Comparison of spontaneous atrial fibrillation electrogram potentials with the P-wave electrogram amplitude in dual chamber pacing with unipolar atrial sensing.

AIMS: Although bipolar sensing is recommended and desirable in patients with dual chamber pacemakers (DDD) and intermittent atrial fibrillation (AF) it is a clinical reality that some patients who are given unipolar atrial leads without a prior history of AF may develop intermittent AF during follow-up. It was therefore the purpose of this prospective study to compare the electrogram amplitudes of AF potentials with sinus rhythm P-wave potentials as a relevant factor for appropriate mode switching in dual chamber pacing with unipolar atrial sensing. METHODS AND RESULTS: Forty-two patients with dual chamber pacemakers, unipolar atrial leads and intermittent AF were studied. Aside from measuring the P-wave potential, it was possible in 14 patients (4 women, 10 men; mean age: 61.8 (+/- 13.3) years) additionally to document spontaneous AF electrogram potentials using pacemaker telemetry. A prospective survey study was performed including a 6 month follow-up period with an outpatient clinic visit every 2-3 weeks. The mean P-wave electrogram amplitude was 3.4 (+/- 1.8) mV (range: 1.4-7.4) compared with the mean amplitude during AF of 2.04 (+/- 1.26) mV (range: 0.8-5.2 mV) indicating a significant attenuation of 40% during AF (P < 0.0001). A linear correlation regression analysis revealed that there was a significant correlation between the P-wave and the AF amplitude (P < 0.0001), with a correlation coefficient of r = 0.867. CONCLUSION: Once it is known that a substantial reduction exists in electrogram amplitude, compared with the P wave electrogram potential, an estimate can be made of whether AF potentials will be sensed, if the programming of atrial sensitivity is congruent with the P-wave characteristics and the presence or absence of myopotential triggering.     

Efficacy and tolerability of continuous overdrive atrial pacing in atrial fibrillation.

Overdrive right atrial pacing has been used to prevent atrial fibrillation, but its efficacy in atrial fibrillation prevention and the patient tolerability and quality of life during high rate pacing remain uncertain. The objective of this study was to test the effects of a consistent atrial pacing algorithm that automatically paced the atrium at 30 ms shorter than the sinus P-P interval for atrial fibrillation prevention. Fifteen patients with sick sinus syndrome implanted with a Thera DR (model 7940 or 7960, Medtronic Inc.) were randomly programmed to rate adaptive dual chamber pacing (DDDR) or DDDR + consistent atrial pacing mode, each for an 8-week study period. The efficacy of consistent atrial pacing was assessed by the number of automatic mode switching and the number of premature atrial complexes. Symptoms and quality of life were assessed by the SF-36 quality of life questionnaire and an atrial fibrillation symptom checklist. The percentage of atrial pacing increased from 57 +/- 32% to 86 +/- 28%. Overall, there was no significant difference in the number of automatic mode switching episodes between DDDR and DDDR + consistent atrial pacing (47 +/- 90 vs 42 +/- 87, P > 0.05), but a significant reduction in premature atrial complexes by 74.7% (P < 0.001). There was no undue increase in atrial rate by the DDDR + consistent atrial pacing mode versus DDDR (63 +/- 13 vs 70 +/- 7 bpm). There was no significant difference in quality of life scores and symptom severity on frequency between the two modes of pacing, but a trend towards a lower frequency of symptoms in the DDDR + consistent atrial pacing mode compared with baseline (29.5 +/- 10.2 vs 25.1 +/- 9.7, P = 0.07). An algorithm that provides consistent atrial overdrive pacing can suppress atrial fibrillation triggering premature atrial complexes without the need to increase the overall atrial rate compared with conventional pacing. The algorithm appears to be well-tolerated, but further studies are needed to address the clinical impact of this atrial fibrillation prevention algorithm.     

Septal atrial pacing for the prevention of atrial fibrillation.

