心房晚电位

自1980年Hombach等第一个报道用体表信号平均技术记录到延迟电位的改变以来,心室晚电位(Ventricular Late Potential,VLP)的研究日趋广泛深入,目前已肯定信号平均心电图(Signal-averaging Electrocardiogram,SAECG)记录VLP在预测心肌梗塞病人发生室速或心脏卒死中有重要价值。随着R波触发型信号平均心电图机在诊断VLP中的应用,有人用这种心电图机,经过调整滤波频率、滤波方式及叠加次数等,检查心房晚电位(Artial Late Potential,ALP),取得了有意义的资料。近年来,Fukanami等首次用P波触发型信号平均心电图检查ALP,取得了较为理想的效果。     

52例心房晚电位与阵发性房颤的临床关联

目的 探讨心房晚电位测试对于预测阵发性房颤发生的临床关联。方法 以P波触发信号平均心电图记录技术测试52例阵发性房颤患者及40例健康对照组的心房晚电位(滤波后的P波时限、P波终末20ms、30ms、40ms的电压均方根值)并进行比较分析。结果 阵发性房颤组的滤波后P波时限为(137.52±2.92)ms,对照组为(113.05±1.20)ms,两组比较有显著性差异(P<0.001);阵发性房颤组的P波终末20ms电压均方根值为(2.65±0.25)μV,对照组为(3.72±0.19)μv,两组比较有显著性差异(P<0.001);阵发性房颤组的P波终末30ms电压均方根值为(3.69±0.32)μV,对照组为(4.71±0.28)μV,两组比较有显著性差异(P<0.02)。结论 P波触发信号平均心电图记录心房晚电位可作为预测阵发性房颇的1个快速、无创性指标。     

阵发性房颤患者的心房晚电位检测

阵发性房颤（ＡＦ）是临床最为常见的快速性心律失常之一。由于其远期的血栓栓塞和致心功能不全性并发症，已成为老年人的重要心血管疾病［１～３］。关于房颤的发病机制人们进行了很多研究，目前认为是由于在心房内出现多个随机性微折返所致［４］。为了寻找折返理论的论据，作者按Ｆｕｋｕｎａｍｉ等［５］报道的方法对３０例阵发性房颤的患者和３０例正常人进行了心房晚电位（Ａｔｒｉａｌｌａｔｅｐｏｔｅｎｔｉａｌ，ＡＬＰ）检查。１　对象和方法１．１　房颤患者入选条件　①房颤病史２０年以上；②每周至少发作一次，每次持续发作３…     

P波触发信号平均心电图记录心房晚电位

众所周知,信号平均心电图(Signal-Averaged Elec-trocardiogram SA-ECG)已较成功地用于检测心室晚电位,临床作为筛选室性心律失常和预测心性猝死的一种无创手段。由于阵发性房颤(paroxysmal atrial fibril-tation Paf)是临床最常见的心律失常之一。Paf 造成的严重后果可使患者全身栓塞发生率5倍于无 Paf 的患者。因此,近年来国外学者也试图用 SA-ECG 技术测量心房终未电位的低幅信号,以便在窦性心律时检出Paf 患者。1988年,Engel 等首次报告测量26例 Paf 和阵发性房扑患者的 SA-ECGP 波晚电位,与正常对照组未见显著差异,以为 SA-ECG 不具备检出 Paf 和阵发房扑患者的功能。1990年,Schrem 等亦有类似报道。其失败的根本原因是使用 R 波触发方式。在 R 波触发方式下,心电信号叠加以 QRS 综合波起点或最大斜率处作为参照时间,逐点叠加波形,适用于检测心室晚     

缺血性心室晚电位的实验研究

本文将14只麻醉犬采用Harris氏法二期结扎左冠状动脉前降支（LAD），从心外膜实时记录心室晚电位（VLP）为标准，对比研究了体表和心外膜信号平均心电图（SA－ECG）检测VLP的价值。结果表明：（1）梗塞区心外膜SA－ECG显示的VLP与实时记录结果显著相关（r=-0.84,P<0.05)；(2)结扎LAD3小时内，体表SA－ECG的VLP阳性率为71．4％（10／14），3－6天降至50％（6／12）；（3）体表SA－ECG特异性较强（91．67％），而敏感性较差（66．67％）；（4）初步确定犬SA－ECG的VLP阳性指标为DQRS≥60ms、D40≥20ms和V20≤16μV。     

心室晚电位

心室晚电位(Ventricular late poten-tials)是与心室某些病变区域存在的缓慢传导有关而延迟除极所出现的舒张期碎裂电活动,因这种晚电位(LPs)通常晚于 QRS 波而出现在 QRS 终了处并延伸至ST 段内,故得名。目前认为 LPs 是预测、预报严重室性心律失常和心脏性猝死的信号。     

