampa Scale of Kinesiophobia, and Pain Self-Efficacy Questionnaire. For heart rate variability analysis, we used the following indices: mean RR, standard deviation of all RR intervals, mean heart rate, root mean square differences of successive RR intervals, triangular index, triangular interpolation of the interval histogram, low-frequency band in arbitrary units and in absolute values, high-frequency band in arbitrary units and in absolute values, standard deviation of the instantaneous beat-to-beat variability (standard deviation 1), long-term standard deviation of continuous RR intervals (standard deviation 2), and Stress Index. We used Student’s t-test for comparisons and Spearman’s coefficient for correlations.RESULTS:We observe insignificant values in the differences between the groups. Disability and self-efficacy were correlated with heart rate variability only in patients with chronic neck pain, whereas catastrophizing and kinesiophobia showed greater correlations with heart rate variability in patients with chronic low back pain.CONCLUSIONS:Autonomic dysfunction of individuals with chronic neck pain, when compared to patients with chronic low back pain, does present insignificant differences.

The association between vitamin D levels and heart rate variability in patients with type 2 diabetes mellitus.

To assess the association between serum vitamin D levels and heart rate variability in patients with type 2 diabetes mellitus (T2DM). This study included 469 patients who were retrospective assessed for eligibility from Changzhou Second People’s Hospital, Affiliated Nanjing Medical University, between March 2013 and June 2020. A total of 191 T2DM patients were recruited and divided into 3 groups. A total of 191 patients were recruited. A significant difference was noted among groups for HbA1c (P < .001), serum uric acid (P = .048), and urea nitrogen (P = .043). The Vitamin D level in deficiency, insufficiency, and sufficient was 23.17, 38.89, and 63.01 nmol/L, respectively. The insufficient group had lower levels of percentage of normal-to-normal intervals differing by more than 50 milliseconds, and the square root of the mean of the squares of the differences between adjacent normal-to-normal R peak-to-R-peak time intervals than the sufficient vitamin D group. Furthermore, patients in deficiency and insufficiency group were associated with high level of low frequency power/high frequency power as compared with sufficient vitamin D group. Finally, serum 25-hydroxyvitamin D (25(OH)D) levels were positively correlated with rMSSD (P = .002). This study found that low serum 25(OH)D levels were associated with reduced heart rate variability parameters in patients with T2DM.

Statistical Associations between Geomagnetic Activity, Solar Wind, Cosmic Ray Intensity, and Heart Rate Variability in Patients after Open-Heart Surgery

The aim of this study was to identify associations of the parameters of heart rate variability (HRV) with the variations in geomagnetic activity (GMA), solar wind, and cosmic ray intensity (CRI) in patients after coronary artery bypass grafting or valve surgery in Kaunas, Lithuania, during 2008–2012. The data from 5-minute electrocardiograms (ECGs) in 220 patients were used. ECGs were carried out at 1.5 months, 1 year, and 2 years after the surgery (N = 495). A lower (higher) very-low-frequency-band (VLF) and a higher (lower) high-frequency band (HF) in normalised units (n.u.) were associated with a low maximal daily 3-hourly ap (the DST index &gt; 1). A lower mean standard deviation of beat-to-beat intervals (SDNN) and VLF, LF, and HF powers were lower in patients when Ap &lt; 8 occurred two days after the surgery, and a low solar wind speed (SWS) occurred two days before the ECG. The effect of CRI was non-significant if the linear trend was included in the model. Low GMA and a low SWS may effect some HRV variables in patients after open-heart surgery. The GMA during the surgery may affect the SDNN in short-term ECG during the longer period.

The Effect of Aquatic Exercise Training on Heart Rate Variability in Patients with Coronary Artery Disease.

(1) Background: Aquatic exercise training is a relatively understudied exercise modality in patients with CAD; with the present study, we sought to compare the impact of short-term 14-day water- and land-based exercise training on heart rate variability (HRV). (2) Methods: We randomized 90 patients after a recent CAD event (myocardial infarction and/or revascularization within 2 months prior to inclusion) to either (i) water-based or (ii) land-based exercise training (14 days, two 30 min sessions daily), or (iii) controls. Before and after the intervention period, all participants underwent 20 min 12-channel high-resolution ECG recordings with off-line HRV analysis, including conventional linear time- and frequency-domain analysis (using the Welch method for fast-Fourier transformation), and preselected non-linear analysis (Poincaré plot-derived parameters, sample entropy, and the short-term scaling exponent α1 obtained by detrended fluctuation analysis). (3) Results: Eighty-nine patients completed the study (mean age 60 ± 8 years; 20 % women). We did not detect significant differences in baseline- or age-adjusted end-of-study HRV parameters, but aquatic exercise training was associated with a significant increase in the linear LF/HF parameter (from 2.6 [1.2–4.0] to 3.0 [2.1–5.5], p = 0.046) and the non-linear α1 parameter (from 1.2 [1.1–1.4] to 1.3 [1.2–1.5], p = 0.043). (4) Conclusions: Our results have shown that a short-term 14-day aquatic exercise training program improves selected HRV parameters, suggesting this mode of exercise is safe and may be beneficial in patients with CAD.

Effect of Radiofrequency Current Application during Catheter Ablation on Heart Rate Variability in Patients with Supraventricular Tachycardia

Effect of Radiofrequency Current Application during Catheter Ablation on Heart Rate Variability in Patients with Supraventricular Tachycardia

Impact of Short-Term Heart Rate Variability in Patients with STEMI Treated by Delayed versus Immediate Stent in Primary Percutaneous Coronary Intervention: A Prospective Cohort Study.

