儿童矫正性大动脉转位伴Ⅲ度房室阻滞的VDD生理性？…

一例１１岁矫正性大动脉转位（ＳＬＬ）的女性患儿有晕厥史１０年，超声心动图证实心内无分流，动态心电图及是生理检查均证实为Ⅲ度房室阻滞，窦房结功能正常，安置ＶＤＤ生理性起搏器，感知与起搏电极间距为１３ｃｍ，Ｐ波振幅２．２ｍＶ，心房感知０．７５ｍＶ心室起搏阈值０．４Ｖ，术后观察心房感知率９８％，给心内无分流的心脏畸形患者安置起搏器要充分考虑生理和生长发育的需要，如合理选择起搏器类型和电极长度，进行电生理     

起搏器电池耗竭的心电图表现及临床意义

目的探讨起搏器电池耗竭的心电图表现及其临床意义。方法对23例临床证实起搏器电池耗竭患者的临床资料及心电图进行回顾性分析。结果起搏频率减慢或起搏频率不均6例;起搏频率奔放1例;感知功能异常6例;起搏功能异常3例;感知及起搏功能均异常4例;起搏方式改变3例。结论起搏器电池耗竭可以有多种心电图表现,但必须结合临床,要除外起搏器系统的机械故障及起搏器参数设置不当引起类似的心电图改变,对于证实起搏器电池耗竭的患者要及时更换起搏器。     

VDD起搏治疗幼儿完全性房室阻滞(附一例报告)

一例３．５岁的女性幼儿因室间隔缺损修补术致迟发性完全性房室阻滞（ＣＡＶＢ）而安置ＶＤＤ起搏器。经锁骨下静脉途径埋置单根心房感知、心室触发起搏电极，使之于右房内塑形并贴靠房壁；起搏器埋于同侧皮下胸大肌筋膜上囊袋内。术中测得起搏阈值０．１Ｖ、脉宽０．４ｍｓ、电极阻抗５２０Ω、Ａ波振幅１．５ｍＶ、Ｖ波振幅１０．６ｍＶ，Ａ波感知设定０．２５ｍＶ。术后房室同步起搏率１００％，临床症状改善。表明ＶＤＤ起搏器不仅埋置简便，而且具有房室同步、频率应答等生理性起搏特点，是治疗幼儿ＣＡＶＢ的理想起搏方式。     

心房感知不良导致心室安全起搏1例

患者男性 ,６２岁 ,因病态窦房结综合征置入Ｂｉｏｔｒｏｎｉｋ公司产ＡｃｔｒｏｓＤＤＤＤ型起搏器 ,起搏参数为 :ＤＤＤ模式 ,基础频率６０次／ｍｉｎ ,滞后频率ＯＦＦ ,睡眠频率５５次／ｍｉｎ,上限频率１３０次／ｍｉｎ ,动态房室间期１８０／１００ｍｓ,安全房室间期 (ＳＡＶＤ)１００ｍｓ,心房、心室不应期为４２５／３００ｍｓ,心房、心室起搏电压均为３．６Ｖ ,起搏脉宽均为０．４ｍｓ,感知灵敏度为１．５／２．５ｍＶ ,心室空白期为２４ｍｓ。术后心电图示起搏器心房电极感知不良 ,心室频繁安全起搏。心电图 (图１)Ａ、Ｂ行心房感…     

儿童矫正性大动脉转位伴Ⅲ度房室阻滞的VDD生理性起搏(附一例报告)

一例１１岁矫正性大动脉转位（ＳＬＬ）的女性患儿有晕厥史１０年，超声心动图证实心内无分流，动态心电图及电生理检查均证实为Ⅲ度房室阻滞，窦房结功能正常。安置ＶＤＤ生理性起搏器，感知与起搏电极间距为１３ｃｍ，Ｐ波振幅２．２ｍＶ、心房感知０．７５ｍＶ、心室起搏阈值０．４Ｖ。术后观察心房感知率９８％。给心内无分流的心脏畸形患儿安置起搏器要充分考虑生理和生长发育的需要，如合理选择起搏器类型和电极长度，进行电生理检查测定心尖至高位右房的距离，同时熟悉复杂心脏畸形影像学的知识对保证安置术的成功十分必要。     

