Heart Rate Variability Triangular Index Research Articles

Heart Rate Variability Triangular Index as a Predictor of Cardiovascular Mortality in Patients With Atrial Fibrillation.

BackgroundImpaired heart rate variability (HRV) is associated with increased mortality in sinus rhythm. However, HRV has not been systematically assessed in patients with atrial fibrillation (AF). We hypothesized that parameters of HRV may be predictive of cardiovascular death in patients with AF.Methods and ResultsFrom the multicenter prospective Swiss‐AF (Swiss Atrial Fibrillation) Cohort Study, we enrolled 1922 patients who were in sinus rhythm or AF. Resting ECG recordings of 5‐minute duration were obtained at baseline. Standard parameters of HRV (HRV triangular index, SD of the normal‐to‐normal intervals, square root of the mean squared differences of successive normal‐to‐normal intervals and mean heart rate) were calculated. During follow‐up, an end point committee adjudicated each cause of death. During a mean follow‐up time of 2.6±1.0 years, 143 (7.4%) patients died; 92 deaths were attributable to cardiovascular reasons. In a Cox regression model including multiple covariates (age, sex, body mass index, smoking status, history of diabetes mellitus, history of hypertension, history of stroke/transient ischemic attack, history of myocardial infarction, antiarrhythmic drugs including β blockers, oral anticoagulation), a decreased HRV index ≤ median (14.29), but not other HRV parameters, was associated with an increase in the risk of cardiovascular death (hazard ratio, 1.7; 95% CI, 1.1–2.6; P=0.01) and all‐cause death (hazard ratio, 1.42; 95% CI, 1.02–1.98; P=0.04).ConclusionsThe HRV index measured in a single 5‐minute ECG recording in a cohort of patients with AF is an independent predictor of cardiovascular mortality. HRV analysis in patients with AF might be a valuable tool for further risk stratification to guide patient management.RegistrationURL: https://www.clinicaltrials.gov; Unique identifier: NCT02105844.

Evidence Based Recommendations for Designing Heart Rate Variability Studies.

Heart rate variability (HRV) analysis is a powerful instrument that provides information about the heart conditions. However, there exist some limitations in the use of HRV in the clinical practice. Examples are the lack of reference values for healthy populations, different HR (Heart Rate) acquisition systems, and varying software packages. Other factors that affect HRV values are the influence of lifestyle, drugs and alcohol consumption, and pollution. In this work, recommendations to perform HRV-based experiments were established. These suggestions refer to best moment of the day to record data, the optimal body position, and the quality and duration of the recorded signals. In this way, HR data from 6 healthy subjects (2 women, 4 men), with median age of 50years old, were recorded during 15days, 3 times a day. Recordings were performed in the following situations: both supine and sitting body positions, in the morning, in the afternoon and at night. Data were processed and HRV analysis was performed. Distorting factors affecting HRV have been determined. The most stable HRV indexes (less variation over the days) have also been established. For this task, a variation coefficient was calculated for each parameter, as the ratio between the standard deviation and the mean value. Results indicated that HR data should be recorded in the morning, the sitting position. Related to signals duration, when comparing HR signals, they should be of equal length (same recording time). In addition, HRVi (HRV triangular index) and MADRR (median of the absolute differences between adjacent RR intervals) resulted in the most robust indexes in both low and high frequency domains. For global indexes, the ApEn (approximate entropy) measure emerged as the most stable one. As a conclusion, researchers must be extremely cautious in studies involving HRV analysis; the moment of the day to record data, the body position, or the quality of recorded data will produce different HR signals, and thus, the values of the HRV parameters will be different in each case. This may clearly bias the conclusions of the study.

