具有自动夺获功能的心室起搏器临床应用

目的：评定15例心室起搏器的自动夺获功能的功效和安全性。方法：15例患者．男性9例，女性6例，年龄37～81岁，均有器质性心脏病．基础心律：10例为慢性心房颤动伴RR长间歇，4例病态窦房结综台征，其中2例合并阵发性心房颤动，1例三度房室阻滞。11例植人Regency SC＋型VVI起搏器，4例植人Regency SR-型VVIR起搏器。结果：起搏器植人后随访1～13个月，起搏器工作良好，QRS(R)振幅9．65±2．55mV．ER振幅785±3．87mV，两者相关系数(r）为0．15（h=55)。应用VARIO方法和自动夺获法测定的起搏阈值均在0．3～15V之间，两者相关系数为0．99(n=46)。极化电位低于lmV者占全部测定例次的e4G，高于1mV的极化电位幅度为1．38 0．13mV(n=37)。结论：与普通VVI(R)起搏器相比，具有自动夺获功能的VVI(R)起搏器功耗低，预计使用寿命长，起搏安全可靠，随访省时。     

有自动夺获功能的双腔起搏器的临床随访

目的观察双腔心室自动阈值夺获起搏器长期的参数变化及安全性.方法我院1999年10月至2000年6月住院植入具有心室自动阈值夺获功能的双腔起搏器20例,观察术中、术后1周、2周、1个月、3个月及6个月后的心室起搏阈值、输出电压、ER振幅、阻抗、极化电位及自动工作方式转换功能.结果术后早期心室起搏阈值、极化电位轻度升高,2周后趋于稳定,其余参数无明显变化,长期的心室起搏电压平均为(1.26±0.38)V.15例术后即刻可以启动自动夺获功能,4例术后1周可启动自动夺获功能,随访期间功能正常,无起搏脱漏现象,且5例伴有阵发性心房颤动的患者,心房颤动时均可发生工作方式转换,未出现起搏器介入性心动过速.1例肥厚梗阻性心肌病患者因术中及术后极化电位较高致自动夺获功能不能启动.结论有自动夺获功能的双腔起搏系统耗能低,安全可靠,满足了患者的生理需要.但对有心内膜病变患者有待进一步观察.     

起搏器自动夺获功能失活的观察分析

观察分析自动夺获(AC)功能无法正常工作的原因。41例患者置入具有AC功能的起搏器,术后1周、1个月、3个月随访体表心电图、动态心电图,应用程控仪进行遥测和程控,测定刺激除极波(ER)振幅、极化电位(PS)等参数,观察AC功能的工作情况。结果:41例经术后随访起搏器功能正常。5例(12.2%)在术中虽经多次调整电极位置,也无法术中使用AC功能。4例ER值始终低,极化电位较高(ER/PS<1.5);1例因噪声干扰太大,术中无法测试ER振幅。5例术中未能打开AC功能者,其中4例于1个月后随访时,ER/PS≥2,将AC功能打开。1例术中起搏电极位置在右室基底部者,R波感知>10mV,ER始终小于2.4mV,多次随访均无法安全使用AC功能。术中打开AC功能的36例中,术后随访时5例需关闭AC功能,其原因:①起搏阈值超高≥4.5V(1例),②大量室性融合波导致频繁后备脉冲释放(2例),③后备脉冲(4.5V/0.5ms)工作时的不适感觉(1例,伴室性融合波导致频繁后备脉冲释放),④局部肌肉抽动引起噪声干扰无法进行ER振幅测试(2例)。结论:多种因素都能影响起搏器AC功能。为保障起搏器可靠安全,低耗能状态,近期的随访观察尤为重要。     

