病态窦房结综合征AAI起搏67例长期随访分析

目的探讨房室传导功能正常的病态窦房结综合征(SSS)AAI起搏治疗的远期疗效和安全性。方法对67例房室传导功能正常的SSS患者行AAI(AAIR)起搏治疗,术后进行临床、心电图和动态心电图的定期随访,平均随访46±4.2月。结果所有患者生活质量明显改善,33例阵发性心房颤动、心房扑动的发作频率及发作持续时间较术前显著减少,3例出现一度房室传导阻滞,但无1例出现二或三度房室传导阻滞。结论房室传导功能正常的SSS患者经AAI(AAIR)起搏治疗的临床疗效可靠和安全性高。     

北京地区召开AAI起搏临床应用研讨会

<正> 1991年3月27日由中国生物医学工程学会心脏起搏技术工程专业委员会北京分会主持在解放军总医院召开了AAI起搏临床应用研讨会。有20余家医院140余人参加。与会者对AAI起搏的生理特点、血液动力学变化、适应证、技术操作、应用价值及随诊观察等方面,进行了交流。认为AAI起搏适用于无房室传导阻滞及无持续性心房颤动(Af)、心房扑动(AF)的病态窦房结综合征(SSS)病人。心房调搏时文氏点>130次/分是房室结功能正常的估价指标。完全性左/右束支阻滞或H-V>55ms以及阵发性AF、Af并非AAI起搏的禁忌证,应结合临床综合考虑。对SSS患者日后发生房室传导阻滞(A-VB)及持续性Af的顾虑也进行了热烈     

长期AAI起搏治疗病心结综合症伴阵发性心房颤动

选择 5例病态窦房结综合征 (SSS)伴心房颤动(Af)的患者 ,发生Af的时间平均为 8.8± 7 9个月 ,房颤持续时间 1小时～ 5个月。心脏电生理检查均有严重的窦房结功能障碍 ,房室传导功能未见明显异常。 5例患者均采用锁骨下静脉穿刺法安装了AAI型心脏起搏器 ,其中 1例术前电复律成功后置入起搏装置。 5例患者均一次置入成功 ,心脏起搏器状态良好。随访 5～ 7年 (平均 5 .8± 1.7年 ) ,4例未发生Af,1例起搏器安装半年后心房颤动再发 ,奎尼丁转复后服用胺碘酮未复发 ,1例房早较多需要长期应用钙拮抗剂。因此 ,对某些SSS患者 ,如果Af发生系由窦性心动过缓触发 ,房室传导功能正常 ,我们初步认为可作为安装AAI型人工心脏起搏器的适应证 ,它既可以缓解SSS引起的症状 ,又可以防止Af的发生。     

AAI起搏的临床与血流动力学观察

本文报告10例病窦综合征(SSS)病人心房按需起搏(AAI)的临床和血流动力学观察资料。病人置入AAI起搏器后,在3～14(平均8)月的随访期中,晕厥等症状消失,心功能良好,无电极脱位和起搏综合征发生。对6例AAI起搏病人,进行了右房、右室和房室结区相同起搏频率的血流动力学观察,结果表明AAI比VVI心排血量(CO)增加18％,结区起搏AAI比VVI CO增加13％。提示AAI不仅保持了房室同步功能,且对维持心室肌的正常收缩顺序也有重要价值。作者认为对有适应症的病人,AAI是一种适用而有效的生理性起搏。     

心房感知起搏器的临床应用现状

目前AAI起搏器在临床上的使用率偏低,为2.33%~4%。AAI起搏对病窦综合征(SSS)的影响优于VVI、DDD起搏,并且术后高度房室阻滞、心房颤动的发生率低。AAI起搏是房室传导功能正常的SSS患者的有益、经济、简便的选择。     