Heart rate variability after radiofrequency ablation of epicardial ganglionated plexuses on the ovine left atrium

BackgroundGanglionated plexuses (GP) are terminal parts of cardiac autonomous nervous system (ANS). Radiofrequency ablation (RFA) for atrial fibrillation (AF) possibly affects GP. Changes in heart rate variability (HRV) after RFA can reflect ANS modulation.MethodsEpicardial RFA of GP on the left atrium (LA) was performed under the general anesthesia in 15 mature Romanov sheep. HRV was used to assess the alterations in autonomic regulation of the heart. A 24 − hour ECG monitoring was performed before the ablation, 2 days after it and at each of the 12 following months. Ablation sites were evaluated histologically.ResultsThere was an instant change in HRV parameters after the ablation. A standard deviation of all intervals between normal QRS (SDNN), a square root of the mean of the squared differences between successive normal QRS intervals (RMSSD) along with HRV triangular index (TI), low frequency (LF) power and high frequency (HF) power decreased, while LF/HF ratio increased. Both the SDNN, LF power and the HF power changes persisted throughout the 12 − month follow − up. Significant decrease in RMSSD persisted only for 3 months, HRV TI for 6 months and increase in LF/HF ratio for 7 months of the follow − up. Afterwards these three parameters were not different from the preprocedural values.ConclusionsEpicardial RFA of GP’s on the ovine left atrium has lasting effect on the main HRV parameters (SDNN, HF power and LF power). The normalization of RMSSD, HRV TI and LF/HF suggests that HRV after epicardial RFA of GPs on the left atrium might restore over time.

Is cardiac autonomic modulation during upper limb isometric contraction and Valsalva maneuver impaired in COPD patients?

PurposeTo evaluate the heart rate variability (HRV) indices and heart rate (HR) responses during isometric contraction (IC) and Valsalva maneuver (VM) in COPD patients.MethodsTwenty-two stable moderate to severe COPD patients were evaluated. R-R intervals were recorded (monitor Polar® S810i) during dominant upper limb IC (2 minutes). Stable signals were analyzed by Kubios HRV® software. Indices of HRV were computed in the time domain (mean HR; square root of the mean squared differences of successive RR intervals [RMSSD] and HRV triangular index [RR tri index]) and in the frequency domain (high frequency [HF]; low frequency [LF] and LF/HF ratio). The HR responses were evaluated at rest, at the peak and at the nadir of the VM (15 seconds). The Valsalva index was also calculated.ResultsDuring IC: time domain indices (mean HR increased [P=0.001], RMSSD, and RR tri index decreased [P=0.005 and P=0.005, respectively]); frequency domain indices (LF increased [P=0.033] and HF decreased [P=0.002]); associations were found between forced expiratory volume in 1 second (FEV1) vs RMSSD (P=0.04; r=−0.55), FEV1 vs HR (P=0.04; r=−0.48), forced vital capacity (FVC) vs RMSSD (P=0.05; r=−0.62), maximum inspiratory pressure (MIP) vs HF (P=0.02; r=0.68). FEV1 and FVC justified 30% of mean HR. During VM: HR increased (P=0.01); the nadir showed normal bradycardic response; the Valsalva index was =0.7.ConclusionCOPD patients responded properly to the upper limb IC and to the VM; however, HR recovery during VM was impaired in these patients. The severity of the disease and MIP were associated with increased parasympathetic modulation and higher chronotropic response.

Lower Heart Rate Variability Is Associated with Lower Pulse Pressure Amplification: Role of Obesity

Background: Heart rate variability (HRV), pulse pressure amplification, and obesity represent risk factors for cardiovascular events. The aims of the present study are (1) to explore the impact of HRV on pulse pressure amplification and (2) to investigate whether the association between HRV and pulse pressure amplification differs in obese and lean subjects. Methods: A total of 342 patients (age 61 ± 11 years) were enrolled. HRV was analyzed concerning both the frequency and time domain as well as concerning the HRV triangular index. Pulse pressure amplification was estimated as the ratio between brachial and carotid pulse pressure, the latter measured with SphygmoCor. Results: Time domain HRV indices were directly correlated with pulse pressure amplification (the lower the HRV indices, the lower the pulse pressure amplification). This association was stronger in obese than in lean subjects after controlling for age and sex. Conclusion: Larger controlled studies are needed to provide a more detailed insight into the relation between HRV and pulse pressure amplification and to determine which pathways are differentially activated in lean and obese subjects.

