Heart Rate Turbulence Research Articles

ПОКАЗАТЕЛИ ТУРБУЛЕНТНОСТИ СЕРДЕЧНОГО РИТМА В КЛИНИЧЕСКОЙ ПРАКТИКЕ

Background. Heart disease is the leading cause of death in developed countries. Approximately half of these fatalities are due to sudden cardiac death. Electrocardiogram recording from the body surface allows stratification of patients according to the risk of cardiac arrest without the use of invasive methods. Arrhythmias, particularly ventricular extrasystole, can affect the sinus rhythm pattern. The change in sinus rhythm that occurs after an extrasystole is defined as heart rate turbulence. This phenomenon is not pathological, but some variants are associated with a risk of fatal arrhythmias. Aim. To analyze the indices and clinical significance of cardiac rhythm turbulence according to Holter monitoring in patients with various cardiological abnormalities at the hospital profile department. Material and methods. The study included 54 patients who were routinely treated in a cardiac hospital. Cardiac rhythm turbulence indices were obtained by Holter monitoring. Patients in severe and moderately severe clinical condition were not included in the study. Concomitant and past somatic diseases affecting the state of heart and cardiovascular system were considered. Results and discussion. Deviations in heart rhythm turbulence indices can be detected both in life- threatening arrhythmias and in benign extrasystoles. They are associated with the influence of the autonomic nervous system, but probably have different mechanisms. Deviations of heart rhythm turbulence indices were associated with left ventricular myocardial hypertrophy of concentric remodeling type and with an increased number of low-risk ventricular extrasystoles. To identify patients with arrhythmias of different risk, various threshold values of cardiac rhythm turbulence indices can be used. Conclusion. Factors likely to affect the indices of cardiac rhythm turbulence such as left ventricular myocardial remodeling and hypertrophy were revealed, as well as changes in autonomic nervous system regulatory function, including those associated with the constitutional features of the patient.

Heart rate variability and heart rate turbulence in patients with vasovagal syncope.

Aim The autonomic nervous system plays an important role in the pathogenesis of vasovagal syncope, but studies on the effect of basal autonomic tone have found confusing results. The aim of this study was to investigate the effect of basal autonomic functions, as assessed by heart rate variability (HRV) and heart rate turbulence (HRT), in patients with vasovagal syncope.Material and methods Patients who underwent head-up tilt test (HUTT) due to unexplained syncope and who had a 24 hr Holter ECG recording in the same period were retrospectively analyzed. Patients with diabetes, a history of myocardial infarction, heart failure, orthostatic hypotension, atrial fibrillation, or use of vasoactive drugs, such as beta blockers, were excluded from the study. 161 patients who met these criteria were included in the study. Time domain HRV parameters from Holter ECG recordings and HRT parameters from patients with sufficient number of ventricular premature contractions were measured.Results The age of the patients varied from 16 to 75 yrs (mean: 44.8±18.5 yrs). HUTT results of 60 (37.2 %) patients were evaluated as positive. There were no significant differences in the basal demographic, clinical, or laboratory findings of the tilt-positive and tilt-negative patient groups. Likewise, there were no significant differences between the time domain HRV parameters and HRT parameters of both groups.Conclusion HRV and HRT parameters reflecting basal autonomic function were not different between HUTT positive and HUTT negative patient groups. These findings suggest that basal autonomic functions have no effect on vasovagal syncope pathogenesis.

Electrical instability of the myocardium during therapy with atorvastatin in patients with postinfarction remodeling

Background and Aims: To study the dynamics of heart rate turbulence (HRT) and late ventricular potentials (LVP) depending on the postinfarction left ventricular (LV) remodeling and the effectiveness of atorvastatin therapy in STEMI patients.