心室晚电位与室性心律失常关系的探讨

心室晚电位(VLP)常见于缺血性心脏病病人,与恶性室性心律失常的发生密切相关。为探讨VLP与室性心律失常的确切关系,我们应用美国ART1200EPX型晚电位分析仪,对心肌梗塞、冠心病心绞痛、心肌炎等222例患者进行了VLP检查,并与143例正常健康人作对照,现报告分析如下。     

缬沙坦对原发性高血压合并阵发性房颤患者心房晚电位的影响

目的:探讨原发性高血压合并阵发性房颤(PAF)患者检测心房晚电位(ALP)的临床价值及缬沙坦对其的影响。方法:30例原发性高血压合并PAF患者为治疗组,用缬沙坦80～160mg/d治疗6个月观察ALP的变化并与对照组比较。采用美国GE MarquetMAC5000型多功能心电图机记录对照组、治疗组缬沙坦治疗前后P波滤波后P波时限(Ad),P波终末20ms(Lp20)、30ms(Lp30)、40ms(Lp40)的电压均方根值。结果:治疗组Ad显著高于对照组,P<0.01,治疗组Lp20、Lp30、Lp40显著低于对照组Lp20、Lp30、Lp40,P<0.01。经过缬沙坦每天80～160mg治疗6个月后治疗组ALP下降、Lp20、Lp30、Lp40均上升,P<0.05或0.01。治疗组房颤发作次数明显减少(P<0.01)。结论:心房晚电位可作为预测原发性高血压患者发生阵发性房颤的一个可靠指标之一,缬沙坦在降低血压的同时,能影响阵发性房颤患者的ALP,可能有预防阵发性房颤的作用。     

A Prospective Study of Atrial Fibrillation After Cardiac Surgery

Background: Atrial fibrillation (AF) is a commonly encountered arrhythmia following cardiac surgery and when sustained, may be associated with significant morbidity. Methods: This large prospective investigation examined a variety of clinical and P wave signal-averaged electrocardiogram (SAECG) parameters to identify independent predictors of AF following cardiac surgery. A total of 272 patients underwent P wave SAECG recording and analysis prior to surgery. Information on their clinical, surgical, and hemodynamic characteristics as well as hospital course was collected. Patients were followed during their postoperative course with telemetry and ECGs. Results: During an observation period of up to 14 days, 79 patients (29%) developed AF 2.5 ± 1.9 days after surgery. Patients who developed AF following cardiac surgery were more likely to be older, undergo valve surgery, to have ejection fraction (EF) < 40%, to have P wave duration on SAECG >140 ms (all P < 0.01), and to take digoxin preoperatively (P < 0.05). A multivariate analysis found that only P wave duration on SAECG >140 ms and EF < 40% were independent predictors of AF following cardiac surgery. The odds ratio of P wave duration on SAECG >140 ms and EF < 40% for the development of AF following cardiac surgery was 3.1 and 2.8, respectively, and 8.7 when combined. Conclusions: Thus, the presence of preexisting abnormal atrial substrate as detected by P wave prolongation on SAECG, and implicated by EF < 40%, clearly predicted a higher risk of AF following cardiac surgery and may provide clinicians with an effective means of identifying those at greatest risk.     

D-二聚体在心房颤动病人血浆中含量变化及临床意义分析

目的观察心房颤动(房颤)病人血浆D-二聚体(D-dimer)水平的变化,并探讨其意义.方法应用免疫比浊法测定63例房颤病人(其中风心病22例,冠心病41例)和20例正常人血浆D-二聚体.结果房颤病人与正常人相比,房颤病人血浆D-dimer浓度为(252.2～456.6)mg/L,显著高于正常人(102.6～389.8)mg/L(P<0.01);风心病病人D-dimer浓度(262.0～446.5)mg/L与冠心病病人D-dimer浓度(252.2～456.6)mg/L比较,无统计学意义.结论房颤病人血浆D-dimer水平升高,与其高发血栓栓塞并发症有关,通过检测血中D-二聚体水平的改变,有助于了解房颤发生血栓栓塞的危险程度.     

