Heart Rate Deceleration Capacity Research Articles

Predictive values of heart rate variability, deceleration and acceleration capacity of heart rate in post-infarction patients with LVEF ≥35.

Background and aimsThe aim was to investigate the predictive values of heart rate variability, deceleration, and acceleration capacity of heart rate in sudden cardiac death in postinfarction patients with left ventricular ejection fraction (LVEF) ≥ 35%.MethodsWe enrolled 138 acute myocardial infarction patients (MI) randomly in sinus rhythm with LVEF ≥ 35% after myocardial infarction. Data on heart rate variability, deceleration runs, deceleration, and acceleration capacity were obtained from 24h‐dynamic electrocardiogram recordings. Clinical characteristics, medications, and echocardiography data were noted. The endpoints were sudden cardiac arrhythmias (SCA), including malignant arrhythmias in the hospital and viewed sudden death out of the hospital. Relationships between autonomic parameters and endpoints were evaluated.ResultsDuring follow‐up for over 24 months in MI patients, 10 patients occurred sudden cardiac arrhythmias. Subjects with SCA showed lower levels of SDNN (p = .018), TP (p = .007), VLF (p < .001), DC (p < .001), and low‐risk DRs (p < .001) than those without SCA. A low SDNN level (HR: 8.888, p = .006), low VLF level (HR: 14.699, p = .016), low DC level (HR: 4.430, p = .045), and higher risk DRs (HR: 3.81, p = .040) were identified as independent risk factors of SCA for postinfarction patients with LVEF ≥ 35%. The area under the ROC curve (AUC) of SDNN, VLF, and DC for identification of SCA were, respectively, 0.724 (p = .019), 0.807 (p < .001), and 0.804 (p = .002). SDNN, VLF, and DC combined assessment area under the ROC curve were 0.828 (p < .001).ConclusionDecreased SDNN, VLF, DC, and abnormal DRs are independently associated with increased risks of sudden cardiac arrhythmias in post‐MI patients with LVEF ≥ 35%. Combined SDNN, VLF, and DC may help identify a high‐risk group of malignant arrhythmias in postinfarction patients.

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

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

Preprocessing Unevenly Sampled RR Interval Signals to Enhance Estimation of Heart Rate Deceleration and Acceleration Capacities in Discriminating Chronic Heart Failure Patients from Healthy Controls.

Objective. The deceleration capacity (DC) and acceleration capacity (AC) of heart rate, which are recently proposed variants to the heart rate variability, are calculated from unevenly sampled RR interval signals using phase-rectified signal averaging. Although uneven sampling of these signals compromises heart rate variability analyses, its effect on DC and AC analyses remains to be addressed. Approach. We assess preprocessing (i.e., interpolation and resampling) of RR interval signals on the diagnostic effect of DC and AC from simulation and clinical data. The simulation analysis synthesizes unevenly sampled RR interval signals with known frequency components to evaluate the preprocessing performance for frequency extraction. The clinical analysis compares the conventional DC and AC calculation with the calculation using preprocessed RR interval signals on 24-hour data acquired from normal subjects and chronic heart failure patients. Main Results. The assessment of frequency components in the RR intervals using wavelet analysis becomes more robust with preprocessing. Moreover, preprocessing improves the diagnostic ability based on DC and AC for chronic heart failure patients, with area under the receiver operating characteristic curve increasing from 0.920 to 0.942 for DC and from 0.818 to 0.923 for AC. Significance. Both the simulation and clinical analyses demonstrate that interpolation and resampling of unevenly sampled RR interval signals improve the performance of DC and AC, enabling the discrimination of CHF patients from healthy controls.

Increased markers of cardiac vagal activity in leucine-rich repeat kinase 2-associated Parkinson's disease.