Predicting the coronary atherosclerosis severity in cardiac patients

Background. Coronary atherosclerosis is an ongoing pathological process, varying from asymptomatic forms to angina pectoris, myocardial infarction and even sudden cardiac death. Early identification of persons with an increased risk of the severe atherosclerosis will promote adequate diagnostic and therapeutic measures to prevent cardiovascular complications.
 Aim. To make a prognostic model determining the probability of a severe coronary atherosclerosis in cardiac patients.
 Material and methods. The actual study included 116 patients of cardiology departments with various degree of coronary atherosclerosis measured by coronary angiography: group I 70% coronary stenosis (50% in case of left main coronary artery), group II those with less severe atherosclerotic process. All patients underwent electrocardiography (ECG) at rest and Holter monitoring. Pathological Q-waves, qualitative and quantitative characteristics of ventricular extrasystoles as well as QRS-fragmentation were assessed in all cases. In individuals having sinus rhythm, heart rate turbulence (HRT), T-wave alternans and QT, QTc dispersion on maximum and minimum heart rate were additionally calculated.
 Results. The prognostic model included the following ECG-markers: HRT, pathological Q-waves, QTc dispersion on maximum heart rate and QRS-fragmentation in lateral leads (I, AVL, V6). All parameters have demonstrated a direct relationship with the likelihood of severe coronary atherosclerosis. The current model took into account 71% of the factors influencing significant atherosclerosis, AUC=0.940.04, the sensitivity and the specificity were 90.0 and 94.4% respectively.
 Conclusion. A comprehensive assessment of the ECG data helps to identify the group with an increased risk of severe coronary atherosclerosis among cardiac patients.

Relationship between heart rhythm turbulence and ventricular arrhythmia in patients with multivessel lesion of coronary arteries

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): MoH Research Grant "Development of methods for differentiated prevention and treatment of potentially dangerous heart rhythm disorders" Prediction of adverse outcomes in patients after myocardial infarction (MI) remains a serious and not completely resolved problem, which pushes researchers to search for new technologies. One of the relatively promising new non-invasive methods for predicting sudden coronary death in patients with coronary heart disease and ventricular arrhythmias (VA) may be an assessment of heart rate turbulence (HRT). Given its important prognostic role, primarily in patients after MI, the aim of this work was to study the relationship between HRT and cardiovascular remodeling in patients with VA with history of MI and multivessel nature of coronary lesions. Materials and research methods 123 patients with history of MI, aged 38 to 76 years (average age 61.0 ± 7.6 years), were included into the study. The multivessel nature of coronary lesions was established based on the results of diagnostic selective coronary angiography. All patients underwent Holter monitoring of the electrocardiogram (HMECG). HRT was determined using two indicators, in accordance with the guidelines: Turbulence Onset (To, %) and Turbulence Slope (Ts, ms/RRi). Results Potentially dangerous ventricular arrhythmias (PDVA) were noted in more than half of the examined patients (n = 67; 54.5%). In analyze of the structure of PDVA, II class of VA, as the highest class, was not observed in any of the examined patients, class III was detected in 35% of cases, IVA – in 37.5%, and IVB – in 27.5%. In assessing the frequency of VAs, according to the Bigger classification, frequent PVC >10 VA/hour was detected in 41.5% of patients. The analysis of the HRT indicators did not reveal a decrease in the mean values both To (-1.2 ± 1.5%) and Ts (3.9 ± 3.1 ms/RRi) indicators in the main group of patients. However, after appropriate separation of the main group, 21.1% of them had disorders of only one (category 1; 15.4%) or both of the HRT indicators (category 2; 5.7%). Category 0 included patients without any disorder of HRT indicators. In analysis of the relationship between the PDVA and the category of HRT reduction, a significant interrelation between them was revealed (Table 1). Result Our study demonstrates presence of strong interrelation between HRT parameters disorder and severity of PDVA. Thus, study of HRT in patients after MI could be a strong and independent predictor of cardiovascular events including sudden cardiac death. Abstract Figure. Tab. 1. Interrelation between HRT and VA

Holter-Derived Autonomic Function, Arrhythmias and Carbohydrate Metabolism in Patients with Class III Obesity Treated with Laparoscopic Sleeve Gastrectomy.

The effects of weight loss following bariatric surgery on autonomic balance, arrhythmias and insulin resistance are still of interest. We prospectively investigated 50 patients with BMI > 40 kg/m2, aged 36.5 (18–56) years who underwent laparoscopic sleeve gastrectomy. Among other examinations, all subjects had 24-h Holter monitoring with heart rate variability (HRV) and heart rate turbulence (HRT) evaluation. After a median of 15 months, BMI decreased from 43.9 to 29.7 kg/m2, the incidence of hypertension decreased from 54 to 32% (p = 0.04) and any carbohydrate disorders decreased from 24 to 6% (p = 0.02). Fasting insulin concentration and insulin resistance index improved significantly (p < 0.001). Improvements in HRV parameters related to the sympathetic autonomic division were also observed (p < 0.001), while HRT evaluation was not conclusive. The enhancement of autonomic tone indices was correlated with reduction of BMI (SDNN-I r = 0.281 p = 0.04; SDNN r = 0.267 p = 0.05), but not with reduction of waist circumference, and it was also associated with decrease of mean heart rate (OR 0.02, 95%CI 0.0–0.1, p < 0.001). The incidence of arrhythmias was low and similar before and after follow-up. In conclusion, improvement of homeostasis of carbohydrate metabolism and autonomic function is observed in relatively young patients after weight loss due to laparoscopic sleeve gastrectomy.