Clinical Implication of Heart Rate Variability in Obstructive Sleep Apnea Syndrome Patients

Obstructive sleep apnea syndrome (OSAS) is a common disease with the prevalence of approximately 10% in general population, and this disease entity is considered to be highly related with the development of cerebrovascular and cardiovascular diseases. In the pathogenesis of cardiovascular disease, maintaining the homeostasis of autonomic nervous system (ANS) is critical. To evaluate the homeostasis of ANS, heart rate variability (HRV) is commonly used. The object of this study was to evaluate the homeostasis of ANS using the parameters of HRV and to elucidate the correlation between the parameters and apnea-hypopnea index (AHI). Retrospective review of 806 patients was performed and 164 patients who were diagnosed as having OSAS by in-room polysomnography and met the criteria of age, sex, and body mass index were enrolled. The calculation of HRV parameters was executed using echocardiographic data from polysomnography. Between the control group (N = 81, AHI < 5) and OSAS patient group (N = 83, AHI > 15), standard deviation of NN (SDNN) intervals, SDNN index, HRV triangular index, very low frequency (VLF), low frequency (LF), 5-minute total power (TP), and low-frequency to high-frequency (LF/HF) ratio showed significant differences. In the correlation analysis between AHI and HRV parameters, only LF/HF ratio was proven to be significant. Elucidating the imbalance of ANS in OSAS patients was feasible by HRV and its parameters.

PP.LB01.19

Objective: Patients with atherosclerotic carotid disease usually do not present clinically overt signs of orthostatic dysregulation. In the present study we aimed at investigating if the presence of atherosclerotic plaque in the carotid sinus may alter baroreceptor function and thus heart rate variability (HRV) time-domain indices of autonomic tone and baroreflex sensitivity. Design and method: This was a cross-sectional study. We evaluated ECG R-R intervals in asymptomatic patients with carotid disease with an intima-media thickening (IMT) more than 0.8 mm. The atherosclerotic artery IMT was determined by B-mode and duplex ultrasonography. Baroreflex sensitivity and autonomic tone were determined through time-domain measures of HRV. Results: Of all time-domain measures of HRV investigated, we identified significant negative linear correlations between the common carotid artery IMT and time-domain HRV indexes reflecting baroreflex and autonomic tone: SDNN (standard deviation of R-R intervals), Spearman's r = −0.57, 95% CI: −0.78 to −0.25, P = 0.001; HRV triangular index (number of all R-R intervals / maximum number), Spearman's r = −0.62, 95% CI: −0.80 to −0.33, P = 0.0002; TINN (triangular interpolation of R-R intervals), Spearman's r = −0.59, 95% CI: −0.78 to −0.28, P = 0.0006. Similar strong negative correlations were found for subclavian IMT. Conclusions: Our data indicate that the SDNN, triangular index and TINN HRV biomarkers may be early predictors of atherosclerotic carotid and subclavian in subjects at risk and may be an indicator for ultrasound evaluation.

Pulmonary Function And Heart Rate Variability Responses To Low- And High-intensity Cycling In Diesel Exhaust