AIMS: Atrial fibrillation (AF) produces significant morbidity and mortality. The current method of permanent pacing of the right atrium (RA) may cause delayed interatrial conduction and predispose to AF. We hypothesized that atrial septal pacing would reduce AF compared with high RA pacing. METHODS AND RESULTS: The patients were randomized into two groups. After randomization, patients received a dual-chamber rate-responsive device capable of mode-switching with advanced telemetry features. Devices were programmed in a standardized manner. To be eligible, the patients were required to have a conventional indication for a permanent pacemaker and recurrent paroxysmal AF. Group 1 was paced from high RA and Group 2 was paced from the atrial septum. Analysis of 43 patients who have completed 6 months of follow-up and 22 patients who completed 12 months of follow-up showed no significant differences in the number of mode-switching episodes or in AF burden between groups (P = NS by Mann-Whitney) although there was a trend for less AF with septal pacing. There were no differences in thresholds, sensing, or lead impedance. Lead parameters remained stable over time and there were no displacements of the electrodes after implantation. No patient experienced lead-related complications. A significant variability in AF burden was noted in this patient population. CONCLUSIONS: Implantation of an atrial-active fixation lead on the atrial septum is safe and feasible. However, this study showed no significant difference between septal pacing and high atrial pacing, using the endpoints of AF duration and number of AF episodes.     

Atrial pacing for suppression of early reinitiation of atrial fibrillation after successful internal cardioversion.

AIMS: To evaluate the efficacy of atrial pacing in the suppression of early reinitiation of atrial fibrillation after successful internal cardioversion. METHODS AND RESULTS: The efficacy of atrial pacing in suppressing early reinitiation of atrial fibrillation was studied in 12 of 45 (29%) patients with early reinitiation of atrial fibrillation after successful cardioversion. These patients were randomized to undergo either repeated defibrillation alone or repeated defibrillation followed by high right atrial pacing at 500 ms in a crossover fashion. In patients with persistent early reinitiation of atrial fibrillation despite atrial pacing at 500 ms and repeated defibrillation, atrial pacing at 300 ms was tested. Lastly, if early reinitiation of atrial fibrillation persisted, administration of intravenous sotalol (1.5 mg. kg(-1)) was tested. Atrial pacing at 500 ms after defibrillation prevented early reinitiation of atrial fibrillation in five of 12 (42%) patients, and was significantly more effective than repeated defibrillation (0/9 patients, 0%, P<0.05). During atrial pacing at 500 ms, the density of atrial premature depolarizations (APDs) was significantly decreased (2.4+/-2.4 APDs. min(-1)vs 16.4+/-9.8 APDs. min(-1), P<0. 05) and the coupling interval of atrial premature depolarization was significantly increased (420+/-32 ms vs 398+/-19 ms, P<0.05) as compared to no pacing. In the remaining seven (58%) patients, atrial pacing at 500 ms failed to prevent early reinitiation of atrial fibrillation, but significantly decreased the density of atrial premature depolarization (3.4+/-2.4 APDs. min(-1)vs 14.2+/-4.8 APDs. min(-1), P<0.05) and delayed the onset of early reinitiation of atrial fibrillation (33+/-17s vs 11+/-11 s, P<0.05). Atrial pacing at 300 ms decreased the coupling interval of atrial premature depolarization as compared to no pacing and during atrial pacing at 500 ms (P<0.05), but without early reinitiation of atrial fibrillation suppression. Administration of intravenous sotalol was effective in preventing early reinitiation of atrial fibrillation in five of seven (71%) patients where pacing failed to suppress early reinitiation of atrial fibrillation. CONCLUSION: The results of this study suggest that atrial pacing can be useful when combined with transvenous defibrillation in patients with early reinitiation of atrial fibrillation.     

No evidence of automatic atrial overdrive pacing efficacy on reduction of paroxysmal atrial fibrillation.