动态心电图在起搏器随访中的作用

为了解安植起搏器术后的工作状态 ,运动 2 4ｈ动态心电图 (ＤＣＧ)对 2 8例起搏器患者进行监测分析共 2 5例次 ,观察起搏器的起搏 ,感知功能及自身心律变化 ,以便有效的调整起搏器的参数 ,取得最有效的起搏效果。1　资料与方法本组 2 8例中男性 18例 ,女性 10例 ,年龄 48～ 83 ( 66 71± 8 14)岁。冠心病 5例 ,病态窦房结综合征 14例 ,三度房室传导阻滞 1例 ,双束支阻滞 3例 ,5例心房颤动 (Ａｆ)伴长间歇 ,随访时间距起搏器安装时间 2Ｗ～ 2年 ,随访次数 1～ 2次 ,起搏器类型ＡＡＩ起搏 8例 ,ＶＶＩ起搏10例 ,ＤＤＤ起搏 10例。采用美国新世…     

动态心电图诊断起搏功能异常的意义

为了解各种起搏器埋置后的工作状况，运用动态心电图（ＤＣＧ）对１９２例起搏患者进行监测分析。１９２例患者六种起搏方式的２４ｈ心搏均数在８９１１７～９６２３９次之间。ＶＶＩ起搏患者中心房颤动的检出率为２６．１％（２９／１１１）、室房传导检出率为１２．６％（１４／１１１）、过感知检出率为３．６％（４／１１１）、起搏故障率为３．６％（４／１１１）。ＡＡＩ起搏中过感知检出率为２３．３％（１０／４３）、起搏故障率为６．９％（３／４３）。低感知检出率：ＶＶＩ起搏为５．４％（６／１１１）、ＡＡＩ起搏为１１．６％（５／４３），两者比较差异无显著性，Ｐ＞０．０５。ＤＤＤ及ＶＤＤ起搏所致介导性心动过速的检出率为２４．３％（９／３７）。起搏器埋置后，起搏及感知功能异常多为间歇性发生，ＤＣＧ监测时间较长，发现起搏功能异常的机率较多，特别是带有脉冲标记的对于分析起搏功能异常帮助更大。有条件者ＤＣＧ可考虑列为起搏器埋置后的常规检查。     

易误认为DDD型起搏器感知不良的表现

例1．患者男、74岁，起搏器随访检查：DDD型（BRIO TM D220），起搏下限频率60bpm，心室不应期330ms，AV延迟200ms，其它参数均在正常数值范围内。图1上中下为动态心电图MV1导联连续描记。其中图1中R3，R12为舒张晚期室性早搏呈右柬支阻滞形．并在早搏后0．20s出现“钉样”起搏脉冲信号。舒张晚期室性早搏的联律间期略短于起搏器的VA间期．即快于起搏器下限频率，起搏器应感知此心室激动，抑制起搏器发放起搏脉冲，重整起搏周期。显然该现象应考虑DDD型起搏器感知不良。     

VVI起搏致类右束支阻滞图形一例

一例 65岁女性 ,因高度房室阻滞而行VVI起搏治疗。术后胸片、超声心动图等检查示起搏电极头端位于右室近心尖部流入道。体表心电图示类右束支阻滞图形。术后检测起搏器感知、起搏功能正常。提示 ,正常右室心尖部或近心尖部起搏 ,可以出现类右束支阻滞图形心电图改变。     

VVI起搏病人心电图的识别

心室按需抑制型起搏器(VVI)是目前应用最为广泛的心脏起搏器。正确识别已安装VVI起搏器的心电图对判断心律失常、起搏器功能和处理有重要意义。 1 VVI起搏器的心电图特点 VVI型起搏器是一种按需式的心室起搏器,即当无自身心律或自律过于缓慢时,起搏器便以固定频率发出刺激起搏心室,因此VVI起搏器产生的心律是一种逸搏心律。当自身心律快于设定的起搏频率时,VVI起搏器即能感知并抑制其发放脉冲。要正确识别安装VVI起搏器病人的心电图,首先要熟悉VVI起搏心电图的特点。 1.1 起搏心电图:VVI起搏器足右室心尖部起搏,故其心电图应是左束支阻滞型ORS-T波型,伴额面电轴显著左偏,     

Dual chamber pacing: how many patients remain in DDD mode over the long term?