Noninvasive Mapping of Human Atrial Fibrillation

Introduction: Invasive high-density mapping of atrial fibrillation (AF) has revealed different patterns of atrial activation ranging from single wavefronts to disorganized activation with multiple simultaneous wavefronts. Whether or not similar activation patterns can also be observed using body surface recordings is currently unknown, and was consequently evaluated in this study.
Methods and Results: Surface electrocardiographic mapping was performed in 14 patients (age 68 ± 14 years) with persistent AF (AF duration 12 ± 18 months). A total of 56 electrocardiographic leads were placed on the chest over the atria on the front (n = 40) and on the back (n = 16). Using 240-second recordings, wavefront propagation maps were automatically computed and visually classified as either type I (single wavefront), II (single wavefront with wave breakages and splitting), or III (multiple simultaneous wavefronts). Almost half of the patients (n = 6) presented most predominantly type III atrial activation, while six patients mostly presented type I activation. The rest of the patients (n = 2) presented mixed type I and type III activations. This classification showed to be highly reproducible over 4 minutes.
Conclusions: Using electrocardiographic body surface mapping during AF, interindividual differences of atrial fibrillatory activation can be observed. The surface activation pattern during AF shows an excellent short-term reproducibility.     

短暂心肌缺血过程中心室晚电位的动态变化

对 38例心肌梗死恢复期的病人 ,应用数字化Holter记录仪 2 4h连续监测心室晚电位 (VLP) ,以判定心肌短暂缺血对VLP的影响。Holter中加强ST段分析软件经人为定标后 ,自动分析记录达到缺血标准的时间及程度 ,其中2 1例在Holter分析中检测出一过性心肌缺血 ,此时VLP参数总QRS波持续时间 (TQRS)、QRS波末期幅度低于 4 0uV信号持续时间 (LAS40 )明显延长 (分别为 10 7.6± 14 .3vs 98.8± 12 .7ms,36 .5± 10 .8vs2 8.4± 9.5ms;P均 <0 .0 0 1) ,QRS波末期最后 4 0ms的均方根电压 (RMS40 )幅值显著减少 (2 8.9± 17.9vs 4 3.5± 2 0 .2uV)。缺血期VLP阳性 14例 ,缺血恢复 2h后VLP阳性 7例。结论 :心肌短暂缺血发作有VLP一过性阳性改变 ,动态心电图技术可捕捉到这一变化     

Clinical Significance of the Left Atrial Appendage Orifice Area

Objective The left atrial appendage (LAA) is one of the major sources of cardiac thrombus formation. Three-dimensional transesophageal echocardiography (TEE) made it possible to perform a detailed evaluation of the LAA morphologies. This study aimed to evaluate the clinical implications of the LAA orifice area. Methods A total of 149 patients who underwent TEE without significant valvular disease were studied. The LAA orifice area was measured using three-dimensional TEE. The patients were divided into two groups according to the LAA orifice area (large LAA orifice group, ≥median value, and small LAA orifice group). The clinical characteristics and echocardiographic findings were evaluated. Results The median LAA orifice area among all patients was 4.09 cm² (interquartile range 2.92-5.40). The large LAA orifice group were older (67.2±10.4 vs. 62.4±15.3 years, p=0.02), more often had hypertension (66.7% vs. 44.6%, p=0.007), and atrial fibrillation (70.7% vs. 39.2%, p＜0.001) than the small LAA orifice group. Regarding the TEE findings, the LAA flow velocity was significantly lower (33.7±20.0 vs. 50.2±24.3, p＜0.001) and spontaneous echo contrast was more often observed (21.3% vs. 8.1%, p=0.02) in the large LAA orifice group. Multivariate models demonstrated that atrial fibrillation was an independent predictor of the LAA orifice area. In the analysis of atrial fibrillation duration, the LAA orifice area tended to be larger as patients had a longer duration of atrial fibrillation. Conclusion Our findings indicated that a larger LAA orifice area was associated with the presence of atrial fibrillation and high thromboembolic risk based on TEE findings. A continuation of the atrial fibrillation rhythm might lead to the gradual expansion of the LAA orifice.     

Value of the atrial signal-averaged electrocardiogram in identifying patients with paroxysmal atrial fibrillation

Atrial signal-averaged electrocardiogram was compared between 25 patients with paroxysmal atrial fibrillation and 20 healthy persons without atrial arrythmias (control). The duration time of the high frequency (50–250 Hz) P wave was significantly (P < 0.01) prolonged in the groups of patients with paroxysmal atrial fibrillation compared with the control group (116 ± 16.4 versus 92 ± 8.1 msec). The diagnostic value of the duration of the high frequency P wave for identifying patients with paroxysmal atrial fibrillation was 104 msec. Using this criterion, a sensitivity of 76% and a specificity of 90% were achieved. Our observation has shown that the atrial signal-averaged electrocardiogram is a useful technique for identifying patients with paroxysmal atrial fibrillation.     