心房起搏的效果和安全性

本文通过对43例单纯心房起搏病例的研究,探讨单纯心房起搏(AAI)的长期效果和安全性。方法和结果选择43例病窦综合征(SSS)患者,其中9例是在心脏直视手术前或术中发现有窦房结功能障碍。所有病人均符合下列心房起搏的指征:①以前无明确的房室传导阻滞(AVB),ECG 示 PR 间期正常;②QRS 间期正常,无室内传导阻滞;③心房快速起搏时(130次/min)房室传导功能正常。随访1～71(平均27±18)个月。起搏器植入时和植入后随访     

心房感知起搏器的临床应用探讨

目的：探讨心房感知起搏器(AAI)的临床应用状况和对病态窦房结综合征(SSS)患者预后的影响。方法：回顾性调查1998-2002年在长征医院进行起搏治疗的175例SSS患者的病例资料。将其中132例患者分成AAI、双腔感知起搏器(DDD)、心室感知起搏器(VVI)三组，定期门诊随访，观察房颤、中风、心力衰竭、起搏器综合征、手术并发症、起搏电极脱位、生活质量改善以及Ⅱ度以上房室传导阻滞(AVB)发生率等临床情况。结果：175例SSS患者中共有AAI适应证42％(73例)，但仅有13％(22例)置入AAI起搏器。AAI组的房颤、中风、心力衰竭发生率显著低于VVI组。AAI组中未发现新发生的AVB。结论：AAI起搏较其他起搏方式更有利于SSS的预后。应该注意纠正临床上AAI起搏器应用率偏低的不合理情况。     

心房感知起搏器的临床应用探讨

目的探讨心房感知起搏器(AAI)的临床应用状况和对病态窦房结综合征(SSS)患者预后的影响. 方法回顾性调查1998-2002年在长征医院进行起搏治疗的175例SSS患者的病例资料.将其中132例患者分成AAI、双腔感知起搏器(DDD)、心室感知起搏器(VVI)三组,定期门诊随访,观察房颤、中风、心力衰竭、起搏器综合征、手术并发症、起搏电极脱位、生活质量改善以及Ⅱ度以上房室传导阻滞(AVB)发生率等临床情况. 结果175例SSS患者中共有AAI适应证42%(73例),但仅有13%(22例)置入AAI起搏器.AAI组的房颤、中风、心力衰竭发生率显著低于VVI组.AAI组中未发现新发生的AVB. 结论AAI起搏较其他起搏方式更有利于SSS的预后.应该注意纠正临床上AAI起搏器应用率偏低的不合理情况.     

心房按需起搏治疗正常房室传导的病态窦房结综合征117例分析

目的:观察心房按需起搏治疗正常房室传导的病态窦房结综合征(SSS)疗效. 方法:回顾性分析117例正常房室传导的SSS患者安装心房按需型起搏器后心功能改变,临床症状变化,房宣传导阻滞和房颤发生率,评估心房按需起搏治疗SSS疗效. 结果:平均随访(8.6±5.2)年,117例SSS患者手术前后心功能无显著变化,左室射血分数(LVEF)术前为(53.4±6.1)%,术后为(56.1±7.2)%(P>0.05).术后随访期间有3例发生房室传导阻滞(2.6%),5例发生房颤(4.3%).所有患者心源性脑缺氧症状均消失. 结论:对正常房室传导SSS患者安装心房按需起搏器是一个明智的选择,手术方法简单,疗效确切且并发症少.     

长期心房与心室起搏对心房颤动发生率的影响

目的 为比较长期心房与心室起博心房颤动(Af)发生率的影响.方法 选择国内较大的三家医院1992年至1994年期间内安装人工心脏起搏器的病人,随访观察心房起搏(安装了AAI、AAIR、DDD及DDDR起博器)和心室起搏(植入了VVI或VVIR起搏器)Af的发生情况.结果 发现心室搏Af发生有逐年增加的趋势,Af4年发生率为33%,5年为41%,6年为52%.单纯心房起搏或房室顺序起搏Af发生率3%,而单纯心室起搏的病人中约40%出现Af,明显高于心房起搏组,P<0.01.结论 研究证明心房起搏可以减少Af的发生,为起搏方式的选择提供了一个客观根据,提示在临床实践中应该尽量选择AAI和DDD等生理性起搏方式.     