Cardiac autonomic dysfunction manifests as reduced heart rate variability (HRV) in idiopathic Parkinson's disease (PD), but no significant reduction has been found in PD patients who carry the LRRK2 mutation. Novel HRV features have not been investigated in these individuals. We aimed to assess cardiac autonomic modulation through standard and novel approaches to HRV analysis in individuals who carry the LRRK2 G2019S mutation. Short-term electrocardiograms were recorded in 14 LRRK2-associated PD patients, 25 LRRK2-non-manifesting carriers, 32 related non-carriers, 20 idiopathic PD patients, and 27 healthy controls. HRV measures were compared using regression modeling, controlling for age, sex, mean heart rate, and disease duration. Discriminant analysis highlighted the feature combination that best distinguished LRRK2-associated PD from controls. Beat-to-beat and global HRV measures were significantly increased in LRRK2-associated PD patients compared with controls (e.g., deceleration capacity of heart rate: p = 0.006) and idiopathic PD patients (e.g., 8th standardized moment of the interbeat interval distribution: p = 0.0003), respectively. LRRK2-associated PD patients also showed significantly increased irregularity of heart rate dynamics, as quantified by Rényi entropy, when compared with controls (p = 0.002) and idiopathic PD patients (p = 0.0004). Ordinal pattern statistics permitted the identification of LRRK2-associated PD individuals with 93% sensitivity and 93% specificity. Consistent results were found in a subgroup of LRRK2-non-manifesting carriers when compared with controls. Increased beat-to-beat HRV in LRRK2 G2019S mutation carriers compared with controls and idiopathic PD patients may indicate augmented cardiac autonomic cholinergic activity, suggesting early impairment of central vagal feedback loops in LRRK2-associated PD.

Turbulence and deceleration capacity of the heart rate in patients with coronary artery disease and implanted cardioverter defibrillator

Aim. To study the possibility of using of heart rate turbulence (HRT) and deceleration capacity (DC) in the risk stratification of fatal events in patients with coronary artery disease (CAD) and implanted cardioverter defibrillator (ICD). Material and methods. The study included 45 patients with sinus rhythm and verified CAD, who had indications for ICD. A 24-hour ECG monitoring was performed with the evaluation of non-invasive predictors of sudden cardiac death. The minimum observation period was 30 months (the average observation period was 48 (42;51) months). Two endpoints were assessed: the onset of deaths and the justified ICD actuations. Results. During the observation period, 10 patients died (5 from progression of heart failure, 2 from recurrent myocardial infarction, 2 from non-cardiac pathology, and 1 died suddenly before implantation of a defibrillator). Arrhythmic events occurred in 13 people. Compared to the surviving patients, deceased patients’ mean DC value was significantly lower (1,25 (0,48;2,23) ms vs 3,3 (1,85;5,40) ms, p=0,016). There were significantly more frequent DC in the high-risk zone (80% vs 34%, p=0,024) and type 2 HRT disorders (80% vs 29%, p=0,009). When comparing patients with arrhythmic events and without them, no significant differences in DC and HRT were detected. According to univariate regression analysis, HRT and DC were risk factors for death (p=0,004 and p=0,006, respectively). Conclusion. Electrophysiological markers reflecting vegetative imbalance (HRT and DC) in patients with CAD and ICD can identify patients with high risk of overall mortality, but it is not associated with the risk of ventricular tachyarrhythmias development.

Changes in heart rate deceleration capacity and variability in resting children with vasovagal syncope