AIMS: Paroxysmal atrial fibrillation (PAF) is frequently encountered in pacemaker patients, most commonly in sick sinus syndrome. The combination of site-specific pacing in conjunction with an overdrive algorithm combined with antiarrhythmic drugs on the incidence of PAF in patients with a conventional indication for pacing is unknown. METHODS AND RESULTS: Patients with pacemaker indication and PAF received a DDDR-pacemaker, which included an automatic atrial overdrive (AO) algorithm. The atrial lead was implanted in either the right atrial appendage (RAA) (n = 83) or the right low-atrial septum (LAS) (n = 94). The algorithm was switched on or off in a 3 month, single blind crossover design and antiarrhythmic drugs were kept stable. A control group of 96 patients (LAS, n = 14; RAA, n = 84) without PAF served as controls to assess any proarrhythmic effect of overdrive pacing. Atrial fibrillation (AF) burden defined as cumulative time in mode switch was not reduced during automatic AO from either the RAA or from the LAS. The reduction was not effective both for AF of short (<24 h) and long (> or =24 h) duration. There was no atrial proarrhythmia induced by the overdrive algorithm in the control group. CONCLUSIONS: We could not demonstrate a reduction of AF burden defined as cumulative time in AF by the AO algorithm, in patients who are paced for standard indications and PAF, neither from the RAA nor from the LAS.     

No incremental benefit of multisite atrial pacing compared with right atrial pacing in patients with drug refractory paroxysmal atrial fibrillation

OBJECTIVE—To evaluate the incremental antifibrillatory effect of multisite atrial pacing compared with right atrial pacing in patients with drug refractory paroxysmal atrial fibrillation paced for arrhythmia prevention alone.
METHODS—In 20 of these patients (mean (SD) age 64 (8) years; 14 female, six male), a single blinded randomised crossover study was performed to investigate the incremental benefit of one month of multisite atrial pacing compared with one month of right atrial pacing. Outcomes included the number of episodes of paroxysmal atrial fibrillation, their total duration obtained from pacemaker Holter memory, and quality of life using a cardiac specific questionnaire (the modified Karolinska questionnaire).
RESULTS—Comparing right atrial with multisite atrial pacing, there was no significant change in either the number of paroxysmal atrial fibrillation episodes (mean (SD): right atrial pacing 77 (98) episodes v multisite pacing 52 (78) episodes, NS) or their total duration (right atrial, 4.8 (5.4) days v multisite, 6.3 (9.8) days, NS). Quality of life scores compared with baseline status were equally improved by either pacing strategy (mean percentage improvement: right atrial, 38%, p = 0.003; multisite, 44%, p = 0.003). There was no significant difference in life scores comparing the two pacing modes.
CONCLUSIONS—Multisite atrial pacing has no incremental antiarrhythmic effect compared with right atrial pacing in patients paced for drug refractory paroxysmal atrial fibrillation. Quality of life is equally improved with either pacing strategy, with no differences between them.


Keywords: multisite atrial pacing; atrial fibrillation; pacing     

心房颤动发作时心房电极的置入

目的:探讨心脏起搏器置入术中心房颤动(房颤)发作时置入心房电极的方法和可靠性。方法:对24例具有心脏起搏器安置指征的慢快综合征患者房颤发作时置入心房电极的方法、术中术后心房电极的参数进行分析。结果:所有病例全部成功置入心房电极。4例阵发性心房扑动(房扑)患者经超速刺激转复2例;普罗帕酮转复8例阵发性房颤、房扑患者4例成功,胺碘酮转复14例阵发性房颤患者6例成功,总转复率45%。12例术后复律后程控测得P波振幅、心房电极阻抗、起搏阈值与12例术中复律患者测得的参数差异无统计学意义(P>0.05);10例房颤患者术中测得心房波为(0.8±0.6)mV,明显小于术后复律后程控测得的P波(1.4±0.5)mV(P<0.05),但两者阻抗无明显差别(P>0.05)。结论:心脏起搏器置入术中房颤发作时置入心房电极安全可靠。     

