起搏预防阵发性心房颤动的机制及疗效研究进展

起搏预防阵发性心房颤动的机制包括:双房起搏、右心房多部位起搏、心房特殊位点起搏、起搏预防程序、心腔内电复律等及其疗效。     

心房起搏预防和治疗心房颤动

近年研究提示心房起搏可以达到预防和治疗心房颤动 (简称房颤 )的目的。本文就房颤发生的病理生理学机制 ,生理性起搏、双房起搏及右房多部位起搏、抗心律失常起搏等在房颤预防和治疗方面的进展予以综述。     

生理性起搏预防和治疗心房颤动的进展

心房颤动已成为起搏器治疗的新的适应证之一。与单心室永久性起搏相比 ,生理性起搏能明显的降低心房颤动的发生率。Bachmann束、房间隔、冠状静脉窦、多部位或双部位心房起搏对心房颤动的预防和治疗作用优于传统右心耳起搏。具有抗心房颤动功能的起搏器可以预防和治疗心房颤动。生理性起搏预防和治疗心房颤动的机制已基本阐明 ,但存在一些问题有待于今后的临床实践中进一步研究加以改进。     

起搏器预防和治疗心房颤动的研究进展

起搏预防和治疗心房颤动 (简称房颤 )的机制为缩短房内传导时间 ,消除房间传导阻滞 ,逆转异常的心房不应期 ,降低心房节律周期的变异性等 ,故可采用起搏心房的特定部位 ,选择适宜的起搏方式、起搏程序以及置入心房除颤器等方法来预防和治疗房颤。     

起搏预防和终止快速性房性心律失常的疗效观察(附3例报告)

观察AT501起搏器起搏预防和终止快速性房性心律失常的疗效。3例病窦综合征(SSS)患者,同时伴有快速性房性心律失常,置入Medtronic公司生产的AT501起搏器,术后1个月打开三种独立的起搏预防治疗功能和3个可程控的起搏终止治疗功能。经8～10个月的随访,患者的临床症状较术前明显改善,通过9790程控仪回顾心律失常发生事件,发现AT501起搏器对快速性房性心律失常的检测准确率为98%,起搏预防治疗功能和起搏终止治疗功能可减少快速性房性心律失常的发作,其中起搏终止治疗的成功率为56%,在270～360ms快速性房性心律失常检测区成功率为78%,在220～270ms快速性房性心律失常检测区成功率为40%。结论:初步临床应用表明,AT501起搏器置入后通过对起搏器的起搏预防和终止治疗功能合理程控,可安全、有效地减少快速性房性心律失常的发作。     

多部位起搏的作用机制和应用的几个基本概念

一、双心房起搏预防阵发性心房颤动的机制　　心房起搏能通过多种机制预防心房颤动(房颤)的发生。如在慢快综合征患者预防房颤的发作是通过抑制房性早搏和降低心房肌复极化的离散度。双心房起搏预防房颤是基于心房内有功能和/或结构上的传导阻滞区,后者是折返性心律失常的产生机制。在阻滞区的两侧同时起搏心房可消除这种折返机制[1](图1)。房内阻滞区是在Koch三角的后边和/或左、右心房之间,而诱发房颤的房性早搏常起源于界嵴(cirstaterminal)。因此同步起搏右心耳和低位右心房(双部位起搏,dual-sitepacing)是基于阻滞区在Koch三角的后方,…     

永久性心脏起搏器对病态窦房结综合征患者合并阵发性心房颤动的预防作用

心房颤动(AF)是临床最常见的一种持续性心律失常，心脏起搏预防AF是目前AF治疗的新途径之一。近年来的研究证明，双腔起搏或心房起搏能降低AF的发生率。vitairon 900E型永久起搏器具有房室顺序起搏和4种预防AF发作的起搏程序。现对我院16例植入Vitaron 900E起搏器的患者定期随访，报道如下。     

双房同步起搏联合预防心房颤动的起搏治疗模式治疗快速房性心律失常的临床应用(附三例报告)

为观察三腔双房起搏联合预防心房颤动 (简称房颤 )的起搏治疗模式治疗快速性房性心律失常的临床效果。研究 3例房间传导阻滞合并快速性房性心律失常 ,并置入三腔双房同步起搏器的患者。起搏器具有房颤预防治疗功能。左房起搏通过冠状静脉窦置入 2 188电极导线 ,左右心房电极导线通过Y形转接器与双腔起搏器连接。DDTA起搏模式 ,随访 6个月 ,观察超驱动起搏、长间期抑制、房性早搏 (简称房早 )后加速起搏功能关闭和开启时 ,患者的临床症状、统计模式转换发生的次数、第一次至第二次房颤发作的间期、平均 2 4h房早记数。结果 :双房同步起搏后 ,患者快速房性心律失常的发作明显减少。超驱动起搏、长间期抑制、房早后加速起搏功能开启时 ,模式转换发生的次数减少、第一次至第二次房颤发作的间期延长、平均 2 4h房早记数明显减少。结论 :初步临床应用提示 :三腔双心房起搏联合预防房颤的起搏治疗模式治疗快速性房性心律失常可行且有效。     