OBJECTIVE--DDD pacing is better than VVI pacing in complete heart block and sick sinus syndrome but is more expensive and demanding. In addition, some patients have to be programmed out of DDD mode and this may have an important impact on the cost-effectiveness of DDD pacing. The purpose of this study was to determine how many patients remain in DDD mode over the long term (up to 10 years). DESIGN--A retrospective analysis of the outcome over 10 years of consecutive patients who had their pacemakers programmed initially in DDD mode. SETTING--A district general hospital. PATIENTS--249 patients with DDD pacemakers. Sixty two patients (24.9%) had predominantly sick sinus syndrome and 180 (72.3%) had predominantly atrioventricular conduction disease. Mean (range) complete follow up for this group of patients was 32 months (1-10 years). RESULTS--Cumulative survival of DDD mode was 83.5% at 60 months. Atrial fibrillation was the commonest reason for abandonment of DDD pacing. Atrial fibrillation developed in 30 patients (12%), with atrial flutter in three (1.2%). Loss of atrial sensing or pacing, pacemaker mediated tachycardia, and various other reasons accounted for reprogramming out of DDD mode in eight patients (3.2%). Overall, an atrial pacing mode was maintained in 91% and VVI pacing was needed in only 9%. CONCLUSIONS--With careful use of programming facilities and appropriate secondary intervention, most patients with dual chamber pacemakers can be maintained successfully in DDD or an alternative atrial pacing mode until elective replacement, although atrial arrhythmia remains a significant problem. There are no good reasons, other than cost, for not using dual chamber pacing routinely as suggested by recent guidelines and this policy can be achieved successfully in a district general hospital pacing centre.     

Acute Evaluation of a Preformed Single-pass VDD/DDD Pacing Lead

The clinical utility of single lead, atrial synchronous, ventricular pacing (VDD), for patients with normal sinus function and heart block is well established. Atrial stimulation, unavailable in VDD systems presents a significant disadvantage. DDD pacing systems however, require the introduction and positioning of two separate leads. The acute human study discussed evaluated a modified version of a commercially available VDD lead with a preshaped lobe, capable of both sensing and pacing the right atrium. P waves and atrial stimulation thresholds were determined in five patients. The mean P-wave was 2.5 ± 1 millivolts. Atrial stimulation in the unipolar configuration was 1.6 ± 0.5 volts and 1.7 ± 0.9 volts in the bipolar configuration. These acute stimulation thresholds and sensing amplitudes were comparable to conventional DDD pacing systems. Therefore, single-lead DDD pacing may be feasible and warrants further study.     

Double blind crossover comparison of the effects of dual chamber pacing (DDD) and ventricular rate adaptive (VVIR) pacing on neuroendocrine variables, exercise performance, and symptoms in complete heart block.

OBJECTIVE--To compare the effects of dual chamber pacing (DDD) and ventricular rate adaptive pacing (activity sensing) (VVIR) in patients with complete heart block. DESIGN--Double blind crossover comparison with one month in each pacing mode. PATIENTS--10 consecutive patients aged 23-74 presenting with complete anterograde atrioventricular block at rest and on exercise and with an intact atrial rate response received Synergyst I (Medtronic) pacemakers. MAIN OUTCOME MEASURES--Symptom scores, maximal exercise performance on a treadmill, and the plasma concentrations of atrial natriuretic peptide, adrenaline, and noradrenaline. RESULTS--No significant differences were identified between pacing modes in symptom scores for dyspnoea, fatigue, and mood disturbance; exercise time; and maximal oxygen consumption. One patient with intact ventriculoatrial conduction developed pacemaker syndrome during VVIR pacing. Resting plasma concentrations of atrial natriuretic peptide were raised in complete heart block and were restored to normal by DDD pacing but not by VVIR pacing. Resting plasma catecholamine concentrations were normal in complete heart block and in both pacing modes. During exercise the increase in the concentrations of all three hormones was similar in both pacing modes. CONCLUSIONS--In patients with complete anterograde and retrograde atrioventricular block, symptoms and maximal exercise performance were no better during DDD than during VVIR pacing.     

Double blind crossover comparison of the effects of dual chamber pacing (DDD) and ventricular rate adaptive (VVIR) pacing on neuroendocrine variables, exercise performance, and symptoms in complete heart block.