动态心房超速起搏预防阵发性房颤

目的观察动态心房超速起搏预防阵发性房颤的临床疗效和安全性。方法选择病态窦房结综合症伴阵发性房颤,并需植入永久起搏器的患者8例,分别植入具有动态心房起搏功能的起搏器,PacessetterTrilogy23643例,VitatronSelectionTM900E5例;随访6个月,前3个月不打开动态心房起搏功能,后3个月打开动态心房起搏功能,根据起搏器记录到的模式转换次数和持续时间来判断其预防房颤发作的疗效。结果打开动态心房起搏功能前后,患者房颤发作的次数分别为2437±956次/月和472±135次/月(P<0.05);模式转换持续时间分别为173±105小时/月和48±25小时/月(P<0.05);房颤负荷分别为33±8%和10±7%(P<0.05)。结论动态心房超速起搏,是阵发性房颤预防治疗的有效和安全的方法之一。     

Influence of pacing modalities on the incidence of atrial fibrillation in patients without prior atrial fibrillation. A prospective study

Aim Many studies suggest that patients who receive a physiologicalpacemaker have a reduced incidence of atrial fibrillation comparedto patients receiving a ventricular pacemaker. Methods In order to evaluate the impact of different pacing modalitieson the incidence of atrial fibrillation, we prospectively analysed210 patients. Patients with previous episodes of atrial fibrillationwere excluded from the study. The patient population included110 patients paced for sick sinus syndrome and 100 patientspaced for total atrio-ventricular block or second degree typeatrioventricular block. Results Patients were followed for 5 years; the incidence of atrialfibrillation was 10% at 1 year, 23% at 3 years and 31% at 5years. There was an increase in the incidence of atrial fibrillationin patients receiving a ventricular pacemaker compared to patientsreceiving a physiological pacemaker. Conclusion The pacing modality appeared to influence the incidence of atrialfibrillation in paced patients; patients with ventricular pacinghad a significantly higher incidence of arrhythmias than didpatients with physiological pacing.     

Pacemaker prevention therapies for the control of drug-refractory paroxysmal atrial fibrillation.

AIMS: Atrial septal pacing has been shown to prevent paroxysmal atrial fibrillation (PAF) refractory to drugs in patients without inappropriate bradycardia. This study assesses the effects of atrial septal pacing using new pacing algorithms designed to prevent the initiation or maintenance of PAF. METHODS AND RESULTS: Eleven Medtronic AT500 and 6 Guidant Pulsar Max pacemakers were implanted. The incremental benefit of prevention pacing therapies was compared with DDDR pacing by analysis of pacemaker-stored electrograms, ambulatory electrocardiography, symptoms and quality of life questionnaires. RESULTS: Atrial septal pacing reduced AF burden by >50% in 13/17 patients (76.5%). Activation of a combined pacing algorithm (atrial pacing preference; atrial rate stabilization; and post mode-switch overdrive pacing) in patients with AT500 pacemakers produced a marginal reduction in AF burden (mean %AF 0.61 ON, 0.73 OFF, P=0.53 ns). Conversely in the Pulsar Max group when atrial pacing preference was activated, AF burden was slightly increased (mean %AF 5.84 ON, 3.73 OFF,P =0.13). Symptoms improved with atrial septal pacing but did not change when prevention algorithms were activated. CONCLUSION: Atrial septal pacing resulted in a marked improvement in AF burden and symptoms. Activation of specific prevention pacing algorithms provided more continuous atrial pacing but had limited and heterogeneous effects on AF burden.     

Conventional and dedicated atrial overdrive pacing for the prevention of paroxysmal atrial fibrillation: the AFTherapy study.