心房起搏治疗心房颤动

近年来起搏器新功能如自动频率夺获心房起搏方式 ,频率平稳功能 ,频率适应性功能的出现 ,以及双心房同步或心房多部位起搏技术的临床应用 ,明显提高了心房起搏的抗心律失常作用 ,使心房起搏已成为治疗心房颤动 (房颤 )的重要、有效的方法。　　一、治疗和预防心房颤动的心房起搏方式　　按照心房起搏部位 ,治疗和预防房颤的心房起搏可分为两种 1单部位心房起搏 [1] :单部位心房起搏的位置可在右心耳、高位右房、右侧房间隔、界嵴、冠状静脉窦开口附近等部位。右心耳是目前最常采用的部位 ,仅需被动固定方式的心房导线电极则可。而高位右房或…     

心脏起搏治疗快速性心律失常最新进展

心脏起搏对缓慢性心律失常的治疗价值是十分肯定的。随着现代起搏技术的不断改进和发展 ,人工心脏起搏的适应证也在不断扩大 ,起搏器不仅以治疗缓慢性心律失常为主要表现的心电衰竭 ,而且开始治疗以快速性心律失常为主的心电紊乱 (如心房颤动、长QT综合征等 )和非心电性心脏病 (如梗阻性肥厚性心肌病、扩张性心肌病合并心力衰竭等 ) ,并取得了良好的疗效 ,起搏治疗快速性心律失常是目前研究的热点之一。1　心脏起搏治疗快速性心律失常的策略和目的1.1　预防心律失常的发生　针对心动过速发生的心电学诱因 ,施行起搏措施 ,预防形成心动过速…     

Prävention von Vorhofflimmern durch Schrittmacherstimulation

Several prospective randomized clinical trials have reported that atrial-based "physiological" pacing is associated with a lower incidence of paroxysmal and permanent atrial fibrillation than single-chamber ventricular pacing in patients with conventional pacemaker indication. Whether atrial pacing itself is antiarrhythmic remains still uncertain. By contrast, right ventricular pacing is considered to beget atrial fibrillation, even in preserved AV synchrony during dual-chamber pacing. A number of clinical trials investigated the impact of sitespecific atrial pacing and advanced atrial pacing algorithms on the secondary prevention of atrial fibrillation. Multisite pacing (dual-site right atrial or biatrial pacing) was demonstrated to add only minimal benefit for the prevention of atrial fibrillation. By contrast, in some studies septal pacing and specific atrial pacing algorithms were reported to reduce the recurrence of atrial fibrillation in selected patients. At present, however, it remains unclear how to identify these patients. In clinical practice, the effectiveness of specific atrial pacing algorithms and/or septal pacing has to be tested out in the individual case. These therapeutic options should be considered in patients with a conventional indication for antibradycardia pacing and, additionally, symptomatic atrial fibrillation.     

Atrial fibrillation: profit from cardiac pacing?

The impact of cardiac pacing on the prevention of atrial fibrillation is under scientific investigation. Several prospective randomised clinical trials have reported that atrial-based physiologic AAI(R)- or DDD(R)-pacing is associated with a lower incidence of paroxysmal and permanent atrial fibrillation than single-chamber ventricular pacing in patients with a conventional pacemaker indication. However, it is still uncertain whether atrial pacing itself has independent antiarrhythmic properties. In contrast, right ventricular pacing is considered to promote atrial fibrillation, even in preserved AV synchrony during dual-chamber pacing. The electrical secondary prevention of atrial fibrillation is mainly based on variations of the atrial pacing site and sophisticated preventive pacing algorithms incorporated in the pacemaker software. Dual-site right atrial and biatrial pacing were reported to exhibit modest to no benefit for the prevention of atrial fibrillation, whereas septal pacing and specific preventive pacing algorithms have been demonstrated to reduce the incidence of atrial fibrillation in a number of clinical trials. However, the role of septal pacing and preventive pacing algorithms still has to be clarified since, overall, study results have been inconsistent so far. One of the main goals of future investigations should be the identification of responder groups of preventive pacing concepts. In clinical practice, the efficacy of pacing algorithms and septal pacing has to be determined in the individual case. These options should be taken into account in patients with symptomatic bradycardia as the indication for cardiac pacing and, in addition, symptomatic atrial fibrillation.     