INTRODUCTION: Exposure to diesel exhaust (DE) prior to exercise increases exercise heart rate and attenuates exercise-induced bronchodilation. However, the effects of exercise combined with air pollution on pulmonary function and heart rate variability (HRV) are unclear. Furthermore, it is often assumed that increases in exercise intensity will increase the dose of air pollution, thus magnifying the resultant health effects. However, how the effects of DE on pulmonary function and HRV are modulated by exercise intensity is unknown. PURPOSE: To determine the effects to low- and high-intensity cycling in DE on pulmonary function and HRV. METHODS: Eighteen males performed 30-minute trials of low (30% VO2peak power) and high-intensity (60% VO2peak power) cycling and a resting control condition. For each subject, each trial was performed once breathing filtered air (FA) and once breathing DE (300ug/m3 of PM2.5), for a total of 6 trials. Pulmonary function and HRV were measured before, immediately after, and 1 h, and 2 h post-exposure to DE or FA. Time domain measures of HRV included the standard deviation of normal-to-normal intervals (SDNN), the root mean square of the mean differences in successive N-N intervals (RMSSD), and the HRV triangular index. Frequency domain analysis included low frequency power (LFP: 0.04–0.15 Hz), high frequency power (HFP: 0.15–0.40 Hz) as well as total power (TP). Additionally, LF and HF normalized units (LFnu, HFnu), and LF/HF ratios were determined. RESULTS: Exposure to DE had no significant effect on pulmonary function or HRV (p<0.05). As expected all time and frequency domain indices of HRV significantly decreased following high-intensity exercise (p<0.05; Pre to post high-intensity exercise: SDNN 1018.7 vs. 730.1 ms, RMSSD 65.2 vs. 19.5 ms, HRV triangular index 14.3 vs. 7.2, LFP 1408.8 vs. 455.7 ms2, HFP 1487.0 vs. 391.1 ms2, TP 4949.0 vs. 1152.8 ms2, HFnu 44.5 vs. 19.8). The exception to this pattern was LFnu and LF/HF ratio, which significantly increased following high-intensity exercise (p<0.05; Pre to post high-intensity exercise: LFnu 51.7 vs. 71.8, LF/HF 1.49 vs. 4.52). CONCLUSION: These data suggest that acute exposure to DE during exercise does not affect pulmonary function or HRV. Furthermore, performing high intensity exercise does not potentiate the effects of DE.

Heart rate variability is augmented in patients with positional obstructive sleep apnea, but only supine LF/HF index correlates with its severity.

Data on cardiac autonomic functioning, as expressed by heart rate variability (HRV), in patients with positional obstructive sleep apnea (p-OSA) disorder are lacking. The purpose of the study was to compare HRV indices between sleep segments derived from supine body position and another body position with and without apneic events, respectively. Our intention was to find some correlation between HRV indices and the pathophysiological characteristics of the corresponding temporal period. Nocturnal polysomnograms derived from twenty-seven patients (22 men) with documented positional apnea were retrospectively reviewed. Patients never treated for OSA and free from diseases/drugs altering HRV were examined. Data from total sleep studies were collected. Two N2 sleep segments, from supine body position with sleep-disordered breathing (SDB) and another body position without SDB were analyzed. Apneic events (namely, apneas, hypopneas, and respiratory effort-related arousals (RERAs)), arousals, number of desaturations, minimum pulse oximetry (SaO2min), time domain variables (average RR, SDNN, SDSD, RMSSD, pNN50, and HRV triangular index) and frequency domain variables (VLF, LF, HF, TP, LF/HF) were recorded for both temporal periods. With the exception of average RR and HF, all other variables were significantly higher in segments with SDB. Only LF/HF_supine ratio was positively correlated with the apneic_supine_index (t = 3.13, p < 0.01) and negatively correlated with SaO2min (t = -2.9, p < 0.01) and the desaturation_supine_index (t = -2.5, p = 0.02). Arousals were negatively correlated with SaO2min (t = -2.8, p < 0.01). SDB augments autonomic tone in patients with p-OSA, but only LF/HF correlates with its severity and might be used as a screening tool in the future. On the contrary, parasympathetic tone, as reflected by HF, remains constant in both periods.