AIMS: This investigation was conducted to determine the effectiveness of several conventional overdrive pacing modalities (single rate and rate responsive pacing at various lower rates) and of four dedicated preventive pacing algorithms in the suppression of paroxysmal atrial fibrillation (AF). METHOD AND RESULTS: In this multi-centre, randomized trial, 372 patients with drug-refractory paroxysmal AF were enrolled. Patients received a dual-chamber pacing device capable of delivering conventional pacing therapy as well as dedicated AF prevention pacing therapies and to record detailed AF-related diagnostics. The primary endpoint was AF burden, whereas secondary endpoints were time to first AF episode and averaged sinus rhythm duration. During a conventional pacing phase, patients were randomized to single rate or rate-responsive pacing with lower rates of either 70 or 85 min(-1) or to a control group with single rate pacing at 40 min(-1). In the subsequent preventive pacing phase, patients underwent pacing at a lower rate of 70 min(-1) with or without concomitant application of four preventive pacing algorithms. A substantial amount of data was excluded from the analysis because of atrial-sensing artefacts, identified in the device-captured diagnostics. In the conventional pacing phase, no significant differences were found between various lower rates and the control group receiving single rate pacing at 40 min(-1) or between single rate and rate-responsive pacing. Patients receiving preventive pacing with all four therapies enabled had a similar AF burden compared with patients treated with conventional pacing at 70 min(-1) (P = 0.47). CONCLUSIONS: The results do not demonstrate a significant effect of conventional atrial overdrive pacing or preventive pacing therapies. However, the observations provided important information for further consideration with respect to the design and conduct of future studies on the effect of atrial pacing therapies for the reduction of AF.     

安置心脏起搏器患者术后心房颤动的多因素分析

目的观察安置心脏起搏器患者术后发生心房颤动(房颤)的相关因素.方法回顾性随访了107例安装起搏器的患者,其中VVI(R)组起搏器共53例,随访时间为(7.09±4.13)年;房室顺序起搏组AAI、VDD(R)、DDD(R)型起搏器共54例,随访时间为(3.41±2.21)年.随访时收集患者置入起搏器时的年龄、心律失常的类型、术前有无阵发性房颤、起搏器的类型、至随访时起搏器置入时间以及术后发生持续性房颤的时间,每例患者至少有一份心电图,部分患者做Holter检查,明确是否发生持续性房颤.通过统计学Logistic回归分析,阐明不同类型起搏器术后发生房颤的影响因素.结果随访的107例中共有17例发生持续性房颤;其中VVI(R)组12例,房颤的发生率为22.64%;房室顺序起搏组5例,房颤的发生率为9.26%.在VVI(R)组,病态窦房结综合征、原有阵发性房颤、起搏器置入后时间均为术后发生房颤的独立影响因素;在房室顺序起搏组,只有原有阵发性房颤是术后发生房颤的影响因素.结论起搏器术后发生房颤有多种影响因素,其中在VVI(R)组,病态窦房结综合征、原有阵发性房颤及起搏器置入后时间均为术后发生持续性房颤的独立影响因素;在房室顺序起搏组,原有阵发性房颤为术后发生持续性房颤的影响因素.     

Paroxysmal atrial fibrillation prevention by pacing in patients with pacemaker indication.

AIMS: The prevent-atrial fibrillation (AF) registry analyses the clinical relevance and usefulness of the four preventive pacing algorithms, available in a family of cardiac stimulators, to prevent atrial fibrillation. METHODS AND RESULTS: This study is a prospective, non-randomized, multicentre registry. Patients are eligible for the registry if they have sick sinus syndrome (SSS) with or without pre-existing atrial fibrillation. The preventive pacing algorithms were programmed for each patient on an individual basis using the diagnostic features of the devices. In the period from April 2000 to April 2001 a total of 68 patients (33 male, 35 female) has been included in the registry in 14 hospitals in Spain. Mean age was 72+/-12 years and the pacemaker indication was SSS in 15 patients (22%) and SSS with paroxysmal AF in 53 patients (78%). The median AF burden for the total group (n=32) was significantly reduced from 3.9 to 1.3% (67%, P=0.034, Wilcoxon signed rank test). The decrease in AF burden was accompanied by a non-significant decrease in the median number of episodes per day from 1.47 to 0.64 (a decrease of 56%). The average atrial pacing % was increased from 72 to 78%. CONCLUSIONS: The prevent-AF registry demonstrated the usefulness of four preventive pacing algorithms in daily clinical practice. During the registry a significant reduction in AF burden and all other endpoints was observed. Dedicated diagnostics were key to adapting the optimal pacing therapy during follow-up.     