OBJECTIVE--To compare the effects of dual chamber pacing (DDD) and ventricular rate adaptive pacing (activity sensing) (VVIR) in patients with complete heart block. DESIGN--Double blind crossover comparison with one month in each pacing mode. PATIENTS--10 consecutive patients aged 23-74 presenting with complete anterograde atrioventricular block at rest and on exercise and with an intact atrial rate response received Synergyst I (Medtronic) pacemakers. MAIN OUTCOME MEASURES--Symptom scores, maximal exercise performance on a treadmill, and the plasma concentrations of atrial natriuretic peptide, adrenaline, and noradrenaline. RESULTS--No significant differences were identified between pacing modes in symptom scores for dyspnoea, fatigue, and mood disturbance; exercise time; and maximal oxygen consumption. One patient with intact ventriculoatrial conduction developed pacemaker syndrome during VVIR pacing. Resting plasma concentrations of atrial natriuretic peptide were raised in complete heart block and were restored to normal by DDD pacing but not by VVIR pacing. Resting plasma catecholamine concentrations were normal in complete heart block and in both pacing modes. During exercise the increase in the concentrations of all three hormones was similar in both pacing modes. CONCLUSIONS--In patients with complete anterograde and retrograde atrioventricular block, symptoms and maximal exercise performance were no better during DDD than during VVIR pacing.     

Cardiac pacing for severe childhood neurally mediated syncope with reflex anoxic seizures

OBJECTIVE—To determine whether permanent cardiac pacing could prevent syncope and seizures in children with frequent severe neurally mediated syncope, and if so whether dual chamber pacing was superior to single chamber ventricular pacing.
METHODS—Dual chamber pacemakers were implanted into 12 children (eight male, four female) aged 2-14 years (median 2.8 years) with frequent episodes of reflex anoxic seizures and a recorded prolonged asystole during an attack. The pacemaker was programmed to sensing only (ODO), single chamber ventricular pacing with hysteresis (VVI), and dual chamber pacing with rate drop response (DDD) for four month periods, with each patient allocated to one of the six possible sequences of these modes, according to chronological order of pacemaker implantation. The parent and patient were blinded to the pacemaker mode and asked to record all episodes of syncope or presyncope ("near miss" events). The doctor analysing the results was blinded to the patient and pacemaker mode.
RESULTS—One patient was withdrawn from the study after the pacemaker was removed because of infection. In the remaining children, both dual chamber and single chamber pacing significantly reduced the number of syncopal episodes compared with sensing only (p = 0.0078 for both). VVI was as effective as DDD for preventing syncope, but DDD was superior to VVI in reducing near miss events (p = 0.016).
CONCLUSIONS—Permanent pacing is an effective treatment for children with severe neurally mediated syncope and reflex anoxic seizures. VVI is as effective as DDD in preventing syncope and seizures, but DDD is superior in preventing overall symptoms.


Keywords: syncope; reflex anoxic seizures; pacing; paediatric cardiology     

Pacing and sensing disturbances in patients with DDD pacemakers in the early period after implantation

OBJECTIVES: We sought to determine the usefulness of ambulatory 24-hour Holter monitoring in detecting asymptomatic pacemaker (PM) malfunction episodes in patients with dual-chamber pacemakers whose pacing and sensing parameters were proper, as seen in routine post-implantation follow-ups.This aspect has not been widely discussed so far. METHODS AND RESULTS: Ambulatory 24-hour Holter recordings [HM] were performed in 100 patients with DDD pacemakers one day after the implantation. Only asymptomatic patients with proper pacing and sensing parameters (assessed on PM telemetry on the first day post-implantation) were enrolled in the study. The following parameters were assessed: failure to pace, failure to sense (both oversensing and undersensing episodes) as well as the percentage of all PM disturbances. Despite proper sensing and pacing parameters, HM revealed PM disturbances in 23% of the patients.Atrial undersensing episodes were found in 12 patients and failure to capture in I patient. T wave oversensing was the most common ventricular channel disorder (9 patients). Malfunction episodes occurred sporadically, leading to pauses of up to 1.6 s or temporary bradycardia, which were, nevertheless, not accompanied by clinical symptoms. No ventricular pacing disturbances were found. CONCLUSION: Asymptomatic pacemaker dysfunction may be observed in nearly 25% of patients with proper DDD parameters after implantation.Thus, ambulatory HM during the early post-implantation period may be a useful tool to detect the need to reprogramme PM parameters.     