Long-term clinical performance of AAI pacing in patients with sick sinus syndrome: a comparison with dual-chamber pacing.

AIMS: In this clinical study, we compared two groups of age-matched patients, AAI and DDD, to evaluate the clinical benefits of AAI pacing in patients with sick sinus syndrome (SSS) and normal atrioventricular (AV) conduction. METHODS AND RESULTS: Ninety-five patients with SSS implanted with AAI pacemakers were compared with 101 SSS patients implanted with DDD pacemakers. Mortality, chronic atrial fibrillation, lead survival rates, and reoperation rates were compared by Kaplan-Meier analysis. Eight AAI devices were switched to DDD due to high-degree (grade 2-3) AV block. The incidence of high-degree AV block was 1.104%/year, with a freedom rate of 88.6% at 10 years. There were no significant differences between the two groups in survival rates (87.8% in AAI vs. 93.4% in DDD at 10 years), freedom from atrial fibrillation (93.6% vs. 90.6%), or freedom from reoperation (71.3% vs. 76.3%). On the other hand, lead failure was twice as frequent in the DDD group than in the AAI group (relative risk=2.045, P=0.0382). CONCLUSION: AAI pacing, a simple system using a single lead and single-chamber pacemaker, can achieve a clinical outcome similar to that of the DDD mode in patients with SSS and normal AV conduction.     

Alteration of left ventricular performance by left bundle branch block simulated with atrioventricular sequential pacing

The effects of atrioventricular (AV) sequential pacing-induced left bundle branch block (LBBB) on left ventricular (LV) performance were evaluated during cardiac catheterization in 9 randomly selected patients being investigated for chest pain. All patients were in normal sinus rhythm with a normal P-R interval and QRS duration. LV performance was assessed by both hemodynamic and angiographie measurements. The maximal rate of LV pressure increase (dP/dt), rate of maximal LV pressure decrease ($\text{?dP}\text{dt}$), LV end-diastolic pressure (LVEDP), end-diastolic volume (LVEDV), end-systolic volume (LVESV), stroke volume and percent ejection (EF) were measured during right atrial and AV sequential pacing at a constant pacing rate. The average pacing rate was 97 ± 3 beats/min (mean ± standard error of the mean). In each patient, both dP/dt and $\text{?}\text{dP}\text{dt}$ decreased significantly (p < 0.001) during AV sequential pacing compared with atrial pacing at the same rate, from 1,541 ± 68 to 1,319 ± 56 mm Hg/s for dP/dt and from 1,506 ± 86 to 1,276 ± 92 for $\text{?dP}\text{dt}$. LVEDP did not change significantly when atrial (17 ± 3 mm Hg) and AV sequential pacing (16 ± 2 mm Hg) were compared. Mean LVEDV did not change during atrial (135 ± 13 ml) or AV sequential pacing (137 ± 14 ml). In contrast, the LVESV during AV sequential pacing was higher by 15 ml (23 % ) (from 48 ± 10 to 63 ± 12 ml) (p < 0.001); as a result, the stroke volume was lower by 13 ml (15%) and the EF decreased by 10 %, from 66 to 56 % (?15 %).These changes in LV performance during acutely induced LBBB by AV sequential pacing as compared with atrial pacing at the same rate were independent of altered preload, because both LVEDP and LVEDV were similar during the 2 different pacing modes. Peak systolic pressure during AV sequential pacing was significantly lower than that during atrial pacing (161 ± 10 vs 145 ± 10 mm Hg, p < 0.01), and thus afterload was presumably altered during the different pacing modes. However, because the observed change in systolic pressure (afterload) was lower during AV sequential pacing, this change should improve rather than result in deterioration of ejection phase indexes. Because the opposite was observed, it is concluded the deterioration in LV function noted during AV sequential pacing must be due in part to the asynchronous pattern of ventricular activation induced by this intervention.     