Heart Rate Turbulence in Patients with Coronary Artery Disease and Its Correlation with Severity of Disease

Heart Rate Turbulence in Patients with Coronary Artery Disease and Its Correlation with Severity of Disease

Chronic vagus nerve stimulation is associated with multi-year improvement in intrinsic heart rate recovery and left ventricular ejection fraction in ANTHEM-HF

PurposeDisturbed autonomic function is implicated in high mortality rates in heart failure patients. High-intensity vagus nerve stimulation therapy was shown to improve intrinsic heart rate recovery and left ventricular ejection fraction over a period of 1 year. Whether these beneficial effects are sustained across multiple years and are related to improved baroreceptor response was unknown.MethodsAll patients (n = 21) enrolled in the ANTHEM-HF clinical trial (NCT01823887, registered 4/3/2013) with 24 h ambulatory electrocardiograms at all time points and 54 normal subjects (PhysioNet database) were included. Intrinsic heart rate recovery, based on ~ 2000 spontaneous daily activity-induced heart rate acceleration/deceleration events per patient, was analyzed at screening and after 12, 24, and 36 months of chronic vagus nerve stimulation therapy (10 or 5 Hz, 250 μs pulse width, 18% duty cycle, maximum tolerable current amplitude).ResultsIn response to chronic high-intensity vagus nerve stimulation (≥ 2.0 mA), intrinsic heart rate recovery (all time points, p < 0.0001), heart rate turbulence slope, an indicator of baroreceptor reflex gain (all, p ≤ 0.02), and left ventricular ejection fraction (all, p ≤ 0.04) were improved over screening at 12, 24, and 36 months. Intrinsic heart rate recovery and heart rate turbulence slope were inversely correlated at both screening (r = 0.67, p < 0.002) and 36 months (r = 0.78, p < 0.005).ConclusionThis non-randomized study provides evidence of an association between improvement in intrinsic heart rate recovery and left ventricular ejection fraction during high-intensity vagus nerve stimulation for a period of ≥ 3 years. Correlated favorable effects on heart rate turbulence slope implicate enhanced baroreceptor function in response to chronic, continuously cyclic vagus nerve stimulation as a physiologic mechanism.

Obstructive sleep apnea increases heart rhythm disorders and worsens subsequent outcomes in elderly patients with subacute myocardial infarction.

OBJECTIVEObstructive sleep apnea (OSA) is a potential cardiovascular risk. We aimed to investigate the association of OSA with heart rhythm disorders and prognosis in elderly patients with new-onset acute myocardial infarction (AMI).METHODSWe prospectively enrolled 252 AMI elderly patients (mean age, 68.5 ± 6.9 years) who were undergoing revascularization and completed a sleep study during their hospitalization. All subjects were categorized into non-OSA (apnea–hypopnea index (AHI) < 15, n = 130) and OSA (AHI ≥ 15, n = 122) groups based on the AHI. The changes in the autonomic nervous system, incidence of arrhythmia during nocturnal sleep, and major adverse cardiovascular and cerebrovascular events (MACCEs) were compared between the groups. RESULTSThe mean AHI value in all AMI patients was 22.8 ± 10.9. OSA patients showed higher levels of body mass index and peak high-sensitivity C-reactive protein and lower levels of minimum nocturnal oxygen saturation (MinSaO2), as well as greater proportion of multivessel coronary artery disease (all P < 0.05). The OSA group also showed significant increases in heart rate variability and heart rate turbulence onset (both P < 0.05) and higher incidence of arrhythmia (including sinus, atrial, and ventricular in origin). At a median follow-up of 6 months (mean 0.8–1.6 years), OSA (AHI ≥ 15) combined with hypoxia (MinSaO 2 ≤ 80%) was independently associated with the incidence of MACCEs (hazard ratio [HR]: 4.536; 95% confidence interval [CI]: 1.461−14.084,P = 0.009) after adjusting for traditional risk factors. CONCLUSIONSOSA and OSA-induced hypoxia may correlate with the severity of myocardial infarction, increase the occurrence of heart rhythm disorders in elderly subacute MI patients, and worsen their short-term poor outcomes.