Atrial fibrillation: profit from cardiac pacing?

Summary The impact of cardiac pacing on the prevention of atrial fibrillation is under scientific investigation. Several prospective randomised clinical trials have reported that atrial-based physiologic AAI(R)- or DDD(R)-pacing is associated with a lower incidence of paroxysmal and permanent atrial fibrillation than single-chamber ventricular pacing in patients with a conventional pacemaker indication. However, it is still uncertain whether atrial pacing itself has independent antiarrhythmic properties. In contrast, right ventricular pacing is considered to promote atrial fibrillation, even in preserved AV synchrony during dual-chamber pacing. The electrical secondary prevention of atrial fibrillation is mainly based on variations of the atrial pacing site and sophisticated preventive pacing algorithms incorporated in the pacemaker software. Dual-site right atrial and biatrial pacing were reported to exhibit modest to no benefit for the prevention of atrial fibrillation, whereas septal pacing and specific preventive pacing algorithms have been demonstrated to reduce the incidence of atrial fibrillation in a number of clinical trials. However, the role of septal pacing and preventive pacing algorithms still has to be clarified since, overall, study results have been inconsistent so far. One of the main goals of future investigations should be the identification of responder groups of preventive pacing concepts. In clinical practice, the efficacy of pacing algorithms and septal pacing has to be determined in the individual case. These options should be taken into account in patients with symptomatic bradycardia as the indication for cardiac pacing and, in addition, symptomatic atrial fibrillation.

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How do atrial pacing algorithms prevent atrial arrhythmias?

With an ageing population, atrial fibrillation has become an increasing cause of hospital admission and morbidity. Pacemaker implantation may prevent atrial tachyarrhythmias by preventing bradycardia and pauses. Implantable devices are now available with specific atrial pacing algorithms designed to prevent atrial arrhythmias. These algorithms work by increasing the atrial pacing rate to achieve continuous overdrive pacing or by responding to triggers such as premature atrial complexes. This article examines how the algorithms work by describing the functions of one of the new generation of pacemakers in detail. Early studies have indicated that the use of preventative pacing can reduce atrial arrhythmia burden and symptomatic atrial fibrillation in selected patients. There are clearly some patients who benefit from implantation of these devices but what remains unclear is how to identify this patient group.     

Merits and Limitations of the Mode Switching Rate Stabilization Pacing Algorithms in the Implantable Cardioverter Defibrillator

Background: The 7250 Jewel AF Medtronic model of ICD is the first implantable device in which both therapies for atrial arrhythmias and pacing algorithms for atrial arrhythmia prevention are available. Feasibility of that extensive atrial arrhythmia management requires correct and synergic functioning of different algorithms to control arrhythmias. Methods and results: The ability of the new pacing algorithms to stabilize the atrial rate following termination of treated atrial arrhythmias was evaluated in the marker channel registration of 600 spontaneously occurring episodes in 15 patients with the Jewel AF. All patients (55±15 years) had structural heart disease and documented atrial and ventricular arrhythmias. Dual chamber rate stabilization pacing was present in 245 (41%) of episodes following arrhythmia termination and was a part of the mode switching operation during which pacing was provided in the dynamic DDI mode. This algorithm could function as the atrial rate stabilization pacing only when there was a slow spontaneous atrial rhythm or in presence of atrial premature beats conducted to the ventricles with a normal AV time. In case of atrial premature beats with delayed or absent conduction to the ventricles and in case of ventricular premature beats, the algorithm stabilized the ventricular rate. The rate stabilization pacing in DDI mode during sinus rhythm following atrial arrhythmia termination was often extended in time due to the device-based definition of arrhythmia termination. This was also the case in patients, in whom the DDD mode with true atrial rate stabilization algorithm was programmed. Conclusions: The rate stabilization algorithms in the Jewel AF applied after atrial arrhythmia termination provide pacing that is not based on the timing of atrial events. Only under certain circumstances the algorithm can function as atrial rate stabilization pacing. Adjustments in availability and functioning of the rate stabilization algorithms might be of benefit for the clinical performance of pacing as part of device therapy for atrial arrhythmias.     