房室传导正常的病窦综合征患者心房或心室起搏的长期随访

评价长期心房或心室起搏对病窦综合征 (SSS)患者心功能及房性心律失常的影响 ,对 1 1 8例SSS伴房室传导正常的患者 (AAI组 56例、VVI组 62例 )进行随访。随访 40 .8± 2 .3个月 ,VVI组 62例中 1 9例NYHA分级增加 ,而AAI组 56例中 4例NYHA分级增加 (P <0 .0 5)。左室射血分数VVI组明显下降 (从 0 .491± 0 .0 4 1至 0 .451± 0 .0 4 3 ,P <0 .0 5) ,而AAI组则增加 (从 0 .482± 0 .0 75增至 0 .535± 0 .0 59,P <0 .0 5)。左房内径VVI组明显增加 (从 33± 6增至 40± 6mm ,P <0 .0 5) ,AAI组从 34± 7增至 36± 6(P >0 .0 5)。房性心律失常发生率VVI组明显增加 (从 35 .5 %增至 45 .2 % ,P <0 .0 5) ,AAI组减少 (从 2 6 .8%降至 0 % ,P <0 .0 1 )。结论 :心房起搏对SSS患者是一安全、可靠的起搏方式 ,可减少房性心律失常的发作 ,有助于患者心功能的改善     

Placement of atrial pacing leads during atrial fibrillation. Feasibility and subsequent lead performance.

AIMS: To assess the feasibility of placing permanent atrial pacing leads during atrial fibrillation (AF) and whether such leads function satisfactorily. METHODS AND RESULTS: Prospective study of 17 consecutive patients in whom permanent atrial leads were positioned during an episode of paroxysmal AF. Fluoroscopic position ('figure of 8' or side-to-side movement and anterior position in RAO projection), lead impedance (> 300 but < 1000 ohms) and intracardiac electrogram (average peak to peak amplitude > 1 mV) were used to define an acceptable lead position. At 8 weeks post implant we measured: pulse duration pacing threshold at 5 V; lead impedance at 5 V and 0.5 ms; intracardiac electrogram (EGM) signal amplitude. At the end of the study we reviewed patients to establish whether AF had become permanent. In all patients, follow-up demonstrated satisfactory lead function. All leads had impedances between 300 and 1000 ohms. Pacing thresholds were all < 0.1 ms at 5 V. Mean atrial EGM amplitude seen in sinus rhythm was 3.3 mV (range 1.2-8.4); in patients where all follow-up was in AF in was 2.1 mV (range 1.5-2.5). Nine patients (53%) developed permanent AF. CONCLUSION: Placing atrial leads during AF is feasible using the technique described. However, some patients progress to chronic AF, eliminating the benefits of atrial pacing.     

PR/RR Interval Ratio During Rapid Atrial Pacing:

Method for Confirming Slow Pathway Conduction. Introduction: Although the AV conduction curve in patients with AV nodal reentrant tachycardia (AVNRT) is usually discontinuous, many patients with this arrhythmia do not demonstrate criteria for dual AV nodal pathways. During rapid atrial pacing, the PR interval often exceeds the pacing cycle length when there is anterograde conduction over the slow pathway and AVNRT is induced. The purpose of this prospective study was to determine the diagnostic value of the ratio of the PR interval to the RR interval during rapid atrial pacing as an indicator of anterograde slow pathway conduction in patients undergoing electrophysioiogic testing. Methods and Results: The PR and RR intervals were measured during rapid atrial pacing at the maximum rate with consistent 1:1 AV conduction in four study groups: (1) patients with inducible AV nodal reentry and the classical criterion for dual AV nodal pathways during atrial extrastimulus testing (AVNRT Group 1); (2) patients with inducible AV nodal reentry without dual AV nodal pathways (AVNRT Group 2); (3) control subjects ≤ 60 years of age without inducible AV nodal reentry; and (4) control subjects > 60 years of age without inducible AV nodal reentry. For both groups of patients with inducible AV nodal reentry, AV conduction was assessed before and after radiofrequency ablation of the slow AV nodal pathway. Before slow pathway ablation, the PR/RR ratio exceeded 1.0 in 12 of 13 AVNRT Group 1 patients (mean 1.27 ± 0.21) and 16 of 17 AVNRT Group 2 patients (mean 1.18 ± 0.15, P = NS Group 1 vs Group 2). After slow pathway ablation, the maximum PR/RR ratio was < 1.0 in all AVNRT patients (Group 1 = 0.59 ± 0.08, P < 0. 00001 vs before ablation: Group 2 = 0.67 ± 0.11; P < 0.00001 vs before ablation). Among both groups of control subjects, the PR/RR ratio was > 1.0 in only 3 of 27 patients with no relation to patient age. Conclusion: The ratio of the PR interval to the RR interval during rapid atrial pacing at the maximum rate with consistent 1:1 AV conduction provides a simple and clinically useful method for determining the presence of slow AV nodal pathway conduction. This finding may be particularly useful in patients with inducible AV nodal reentry without dual AV nodal physiology on atrial extrastimulus testing.     