Detection of cardiac involvement in pulmonary sarcoidosis using high-resolution Holter electrocardiogram.

BackgroundEarly detection of cardiac involvement in patients with sarcoidosis is important but currently unresolved. The aim of this study was to elucidate the utility of frequency domain microvolt T‐wave alternans (TWA), signal‐averaged ECG (SAECG), and heart rate turbulence (HRT) using 24‐hour Holter ECG for detecting cardiac involvement in patients with pulmonary sarcoidosis.MethodsThis study consisted of consecutive 40 pulmonary sarcoidosis patients (11 males, 62 ± 13 years) who underwent 24‐hour Holter monitoring with and without cardiac involvement. All patients underwent frequency domain TWA, SAECG, and HRT using 24‐hour Holter monitoring. Patients with atrial fibrillation pacing or wide QRS electrocardiogram were excluded.ResultsAfter 14 patients were excluded, a total of 26 patients (six males, 59 ± 14 years) were evaluated. Seven patients had cardiac involvement (cardiac sarcoidosis [CS] group). On the Holter SAECG, duration of low‐amplitude signals <40 μV in the terminal filtered QRS complex (LAS40) was significantly higher, and root mean square voltage of the terminal 40 ms of the filtered QRS complex (RMS40) was significantly lower in the CS group compared with the non‐CS group (LAS40: 61.4 ± 35.9 vs 37.6 ± 9.2 ms; P = .018, RMS40: 11.4 ± 10.3 vs 23.6 ± 13.2 ms; P = .023). Prevalence of positive late potential (LP) was also significantly higher in the CS group than that in the non‐CS group (85.7% vs 31.5%; P = .026). The sensitivity, specificity, positive, and negative predictive values of LP for identifying patients with cardiac involvement were 85.7%, 68.4%, 50.0%, and 92.8%, respectively.ConclusionHolter SAECG may be useful for detecting cardiac involvement in patients with pulmonary sarcoidosis.

Assessment of heart rate turbulence in dogs with myxomatous mitral valve disease.

Background:Myxomatous mitral valve degeneration (MMVD) is the most common heart disease affecting small dogs, it reduces cardiac output resulting in compensatory adaptation of the autonomic nervous system. Chronically, it leads to reduced heart rate variability (HRV) which is an accurate marker for autonomic balance. More than two decades ago in human medicine an indicator of autonomic balance that happens after a premature ventricular beat, it was described as heart rate turbulence (HRT). In humans with ischemic heart disease, the absence of HRT has proven to be a more accurate and an independent indicator of mortality than known HRV parameters. Currently, there are very few studies of HRT in dogs and it is still not tested in small dogs within different stages of myxomatous mitral valve disease.Aim:The aim of this study was to assess the HRT indicators, onset and slope, in small dogs with myxomatous mitral valve disease and to statistically test it.Methods:Dogs under 25 kg had electrocardiogram and echocardiography performed and, in some patients, holter monitoring was carried out. Data were divided into groups B1, B2, C, and D for mean comparison with analysis of variance and Tukey test. In addition, receiver operating characteristic (ROC) curve for differentiating among symptomatic and asymptomatic dogs and for differentiating between remodeled and non-remodeled hearts. The Pearson was executed after correlations of turbulence onset (TO) and turbulence slope (TS) with commonly used echocardiographic parameters.Results:Variance analyses held significant differences in TO and TS between stages B1 from stages C and D, while B2 held similarity to the other groups. In the receiver operating curve was found a very good area under the curve for differentiating among symptomatic and asymptomatic dogs and remodeled and non-remodeled dogs. Few echocardiography parameters held weak correlation with TO while others held weak to moderate correlation with TS.Conclusion:In dogs with MMVD and without other diseases, HRT is a feasible indicator for autonomic balance. Our result suggests HRT changes as the MMVD progresses and congestive heart failure is present. More studies with HRT are needed. The number of ventricular premature contractions (VPCs) may be the strongest limitation for the technique.