The relationship between TCM syndromes of primary hypertension and heart rate variability

Objective To investigate the relationship between primary TCM syndromes and heart rate variability in hypertension, evaluate the development of disease. Methods 182 hypertension patients were recruited in accordance with the standard of hypertension. According to the Chinese medicine dialectical criteria, these patients were further divided into 5 groups, namely, hyperactivity of liver-fire group, phlegm-dampness retention group, blood stasis group, hyperactivity of Yang due to yin deficiency group and Qi and blood deficiency group. Another 60 healthy people were recruited as a control group. 24h Holter was adopted to monitor heart rate variability. Results Analysis of TCM syndromes and heart rate variability, anger on inflammation group had positive relation with SDNN, RMSSD, LF, HF and TP（r were respectively 0.161,0.372, 0.223, 0.281, 0.301）;Phlegmy wet resistance groups had positive relation with SDNN, HRV triangular index, VLF, LF, VLF/HF, LF/HF, LFnorm.（r were respectively 0.175, 0.211, 0.174, 0.262, 0.159, 0.264, 0.263）;blood stasis group had negative relation with LF/HF, LFnorm（r were respectively-0.185、-0.018）.Yang due to yin deficiency group had negative relation with SDNN, RMSSD, VLF, LF.（r were respectively -0.204, -0.161,-0.184,-0.197）;Qi and blood deficiency group had negative relation with SDNN, SDANN, RMSSD and HRV triangular index, VLF, LF, LFnorm, and had positive relation with HFnorm（r were respectively-0.353,-0.348,-0.258, -0.303, -0.268, -0.361, -0.352, 0.267）. Conclusion Hypertension patients with different type of＆nbsp;TCM syndromes had different characteristics of autonomic nerve functional disorders, which both reflected the important pathological changes of TCM syndromes and had close relation with the course of hypertension, providing objective basis for clinical diagnosis of syndrome differentiation. Key words: Hypertension; TCM syndrome differentiation; Heart rate variability（HRV）

Autonomic activity and leptin in Africans and whites

Evidence exists that leptin enhances sympathetic activity and may thereby contribute to the development of obesity-related hypertension. Sympathetic activation also seems more prominent in Africans than whites. We compared leptin levels, and different markers of autonomic activity between Africans and whites, and determined whether a relationship exists between leptin and autonomic activity. The study included 409 African and white school teachers (aged, 44.6 ± 9.6 years). We determined leptin in serum and measured ambulatory blood pressure. Markers reflecting autonomic activity included renin, cortisol, baroreflex sensitivity, ambulatory heart rate and heart rate variability (HRV) components (assessed by 24-h ECG recordings in the frequency and geometric domain). Africans had higher leptin levels, BMI, blood pressure and heart rate (all P < 0.001) as well as lower HRV triangular index and HRV total power (P < 0.001). After also adjusting for BMI in multivariate regression analyses, in African men, renin (β = 0.228; P = 0.033), night-time heart rate (β = 0.184; P = 0.034), HRV triangular index (β = -0.230; P = 0.010) and HRV total power (β = -0.214; P = 0.046) associated with leptin. In white men, leptin associated with 24-h heart rate (β = 0.376; P < 0.001), as well as day and night-time heart rate (both P < 0.01), HRV triangular index (β = -0.335; P < 0.001) and HRV total power (β = -0.403; P < 0.001). In African women, we observed an association of leptin with the total power component of HRV (β = -0.221; P = 0.015) and a borderline association with renin (β = 0.219; P = 0.057). No significant associations were apparent in the white women. We found that leptin is independently associated with different markers of autonomic activity, especially in men.

Psychosocial, physical, and autonomic correlates of depression in korean adults: results from a county-based depression screening study.