Objective To investigate the changes in heart rate deceleration capacity(DC) and heart rate va-riability(HRV) parameters in children with vasovagal syncope(VVS), to assess the basic autonomic function of children with VVS, and to explore the reference value of DC for the diagnosis of VVS in children. Methods VVS group included 62 patients diagnosed with VVS in the Cardiovascular Department of Children′s Hospital Affiliated to Capital Institute of Pediatrics from June 2015 to December 2017, 56 outpatients undergoing physical examination were selected as the healthy control group, and the changes in DC and HRV matched to age and gender were analyzed respectively.Indexes of DC and HRV of both groups of children in health control group and children with VVS were compared among different age groups or different genders. Results (1)Analysis of DC and HRV based on age or gender: whether in healthy children or in children with VVS, DC and HRV parameters varied significantly in the range of different ages, while they were the same in children with different genders.(2)Comparison of DC and HRV in school-age and puberty children between VVS group and healthy control group: in school-aged children, DC of VVS group was significantly higher than that of healthy control group [(6.8±1.0) ms vs.(6.0±0.7) ms, t=-2.412, P<0.01]. Mean square root rates of succe-ssive normal sinus RR interval differences(rMSSD) increased, and the difference was significant (P<0.05). In children at puberty, DC in children of VVS group was significantly higher than that in the healthy control group [(7.4±1.2) ms vs.(6.6±1.1) ms, t=-2.742, P<0.01], rMSSD, LF and HF value were significantly higher compared with those of the healthy control group (all P<0.05). (3)Predictive value of DC on VVS: the binary Logistic regression analysis found that only DC was associated with VVS in different age groups.By using receiver operating characteristic curve to analyze the predictive value of DC on VVS, it was found that when making DC 6.5 ms for school age and 7.0 ms at puberty as the threshold, a better prediction of VVS could be achieved with good sensitivity and specificity. Conclusions Children′s autonomic nervous function changes with age, and DC and HRV parameters change significantly during adolescence and at school age.Children with VVS may have abnormally increased vagal tone.When DC ≥6.5 ms at school age or DC≥7.0 ms at puberty, it may have a reference value for the diagnosis of VVS. Key words: Vasovagal syncope; Deceleration capacity; Heart rate variability; Autonomic nervous function

Periodic repolarization dynamics as a risk predictor after myocardial infarction: Prospective validation study

Periodic repolarization dynamics (PRD) is a novel electrocardiographic phenomenon that refers to sympathetic activity-associated low-frequency modulations of cardiac repolarization. Retrospective post-myocardial infarction (MI) studies revealed that increased PRD indicates an increased risk of subsequent death. This is the first prospective study to validate PRD in patients after MI receiving up-to-date treatment. Four hundred fifty-five survivors of MI (age ≤80 years) in sinus rhythm were enrolled. PRD was assessed from 20-minute electrocardiographic recordings (2048 Hz) and prospectively dichotomized at 5.75 deg2. Primary and secondary end points were total mortality and cardiovascular mortality, respectively. Multivariable analyses additionally included Global Registry of Acute Coronary Events score (dichotomized at >140), left ventricular ejection fraction (dichotomized at ≤35%), diabetes mellitus, and deceleration capacity of heart rate (dichotomized at ≤2.5ms). The prognostic power of PRD was evaluated using receiver operating characteristic curve analysis, Cox regression analysis, and the integrated discrimination improvement index. During a median follow-up period of 27 months, 47 patients died. Twenty-three of these deaths were classified as cardiovascular. Increased PRD was significantly associated with both end points, yielding areas under receiver operating characteristic curves of 69.3% (60.2%-77.8%) and 79.1% (69.7%-86.7%) for total mortality and cardiovascular mortality, respectively (P < .001 for both). In multivariable analysis, increased PRD indicated a 2.2- and 9.5-fold risk of total mortality and cardiovascular mortality (P = .024 and P = .003, respectively). Addition of PRD to the models significantly improved the integrated discrimination improvement index for total (P = .047) and cardiovascular mortality (P = .007). PRD is a strong and independent predictor of total mortality and cardiovascular mortality in patients after MI treated with contemporary therapy.

Polyscore of Non-invasive Cardiac Risk Factors.

