自主神经在阵发性心房颤动发生中的作用

目的 探讨自主神经在阵发性心房颤动发生中的作用。方法 分析31例阵发性房颤患者47次房颤（〉30s）发作前动态心电图心率变异性时域和频域指标。患者分为器质性心脏病组（19例）和非器质性心脏病组（12例）。根据房颤发作前频域指标变化，将阵发性房颤分为3组：房颤发作前心率变异性频域指标低频（LF）成分增加，LFIHF比例增加为交感神经介导房颤，房颤发作前心率变异性频域指标高频（HF）成分增加，LF／HF比例减小为迷走神经介导房颤，其余的为未分类房颤。结果 器质性心脏病组房颤发作28次，其中交感神经介导房颤17次（60．7％），非器质性心脏病组房颤发作19次，迷走神经介导房颤12次（63．2％）。结论 自主神经在房颤的发作中起着重要的作用，器质性心脏病中的阵发性房颤多为交感神经介导房颤。非器质性心脏病中的阵发性房颤多为迷走神经介导房颤。     

Predictive value of HMGB1 for atrial fibrillation recurrence after cryoballoon ablation in paroxysmal atrial fibrillation patients

BackgroundCryoballoon ablation (CBA) is recommended for patients with symptomatic drug refractory paroxysmal atrial fibrillation (pAF). However, substantial atrial fibrillation (AF) recurrence is common during follow‐up. Searching for a potential biomarker representing both myocardial injury and inflammation to identify patients at high risk of AF recurrence after CBA is very meaningful for postoperative management of AF patients.HypothesisTo evaluate the clinical efficacy of high‐mobility group box 1 (HMGB1) protein released from the left atrium to predict AF recurrence in pAF patients after CBA at 1‐year follow‐up.MethodsWe included 72 pAF patients who underwent CBA. To determine the expression levels of HMGB1, left atrial blood samples were collected from the patients before CBA and after the procedure through the transseptal sheath. Patients were followed up for AF recurrence for 1 year.ResultsA total of 19 patients of the 72 experienced AF recurrence. The level of postoperative HMGB1 (HMGB1post) was higher in the AF recurrence group than in the AF non recurrence group (p = .03). However, no differences were noted in the levels of other biomarkers such as preoperative high‐sensitivity C‐reactive protein (hs‐CRP), postoperativehs‐CRP, and preoperative HMGB1 between the two groups. Multiple logistic regression analysis revealed that a higher level of serum HMGB1post was associated with AF recurrence (odds ratio: 5.29 [1.17–23.92], p = .04). Receiver operating characteristic analysis revealed that HMGB1post had a moderate predictive power for AF recurrence (area under the curve: 0.68; sensitivity: 72%; and specificity: 68%). The 1‐year AF‐free survival was significantly lower in patients with a high HMGB1post level than in those with a low HMGB1post level (hazard ratio: 3.81 [1.49–9.75], p = .005).ConclusionIn pAF patients who under went CBA, the level of HMGB1 after CBA was associated with AF recurrence and demonstrated a moderate predictive power. Thus, we offer a potential biomarker to identify pAF patients at high risk of AF recurrence.     

Heart rate variability measures during sinus rhythm predict cycle length entropy during atrial fibrillation