Electrophysiological determinants of atrial fibrillation in sinus node dysfunction despite atrial pacing.

AIMS: The effectiveness of atrial pacing in reducing the incidence of atrial fibrillation in patients with sinus node dysfunction is incomplete, and the correlation between electrophysiological atrial properties and the effect of permanent atrial pacing has been poorly investigated. Accordingly, the aim of the present study was to correlate electrophysiological data, in terms of atrial refractoriness, conduction parameters, and propensity to atrial fibrillation induction, and the likelihood of atrial fibrillation after DDD device implantation. METHODS AND RESULTS: The authors reviewed electrophysiological data of 41 patients with sinus node dysfunction (mean age 70 +/- 8 years, who were investigated free of anti-arrhythmic treatments before pacemaker implantation. At a drive cycle length of 600 ms, effective and functional refractory periods, S1-A1 and S2-A2 latency, A1 and A2 width, and latent vulnerability index (effective refractory period [ERP] A2), were measured. Atrial fibrillation induction was tested with up to three extrastimuli in 34 patients. Induction of sustained atrial fibrillation (> 1 min) was considered as the end-point. P-wave duration on the surface ECG in lead II/V1 was also measured. Minimal atrial rate was programmed between 60 and 75 bpm (mean: 64 +/- 4 bpm). After implantation, the patients were followed-up for 28 +/- 17 months, and ECG-documented occurrence of atrial fibrillation was determined. Electrophysiological characteristics of patients with (n = 12) or without (n = 29) paroxysmal atrial fibrillation before implantation were similar. When comparing patients with (n = 11) or without (n = 30) post-pacing atrial fibrillation occurrence, no differences were found in age, underlying heart disease, left atrial size, minimal pacing rate, and follow-up duration. Additionally, between the two former groups, there was no significant difference in terms of effective refractory periods (233 +/- 47 ms vs 239 +/- 25 ms), functional refractory periods (280 +/- 48 ms vs 272 +/- 21 ms), S1-A1 (44 +/- 20 ms vs 37 +/- 13 ms) and S2-A2 latency (77 +/- 28 ms vs 66 +/- 22 ms), and A1 duration (60 +/- 23 ms vs 53 +/- 16 ms). In contrast, in patients with post-pacing atrial fibrillation occurrence, the P wave was more prolonged (116 +/- 22 ms vs 98 +/- 13 ms; P < 0.01), A2 was longer (116 +/- 41 ms vs 87 +/- 27 ms; P < 0.01), effective refractory periods/A2 was lower (2.1 +/- 0.4 cm vs 3.1 +/- 1.4 cm; P < 0.05), and rate of atrial fibrillation induction was higher (8/11 patients vs 8/23 patients; P < 0.05). Electrophysiological characteristics of patients free of post-pacing atrial fibrillation with associated (n = 6) or unassociated (n = 24) paroxysmal atrial fibrillation history before implantation were quite similar. In patients with post-pacing atrial fibrillation with associated (n = 6) or unassociated atrial fibrillation history (n = 5) before implantation, effective refractory periods was statistically different (207 +/- 23 ms vs 264 +/- 46 ms; P < 0.05). Values of effective refractory periods < 220 ms were significantly more frequent in patients with post-pacing atrial fibrillation than in patients without (4/11 patients vs 2/30 patients; P < 0.05). When comparing patients with post-pacing atrial fibrillation with effective refractory periods > or = 220 ms (n = 7) and < 220 ms (n = 4), A2 duration was remarkably prolonged (145 +/- 42 ms vs 90 +/- 11 ms; P < 0.05) in those with effective refractory periods > or = 220 ms. By contrast, between the two groups, effective refractory periods/A2 were identical (2.08 +/- 0.6 cm vs 2.15 +/- 0.3 cm; P = n.s.). CONCLUSION: Prolonged atrial refractoriness, lesser degrees of conduction disturbance and a lower rate of atrial fibrillation induction seem to be predictive of stable sinus rhythm. In contrast, patients with persistence of atrial fibrillation despite pacing have a more abnormal and inhomogeneous atrial substrate, as well as a higher rate of atrial fibrillation induction. Prolonged P wave, shortened refractoriness, or remarkably abnormal conduction disturbances in the presence of prolonged refractoriness limit the effectiveness of standard atrial pacing in atrial fibrillation prevention. Identification of predictive criteria of failure of single-site atrial pacing may be used to consider dual-site atrial pacing in such patients with sinus node dysfunction.     