Non-invasive risk stratification of cardiac patients has been the subject of numerous studies. Most of these investigations either researched unique risk predictors or compared the predictive power of different predictors. Fewer studies suggested a combination of a small number of non-invasive indices to increase the accuracy of high-risk group selection. To advance non-invasive risk assessment of cardiac patients, we propose a combination score (termed the Polyscore) of seven different cardiac risk stratifiers that predominantly quantify autonomic cardiovascular control and regulation, namely the slope of heart rate turbulence, deceleration capacity of heart rate, non-invasively assessed baroreflex sensitivity, resting respiration frequency, expiration triggered sinus arrhythmia, post-ectopic potentiation of systolic blood pressure, and frequency of supraventricular and ventricular ectopic beats. These risk stratification tests have previously been researched and their dichotomies defining abnormal results have been derived from previous reports. The Polyscore combination was defined as the number of positive tests among these seven risk predictors, giving a numerical scale which ranges from 0 (all tests normal) to 7 (all tests abnormal). The Polyscore was tested in a population of 941 contemporarily treated survivors of acute myocardial infarction (median age 61 years, 182 females) of whom 72 (7.65%) died during a 5-year follow-up. In these patients, all the risk predictors combined in the Polyscore were assessed during in-hospital 30-min simultaneous non-invasive recordings of high-frequency orthogonal electrocardiogram, continuous blood pressure and respiration. Compared to Polyscore 0 stratum, the hazard ratios of mortality during follow-up increased almost exponentially in strata 1 through 7 (vs. stratus 0, the hazard ratios were 1.37, 1.96, 7.03, 15.0, 35.7, 48.2, and 114, in strata 1 to 7, respectively; p < 0.0001). This allowed selecting low-risk (Polyscore ≤ 2), intermediate risk (Polyscore 3 or 4) and high-risk (Polyscore ≥ 5) sub-groups of the population that differed greatly in the Kaplan–Meier probabilities of mortality during follow-up. Since the Polyscore was derived from recordings of only 30-min duration, it can be reasonably applied in different clinical situations including population-wide screening. We can therefore conclude that the Polyscore is a reasonable method for cardiac risk stratification that is ready for prospective validation in future independent studies.

Male Patients With Dilated Cardiomyopathy Exhibiting a Higher Heart Rate Acceleration Capacity or a Lower Deceleration Capacity Are at Higher Risk of Cardiac Death.

The effects of dilated cardiomyopathy (DCM) on cardiac autonomic regulation and electrophysiology, and the consequences of such changes, remain unclear. We evaluated the associations between heart rate acceleration capacity (AC) and deceleration capacity (DC), heart structural and functional changes, and cardiac death in 202 healthy controls and 100 DCM patients. The DC was lower and the AC was higher in DCM patients (both males and females). Multivariable, linear, logistic regression analyses revealed that in males, age was positively associated with AC in healthy controls (N = 85); the left atrial diameter (LAD) was positively and the left ventricular ejection fraction (LVEF) was negatively associated with AC in DCM patients (N = 65); age was negatively associated with DC in healthy controls (N = 85); and the LAD was negatively and the LVEF was positively associated with DC in DCM patients (N = 65). In females, only age was associated with either AC or DC in healthy controls (N = 117). Kaplan–Meier analysis revealed that male DCM patients with greater LADs (≥46.5 mm) (long-rank chi-squared value = 11.1, P = 0.001), an elevated AC (≥-4.75 ms) (log-rank chi-squared value = 6.8, P = 0.009), and a lower DC (≤4.72 ms) (log-rank chi-squared value = 9.1, P = 0.003) were at higher risk of cardiac death within 60 months of follow-up. In conclusion, in males, DCM significantly affected both the AC and DC; a higher AC or a lower DC increased the risk of cardiac death.

Correlations of thyroid hormone with deceleration capacity of heart rate and heart rate variability in children with hyperthyroidism