Introduction: Several noninvasive measures of cardiac risk such as heart rate variability (HRV) cannot be used in patients with atrial fibrillation (AF). One promising exception is the measure of ventricular cycle length entropy (VCLE) where initial data suggest that a reduction in VCLE portends an increased risk of cardiac death in patients with chronic AF. In this study, we hypothesized that measures of short‐term HRV during sinus rhythm would correlate with measures of cycle length entropy during paroxysms of AF. Methods: We tested 25 Holter recordings of paroxysmal AF from the Physionet AF Prediction Database. We calculated HRV parameters including standard deviation of all NN intervals (SDNN), the root mean square root of the differences between adjacent NN intervals (RMSSD), standard deviation of 5‐minute averages of NN intervals (SDANN), percentage of adjacent NN interval differences >50 ms (pNN50), and interbeat correlation coefficient (ICC) from 30 minutes of normal sinus rhythm, and entropy measures (the Shannon Informational Entropy [ShEn] and Average of Approximate Entropy [ApEn]) from 5 minutes of AF that occurred during the same 24‐hour monitor. Pairwise correlations were used to assess associations, as regression residuals were normally distributed. Results: The mean entropy measures during AF were: ShEn: 4.78 ± 0.82, ApEn: 0.198 ± 0.21. When assessed during the 30 minutes immediately preceding AF onset, ICC showed a significant negative correlation with both ShEn (r =–0.65, P < 0.001) and ApEn (r =–0.60, P < 0.01). RMSSD also correlated with both ShEn (r = 0.41, P = 0.04) and ApEn (r = 0.39, P = 0.05), but other HRV measures showed no correlation with VCLE during AF. Conclusion: Reductions in RMSSD or increases in ICC, two short‐term HRV measures that are known to reflect parasympathetic function in sinus rhythm, are correlated with reductions in the entropy of ventricular response intervals during AF. Our findings suggest that entropy during AF may be modulated, in part, by vagal innervation.     

高敏C反应蛋白对心房颤动患者电复律后再发的预测

目的通过检测患者血清高敏C反应蛋白(hs-CRP)水平,探讨其对非瓣膜性心房颤动(房颤)患者电复律后再发的预测价值。方法非瓣膜性持续性房颤经电复律的患者126例,男性73例,女性53例,平均年龄(64±10)岁,在电复律前,测定hs-CRP,依据hs-CRP水平将患者分为3组,低水平组41例,hs-CRP<2.0 mg/L,中等水平组47例,hs-CRP 2.0~3.0 mg/L,高水平组38例,hs-CRP>3.0 mg/L。随访6个月,复查24 h动态心电图,观察房颤的复发情况。结果3组在年龄、房颤时间、左心房大小、心功能方面比较差异无统计学意义(P>0.05)。6个月随访时,低水平组房颤的复发率7.3%,远低于中等水平组的21.3%和高水平组的36.8%,差异有统计学意义(P<0.001),中等水平组房颤的复发率低于高水平组(P<0.05),Cox回归分析显示,hs-CRP水平与电复律后,房颤再发呈显著正相关(OR=3.22,95%CI:1.58~13.41)。结论非瓣膜性持续性房颤电复律后,hs-CRP水平与房颤的中期再发有关,hs-CRP可以作为房颤电复律后再发的独立预测因子。     

Determinants of a reduced heart rate variability in chronic atrial fibrillation

Background: We aimed to evaluate whether clinical factors, which influence heart rate variability (HRV) in the presence of undisturbed sinus rhythm, have any associations with HRV in patients with permanent atrial fibrillation (AF). Methods: One hundred ninety‐seven consecutive patients with permanent AF were included (122 males, 75 females, aged 64 ± 11 years, range 25–85). In each patient a 24‐hour electrocardiographic recording was performed and an HRV fraction (HRVF)—the index based on scatter plot numerical processing—was calculated. Additionally, standard HRV measures were analyzed. Reduced HRVF was defined as its value lower than lower normal limit. Demographic and clinical factors were examined for their association with a reduced HRVF by means of a univariate and multivariate logistic regression analysis. Results: The reduced HRVF was associated with advanced age, clinical diagnosis of a previous MI or dilated cardiomyopathy, presence of diabetes, depressed left ventricular function, NYHA class > II, treatment regimen, use of digoxin, diuretics or antiarrhythmic agents, nonuse of beta‐blockers, and increased heart rate. The independent determinants that sustained after multivariate analysis were: heart rate (per 10 bpm increase, odds ratio 2.77 [1.88–4.07]), age (per 5 years increase 1.43 [1.1–1.85]), depressed left ventricular EF (<30% vs higher 2.26 [1.19–4.31]), and presence of diabetes (3.45 [1.1–10.85]). The HRVF correlated moderately with standard HRV measures. This index showed also the strongest correlation with left ventricular ejection fraction. Conclusion: We concluded that advanced age, left ventricular systolic dysfunction, increased heart rate, and presence of diabetes are cofactors of a reduced HRV in AF patients. Thus, the determinants of heart rate variability in the presence of atrial fibrillation are the same as those in sinus rhythm. Ann Noninvasive Electrocardiol 2011;16(4):321–326     