Clinical surveillance of a thin bipolar pacing lead

A total number of 415 co-radial, bipolar pacing leads (189 atrial leads; 226 ventricular leads) were implanted in 228 patients between November 1994 and July 1999. Mean pacing thresholds at the implantation were normal at 0.6 V in the atrium and at 0.4 V in the ventricle with a pulse duration of 0.4-0.5 ms. Lead impedance was relatively low (337-447 ohms for atrial leads; 369-459 ohms for ventricular leads) at the implantation and during the follow-up periods. No definite failure in lead materials was observed in either atrial or ventricular leads (mean follow-up of 19.7 and 19.2 months, respectively: up to 52.9 months for both leads). Predicted clinical surveillance up to 10 years calculated statistically showed that the upper 95% confidence limit was a constant of 100%. The lower 95% confidence limits at 5, 7, and 10 years were estimated to be 98.0%, 97.2%, and 96.0%, respectively. From the present study, the ThinLine lead is reliable for both sensing and pacing thresholds, and has excellent predicted lead longevity. Nevertheless, further observation is required regarding cost performance, such as early replacement of the pacemaker generator, because of the lower pacing lead impedance.     

The role of pacing mode in the development of atrial fibrillation.

Asynchronous ventricular pacing has been shown to increase the risk of development of atrial fibrillation (AF) because of various mechanisms: retrograde atrioventricular (AV) conduction with increase in atrial pressure causing acute atrial stretch and reverse flow in the pulmonary veins, mitral regurgitation, reduced coronary blood flow, adverse neuroendocrine reactions, etc. Dual-chamber pacing preserves atrioventricular synchrony. However, in randomized multicentre trials comparing VVI(R) with DDD(R) pacing, AF is only slightly less frequent in the dual-chamber mode. This is most likely due to unnecessary ventricular pacing, which is frequent in dual-chamber pacing. At nominal values, dual-chamber devices usually do not permit intrinsic AV conduction but promote delivery of the ventricular stimulus at an inappropriate time in an inappropriate place. Programming of long AV delays facilitates spontaneous AV conduction but usually cannot completely avoid unnecessary ventricular pacing and causes other problems in the dual-chamber mode. Atrial septal lead placement can improve left-sided AV synchrony and promote spontaneous AV conduction. Programming of the AAI(R) mode is superior to the dual-chamber mode but cannot be used if AV conduction is impaired intermittently or permanently. Therefore, dedicated algorithms enhancing spontaneous AV conduction in the dual-chamber mode are desirable for a large proportion of pacemaker patients.     

AAI pacing mode: When is it indicated and how should it be achieved?