Pacing delivered rate and rhythm control for atrial fibrillation

PURPOSE OF REVIEW: Device therapy for atrial fibrillation remains contentious despite the recognized benefit of atrial pacing in sinus node dysfunction. There are various new specialized pacing algorithms that aim to provide rhythm or rate control in atrial fibrillation. We review the various options for device therapy and the evidence available concerning their effectiveness. RECENT FINDINGS: Randomized trials on preventative algorithms for atrial fibrillation have not shown consistent benefit. Anti-tachycardia pacing for atrial fibrillation has inherent problems illustrated in this review and has failed to demonstrate objective improvement except in the case of atrial flutter. Several large randomized trials have demonstrated an adverse outcome with right ventricular apical pacing. These studies have shown an increase in atrial fibrillation with ventricular pacing. Recent studies have emphasised the importance of right ventricular apical pacing in burden of atrial fibrillation and therefore we discuss the likely confounding effect on previous trials and speculate on future directions. SUMMARY: The use of a device with atrial fibrillation prevention algorithms in a patient with a bradycardia indication for pacing is not unreasonable but there is no hard evidence of benefit. Patients with sinus node dysfunction should be paced in the atrium alone. There is no indication for use of a device for atrial fibrillation without a conventional indication for 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.     

Combined efficacy of atrial septal lead placement and atrial pacing algorithms for prevention of paroxysmal atrial tachyarrhythmia

INTRODUCTION: The combined role of atrial septal lead location and atrial pacing algorithms in the prevention of atrial tachyarrhythmias (AT/AF), including both atrial fibrillation and flutter, is unknown. We tested the hypothesis that atrial prevention pacing algorithms could decrease AT/AF frequency in patients with atrial septal leads, bradycardia, and paroxysmal AT/AF. METHODS AND RESULTS: A total of 298 patients (age 70 +/- 10 years; 61% male) from 35 centers were implanted with a DDDRP pacing system including three AT/AF prevention pacing algorithms. Lead site was randomized at implant to right atrial septal or nonseptal. Patients were randomized 1 month postimplant to AT/AF prevention ON or OFF for 3 months and then crossed over for 3 months. Patients logged symptomatic AT/AF episodes via a manual activator. Prevention efficacy was evaluated based on intention-to-treat in 277 patients (138 septal) with complete follow-up. No changes in device-recorded AT/AF frequency or burden were observed with algorithms OFF versus ON or between patients randomized to septal versus nonseptal lead location. Analysis of other secondary outcomes revealed that AT/AF prevention pacing resulted in decreased atrial premature contractions in both the septal (1.9 [0.2-8.7] vs 3.3 [0.3-10.6]x 103/day; P < 0.01) and nonseptal groups (0.9 [0.2-3.3] vs 1.3 [0.3-5.5]x 103/day; P < 0.001). Patients with septal leads had fewer symptomatic AT/AF episodes ON versus OFF (1.4 +/- 3.0 vs 2.5 +/- 5.2/month, P = 0.01). CONCLUSION: The combination of three atrial prevention pacing algorithms did not decrease device classified atrial tachyarrhythmia frequency or burden during a 3-month cross-over period in bradycardic patients and septal or nonseptal atrial pacing leads. Prevention pacing was associated with decreased frequency of premature atrial contractions and with decreased symptomatic atrial tachyarrhythmia frequency in patients with atrial septal leads.     

Prävention von Vorhofarrhythmien durch Stimulation

BACKGROUND: Atrial fibrillation is the most frequent arrhythmia. It can impair quality of life considerably. Due to thromboembolic complications it contributes to the patients' morbidity and mortality and to the costs for their medical treatment. PREVENTION: In chronic atrial fibrillation there is a need for adequate anticoagulation and heart rate control. In paroxysmal and intermittent atrial fibrillation it should be sought to prevent its progression to chronic atrial fibrillation. Since atrial fibrillation initiates negative processes of remodeling within the atrial myocardium, it has the tendency to perpetuate itself. From a theoretical point of view, it can be expected that all means which prevent episodes of atrial fibrillation or which terminate it immediately after its onset, are able to prevent or at least to delay the progression to chronic atrial fibrillation. Pharmacologic treatment is usually used to prevent recurrences of atrial fibrillation. Based on the actual data it can also be expected that pacemakers with special preventive pacing algorithms are able to reduce the atrial arrhythmic burden. Besides consequent overdrive pacing, more sophisticated algorithms like "suppression of premature atrial contractions", "post exercise response", "automatic rest rate" or "post mode-switch pacing" have been developed. They can be applied either alone or in combination with special lead positions (interatrial septal pacing or pacing of the triangle of Koch) or special stimulation configurations like dual site right atrial pacing or biatrial pacing. These pacing strategies cover the most relevant onset mechanisms of atrial fibrillation. Furthermore, there are algorithms to treat atrial tachyarrhythmias actively by antitachycardia pacing (ATP). First clinical results have shown that about 2/3 of the diagnosed atrial tachyarrhythmias could be terminated by these means immediately after their onset. ONGOING TRIALS: This article gives an overview over the principles of pacing in the management of atrial arrhythmias and ongoing clinical trials in this field. Before a definite judgement on the clinical relevance of these new preventive and therapeutic pacing strategies can be given, the results of these ongoing controlled clinical studies have to be analyzed.