Influence of Filtering Techniques on the Time-Domain Analysis of Signal-Averaged P Wave Electrocardiogram

Differences in P Wave Filtering Techniques. introduction : The advent of signal-averaged ECG (SAECG) systems for P wave analysis has made it important to determine if the use of different filtering techniques in these systems is diagnostically equivalent.
Methods and Results : Three different high-pass filtering techniques and two cutoff frequency values were used: 29- and 40-Hz Butterworth bidirectional filter (BB29, BB40), 29-and 40-Hz Butterworth unidirectional filter (UB29, UB40), and 29- and 40-Hz least mean square filter (LIV1S29, LMS40). Normal healthy volunteers (n = 36) and patients with documented paroxysmal atrial fibrillation (n = 23) were analyzed. A custom-built SAECG system and standard bipolar orthogonal leads were used. Noise was reduced to < 0.3 μV. P wave total duration, root mean square voltage of the terminal 20, 30, and 40 msec of the filtered vector magnitude, and the area under the curve between the onset and offset of averaged unfiltered and filtered P wave vector magnitude were analyzed. Only the duration of the P wave showed statistically significant differences between groups, being longer in the PAF group for all filters and cutoff frequencies studied. A bias increment of -20 msec was detected in unidirectional and least mean square filters as compared to the bidirectional filter. Sensitivity, specificity, and predictive accuracy were > 70% for all filters; the BB40 filter yielded the best performance.
Conclusion : The normality limits derived from one filter cannot be applied directly to recordings obtained from the other filters. Critical limits must be established individually for different software settings.     

Clinical Significance of Early Recurrences of Atrial Tachycardia After Atrial Fibrillation Ablation

Early Recurrence After AF Ablation. Background: Atrial tachycardia (AT) commonly recurs within 3 months after radiofrequency catheter ablation for atrial fibrillation (AF). However, it remains unclear whether early recurrence of atrial tachycardia (ERAT) predicts late recurrence of AF or AT. Methods: Of 352 consecutive patients who underwent circumferential pulmonary vein isolation with or without linear ablation(s) for AF, 56 patients (15.9%) with ERAT were identified by retrospective analysis. ERAT was defined as early relapse of AT within a 3‐month blanking period after ablation. Results: During 21.7 ± 12.5 months, the rate of late recurrence was higher in patients with ERAT (41.1%) compared with those without ERAT (11.8%, P < 0.001). In a multivariable model, positive inducibility of AF or AT immediately after ablation (65.2% vs 36.4%, P = 0.046; odd ratio, 3.9; 95% confidence interval, 1.0–14.6) and the number of patients who underwent cavotricuspid isthmus (CTI) ablation (73.9% vs 42.4%, P = 0.042; odd ratio, 4.5; 95% confidence interval, 1.1–19.5) were significantly related to late recurrence in the ERAT group. The duration of ablation (174.3 ± 62.3 vs 114.7 ± 39.5 minutes, P = 0.046) and the procedure time (329.3 ± 83.4 vs 279.2 ± 79.7 minutes, P = 0.027) were significantly longer in patients with late recurrence than in those without late recurrence following ERAT. Conclusions: The late recurrence rate is higher in the patients with ERAT compared with those without ERAT following AF ablation, and is more often noted in the patients who underwent CTI ablation and had a prolonged procedure time. Furthermore, inducibility of AF or AT immediately after ablation independently predicts late recurrence in patients with ERAT. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1331‐1337, December 2010)     

Development and Validation of Diagnostic Criteria for Atrial Flutter on the Surface Electrocardiogram

Background: There are no universally accepted ECG diagnostic criteria for atrial flutter (AFL), making its differentiation from “coarse” atrial fibrillation (AF) difficult. Methods: To develop diagnostic criteria for AFL, we examined two sets of ECGs. Set 1 consisted of 100 ECGs (50 AF, AFL) with diagnoses confirmed by intracardiac recordings. Criteria evaluated were presence of F waves in the frontal plane leads, F waves in V₁, sawtooth F waves, rate, and regularity of ventricular response. Set 2 included 200 ECGs taken from the hospital database each of which had already been interpreted by a cardiologist as either AF (n = 100) or AFL (n = 100). Set 2 was blindly read by electrophysiologists whose consensus‐diagnoses were compared to the diagnoses made by using the best criteria identified from the Set 1 data. Results: The criteria of frontal plane F waves, regular or partially regular ventricular response, and their combination had sensitivities of 92%, 98%, and 90% and specificities of 100%, 78%, and 100% in Set 1 for the diagnosis of AFL. In Set 2, concordance of electrophysiologist and cardiologist diagnoses was only 84%. The criteria of frontal plane Fwaves, regular or partially regular ventricular response, and their combination resulted in concordances with the cardiologist diagnoses of 85%, 85%, and 82% and with the electrophysiologist‐consensus diagnoses of 90%, 89%, and 94% (P < 0.001). Conclusions: The criteria of frontal plane F waves and regular or partially regular ventricular response aid in the proper diagnosis of AFL. Because management strategies may differ for AF and AFL, it is important to adopt a more rigorous diagnostic approach.