ObjectiveWe aimed to investigate the prevalence and psychosocial and neurophysiological correlates of depression in a large county-based cohort of Korean adults.MethodsWe recruited 2355 adults from a rural county-based health promotion program. The following psychometric scales were used: the Center for Epidemiologic Studies Depression scale (CES-D) was used to assess depression, the General Health Questionnaire (GHQ) was used to evaluate stress, and the Medical Outcome Study Social Support Survey (MOS-SSS) was used to determine perceived social support. Heart rate variability (HRV) was used to assess neurophysiological properties. The psychosocial and neurophysiological variables of adults with depression (CES-D score ≥25) and without depression (CES-D score <25) were statistically compared. A logistic regression model was constructed to identify factors independently associated with depression.ResultsWe estimated that 17.7% of the subjects had depression, which was associated with old age, being female, being single, less religious affiliation, high education, low body mass index (BMI), low levels of aerobic exercise, low social support, and a low HRV triangular index. The explanatory factors of depression included high education, less religious affiliation, low levels of current aerobic exercise, low BMI, and low social support.ConclusionGiven the relatively high prevalence of overall depression, subsyndromal depression should also be regarded as an important issue in screening. The independent factors associated with depression suggest that practical psychosocial intervention, including brief psychotherapy, aerobic exercise, and other self-help methods should be considered. In addition, the HRV results suggest that further depression screening accompanied by neurophysiological features would require fine methodological modifications with proactive efforts to prevent depressive symptoms.

Heart rate variability (HRV) in sleep apnea patients

Obstructive sleep apnea syndrome (OSAS) is a common disease with the prevalence of about 10% in general population. This disease entity is considered to be highly related with the development of cerebrovascular and cardiovascular diseases. In the pathogenesis of cardiovascular disease, maintaining the homeostasis of autonomic nervous system (ANS) is critical. To evaluate the homeostasis of ANS, heart rate variability (HRV) is commonly used. The object of this study was to evaluate the homeostasis of ANS using the parameters of HRV and to elucidate the correlation between the parameters and apnea–hypopnea index (AHI). Retrospective review of 806 patients was performed and 164 patients who met the criteria of age, sex, and body mass index (BMI) were enrolled. Between the control group ( N = 81; AHI < 5) and OSAS patient group ( N = 83;AHI > 15), SDNN, SDNN index, HRV triangular index, VLF, LF, TP, and LF/HF ratio showed significant differences. In the correlation analysis between AHI and HRV parameters, only LF/HF ratio was proven to be significant. Elucidating the imbalance of ANS in OSAS patients was feasible by HRV and its parameters.

Relation between emotional distress and heart rate variability in patients with an implantable cardioverter‐defibrillator

We investigated the relationship between Type D personality, depression, and anxiety, and heart rate variability (HRV) in 64 patients with an implantable cardioverter-defibrillator (ICD). HRV was obtained via 24-h Holter monitoring, and 24-h, 30-min daytime rest and 30-min nighttime sleep HRV were analyzed. In adjusted analyses, significant associations (standard deviation of normal-to-normal [NN] intervals [SDNN]: p = .043; standard deviation of NN intervals over 5-min periods [SDANN]: p = .010) and a trend (HRV triangular index: p = .09) were found for Type D personality, and trends were found for depression (lower RMSSD: p = .10; lower pNN50: p = .09). During daytime rest, similar results were found for anxiety and depression. During sleep, only noteworthy adjusted associations were found for depression (lower root mean square of successive differences in NN intervals [RMSSD]: p = .06; lower pNN50: p = .043). A Benjamini-Hochberg correction for multiple testing led to reduction of the number of significant relationships, but there was still support for lower autonomic control patients with Type D personality and depression. Future research with larger sample sizes is warranted.