ZV1,ZV5导联心室晚电位的检出率及临床意义

用Ｘ、Ｙ、Ｚ正交导联和改良的ＺＶ１、ＺＶ５导联，对３８例室性早搏病人进行心室晚电位检测。结果显示ＺＶ１、ＺＶ５导联法晚电位阳性率明显高于Ｘ、Ｙ、Ｚ正交导联法（ｕ＝４．６９，Ｐ〈０．０１），改进、弥补了Ｘ、Ｙ、Ｚ正交导联对晚电位“稀释”的不足。用ＤＣＧ同时记录，发现ＺＶ１导联法晚电位阳性与右室起源的早搏有关；ＺＶ５导联法记录的晚电位与左室起源的早搏有关。显示改良的ＺＶ１、ＺＶ５导联与传统的Ｘ、Ｙ、Ｚ     

具有多种抗心房颤动模式起搏器的临床应用

目的:评价心房程序起搏预防和治疗阵发性房颤的效果。方法:对15例阵发性房颤患者置入Selection 900E(AF2.0)型起搏器,调查分析术前2个月和术后2个月及4个月阵发性房颤事件各指标。 结果:患者术后2个月及4个月较术前2个月在有症状阵发性房颤事件数有明显地降低(34.2±18.01,19.73±7.79对66.30±26.06);术后4个月较术后2个月有症状阵发性房颤事件数、阵发性房颤事件总数、房颤总持续时间、房颤负荷均降低(P<0.05),而心房起搏比率无明显改变。 结论:生理性心房程序起搏减少阵发性房颤事件的发生,降低房颤负荷,并可以明显减少临床抗心律失常药物使用的种类和剂量。     

VVI起搏后心房颤动的发生率及影响因素

为探讨ＶＶＩ起搏后心房颤动（Ａｆ）发生率及影响因素，分析我院２９６例ＶＶＩ起搏患者，并与同期２２例生理性起搏（ＡＡＩ５例，ＤＤＤ１７例）患者比较，发现ＶＶＩ起搏后Ａｆ发生率为２５７％（７６／２９６），而生理性起搏后Ａｆ发生率仅４５％（１／２２），有显著性差异Ｐ＜００５）。同时分析比较了ＶＶＩ起搏后Ａｆ发生率与７种影响因素的关系，发现Ａｆ发生率增加除与性别无明显关系外（Ｐ＞００５），在统计学上有显著差异的因素是：年龄较大（≥６０岁，Ｐ＜００５），术前有高血压史（Ｐ＜００１），心功能不全（＞Ⅱ级，Ｐ＜００１），左房内径较大（≥４５ｍｍ，Ｐ＜００１），病态窦房结综合征（无房室传导阻滞，Ｐ＜００５），ＶＶＩ起搏时间较长（≥３年，Ｐ＜００５）。     