Sağlıklı Postmenopozal Kadınlarda Kalp Hızı Türbülansı Analizi

Objective: The aim of the present study was to investigate heart rate turbulence (HRT) parameters in postmenopausal women. Material and Methods: A total of 40 postmenopausal women and 43 healthy, regularly menstruating premenopausal women were taken as study and control groups, respectively. All patients had biochemical blood examination, 2-D echocardiography and 24-hour Holter monitorization. HRT parameters, namely turbulence onset (TO) and turbulence slope (TS) were calculated. Results: Age, body mass index (BMI), systolic and diastolic pressure, total cholesterol and LDL levels were higher in the postmenopausal group, whereas HDL levels were higher in the premenopausal group (p<0.05). TO was significantly higher, TS was significantly lower in postmenopausal women compared to premenopausal women (-2.76±1.34 vs 0.60±1.30 and 3.60±1.54 vs 1.60±1.48, p=0.000 for both, respectively). TO was positively correlated, TS negatively correlated with age, BMI, systolic and diastolic blood pressure and LDL cholesterol level. According to multivariate analysis only menopausal status and age had an independent effect on HRT parameters. Receiver operating characteristic analysis showed that the cut-off values of TO and TS for predicting menopausal status were 0.959 and 0.165, respectively (0.835 anti-image). These results showed that TO and TS had diagnostic value for predicting menopausal status. Conclusion: Postmenopausal women had blunted HRT response. It is a simple and easily obtainable test and should be implemented in cardiac evaluation in daily practice.

The evaluation of ventricular arrhythmia risk by using electrocardiographic parameters in patients with dipper and non-dipper hypertension

Aim: Non-dipper hypertension (NDHT) is associated with increased cardiovascular mortality. Lots of different electrocardiographic parameters can be used for this purpose. Some electrocardiographic repolarization parameters and some particular parameters obtained from 24 hours holter recordings frequently were used. The aim of this study was to evaluate ventricular arrhythmia risk by using most of this electrocardiographic parameters in patients with dipper hypertension (DHT) and NDHT.Material and methods: 220 patients with hypertension were included this study. Patients were divided into two groups as DHT and NDHT according to the 24 hours ambulatory blood pressure monitoring. Two groups were compared with electrocardiography and echocardiography parameters and also were compared with heart rate variability (HRV) and heart rate turbulence (HRT) parameters.Results: There were no significant differences between DHT and NDHT groups with regard to demographic and laboratory datas. Also echocardiography parameters normally distributed and have no significant differences between two groups. There were no significant differences between DHT and NDHT groups with regard to left ventricular mass index (p=0.280). Although QT, QT dispersion, HRV and HRT parameters differences were not statistically significant , results were in favour of DHT in terms of ventricular arrhythmia risk. Conclusion: When hypertensive patients having no statistically significant differences in terms of left ventricular diamaters and left ventricular mass between them were divided as DHT and NDHT; there were no statistically significant differences between two groups with regard to electrocardiographic ventricular arrhythmia parameters although results were in favour of DHT.

Sudden death and its predictors in myocardial infarction survivors in an Indian population.

ObjectiveThis study was conducted to assess the incidence of sudden cardiac death (SCD) in post myocardial infarction patients and to determine the predictive value of various risk markers in identifying cardiac mortality and SCD.MethodsLeft ventricular function, arrhythmias on Holter and microvolt T wave alternans (MTWA) were assessed in patients with prior myocardial infarction and ejection fraction ≤ 40%. The primary outcome was a composite of cardiac death and resuscitated cardiac arrest during follow up. Secondary outcomes included total mortality and SCD.ResultsFifty-eight patients were included in the study. Eight patients (15.5%) died during a mean follow-up of 22.3 ± 6.6 months. Seven of them (12.1%) had SCD. Among the various risk markers studied, left ventricular ejection fraction (LVEF) ≤ 30% (Hazard ratio 5.6, 95% CI 1.39 to 23) and non-sustained ventricular tachycardia (NSVT) in holter (5.7, 95% CI 1.14 to 29) were significantly associated with the primary outcome in multivariate analysis. Other measures, including QRS width, heart rate variability, heart rate turbulence and MTWA showed no association.ConclusionsAmong patients with prior myocardial infarction and reduced left ventricular function, the rate of cardiac death was substantial, with most of these being sudden cardiac death. Both LVEF ≤30% and NSVT were associated with cardiac death whereas only LVEF predicted SCD. Other parameters did not appear useful for prediction of events in these patients. These findings have implications for decision making for the use of implantable cardioverter defibrillators for primary prevention in these patients.