AAI pacing offers better hemodynamic characterstics than dual-chamber pacing and is the optimal mode for patents with sick sinus syndrome without AV conduction disorders. AAI pacing may be achieved by single-chamber atrial, by programming a dual-chamber pacemaker to the AAI mode, or by programming a dual-chamber pacemaker to DDD mode with a long AV delay. The annual incidence of AV block development in patients with sick sinus syndrome is low, probably 1-5%, but there is no method of detecting patients immune to future development of AV block. Chronotropic is often present in patients with sick sinus but the value of additional rate response is not yet established. Our recommendations for the choice of the method of pacing are discussed.     

Long-term reliability of AAI mode pacing in patients with sinus node dysfunction and low Wenckebach block rate.

AIMS: To compare the risk of atrioventricular (AV) conduction disturbance between patients with sinus node dysfunction on AAI pacing who had a low or high Wenckebach block rate (WBR). METHODS AND RESULTS: Patients with sinus node dysfunction and normal AV conduction those underwent an electrophysiological study were studied. The patients were classified into two groups: Group L was with the patients with a WBR of 100 to 129 per minute and Group H was with the patients with a WBR > or = 130 per minute. All patients followed up every 3-6 months after an AAI pacemaker implantation. A total of 102 patients, including 35 Group L and 67 Group H, were followed for 90 +/- 44 months. Six patients died from non-cardiac cause and five patients required a new atrial lead implantation due to lead failure during follow-up. Symptomatic bradycardia requiring a new ventricular lead implantation developed in four patients (annual incidence 0.5%). In Group L, two patients developed AV block (annual incidence 0.7%). In Group H, two patients developed bradycardic atrial fibrillation (annual incidence 0.4%). Kaplan-Meier analysis revealed no significant difference between the two groups (P = 0.2983). CONCLUSION: These results suggest that a long-term risk of developing AV conduction disturbance is low even in patients with a WBR of 100 to 129 per minute.     

Atrial pacing and sensing characteristics in heart failure patients undergoing cardiac resynchronization therapy.

Patients with heart failure and sinus rhythm undergoing cardiac resynchronization therapy (CRT) require the proper detection of atrial signals and reliable atrial pacing for AV-synchronous ventricular pacing. The study aim was to compare atrial pacing and sensing characteristics in patients with transvenous CRT and patients with standard pacing indications. METHODS: The study group consisted of 31 heart failure patients with depressed left ventricular function and bundle branch block, and the control group of 124 patients with dual-chamber pacemakers because of standard pacing indications. The bipolar steroid-eluting atrial screw-in lead Tendril DX 1388 T (St. Jude Medical) was implanted and connected to pulse generators that provide similar diagnostic features. The unipolar pacing threshold at 0.4 ms duration, bipolar sensing threshold, and unipolar pacing impedance were determined at implantation and after 1, 3, and 6 months. RESULTS: At implantation, the atrial pacing threshold was significantly higher in the CRT group than in the control group, 1.07+/-0.99 V versus 0.74+/-0.36 V (P<0.01). Similar pacing thresholds were recorded after 1 month. The pacing threshold in the CRT group was significantly higher at 1.46+/-0.92 V after 3 and 1.50+/-0.94 V after 6 months (control group: 0.96+/-0.25 V at month 3; 0.98+/-0.32 V at month 6; P<0.05). Sensing threshold was similar at implantation with 2.36+/-1.87 mV in the CRT and 2.54+/-0.78 mV in the control group. The sensing threshold in the CRT group decreased to 1.64+/-0.8 6mV after 3 and to 1.71+/-0.71 mV after 6 months and was significantly lower compared with the control group (2.16+/-0.57 mV at month 3; 2.27+/-0.9 8mV at month 6; P<0.05). At implant, the atrial pacing impedance was not different between the two groups with 443+/-156 ohms in the CRT and 416+/-116 ohms in the control group. During follow-up, the impedance became significantly lower in the CRT group compared with the control group (404+/-84 ohms versus 452+/-101 ohms at month 3; P<0.05). CONCLUSIONS: Compared with patients with standard pacing indications, CRT recipients have less good electrical characteristics in the atrium. Atrial pacing and sensing function should be closely monitored in CRT patients.