Objective Patients with ST-segment elevated myocardial infarction (STEMI) have been treated with the delayed stent strategy to reduce the occurrence of postoperative no-reflow and improve the recovery of postoperative cardiac function. However, the effects of electrocardiac activity and autonomic nerve function after primary percutaneous coronary intervention (pPCI) have been rarely reported. The purpose of this study was to investigate the effects of short-term heart rate variability (HRV) in patients with STEMI treated by immediate stent (IS) and delayed stent (DS) strategy. Methods A total of 178 patients with STEMI were divided into 124 cases (69.66%) in the IS group and 54 cases (30.34%) in the DS group from July 2019 to September 2021. The mean heart rate, premature ventricular contraction (PVC), left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVED), and HRV indexes were compared between the two groups. Results In terms of cardiac electrical stability, the number of PVCs, the percentage of PVCs, and the number of paired PVCs in the DS group were lower than those in the IS group. In terms of HRV, high frequency (HF) and standard deviation of all NN (SDNN) intervals were higher in the patients with DS strategy than IS strategy. There were no significant differences in the LVED and LVEF between the two groups. Conclusion Compared to the IS strategy, the DS strategy in pPCI in patients with STEMI has advantages in postoperative cardiac electrical stability and short-term cardiac autonomic nerve function, with no difference in postoperative short-term cardiac function.

The short-term effect of weather variables on heart rate variability in patients after open-heart surgery

ABSTRACT The aim of the study was to detect the associations between heart rate variability (HRV) and weather variables in patients who underwent coronary artery bypass grafting or valve surgery. The study was performed in Kaunas, Lithuania, during 2008–2012. We used data of 220 patients. HRV was assessed by a 5-minute electrocardiogram. The data were collected at 1.5 months, 1 year, and 2 years after the surgery (495 measurements). A negative association of standard deviation of beat-to-beat interval (SDNN), very low frequency (VLF), low frequency, and high frequency (HF) powers with a decrease in air temperature (T) during a 3-day period in the range of T < 1°C wind speed >2.75 knots 2 days before, and the daily North Atlantic Oscillation indices were observed. The effect of wind speed on SDNN and VLF power was stronger in males. Two days after relative humidity >89%, a lower mean VLF and higher HF in normalized units were found; in females, this effect was stronger 1.5 months after the surgery. Among patients after open-heart surgery, the HRV variables may be related to specific weather changes and the effect of weather was different for males and females and at different times after the surgery.

Investigation of heart rate variability of patients undergoing coronary artery bypass grafting using the statistical signal characterization method.

Autonomic function can be estimated non-invasively using heart rate variability (HRV). HRV of patients undergoing coronary artery bypass grafting (CABG) is investigated in time-domain and frequency-domain before and after CABG to study the effect of operation on the status of patients. The main purpose of this work is to evaluate the effect of CABG surgery on patients with ischemic heart disease (IHD) before operation, and to monitor the status of patients on day 6 and day 30 after the CABG operation. The statistical signal characterization (SSC) technique is used in this work in order to derive different morphology-based parameters to indirectly describe time-domain and frequency-domain HRV parameters in 24 patients undergoing CABG operation, before the operation (Group 1: G1), 6days after operation (Group 2: G2) and 30days after operation (Group 3: G3). The data is obtained from the Sultan Qaboos University Hospital in Oman. The SSC parameters Mean(mt) and Mean(dt) are reduced in all 24 patients and in 23 out of 24 patients in G2 compared to G1 (6-days after operation compared with before operation), respectively. Comparing G3 to G1 the reduction in Mean(mt) and Mean(dt) is noted in 18 of the 24 patients. The parameters Mean(mt) and Mean(dt) are successful parameters to follow the HRV for patients undergoing CABG surgery. A relation between those SSC parameters and the HRV time-domain and frequency-domain parameters is investigated in this paper to understand the physiological behavior of the patients.

Characteristics of heart rate variability in patients with vestibular migraine

Objective: To analyze the characteristics of heart rate variability (HRV) in patients with vestibular migraine (VM) and to explore its possible mechanism. Methods: Forty-eight patients with VM [17 males and 31 females, age (36.2±9.2) years], 44 patients with migraine [15 males and 29 females, age (34.4±9.0) years], and 30 patients with health check-ups during the same period [12 males and 18 females, age (34.6±6.5) years old] were selected as study subjects. Ambulatory ECG monitoring was performed in all subjects, and the HRV characteristics of each group were analyzed from both daytime and nighttime time phases. Time domain parameters were analyzed: standard deviation of normal to normal (SDNN), root mean square of successive differences (RMSSD), and percentage of normal to normal intervals differing by more than 50 ms (pNN50). The parameters in the frequency domain were analyzed: high frequency power (HF), low frequency power (LF), and the ratio of low frequency to high frequency power (LF/HF). Statistical analysis of the data was performed using SPSS 26.0 software. Results: At night, RMSSD (F=6.694) and HF (F=9.434) were lower in the VM and migraine groups compared to the control group, while LF/HF (F=16.049) and LF (F=9.434) were elevated compared to the control group, with statistically significant differences (P<0.05 or P<0.01), while LF was significantly elevated in the VM group compared to the migraine group, with a statistically significant (P<0.05). On the daytime measurements, mainly LF was elevated in the vestibular migraine group compared with the control group, while RMSSD was decreased compared with the control group, with statistically significant differences (P<0.05). Conclusion: Autonomic dysfunction characterized by sympathetic hyperfunction and vagal hypofunction is present in VM patients and is more pronounced at night. In addition, the degree of autonomic dysfunction may be more pronounced in VM patients than in migraine patients.

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.