Heart Rate Turbulence Predicts Survival Independently From Severity of Liver Dysfunction in Patients With Cirrhosis.

BackgroundReduced heart rate variability (HRV) is an independent predictor of mortality in patients with cirrhosis. However, conventional HRV indices can only be interpreted in individuals with normal sinus rhythm. In patients with recurrent premature ventricular complexes (PVCs), the predictive capacity of conventional HRV indices is compromised. Heart Rate Turbulence (HRT) represents the biphasic change of the heart rate after PVCs. This study was aimed to define whether HRT parameters could predict mortality in cirrhotic patients.Materials and Methods24 h electrocardiogram recordings were collected from 40 cirrhotic patients. Turbulence Onset was calculated as HRT indices. The enrolled patients were followed up for 12 months after the recruitment in relation to survival and/or transplantation.ResultsDuring the follow-up period, 21 patients (52.5%) survived, 12 patients (30%) died and 7 patients (17.5%) had liver transplantation. Turbulence Onset was found to be strongly linked with mortality on Cox regression (Hazard ratio = 1.351, p < 0.05). Moreover, Turbulence Onset predicted mortality independently of MELD and Child-Pugh’s Score.ConclusionThis study provides further evidence of autonomic dysfunction in cirrhosis and suggests that HRT is reliable alternative to HRV in patients with PVCs.

The evolution of markers of sudden death on the background of highly effective atorvastatin therapy in patients with STEMI

Background and Aims: to evaluate the role of highly effective atorvastatin therapy on the dynamics of heart rate turbulence (HRT) and late ventricular potentials (LVP) in STEMI patients.

Evolution of Heart Rate Variability and Heart Rate Turbulence in Patients with Depressive Illness Treated with Selective Serotonin Reuptake Inhibitors.

Background and objectives: Major depressive disorder (MDD) and cardiovascular diseases (CVDs) represent serious and prevalent medical conditions. Autonomic nervous system (ANS) dysfunctions, expressed by parameters of heart rate variability (HRV) and heart rate turbulence (HRT), have been repeatedly associated with depression. The aim of our study was to identify potential HRV and HRT alterations in patients with MDD, before and after selective serotonin reuptake inhibitor (SSRI) therapy, and to observe any correlations between these parameters and the severity of depressive symptoms. Another aim was to evidence if there was a normalization or improvement of HRV and HRT parameters that paralleled the reduction of the intensity of depressive symptoms. Materials and Methods: We studied heart rate variability (HRV) and heart rate turbulence (HRT) in a sample of 78 patients, aged under 51 years, who were referred to our outpatient clinic between June 2017 and December 2019, for complaints in the context of a new onset major depressive disorder (MDD), before and after therapy with SSRIs. Results: By using 24 h Holter ECG monitoring, we evidenced alterations of HRV and HRT parameters, significantly correlated with the severity of depressive symptoms (p < 0.001), as assessed by the Montgomery–Åsberg Depression Rating Scale (MADRS). Our results indicated that these parameters improved following one and six months of SSRI therapy, when a partial or total remission of depressive symptoms was achieved (p < 0.001). Changes in HRV parameters were correlated with the reduction of the severity of depression. Conclusions: In our study group, we highlighted, through 24 h ECG Holter monitoring, frequent and clear HRV and HRT abnormalities that were statistically correlated with the severity of depressive symptoms. Furthermore, we were able to document a progressive improvement of these parameters, which corresponded with the improvement of depressive symptoms under SSRI therapy, when compared to the values measured before the commencement of antidepressant pharmacotherapy.

Multi-year improvement in autonomic tone, baroreceptor sensitivity, and cardiac electrical stability using vagus nerve stimulation in patients with HFrEF in the ANTHEM-HF study