持续性心房颤动患者心率变异性与脑钠尿肽的关系

目的:探讨持续性心房颤动患者心率变异性与脑钠尿肽（BNP）的相关性。方法: 入选45例持续性心房颤动患者,20例正常对照组。行24小时动态心电图检查,检测心率变异性时域指标,并行BNP测定,再分析以上两者的相关性。结果: 持续性房颤患者与对照组比较,心率增快,心率变异性时域指标SDNN、RMSSD、PNN50显著增加（P<0.01）;平均RR间期（RINNT）实测值与BNP呈负相关;以平均心率矫正后的有关心率变异时域指标RMSSDDdiff和PNN50Ddiff与BNP呈正相关。结论: 持续性心房颤动患者心率变异性时域参数增加,BNP受心率和心率变异性改变的影响。     

Factors predicting success rate and recurrence of atrial fibrillation after first electrical cardioversion in patients with persistent atrial fibrillation

BACKGROUND: The recurrence rate of atrial fibrillation (AF) after elective cardioversion is high. HYPOTHESIS: The study aimed to identify clinical predictors for successful electrical cardioversion and maintenance of sinus rhythm after a first electrical cardioversion in patients with persistent AF without concomitant antiarrhythmic drugs of class I and III. METHODS: Consecutive outpatients (n = 166) with persistent AF for > 1 month, scheduled for elective cardioversion, were prospectively included in the study. A clinical investigation, echocardiographic assay, and Holter electrocardiogram (ECG) before and ECG 4 weeks after cardioversion, were performed in all patients. RESULTS: The mean age of the patients was 68 years (range 45-83) and duration of AF was 5 (1-48) months. Sinus rhythm was established in 124 (75%) patients. In multivariate analysis, only duration of AF < 6 months (p < 0.04, odds ratio [OR] 2.2, 95% confidence interval [CI] 1.1 to 4.7) and patients weight (p < 0.03, OR 2.3, 95% CI 1.1 to 4.8 for weight < 80 kg) were identified as independent predictors of successful cardioversion. At 4 weeks after cardioversion, only 46 (37%) of 124 patients maintained sinus rhythm. Independent factors for maintenance of sinus rhythm, in multivariate analysis, were AF <3 months (p < 0.04, OR 2.5, 95% CI 1.1 to 5.6), treatment with beta blockers (p < 0.00001, OR 7.0, 95% CI 3.0 to 16.3) or verapamil/diltiazem (p < 0.04, OR 3.6, 95% CI 1.1 to 12.1), and right atrial dimension < 37 mm (p < 0.02, OR 5.9, 95% CI 1.4 to 25.4). CONCLUSIONS: In patients with persistent AF, the patient's weight and the duration of AF are independent predictors for a successful cardioversion. Short duration of AF, treatment with beta blockers or verapamil/diltiazem, and right atrial area/dimension are independent predictors for maintenance of sinus rhythm.     

Effect of atrial fibrillation duration on probability of immediate recurrence after transthoracic cardioversion

INTRODUCTION: An immediate recurrence of atrial fibrillation (IRAF) appears to be more common after early restoration of sinus rhythm with an implantable atrial defibrillator than after elective transthoracic cardioversion, which suggests that the probability of IRAF may be related to the duration of AF. METHODS AND RESULTS: Transthoracic cardioversion was performed 85 +/- 187 days (range 7 minutes to 8 years) after the onset of atrial fibrillation in 315 patients (mean age 61 +/- 13 years). IRAF was defined as a recurrence of AF within 60 seconds after restoration of sinus rhythm. IRAF occurred in 56% of patients when cardioversion was performed within 1 hour of the onset of AF compared with 12% of patients when cardioversion was performed after 24 hours of AF (P < 0.001). The duration of AF was the only independent predictor of IRAF among the clinical variables of age, gender, structural heart disease, antiarrhythmic drug therapy, and cardioversion energy (P < 0.01). CONCLUSION: IRAF is more likely to occur when the duration of AF is <1 hour than when the duration is >24 hours. This observation has clinical implications for the most appropriate timing of cardioversion, particularly in patients who receive device therapy for AF.     