Kappa 700型双腔起搏器的临床随访

观察具有自动夺获功能的双腔起搏器 (Kappa 70 0 )置入后参数的变化和安全性情况。随访 1 3例置入Kappa70 0型起搏器患者 ,观察术中、术后 1周及术后 1 ,3,6个月心室起搏阈值、输出电压、输出脉宽、电极阻抗、R波振幅的变化 ,了解起搏器的工作情况。术后测得的起搏阈值较术中明显升高 ( 0 .71± 0 .2 3Vvs 0 .39± 0 .0 6V ,P <0 .0 5 ) ,术后不同时间测得的起搏阈值无明显差异。R波振幅术中、术后无明显差异。术后阻抗较术中明显降低 ( 62 5 .7± 1 2 3.0Ωvs 894.3± 1 90 .3Ω ,P <0 .0 5 ) ,术后 1个月后的阻抗基本稳定。起搏器自动夺获功能打开后 ,平均输出电压为 0 .96～ 1 .1 6V ,平均输出脉宽 0 .32～ 0 .34ms,平均心房感知灵敏度 0 .71～ 0 .83mV ,心室感知灵敏度 3.82～3.91mV。随访期间起搏、感知功能正常 ,无误感知现象。具有自动夺获功能的双腔起搏器输出电压低 ,安全可靠。     

闭环刺激双腔频率适应性起搏器的临床应用

目的介绍感知体动和精神活动的闭环刺激双腔频率适应性起搏器的初步应用经验.方法植入第3d开启闭环刺激频率适应功能,患者进行坐卧位、散步、快走、上下楼、思考等活动,第7d动态心电图检查和起搏器程控.3个月后随访,重复上述活动和检查,对比分析结果.结果18例患者植入闭环刺激双腔频率适应性起搏器(Biotronik公司的Inos2CLSDDDR),心室起搏阈值0.3～0.7(0.4±0.3)V,R波振幅9.5～21.8(14.6±7.5)mV,阻抗520～870(610±78)Ω;心房起搏阈值0.3～0.8(0.5±0.3)V,A波振幅7.2～16.4(11.6±5.7)mV,阻抗510～872(697±92)mV.随访50～486(236±107)d,均为频率适应性双腔起搏,体力和脑力活动时起搏频率能按需增加.与植入时相比,频率适应功能增强且更加个体化.结论Inos2CLS除适应体动变化外,还能适应精神负荷变化,自动完成初始参数和昼夜频率调整,程控简单,随访方便.     

自动阈值夺获型起搏器心室除极波值与QRS波振幅的相关性研究

目的探讨具有自动阈值夺获功能的起搏器患者起搏的心室除极波值(evoked response,ER)与自主QRS波振幅及有关因素的相关性。方法对161例置入ST.JUDE公司生产的、具有自动阈值夺获功能起搏器患者术中分别测定的自主QRS波R波振幅值、阻抗、起搏阈值及起搏ER值并对ER值的有关因素进行相关分析。结果R波振幅值13.08±4.82mV,ER值99%可信区间11.90~15.01mV,二者相关系数r值为0.05(P>0.05)。结论置入自动阈值夺获功能起搏器时,自主QRS波振幅的高度与ER值之间无相关性,术中应单独进行ER值的测试,以策安全。     

双房单室三腔起搏器治疗病窦综合征并快速房性心律失常

观察双心房、单心室三腔起搏器治疗病窦综合征合并阵发性房性快速心律失常患者的疗效。三根电极导线分别置入冠状静脉窦内、右心耳和右室心尖部行三腔起搏。冠状窦电极导线与右心房电极导线通过一个Y型转接器构成心房部分。结果 :10例患者 ,9例经左锁骨下静脉径路置入导线 ,1例因存在残存左上腔静脉 ,从右锁骨下静脉置入。 10例中 9例冠状窦电极导线置于冠状静脉窦中部、1例置于冠状静脉窦远端。冠状窦起搏阈值为 1.0 6±0 .2 0V、起搏阻抗 6 11± 115 .8Ω、P波振幅为 4.0 7± 0 .88mV ;右室电极起搏阈值为 0 .5 3± 0 .12V、起搏阻抗 6 70 .3±191.7Ω、R波振幅为 9.6 6± 1.87mV。随访 5～ 2 4个月有 9例起搏器呈DDD工作方式 ,1例呈AAT工作方式。起搏和感知功能良好。 10例中 8例快速性房性心律失常完全控制 ,2例发作次数减少 ,持续时间明显缩短。无一例出现并发症。结论 :三腔起搏器技术安全、可靠。适合于缓慢型心律失常合并阵发性房性快速性心律失常     