To investigate deceleration capacity of heart rate (DC), acceleration capacity of heart rate (AC), and heart rate variability (HRV) in children with hyperthyroidism and the correlations of serum thyroid hormone levels with DC, AC, and HRV. A total of 47 children with hyperthyroidism were enrolled as hyperthyroidism group and 50 healthy children were enrolled as control group. The subjects in the two groups underwent 24-hour ambulatory electrocardiography. The two groups were compared in terms of DC, AC, heart rate (HR), HRV parameters [standard deviation of normal-to-normal RR intervals (SDNN), standard deviation of average normal-to-normal RR intervals (SDANN), root mean square of successive differences between adjacent RR intervals (RMSSD), low-frequency power (LF), and high-frequency power (HF)]. The correlations of thyroid hormone indices [free triiodothyronine (FT3) and free thyroxin (FT4)] with DC, AC, and HRV were analyzed. Compared with the control group, the hyperthyroidism group had significantly lower DC, SDNN, SDANN, RMSSD, LF, and HF and significantly higher AC and HR (P<0.05). In the children with hyperthyroidism, serum FT3 and FT4 levels showed significant negative correlation with DC, SDNN, SDANN, RMSSD, LF, and HF and significant positive correlation with AC and HR (P<0.05). Children with hyperthyroidism have cardiac autonomic nerve dysfunction manifested as reduced vagal tone. Vagal tone decreases with the increasing serum thyroid hormone levels, suggesting an increased risk of cardiovascular disease.

Autonomic Nervous System Activity for Risk Stratification of Emergency Patients With Pneumonia

BackgroundCommunity-acquired pneumonia (CAP) causes appreciable morbidity and mortality in adults, especially in those ≥65 years of age. At hospital admission, an immediate and reliable risk assessment is necessary to detect patients with possible fatal outcome. ObjectiveWe aimed to evaluate markers of the autonomic nervous system based on an electrocardiogram to predict mortality in patients with CAP. MethodsFor this purpose, the deceleration capacity (DC) of heart rate was calculated in 253 patients who presented to the emergency department with CAP. The 30-day mortality rate was defined as the primary endpoint (PEP). The secondary endpoint was the total mortality within 180 days. ResultsPEP was reached in 33 patients (13%). The DC, measured in milliseconds, was significantly lower in patients who reached the PEP than in those who did not (2.3 ± 1.5 ms vs. 3.6 ± 2.3 ms, p = 0.004). The DC was also significantly lower in nonsurvivors than in survivors at the time of the secondary endpoint (2.3 ± 1.5 ms vs. 3.7 ± 2.4 ms, p < 0.001). Our results indicate that DC is an independent predictor of 30- and 180-day mortality. ConclusionDC was independently associated with death from CAP in our study. As a practical consequence, DC could be useful in triage decisions. Patients with certain high risks could benefit from adjuvant treatment and special medical attention.

Deceleration Capacity of Heart Rate After Acute Altitude Exposure.

The autonomic nervous system plays a crucial role in adaptive changes after high-altitude exposure. Deceleration capacity (DC) of heart rate is an advanced marker of heart rate variability (HRV) that predominantly reflects the vagal activity of the cardiac autonomic nervous system. The impact of high-altitude exposure on DC has not been investigated yet. In eight healthy individuals we performed a high-resolution digital 30-min electrocardiography in Frank leads configuration at baseline (521 m altitude), immediately after ascent to the Environmental Research Station Schneefernerhaus (UFS) at Zugspitze (2650 m altitude) and after a sojourn of 24 hours at this altitude. DC of heart rate was assessed using customized software. In addition, standard parameters of HRV were assessed. DC decreased significantly from 10.2 ± 0.8 ms to 8.9 ± 1.0 ms (p < 0.05) after acute altitude exposure. After a sojourn of 24 hours at high altitude, DC remained low at 8.6 ± 1.2 ms. There were no significant changes in standard parameters of HRV. Our findings show for the first time a decrease of DC of heart rate providing a novel insight into the dysbalance of autonomic nervous system at high altitude.

Autonomic function as indicated by heart rate deceleration capacity and deceleration runs in type 2 diabetes patients with or without essential hypertension.