心率与心房颤动关系的研究进展

心房颤动（简称“房颤”）是临床上最常见的心律失常,其发病率随年龄增长而增加。心房重构是房颤的核心机制,包括电重构、结构重构及自主神经重构。自主神经功能障碍在房颤的发生、发展中起着重要的作用,而心率可以间接反映自主神经功能。心率与房颤发生的关系以及房颤射频消融术后心率变化与房颤复发关系复杂,且一直在研究中。     

阵发性心房颤动患者环肺静脉消融术后心率变异性变化及其对消融效果的影响

目的 评价环肺静脉消融（CPVA）对阵发性心房颤动（PAF）患者自主神经功能及其预后的影响。方法 连续入选2011年1月至2011年12月就诊的接受CPVA的PAF患者110例[年龄（59.07±11.54）岁,男67例,女43例],患者均接受CPVA至肺静脉电隔离。分别于消融前及术后第2天行动态心电图检查,观察心率变异性（HRV）时域指标变化及其对消融效果的影响。结果 随访14.46±5.57个月,心房颤动（AF）消融成功率为72.45%（71/98）。完成随访的98例患者中,AF无复发71例,设为消融成功组（男45例、女26例）;复发27例,设为消融复发组（男15例、女12例）。两组消融前HRV相似,消融后HRV显著降低（P＜0.05）;消融成功组HRV均较消融复发组进一步显著降低（P＜0.05）。结论 CPVA使HRV显著降低,产生去自主神经效应,这可能是CPVA治疗PAF的机制之一。增加去神经效应对PAF消融长期成功率有一定影响,明确了AF射频消融与HRV之间的关系。     

Association between adiponectin‐to‐leptin ratio and heart rate variability in new‐onset paroxysmal atrial fibrillation: A retrospective cohort study

BackgroundThe adiponectin‐to‐leptin (A/L) ratio has been identified as a potential surrogate biomarker for metabolic disorders. However, it remains unknown whether the serum A/L ratio is associated with heart rate variability in paroxysmal atrial fibrillation (AF).MethodsFor this retrospective study, we included consecutive patients who underwent 24‐h long‐range electrocardiogram examination in our center for paroxysmal AF. The results of echocardiography, heart rate variability tests, and blood tests were also retrieved. Multivariate line regression analysis was performed to evaluate identify factors independently associated with heart rate variability.ResultsAmong the 85 included patients with paroxysmal AF, the median A/L ratio was 1.71. Univariate analysis indicated that patients with a low A/L ratio (<1.71, n = 42) had a lower high‐frequency (HF) power and a higher hs‐CRP level, low‐frequency (LF) power, and LF/HF ratio than those with a high A/L ratio (≥1.71, n = 43). Multivariate linear regression analysis showed that the serum leptin concentration was independently and positively associated with LF (β = 0.175, p = .028), while the serum adiponectin concentration was independently and positively associated with HF (β = 0.321, p = .001). Moreover, the A/L ratio was independently and negatively associated with the LF/HF ratio (β = −0.276, p = .007).ConclusionsThe A/L ratio was independently and negatively associated with the LF/HF ratio in patients with new‐onset paroxysmal AF.     

Fluctuation in autonomic tone is a major determinant of sustained atrial arrhythmias in patients with focal ectopy originating from the pulmonary veins

INTRODUCTION: This study was designed to analyze dynamic changes in autonomic tone preceding the onset of sustained atrial arrhythmias in patients with focal atrial fibrillation (AF) to determine why patients with frequent discharge from the arrhythmogenic foci develop sustained AF. METHODS AND RESULTS: Holter tapes from 13 patients (10 men and 3 women; mean age 53 +/- 5 years) with paroxysmal "lone" AF (mean 18 +/- 13 episodes per week) and a proven focal origin (pulmonary veins in all cases) were analyzed. A total of 38 episodes of sustained (>30 min) were recorded and submitted to frequency-domain heart rate variability analysis. Six periods were studied using repeated measures analysis of variance: the 24-hour period, the hour preceding AF, and the 20 minutes before AF divided into four 5-minute periods. A significant increase in high-frequency (HF, HF-NU) components was observed during the 20 minutes preceding AF (P = 0.003 and 0.002, respectively), together with a progressive decrease in normalized low-frequency (LF-NU) components (P = 0.035). An increase in LF/HF ratio followed by a linear decrease starting 15 minutes before sustained AF also was observed, indicating fluctuations in autonomic tone, with a primary increase in adrenergic drive followed by a marked modulation toward vagal predominance immediately before AF onset. CONCLUSION: In patients with focal ectopy originating from the pulmonary veins, sustained episodes of atrial arrhythmias are mainly dependent on variations of autonomic tone, with a significant shift toward vagal predominance before AF onset.     