VVI型起搏器更换时心室电极直接参数的变化及临床意义

研究长期起搏器治疗后起搏阈值、电极阻抗的变化及电极使用的寿命。 32例病人 ,在起搏器置入术及更换术时 ,用起搏器分析仪直接测量心室电极参数。心室电极在体内埋置时间为 10 4 .2 2± 30 .10 (49～ 16 8)个月。置入时起搏阈值为 0 .72± 0 .33(0 .2～ 1.5 )V ,更换脉冲发生器时为 1.85± 0 .75 (1.0～ 3.5 )V ,P <0 .0 0 0 1。更换脉冲发生器时起搏阈值是置入时的 2 .5 7倍 ,增加幅度为 2 0 1.2 %± 16 2 .9% (10 %～ 70 0 % ) ,增加绝对值为 1.13± 0 .71(0 .1～2 .5 )V。置入时电极阻抗为 6 4 2 .83± 185 .39(333～ 980 )Ω ,更换脉冲发生器时为 70 2 .79± 73.0 0 (40 2～ 12 4 0 )Ω ,P >0 .0 5。更换起搏器后 ,对继续使用原心室电极的 2 8例随访 5 4 .91± 5 1.2 1(1～ 16 8)个月。 3例在更换术后 1～ 2 4个月分别出现起搏及感知障碍 ,再次手术时发现导管不全断裂、绝缘包鞘破损及微脱位。结论 :置入性右心室心内膜电极在使用 8年以上 ,大部分的直接参数在正常范围 ,可考虑继续使用 ,但早年生产的电极 ,更换术时参数即使正常 ,亦不排除电极可能短期内发生故障 ,须随访及定期复查。     

具有阈值夺获功能的双腔起搏器临床应用及观察

目的观察具有阈值夺获功能的双腔起搏器参数变化,提取储存数据协助临床诊断并评估其安全性. 方法2001年12月～2002年10月植入20例具有阈值夺获功能的双腔起搏器,观察术中、术后1个月、3个月、6个月参数,包括心室阈值、输出电压、阻抗、ER振幅、极化电位,自动模式转换功能,心率事件统计,睡眠功能等.     

Premier起搏器临床应用的初步体会

对12例安置 Premier 起搏器的病人进行观察。安置时起搏阈值0.44±0.1 V、阻抗506±98 Ω(5 V 起搏时)、R波振幅8.58±6.3 mV。随访2～8个月,测得在0.8 V 起搏时的脉宽阈值为0.18～0.24 ms,显示其有良好的低阈值性能。程控取1.6 V、0.3～0.36 ms 就可保证安全有效的起搏。初步体会该起搏器性能良好,配合激素电极可节省耗电量和延长起搏器寿命。预计其寿命可超过16年。     

普通电极导线行右房左室或双心室起搏的初步临床观察

探讨普通电极导线置入心脏静脉起搏左室的可行性。选择 9例患者为研究对象 ,其中扩张型心肌病 3例、缺血性心脏病 3例、其他 3例 ,均伴不同程度的心力衰竭 ,心功能Ⅱ～Ⅳ级。所有患者都安置DDD起搏器。窦性心律伴房室阻滞 (AVB)或完全性左束支阻滞 (CLBBB)患者 ,行右房左室顺序起搏 ;房颤患者行双心室起搏。左心室起搏是将普通右心室导线 (MedtronicCapSureSP 4 0 2 3)通过冠状窦送入心脏静脉施行的。结果 :7例成功 ,2例失败。导线定位在左室后静脉 1例、后侧静脉 3例、侧静脉 3例。术中测左室起搏阈电压、阻抗和R波振幅分别是 0 .7± 0 .2V、6 2 3± 6 6Ω、10 .1± 6 .0mV。术后 2～ 18个月阈电压、阻抗分别是 0 .5± 0V、5 2 1± 5 1Ω。术后 1～ 2周平均心功能从2 .9级改善到 1.9级 ,平均心胸比值从 0 .6 1缩小到 0 .5 7,平均左室射血分数从 0 .39升至 0 .4 4。随访期未发现左室导线脱位 ,膈肌起搏等并发症。结论 :普通电极导线置入心脏静脉长期起搏左心室是可行的、牢靠的。     

Long-term results of endocardial pacing with Autocapture threshold tracking pacemakers in children.