Noninvasive evaluation of cardiac autonomic modulation in children with primary Raynaud’s phenomenon: a controlled study

This study aimed to objectively evaluate autonomic nervous function in children with primary Raynaud’s phenomenon (PRP). Thirty-two children with PRP and 30 healthy subjects were included in the study. We analyzed heart rate variability (HRV) in the time domain by the following six standard time-domain measures: standard deviation of all normal R-R intervals during 24 h (SDNN), standard deviation of all normal R-R intervals for all 5-min segments (SDNNi), standard deviation of the average normal R-R intervals for all 5-min segments (SDANN), root mean square of the successive normal R-R interval difference, percentage of successive normal R-R intervals longer than 50 ms, and triangular index (integral of the density distribution of NN intervals divided by the maximum of the density distribution). The mean heart rate throughout 24 h was significantly higher in the PRP group than in the control group (p = 0.001). Although heart rate during the activity period was not significantly different from that during the night period, it was higher in the PRP group than in the control group (p = 0.002). In children with PRP, HRV analysis showed significantly lower values of SDNN (p = 0.01), SDNNi (p = 0.005), SDANN (p = 0.02), and HRV triangular index (p = 0.02) compared with the control group. HRV analysis for sympathovagal balance demonstrated a preponderance for the sympathetic component in patients with PRP. We conclude that all time-domain parameters evaluated in HRV analysis are significantly lower in children with PRP than in healthy subjects.

Electrocardiographic findings during marathon running in healthy athletes using a new telemedical approach

Objective: Despite the beneficial effects of regular endurance exercise on cardiovascular mortality and morbidity, complex ventricular arrhythmias and atrial fibrillation seem to be common in elite and amateur endurance athletes. Nevertheless, data on arrhythmias during endurance exercise is sparse. Our goal was to proof the feasibility for recording electrocardiogram (ECG) during marathon running, and to compare the first hour with the last hour of running. Methods: 11 healthy, male recreational athletes were equipped with a long-term Tele-ECG with continuous recording of the heart rhythm during running a marathon. All ECG data were directly transferred via mobile network from the device to the Telemedicine center (Campus, Berlin, Germany) for a subsequent online diagnosis (Streaming-Telemedtechnology) The recorded data was analyzed offline. Results: One runner had to be excluded due to artifact superimposed recording quality. Therefore 10 male runners were included in our study and completed a full or a half marathon. No episodes of atrial fibrillation could be detected. Two participants showed less than 10 ventricular premature beats (VPB) during running (Lown classification I). In another two athletes 15 polymorphic VPB (Lown classification IIIa) and 117 VPB (Lown classification IV b), including 8 couplets and one triplet were observed, respectively. There was no significant difference between the first and last hour of running concerning the number of ventricular premature beats (3.4±10.8 vs. 1.6±4.4, P = ns), mean heart rate (139.8±32.6 vs. 130.6±39.2 bpm, P = ns), maximal heart rate (150.0±32.3 vs. 149.4±37.1 bpm, P = ns), rate corrected QT-interval (444.3±35.7 vs. 439.2±25.2 ms, P = ns). Concerning heart rate variability (HRV), it remained unchanged during marathon running {HRV triangular index 11.2±9.9 vs. 10.9±8.5, P = ns; Standard deviation of all NN intervals (SDNN) 85.4±67.0 vs. 109.0±62.7 ms, P = ns}. Conclusion: We showed that ECG recording and immediate transmission of the signal by telemedicine during marathon running is feasible. In general, ventricular and supraventricular arrhythmias were rare during endurance sport in our athletes. In addition, there were no significant changes in ECG parameters during marathon running.

GW24-e2110 Analysis of Holter changes at acute and convalescence stage of myocardial infarction

ObjectivesAcute myocardial infarction can cause various arrhythmias. It is postulated that activation of autonomic nervous system induced arrhythmias. The developments of dynamic electrocardiogram provide some methods to evaluate the alternations...