Persistent atrial fibrillation worsens heart rate variability, activity and heart rate, as shown by a continuous monitoring by implantable biventricular pacemakers in heart failure patients

Background: Atrial fibrillation (AF) induces loss of atrial contribution, heart rate irregularity, and fast ventricular rate.
Objectives: The objectives of the study were to accurately measure AF incidence and to investigate the mutual temporal patterns of AF and heart failure (HF) in patients indicated to cardiac resynchronization therapy.
Methods: Four hundred ten consecutive patients (70% male, age 69 ± 11) with advanced HF (NYHA = 3.0 ± 0.6), low ejection fraction (EF = 27 ± 9%), and ventricular conduction delay (QRS = 165 ± 29 ms) received a biventricular pacemaker. Enrolled patients were divided into two groups: G1 = 249 patients with no AF history, G2 = 161 patients with history of paroxysmal/persistent AF.
Results: In a median follow-up of 13 months, AF episodes longer than 5 minutes occurred in 105 of 249 (42.2%) G1 patients and 76 of 161 (47.2%) G2 patients, while AF episodes longer than one day occurred in 14 of 249 (5.6%) G1 patients and in 36 of 161 (22.4%) G2 patients. Device diagnostics monitored daily values of patient activity, night heart rate (NHR), and heart rate variability (HRV). Comparing 30-day periods before AF onset and during persistent AF, significant (P < 0.0001) changes were observed in patient activity, which decreased from 221 ± 13 to 162 ± 12 minutes, and in NHR, which increased from 68 ± 3 to 94 ± 7 bpm. HRV significantly decreased (from 75 ± 5 ms before AF onset to 60 ± 6 ms after AF termination). NHR during AF was significantly (P < 0.01) and inversely correlated (R²= 0.73) with activity, with a significant lower activity associated with NHR ≥ 88 bpm.
Conclusion: AF is frequent in HF patients. Persistent AF is associated with statistically significant decrease in patient activity and HRV and NHR increase.     

阵发性心房颤动发作前后心率变异性的变化

目的探索自主神经活动在阵发性心房颤动中的作用.方法在动态心电图上测量分析了25例阵发性房颤患者53阵次心房颤动发作前后及白天(6:00～22:00)和夜间(22:00～6:00)的心率变异指标(SDNN、LF、HF、LF/HF)的变化.结果房颤发作前1h SDNN、HF较终止后1h显著升高(p＜0.01),LF/HF显著降低(p＜0.01),LF无变化;LF、HF白天均高于夜间(分别为p＜0.05和p＜0.01),夜晚LF高于HF(p＜0.05),白天与夜间SDNN、LF/HF无差异,白天LF与HF无差异.结论阵发性心房颤动患者存在着明显的自主神经功能失常,特别是白天迷走神经张力增强;迷走神经张力增强是阵发性房颤的重要原因.     

Burden and timing of premature atrial contractions after electrical cardioversion of persistent atrial fibrillation do not predict its recurrence

BACKGROUND: The heart is susceptible to recurrence of atrial fibrillation (AF) during the period immediately following conversion to sinus rhythm (SR). It is less clear whether various onset or trigger mechanisms can predict AF recurrence after direct current (DC) cardioversion of persistent AF. METHODS: In this study, 172 patients (117 men), mean age 69 +/- 11 y, and with persistent AF underwent elective electrical cardioversion. A detailed analysis was made of the heart rhythm and potential AF trigger mechanisms based on 5 min electrocardiogram (ECG) recordings after conversion. RESULTS: Of 151 patients discharged in SR, 45 (30%) had a recurrence of AF within 1 wk. Premature atrial contractions (PACs) were the most common potential trigger, occurring on an average of 3/min. They were equally frequent in patients with and without immediate and early reinitiation of AF, and in patients with and without AF recurrence at the 1-wk follow-up visit. Other trigger mechanisms were too infrequent to allow conclusions. CONCLUSION: Premature atrial contractions were the most common potential trigger mechanism occurring immediately after cardioversion in patients with persistent AF. However, they neither predicted immediate and/or early reinitiations, nor recurrences during the first wk after cardioversion.     