PurposeSympathovagal imbalance is a common underlying disorder in hypertension and diabetes. This study characterized autonomic nervous system function, indicated by heart rate deceleration capacity (DC) and deceleration runs (DRs), in patients with type 2 diabetes mellitus (T2DM), with or without concomitant essential hypertension.Subjects and methodsWe recruited 50 healthy subjects, 50 patients with T2DM, and 95 with T2DM and essential hypertension. DC, DRs (DR2, DR4, and DR8, ie, episodes of 2, 4, or 8 consecutive beat-to-beat heart rate decelerations, respectively), and heart rate variability were determined by dynamic electrocardiogram. Biochemical markers of glucose and lipid metabolism, including glycated hemoglobin (HbA1c) and high-density lipoprotein cholesterol (HDL-C), were measured from blood samples.ResultsBoth T2DM groups featured lower DC, SD of all normal-to-normal sinus RR intervals over 24 h (SDNN), root mean square of the successive normal sinus RR interval difference, and all DR values, but higher average heart rate (AHR) and acceleration capacity (AC), than healthy subjects. There were significant associations between the following: DC and HbA1c, systolic blood pressure (SBP), AHR, age, and HDL-C; DR2 and AHR, SBP, and HbA1c; DR4 and HbA1c, age, SBP, and HDL-C; and DR8 and HbA1c, AHR, and age. In both T2DM groups, HbA1c correlated negatively with DC, DR2, and SDNN, and positively with AC and AHR; homeostasis model assessment-insulin resistance index correlated negatively with DC, all DRs, and SDNN, and positively with AC.ConclusionCompared with healthy subjects, T2DM patients with or without essential hypertension have lower DC and DRs. DC and DRs correlate negatively with blood glucose and insulin resistance index.

Deterioration of Deceleration Capacity of Heart Rate is Associated with Left Ventricular Hypertrophy in End-Stage Renal Disease Population.

Left ventricular hypertrophy (LVH) is prevalent in patients with end-stage renal disease (ESRD), and may be secondary to arterial stiffness and volume overload. It is unclear whether LVH is caused by autonomic nerve dysregulation (AND), a frequent condition in patients with ESRD that is characterized by sympathetic hyperactivity and vagal withdrawal. We hypothesized that AND estimated by heart rate variability (HRV) may be associated with LVH in patients with ESRD. We prospectively enrolled patients with ESRD undergoing hemodialysis. Cardiac function and LVH were assessed using echocardiography according to the recommendations of the American Society of Echocardiography. Holter recordings were used to quantify HRV and deceleration capacity (DC). Dataon comorbidities and medications, and serum markers were obtained. Logistic regression analysis was performed. Among the 281 included patients, 63% had LVH. The patients with LVH were older, had more comorbidities and advanced diastolic dysfunction than those without LVH. The root mean square of successive differences (rMSSD) (9.10 ± 5.44 versus 13.25 ± 8.61; p = 0.004) and DC (2.08 ± 1.90 versus 3.89 ± 1.45; p = 0.021) were lower in the patients with LVH than that in those without LVH. Multivariate regression analysis showed that hypertension, asymmetrical dimethylarginine (ADMA), advanced diastolic dysfunction grade, rMSSD, and DC were independently associated with LVH. Among these variables, DC and ADMA showed the highest diagnostic value for LVH with areas under curves of 0.701 and 0.751, respectively. AND is independently associated with LVH in patients with ESRD.

Heart rate variability for rapid risk stratification of emergency patients with malignant disease.

Neoplasms are the second most common diseases in western countries. Many patients with malignant diseases repeatedly present themselves in the emergency department (ED). Due to limited capacities, appropriate risk stratification strategies for cancer patients have to be developed. This study assesses if deceleration capacity (DC) of heart rate as a parameter of heart rate variability predicts mortality in emergency patients with malignant diseases. Prospectively, 140 adults with different entities of malignant diseases who presented in the medical ED were included. Primary and secondary endpoints were intrahospital mortality and mortality within 180days, respectively. We calculated DC from short-term ECG readings of the surveillance monitors. Additionally, the Modified Early Warning Score (MEWS) and laboratory parameters such as white blood cells (WBC), lactate dehydrogenase, serum hemoglobin, and serum creatinine were determined. The median age of the patients was 65 ± 14years. 19.3% of the patients died within the hospital stay and 57.9% died within 180days. DC and WBC were independent predictors of intrahospital death reaching a hazard ratio (HR) of 0.79 (95% confidence interval (CI) 0.63-0.993, p = 0.043) and of 1.00 (95% CI 1.00-1.00, p = 0.003), respectively. DC and serum creatinine independently predicted death within 180days (HR 0.90, 95% CI 0.82-0.98, p = 0.023 and HR 1.41, 95% CI 1.05-1.90, p = 0.018, respectively). Deceleration capacity of heart rate is suitable for rapid risk assessment of emergency patients with malignant diseases.