AIM: We aimed to evaluate the long-term results of endocardial pacing with Autocapture threshold tracking pacemakers in children. METHODS AND RESULTS: Implantation and follow-up data of 20 children with these pacemakers were retrospectively evaluated. The pacemakers were implanted subpectorally in five and subcutaneously in 15 patients. The indication for pacing was high-grade atrioventricular block in 18 cases. The mean age at implantation was 7+/-4.8 years. Four patients were pacemaker dependant (heart rate < 30 bpm). At implantation, the mean pacing threshold was 0.5 V at 0.5 ms. The mean evoked response (ER) signal was 8.5+/-3.6 mV, and the polarisation signal (PS) was <1 mV in 15 patients and 1-2 mV in five patients. During the mean follow-up period of 60 months, mean ER signal decreased significantly to 7.7+/-6.3 mV at 24 months and 6.5+/-2.5 mV at 60 months (P < 0.05). In four of 15 patients (26.6%), with a predischarge PS value of <1 mV, it increased between 1 and 2 mV over time. During follow-up, autocapture function was deactivated in six (30%) patients; due to inappropriate ER/PS values in four and due to severe muscle twitching in two with subpectoral implants. These problems occurred during a median period of 21 months after implantation. Generators were replaced in three patients with Microny pacemakers because of battery depletion at 54, 66 and 78 months. In two of them autocapture function had been working since implantation. In seven of 10 patients, who completed > or = 60 months of follow-up, battery impedances were still at the predischarge level. CONCLUSIONS: Autocapture function works well in most children at implantation. Mean ER signal significantly decreases over time despite stable pacing parameters. Autocapture function may become nonoperational due to decreased ER signal in some patients. Muscle twitching may be an important problem that may result in discontinuation of autocapture function in children with subpectoral implants.     

Pacing threshold changes after transvenous catheter countershock

The serial changes in pacing threshold and R-wave amplitude were examined after insertion of a countershock catheter in 12 patients referred for management of recurrent ventricular tachyarrhythmias. In 6 patients, values before and immediately after catheter countershock were monitored. Pacing threshold increased (from 1.4 ± 0.2 to 2.4 ± 0.5 V, mean ± standard error of the mean, p < 0.05) while the R-wave amplitude decreased (bipolar R wave from 5.9 ± 1.1 to 3.4 ± 0.7 mV, p < 0.01; unipolar R wave recorded from the distal ventricular electrode from 8.9 ± 1.8 to 4.6 ± 1.2 mV, p < 0.01; and proximal ventricular electrode from 7.7 ± 1.5 to 5.0 ± 1.0 mV, p < 0.01). A return to control values occurred within 10 minutes. In all patients, pacing threshold increased by 154 ± 30% (p < 0.001) during the first 7 days that the catheter was in place. It is concluded that catheter countershock causes an acute increase in pacing threshold and decrease in R-wave amplitude. A catheter used for countershock may not be acceptable as a backup pacing catheter.     