Initiating mechanisms of paroxysmal atrial fibrillation.

BACKGROUND: The understanding of the onset mechanisms of paroxysmal atrial fibrillation (AF) may help to develop preventive therapy. Specific heart rate (HR) patterns and autonomic changes immediately before the onset of paroxysmal AF are not fully investigated. We undertook the present study to assess HR and heart rate variability (HRV) changes before the onset of AF using 24-h Holter electrocardiographic analysis in patients without antiarrhythmic medication. METHODS AND RESULTS: In 27 patients, 48 episodes of AF, lasting more than 30s and preceded by sinus rhythm for more than 1h were analysed. The hour preceding AF was divided in 5- and 30 min blocks. HR was also analysed in the last 15 beats. In 21% of the episodes, HR decreased >or=5% in the last 5 min (defined as deceleration); it increased >or=5% in 37% (defined as acceleration). HR, standard deviation (SD) and SD corrected for RR interval changed significantly in the last 5 min in the total group. Acceleration and deceleration were already visible over 30-min blocks in both these subgroups; changes in SD were only seen in the accelerators. The number of atrial premature beats (PACs) increased before AF, most clearly in the accelerators. Spectral HRV analysis revealed no additional information. CONCLUSIONS: Changes in HR, SD, and an increased number of PACs herald AF from at least 30 min before onset, more pronounced in accelerators. Spectral HRV parameters are not useful to foresee AF onset. This has possible implications for device therapy.     

Lack of prevention of heart failure by serial electrical cardioversion in patients with persistent atrial fibrillation

OBJECTIVE—To investigate the occurrence of heart failure complications, and to identify variables that predict heart failure in patients with (recurrent) persistent atrial fibrillation, treated aggressively with serial electrical cardioversion and antiarrhythmic drugs to maintain sinus rhythm.DESIGN—Non-randomised controlled trial; cohort; case series; mean (SD) follow up duration 3.4 (1.6) years.SETTING—Tertiary care centre.SUBJECTS—Consecutive sampling of 342 patients with persistent atrial fibrillation (defined as > 24 hours duration) considered eligible for electrical cardioversion.INTERVENTIONS—Serial electrical cardioversions and serial antiarrhythmic drug treatment, after identification and treatment of underlying cardiovascular disease.MAIN OUTCOME MEASURES—heart failure complications: development or progression of heart failure requiring the institution or addition of drug treatment, hospital admission, or death from heart failure.RESULTS—Development or progression of heart failure occurred in 38 patients (11%), and 22 patients (6%) died from heart failure. These complications were related to the presence of coronary artery disease (p < 0.001, risk ratio 3.2, 95% confidence interval (CI) 1.6 to 6.5), rheumatic heart disease (p < 0.001, risk ratio 5.0, 95% CI 2.4 to 10.2), cardiomyopathy (p < 0.001, risk ratio 5.0, 95% CI 2.0 to 12.4), atrial fibrillation for < 3 months (p = 0.04, risk ratio 2.0, 95% CI 1.0 to 3.7), and poor exercise tolerance (New York Heart Association class III at inclusion, p < 0.001, risk ratio 3.5, 95% CI 1.9 to 6.7). No heart failure complications were observed in patients with lone atrial fibrillation.CONCLUSIONS—Aggressive serial electrical cardioversion does not prevent heart failure complications in patients with persistent atrial fibrillation. These complications are predominantly observed in patients with more severe underlying cardiovascular disease. Randomised comparison with rate control treatment is needed to define the optimal treatment for persistent atrial fibrillation in relation to heart failure.