Low heart deceleration capacity imply higher atrial fibrillation-free rate after ablation

How deceleration capacity (DC) and acceleration capacity (AC) of heart rate associated with atrial fibrillation (AF) and ablation is still not clear. The dynamic changes of AC, DC and conventional heart rate variability (HRV) parameters were characterized in 154 subjects before circumferential pulmonary veins isolation (CPVI) and three days, 3 months and 6 months after CPVI. The DCs of the recurrent group decreased significantly at each time point after CPVI; the DCs of the recurrence-free group before CPVI and three days, 3 months and 6 months after CPVI were 7.06 ± 1.77, 3.79 ± 1.18, 4.22 ± 1.96 and 3.97 ± 0.98 ms respectively, which also decreased significantly at each time point and were significantly lower than these of recurrent group. Conversely, the AC of recurrent and recurrence-free groups increased significantly at each time point after CPVI; the ACs of recurrence-fee group were significantly higher than these of recurrent group at each time point. No stable difference trend of HRV parameters was found between two groups. Further Kaplan–Meier analysis showed that DC < 4.8 ms or AC ≥ −5.1 ms displayed significant higher recurrence-free rates. In conclusion, high AC and low DC imply higher AF-free rate after ablation.

Analysis of influencing factors of heart rate deceleration capacity in patients with dilated cardiomyopathy

Objective: To investigate the determinants affecting the heart rate deceleration capacity (DC) in patients with dilated cardiomyopathy (DCM). Methods: One hundred patients with DCM (DCM group) and 202 healthy subjects (control group) were respectively enrolled. Echocardiography and 24 hours electrocardiogram were performed in all subjects. DC value was compared between the two groups. Multiple regression analysis was made to evaluate the related determinants of DC ((age, sex, echocardiographic parameters including the left atrial diameter (LAD) and left ventricular ejection fraction (LVEF)). Results: (1) DC value was significantly lower in DCM group than in control group( (4.40±2.03) ms vs. (7.30±1.81) ms, P<0.01), prevalence of DC value≤4.5 ms was significantly higher in DCM group than in control group (62% vs. 6%, P<0.01). (2) DC value in the DCM group decreased in proportion to increasing LAD dimension, DC value was (5.60±2.04) ms, (4.50±2.07) ms and (3.60±1.62) ms (P<0.05) in DCM patients with LAD≤40 mm, 40 mm<LAD≤50 mm and LAD>50 mm, respectively. (3) DC value in the DCM group was negatively related to the LAD (r=-0.366, P<0.01), positively related to the LVEF (r= 0.241, P<0.01), but not related with age and sex. Multiple factors regression analysis showed that increased LAD was related to the reduced DC values independtly. Conclusion: DC value of the patients in the DCM group is decreased, which indicate the decrease of the vagus nerve tension, and increased LAD is related to the reduced DC value independtly in DCM patients.