Long-term follow-up of pacemakers with an Autocapture pacing system

The aim of this study was to evaluate the safety and performance of the Autocapture pacing system during a 5-year follow-up period. The study was conducted retrospectively between May 1996 and May 2001. Sixty consecutive patients who had undergone VVI pacemaker implantation using an Autocapture program with leads 1402T (n: 31) and 1452T (n: 29) were included in the study. Intraoperative measurements including a ventricular stimulation threshold test, sensing of intrinsic R wave (mV), and lead impedance (W) were done by a standard pacing system analyzer. Evoked responses (ER, mV) and polarization signals (PS, mV) were measured after the pocket was closed. Pacing thresholds by Autocapture (AC thrd, V) and Vario (Vario thrd, V), battery current (mA), and battery impedance (kW) were also repeated during predischarge and 1, 6, 12, 18, 24, 30, 40, 50, and 60 months after discharge. According to the ER and PS values an Autocapture algorithm could be activated in 49 patients (88%). The Autocapture algorithm remained active during the follow-up in all of these patients. In patients with inappropriate ER and PS values (11 patients, 12%), pacemakers were programmed to a VVIR pacing mode and Autocapture algorithm was inactivated. ER and PS values did not reach appropriate values to activate the Autocapture algorithm in any of these patients in consecutive follow-ups. Twenty-four-hour Holter monitoring could be conducted in 32 patients (53%). In all recordings, when the loss of capture occurred, it was confirmed that back-up pacing continued. When the first measurements recorded during implantation were compared to approximately the 5th year measurements; ER (9.2 mV vs 9.6 mV), PS signal (1.13 +/- 0.30 mV vs 1.15 +/- 0.72 mV), AC thrd (0.4 V vs 1.2 V), Vario thrd (0.7 V vs 1.3 V), and lead impedance (502 ohm vs 620 ohm) were not changed significantly. Battery impedance increased 1 kOhm between 30-40 months of the implantation. Seven deaths occurred during follow-up. Three patients had fatal myocardial infarction, one died due to a non-cardiac event, and the remaining three died due to progressive heart failure. Conclusion: ER, R wave amplitude, and PS, which are the main parameters for the continuation of Autocapture function, did not change significantly during long-term follow-up. High output back up pacing provided additional safety for sudden rises in threshold. The Autocapture pacing algorithm was found to be effective and reliable during long-term follow-up.     

Feasibility,safety and outcomes of left bundle branch pacing in octogenarians

ObjectivesLeft bundle branch pacing (LBBP) provides physiological pacing at low and stable threshold. The safety and efficacy of LBBP in elderly population is unknown. Our study was designed to assess the safety, efficacy and electrophysiological parameters of LBBP in octogenarian (≥80 years) population.ResultsLBBP was successful in 10 out of 11 patients. Mean age 82.1 ± 2.5 yrs. Follow up duration 7.7 months(range4–10). Indication for pacing included atrioventricular (AV) block 5 patients, Left bundle branch block (LBBB) with low ejection fraction (EF) 4 patients, sinus node dysfunction in 1. QRS duration reduced from 145.9 ± 27.7ms to 107.1 ± 9.5ms (p value0.00001) LV ejection fraction increased from 47.6% to 58.4% after LBBP (p value0.017). Pacing threshold was 0.58 ± 0.22 V and sensed R wave 17.35 ± 6.5 mV and it remained stable during follow up. LBBB with low EF patients also showed similar reduction in QRS duration along with improvement in LVEF.ConclusionLBBP is a safe and effective strategy (91% acute success) of physiological pacing in elderly patients. LBBP also provided effective resynchronization therapy in our small group of elderly patients. The pacing parameters remained stable over a period of 10 months follow up.     

DDD and single-lead VDD pacing: evaluation of atrial signal dynamic changes

BACKGROUND: Single-lead VDD pacing systems are an alternative to conventional DDD pacemakers in patients with atrioventricular (AV) block and normal sinus function. HYPOTHESIS: The aim of this study was to assess changes of P-wave amplitude occurring in dynamic conditions in two groups of patients with a single-lead VDD and with a DDD pacing system, respectively. METHODS: Twenty-eight patients with second- or third-degree AV block and normal sinus function were enrolled prospectively into the study. Seventeen patients were implanted with a single-lead VDD pacing system and 11 with a DDD pacemaker. Patients were evaluated at 3 months (all patients) and at 6 months (26 patients) at supine and in dynamic conditions (postural changes, hyperventilation, and during exercise). RESULTS: Mean P-wave values at supine were 1.92 +/- 1.10 mV at 3 months and 1.76 +/- 1.01 mV at 6 months for VDD systems, and 4.63 +/- 2.18 mV at 3 months and 4.58 +/- 2.80 mV at 6 months for DDD pacemakers. In dynamic conditions, P-wave amplitude changes compared with supine condition ranged between -74 and +226% in VDD, and between -53 and +138% in DDD; however P-wave amplitudes showed no significant changes compared with baseline. Moreover, changes in atrial signal amplitudes did not occur randomly, and in both systems P-wave amplitudes remained significantly correlated with supine values. CONCLUSIONS: A wide range of P-wave amplitude variations occurs in different postural conditions or during exercise, both with single-lead VDD and DDD pacing systems. However, with appropriate programming of atrial sensitivity based on supine values, constant atrial tracking can be maintained.