单纯碎裂电位指导心房颤动消融的初步临床观察

目的探讨碎裂电位指导心房颤动（房颤）射频导管消融的可行性。方法22例药物治疗无效有症状的房颤患者（阵发性16例,持续性6例）,在自发或诱发房颤时,用Carto构建左心房或左、右心房的三维模型并标测、消融碎裂电位,终点是消除标测到所有碎裂电位或转复窦性心律。结果碎裂电位消融后,13例（59％）转复为窦性心律（直接转复7例,先转为房性心动过速（房速）／心房扑动（房扑）然后转复6例）,9例消融未转复窦性心律患者行电复律或药物复律成功。6例复发（5例房速／房扑,1例阵发性房颤）再次消融,5例成功,随访3—18（10．9±4．8）个月,共有16例（73％）无快速房性心律失常事件,碎裂电位主要分布于左侧房间隔、肺静脉周围、左心房顶部。碎裂电位消融后房颤终止前房颤周期与碎裂电位消融前相比明显延长[（157±18）ms vs （211±32）ms,P〈0．05]。除一例发生心脏压塞且心包穿刺成功引流外,无消融术相关的并发症和后遗症。结论碎裂电位指导房颤导管射频消融安全有效可行。     

Atrial pacing for prevention of atrial fibrillation: assessment of simultaneously implemented algorithms.

AIMS: Several preliminary studies indicated that right atrial pacing could prevent atrial tachyarrhythmias (ATA). We sought to compare the safety and the efficacy of atrial-based pacing supplemented by dedicated combined algorithms with conventional atrial pacing in the prevention of ATA. METHODS: Fifty-five patients with a history of recurrent paroxysmal ATA implanted with a dual-chamber pacemaker were studied during two randomized cross-over pacing periods (conventional DDD and DDD with ATA prevention algorithms) of 6 months duration. The primary endpoint was the burden of ATA episodes recorded by the device mode switch algorithm. RESULTS: The cross-over analysis did not demonstrate any significant difference between the two pacing modes: 254+/-533 h of ATA during the control period versus 238+/-518 h during the ATA prevention period. Analysis of a subgroup of patients found that those with the lower percentage of ventricular pacing benefited from ATA prevention algorithms (120+/-182 h versus 225+/-350 h during the control period; P < 0.04). CONCLUSION: When compared with DDD pacing at 70 bpm, ATA prevention algorithms have not demonstrated significant efficacy. However, a subgroup of patients with preserved native AV conduction (low percentage of ventricular pacing) responded to ATA prevention algorithms.     

老年对慢性心房颤动患者左房复杂碎裂电位的影响

目的 评价老年对非瓣膜病心房颤动（简称房颤）患者左房复杂碎裂电位（CFAEs）的影响。方法 前瞻性入选116例行导管消融的慢性房颤患者。 以60岁为界,分为老年组（n=48）与非老年组（n=68）。 在CARTO系统指导下记录局部稳定的心内膜电图。 应用CARTO系统内置的CFAEs分析软件进行分析。 以间期置信水平（ICL）来评估CFAEs的特点。 CFAEs指数定义为 ICL≥7 区域的面积与左房表面积的比值。 将左房分为前壁、后壁、顶部、下壁、外侧壁、间隔六个部分,评价CFAEs在左房不同位置的分布特征。 结果 老年组男性患者比例显著低于非老年组,合并高血压、脑卒中的比例显著高于非老年组（P均〈0. 05）。 老年组最大ICL显著大于非老年组[（16.7±2.0） vs （15.7±2.2）,P=0. 014）],老年组CFAEs指数显著高于非老年组[（60. 4%±22.9% ） vs （48. 6%±22. 3% ）,P=0. 007）]。 老年组左房前壁、间隔的CFAEs的分布比例显著大于非老年组。 年龄与CFAEs指数呈正相关（r=0. 244, P=0. 008）。 结论 老年慢性房颤具有广泛的 CFAEs。