An inverse correlation between TNF alpha serum levels and heart rate variability in patients with heart failure

BackgroundRecent evidence indicates that chronic heart failure (CHF) is accompanied by both activation of the immune system and autonomic imbalance. There is a growing body of evidence that increased levels of proinflammatory cytokines and other inflammatory markers have important roles as mediators of disease progression and markers of mortality in patients with CHF. ObjectiveThe aim of this study was to investigate connection between autonomic imbalance [obtained by analysis of heart rate variability (HRV)] and activation of the immune system [as measured by serum levels of tumor necrosis factor (TNF)-α] in patients with chronic heart failure. Materials and methodsThis cross-sectional study included 21 patients with CHF and 8 age- and gender-matched healthy control subjects. We assessed HRV by 24-hour electrocardiographic Holter monitoring and measured serum levels of TNF-α using an enzyme-linked immunosorbent assay. Clinical assessment and echocardiography were also performed. ResultsThere was an inverse correlation between serum level of TNF-α and a time-domain parameter of HRV – SDNN (r=−0.542, p<0.05). A similar result was found for HRV triangular index, a geometric measure of HRV (r=−0.556; p<0.05). The correlation was stronger for subjects with a diabetes mellitus, females, and TNFA2 allele carriers (an “A” at position −308A). The pNN50, indirect marker of cardiac vagal activity, was not significantly associated with serum concentration of TNF-α. ConclusionsIn conclusion, the results of the present study indicate that increased serum TNF-α level is significantly associated with reduced HRV indices, suggesting that activation of the immune system in patients with CHF is closely related to autonomic imbalance.

Association of auricular pressing and heart rate variability in pre-exam anxiety students.

A total of 30 students scoring between 12 and 20 on the Test Anxiety Scale who had been exhibiting an anxious state > 24 hours, and 30 normal control students were recruited. Indices of heart rate variability were recorded using an Actiheart electrocardiogram recorder at 10 minutes before auricular pressing, in the first half of stimulation and in the second half of stimulation. The results revealed that the standard deviation of all normal to normal intervals and the root mean square of standard deviation of normal to normal intervals were significantly increased after stimulation. The heart rate variability triangular index, very-low-frequency power, low-frequency power, and the ratio of low-frequency to high-frequency power were increased to different degrees after stimulation. Compared with normal controls, the root mean square of standard deviation of normal to normal intervals was significantly increased in anxious students following auricular pressing. These results indicated that auricular pressing can elevate heart rate variability, especially the root mean square of standard deviation of normal to normal intervals in students with pre-exam anxiety.

Autonomic dysfunction and circadian blood pressure variations in people with impaired glucose tolerance

To assess circadian blood pressure variability in people with impaired glucose tolerance and a healthy control population. Seventy-five people with impaired glucose tolerance and 40 healthy volunteers (frequency matched on 10-year age bands and sex) underwent a detailed neurological assessment. Autonomic neuropathy was detected by the five standard cardiovascular autonomic tests and heart rate variability was characterized by the triangle index. Diurnal indices were assessed by 24-h ambulatory blood pressure monitoring. Systolic and diastolic diurnal indices were defined as: (mean daytime blood pressure - mean night-time blood pressure) × 100/mean daytime blood pressure. Mean 24-h systolic and diastolic blood pressure was significantly higher in the group with impaired glucose tolerance compared with the control group [126 ± 12 (mean ± SD) vs. 117 ± 10, 75 ± 7 vs. 71 ± 6 mmHg, both P < 0.05). Systolic and diastolic diurnal indices and heart rate variability triangular index were significantly lower in people with impaired glucose tolerance compared with control subjects (9.1 ± 7.8 vs. 13.2 ± 5.4, 14.5 ± 9.7 vs. 18.4 ± 7.1 mmHg, 28.0 ± 8.4 vs. 39.5 ± 9.3, all P < 0.05). Differences in mean diastolic blood pressure, heart rate variability triangular index and the frequency of non-dippers between those with impaired glucose tolerance and control subjects seemed to be independent of BMI and the presence of cardiovascular autonomic neuropathy, as simultaneous adjustment for BMI and cardiovascular autonomic neuropathy had no major effect on the results. Our data suggest that people with impaired glucose tolerance have increased diastolic blood pressure and abnormal circadian blood pressure regulation, independent of obesity and the presence of cardiovascular autonomic neuropathy.