Abstract Background HFrEF patients experience long-term deterioration of autonomic function and cardiac electrical stability linked to increased sudden cardiac death risk. ANTHEM-HF (NCT01823887) reported improved baroreceptor sensitivity (heart rate turbulence, HRT), heart rate variability (rMSSD), and reduced cardiac electrical instability (T-wave alternans, TWA) after 12 months of chronic vagus nerve stimulation (VNS). It is unknown whether these benefits persist long-term. Methods HRT, rMSSD, TWA, and VT occurrence were evaluated during chronic VNS in all patients with symptomatic HFrEF with available 36-month follow-up data (n=25). ECGs were analyzed before Autonomic Regulation Therapy system implantation (LivaNova USA) and after chronic cervical VNS. Results Improvement in HRT slope persisted at 24 months (8.1±1.2 ms/RR interval, p=0.02) and 36 months (7.9±0.9 ms/RR interval, p=0.03) of VNS compared to baseline. RMSSD increase continued at 24 months (34.6±2.7 ms2, p&amp;lt;0.02) and 36 months (36.4±2.0 ms2, p=0.002). Peak TWA levels remained reduced at 24 months (47.8±1.3 μV, p&amp;lt;0.0001) and 36 months (46.1±1.6 μV, p&amp;lt;0.0001). No sudden death, VF, or sustained VT occurred, and patients with nonsustained VT decreased from 11 (44%) at baseline to 1 (5%) at 24 months (p&amp;lt;0.003) and 2 (11%) at 36 months (p&amp;lt;0.02). Conclusion In patients with HFrEF, chronic VNS appears to confer persistent 3-year improvements in autonomic tone, baroreceptor sensitivity, and cardiac electrical stability. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): LivaNova PLC

Assessment of arrhythmias and cardiac autonomic tone at a relatively young age patients with obesity class III.

There is no sufficient data on arrhythmias occurrence in obesity class III. The influence of hyperinsulinemia and insulin resistance on arrhythmias and cardiac autonomic tone is also of ongoing interest in these subjects. We prospectively studied 81 selected patients with body mass index >40 kg/m2 , aged 34 (18-65) years. Among other examinations all subjects underwent electrocardiography and Holter monitoring with heart rate variability (HRV) and turbulence (HRT) evaluation. Controls consisted of 45 healthy, sex- and aged-matched lean volunteers. In patients median BMI was 44.5 kg/m2 (40.1-58.1), benign arterial hypertension was present in 43.2% and dysglycemia in 27.2% of cases. In the group with obesity longer PR interval (P < .001) and corrected QT interval (P < .001) were observed, while in Holter monitoring no significant differences in supraventricular or ventricular arrhythmias and also bradyarrhythmias prevalence were observed in comparison to controls. In individuals with obesity HRV indices associated with sympathetic tone were significantly impaired and also abnormal HRT values (21.9 vs 0%, P = .04) were more frequently observed. There were no significant correlations between anthropometric obesity parameters and fasting insulin concentration, insulin resistance index and also HRV/HRT parameters in studied individuals. Univariate regression analysis revealed that only age influenced abnormal HRT occurrence (OR 1.69, 95%CI 1.08-2.98, P = .04). In conclusions, patients with obesity class III at a relatively young age who reported they felt healthy, do not present increased prevalence of arrhythmias, including life-threatening ones. Cardiac autonomic dysfunction is observed in these patients, however it has not been shown to be associated with anthropometric measurements.

Electrical myocardial instability as a problem of modern therapeutic practice – the realities of prognosis (a literature review)

The aim of the study – to analyze the latest research to predict development of myocardial electrical instability on the basis of literature data.Materials and methods. An analysis of the literature sources which cover prediction methods of electrical myocardial instability development.Results. The analysis of the literature shows that electrical myocardial instability, which is based on the heart’s response to various pathogenic factors, leads to significant changes in the electrophysiological properties of the heart muscle, is clinically manifested in heart rhythm and conductivity disturbances and prognostically characterized by different risk of developing fatal cardiac events.Conclusions. Non-invasive methods for assessing electrical myocardial instability include: echocardiography, Holter monitoring of the electrocardiogram, identification of depolarization change indicators – the phenomenon of QRS fragmentation, late ventricular potentials, repolarization change indicators – microvolt T-wave alternation, QT interval dispersion, autonomic nervous system parameters – heart rate variability and turbulence. With a view to determining the arrhythmogenic substrate, cardiac magnetic resonance imaging can be performed. Markers of fibrosis make it possible to control the assessment of individual risk for electrical myocardial instability. Prediction and prevention of electrical myocardial instability in patients with hypertension without / and in combination with ischemic heart disease, based on a study of the relationship between the presence of frequent ventricular extrasystole, such as electrical myocardial instability, and plasma fibrosis biomarkers (aldosterone, galectin-3 and transforming growth factor-β1) have not been clarified in the studies.