Biosignal-guided personalized therapy

Abstract Sudden cardiac death (SCD) is the leading single cause of death in the industrialized world. Current guidelines recommend a prophylactic implantation of an implantable cardioverter-defibrillator (ICD) in patients with reduced left-ventricular ejection fraction (LVEF ≤ 35%). However, most deaths after myocardial infarction (MI) occur in patients with normal or moderately reduced LVEF (&gt;35%). There is a large body of evidence that cardiac autonomic dysfunction after MI is linked to increased susceptibility to malignant arrhythmias. Deceleration capacity of heart rate (DC) and periodic repolarization dynamics (PRD) are novel ECG-based risk markers, which capture different facets of cardiac autonomic dysfunction. Both parameters are strong and independent predictors of mortality and SCD after MI. Previous studies indicated that combined assessment of DC and PRD allows identification of a new high-risk group among post-infarction patients that is not addressed by current guidelines, thus opening new perspectives for biosignal-guided personalized therapies.

Deceleration capacity of heart rate predicts 1-year mortality of patients undergoing transcatheter aortic valve implantation.

Risk prediction in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI) is challenging. Development of novel markers for patient risk assessment is of great clinical value. Deceleration capacity (DC) of heart rate is a strong risk predictor in post-infarction patients. DC provides prognostic information in patients undergoing TAVI. We enrolled 374 consecutive patients with severe AS undergoing TAVI. All patients received 24-hour Holter recording or continuous heart-rate monitoring to assess DC before intervention. Primary endpoint was all-cause mortality after 1 year. Forty-nine patients (13.1%) died within 1 year. DC was significantly lower in nonsurvivors than in survivors (1.2 ± 4.8 ms vs 3.3 ± 2.9 ms; P < 0.001), whereas the logistic EuroSCORE and EuroSCORE II were comparable between groups (logistic EuroSCORE: 27.3% ± 17.0% vs 22.9% ± 14.2%; P = 0.122; EuroSCORE II: 8.0% ± 6.9% vs 6.7% ± 4.8%, P = 0.673). One-year mortality in the 116 patients with impaired DC (<2.5 ms) was significantly higher than in patients with normal DC (23.3% vs 8.5%; P < 0.001). In multivariate Cox regression analysis that included DC, sex, paroxysmal atrial fibrillation, hemoglobin level before TAVI, and logistic EuroSCORE, DC was the strongest predictor of 1-year mortality (hazard ratio: 0.88, 95% confidence interval: 0.85-0.94, P < 0.001). DC yielded an AUC in the ROC analysis of 0.645. DC of heart rate is a strong and independent predictor of 1-year mortality in patients with severe AS undergoing TAVI.

Periodic repolarization dynamics in patients with moderate to severe aortic stenosis

BackgroundPeriodic repolarization dynamics (PRD) refers to low-frequency oscillations of cardiac repolarization, most likely related to phasic sympathetic activation. Increased PRD is a validated predictor of mortality after myocardial infarction and in ischemic heart disease, but has not been tested in aortic valve stenosis (AS). Here, we assessed PRD in patients with AS and tested its correlation with clinical and hemodynamic parameters as well as markers of heart rate variability (HRV). Materials and methodsWe prospectively enrolled 139 consecutive patients with moderate to severe AS in sinus rhythm. In all patients we performed a 24-h Holter ECG in Frank–leads configuration. We assessed PRD according to previously published technologies from the nocturnal hours (0am–6am) and dichotomized PRD at the established cut-off value of ≥5.75deg2. In addition to clinical and hemodynamic markers, we also assessed deceleration capacity (DC) of heart rate, heart rate turbulence and standard HRV parameters. ResultsIn the patients studied, PRD was 6.55±3.96deg2. Seventy-three patients (52.5%) had increased PRD. Among them, 36 (49.9%) patients were classified as being asymptomatic. There was no association between increased PRD and clinical or hemodynamic markers, including presence of symptoms, NYHA-classification, aortic valve area, and left-ventricular ejection fraction. Thirty-three of the 73 (45.2%) patients with PRD ≥5.75deg2 also suffered from decreased vagal tonic activity by means of abnormal DC (≤2.5ms) indicating severe autonomic dysfunction. ConclusionPrevalence of increased PRD is high among patients with moderate to severe AS. Patients with increased PRD cannot be identified by clinical or hemodynamic markers Future studies should test the prognostic value of PRD in patients with AS.