中老年起博器植入患者的动态心电图分析

目的探讨动态心电图（DCG）监测对起搏器起搏及感知功能异常的诊断价值。方法采用美国惠普43400B型DCG分析系统,对95例年龄在50岁以上植入起搏器的患者进行随访,分析起搏、感知功能及与起搏器相关的心律失常并与常规心电图对照。结果共检出起搏器功能障碍23例,其中间歇性起搏功能障碍2例（占2%）,间歇性感知功能障碍21例（占22%）。检出与起搏器相关的心律失常17例（18%）。而常规心电图仅发现感知功能障碍2例。两种检查方式在检测间歇性感知功能障碍及与起搏器相关的心律失常方面存在显著性差异（P<0.01）。检出起搏功能异常的差异性未达到显著水平。DCG对3种类型（AAI、VVI、DDD）之间感知功能异常检出率无显著性差异。根据DCG结果,进行临床相应处理后,起搏器的起搏及部分感知功能障碍消失,相关心律失常引起的临床症状逐渐消失。结论起搏器的起搏、感知功能障碍及与起搏器相关的心律失常多为间歇性发生,DCG对其检出率较高,并可系统了解起博器工作状态及各种心律失常,是对起博器随访的重要手段之一。     

Feasibility of dual-chamber (DDD) pacing via a single-pass (VDD) pacing lead employing a floating atrial ring (dipole): case series, future considerations, and refinements

The objective of this study was to assess the feasibility of DDD pacing from a standard single-pass VDD pacemaker system. Over the past 2 decades significant advances have been made in the development of single-pass VDD pacing systems. These have been shown in long-term prospective studies to effectively preserve atrioventricular (AV)synchrony in patients with AV block and normal sinus node function. What remains problematic is the development of a single-pass pacing system capable of DDD pacing. Such a lead configuration would be useful in those patients with peripheral venous anomalies and in younger patients with congenital anomalies, which may require lead revisions in the future. In addition, with the increased use of resynchronization (biventricular pacing) therapy, the availability of a reliable single-pass lead will minimize operative time, enhance patient safety, and minimize the amount of hardware within the heart. The feasibility of DDD pacing via a Medtronic Capsure VDD-2 (Model #5038) pacing lead was evaluated. Twenty patients who presented with AV block and normal sinus node function were recruited for this study. Atrial pacing thresholds and sensitivities were assessed intraoperatively in the supine position with various respiratory maneuvers. Five patients who agreed to participate in long-term follow-up received a dual-chamber generator and were evaluated periodically over a 12-month period. Mean atrial sensitivity was 2.35 +/- 0.83 mV at the time of implantation. Effective atrial stimulation was possible in all patients at the time of implantation (mean stimulation threshold 3.08 +/- 1.04 V at 0.5 ms [bipolar], 3.34 +/- 0.95 V at 0.5 ms [unipolar]). Five of the 20 patients received a Kappa KDR701 generator, and atrial electrical properties were followed up over a 1-year period. There was no significant change in atrial pacing threshold or incidence of phrenic nerve stimulation over the 1-year follow-up. A standard single-pass VDD pacing lead system was capable of DDD pacing intraoperatively and during long-term follow-up. Despite higher than usual thresholds via the atrial dipole, pacemaker telemetry revealed < 10% use of atrial pacing dipole over a 12-month period, which would minimally deplete the pacemaker's battery. In addition, the telemetry confirmed appropriate sensing and pacing of the atrial dipole throughout the study period. At this time such systems can serve as back-up DDD pacing systems with further refinements required to optimize atrial thresholds in all patients.     

Arrhythmia induction during atrial pacing with atrial floating electrodes

Atrial pacing with floating electrodes primarily designed for single lead VDD systems has disadvantages attributable to the floatability of the electrodes. Body and breathing movements cause changes in the position of the atrial dipole that can lead to failure of atrial capture and sensing, and even alternation of the stimulated chamber. We report the induction of typical intranodal tachycardia episodes related to intermittent failure of atrial capture in a patient with an implanted single lead DDD pacing system. Such systems pose a substantial risk of potentially arrhythmogenic asynchronous pacing.     

Pseudo failure of sensing in patients with universal pacemakers and junctional rhythms

Ventricular fibrillation has been only rarely observed as a complication of cardiac pacing after the advent of demand pacemakers. Automatic AV sequential pacing (DDD) may provide the setting for ventricular fibrillation in patients with junctional rhythms. In this report we present two patients with implanted DDD pacemakers in whom ventricular pacemaker spikes were seen occurring on top of the T wave during episodes of junctional rhythm. This apparent lack of sensing of QRS complexes does not represent pacemaker malfunction, but rather, is the result of physiologic lack of sensing (blanking) which occurs 56 to 100 msec. following the output of the atrial and ventricular channels. During junctional rhythm when the atrial spike occurs at the beginning of a QRS complex the ventricular channel is blanked and does not sense the intrinsic ventricular activity and thus, ventricular output occurs during repolarization. Increasing the maximum pacemaker rate and decreasing the AV delay will reduce the chance occurrence of this phenomenon.