起搏器置入术中单双极起搏与感知测试的电参数差异

25例患者置入埋藏式起搏器,心房和心室导线到位固定后,测试比较单极和双极起搏与感知参数。结果:心房、心室导线单极起搏阈电压、电阻抗较双极起搏高,单极感知的P/QRS波振幅较双极感知低。     

起搏器植入术中双极导线单、双极模式参数的比较

目的比较起搏器植入术中双极导线单、双极模式的参数。方法共入选117例患者,术中共植入78根心房双极导线和117根心室双极导线,以Medtronic 5318起搏分析仪测试起搏参数,固定脉宽为0.42 ms。结果术中双极导线单极模式与双极模式的起搏阈值无差异(P均>0.05);双极模式的P/R波振幅高于单极模式(P均<0.01);心房、心室双极模式的阻抗均大于单极模式(P均<0.05)。术后随访无1例有阈值异常增高,导线脱位或断裂发生。结论双极导线单、双极模式的起搏阈值无差异;双极模式的感知优于单极模式,而阻抗较单极模式高。     

起搏电极导线脱位的临床探讨

报道 6例起搏器电极导线脱位 ,1例为VDD起搏器 ,其余 5例均为DDD起搏器。共 8根电极导线脱位 ,7根为电极导线游动、1根呈微脱位。脱位后 ,2例再次发生晕厥、3例有明显症状 ,脱位电极导线均为双极电极导线。与以往电极导线脱位率相比 ,双极电极导线在临床中应用增多后引起的起搏电极脱位率有所增高 ,约占同期起搏器总数量的 2 %。这一现象应给予充分重视 ,并采取相应措施减少和预防其发生     

永久起搏器单双极导线工作性能比较

目的:观察单、双极导线于起搏器置入术中及术后起搏阈值、感知、阻抗的变化规律并比较其差异.方法:对2005-07-2008-04间所有置入双极导线可程控极性起搏器的患者共208例(男101例,女107例,平均年龄63岁)随访1年,分别在置入时、术后1周、1个月、3个月、6个月及1年测试单、双极起搏阈值、阻抗以及P/R振幅,比较同一时间不同极性间各项指标的差异以及同一极性不同时间各项指标的变化情况.结果:无论心房还是心室导线,术中双极起搏能量及电压阈值均显著低于单极(P<0.01).术后1周以及长期随访时二者能量阈值无显著性差异,单极起搏电压阈值低于双极(P<0.01).从术后1周开始,心房和心室双极电压及能量阈值均有升高趋势,心室单极电压及能量阈值有升高趋势.心房单极电压及能量阈值自术后1周开始下降,术后12个月仍低于术中水平.无论心房还是心室导线,双极阻抗于术中及术后任何时间均高于单极(P<0.01),双极P/R振幅于术中及术后任何时间均高于单极(P<0.01).结论:无论心房还是心室导线,术中以及术后起搏压阈值、阻抗以及P/R振幅在单、双极状态下均明显不同,而起搏能量阈值在术中单极高于双极,术后二者无差别.     

起搏器与电极导线不匹配一例

患者女性,61岁,因Ⅲ度房室传导阻滞植入DDD起搏器。心房、心室电极导线参数测试满意后与起搏器连接,心电监护示:心房率78次/分,心室率38次/分,未见心室起搏心律。术中探查,用程控仪测心室电极阻抗9999Ω,心房电极阻抗正常;然后将心房、心室电极导线互换分别插入起搏器心室、心房电极插入孔,测试示:心室电极导线阻抗9999Ω,心房电极导线阻抗正常。提示:心室电极导线与起搏器不匹配,更换心室电极导线,起搏器呈VDD起搏模式。     

起搏电极导线脱位

起搏电极导线脱位是起搏器术后常见的并发症。大多为发生在起搏器术后6周内的早期脱位,心房电极和双室同步起搏的冠状窦电极的脱位率较高。诊断电极脱位最简便、有效的检查是心电图和X线片,对疑诊患者,应进行起搏器程控。典型的电极导线脱位表现为起搏阈值升高和/或电极导线阻抗降低,严重脱位尚可引起感知不良。根据起搏器置入的时间、患者临床表现、脱位的电极导线情况以及起搏器功能障碍的程度不同,处理方法亦不同,而积极预防是最好的防治电极导线脱位的方法。     

主动固定电极导线行心脏特殊部位起搏的临床应用

目的探索主动固定电极导线行心脏特殊部位起搏临床应用的可行性和安全性。方法需要安置心脏起搏器患者88例,其中男54例、女34例,年龄67.6±24.3(28～91)岁。患者为缓慢性心律失常或者严重心力衰竭,放置主动固定电极导线,测定有关参数并随访观察。结果手术顺利完成,未出现严重并发症。共使用主动电极导线151根,其中心室电极导线88根(右室流出道间隔部80根,右室流入道间隔部5根,右室中间隔3根);心房电极63根(右心耳37根,低位房间隔10根,高位房间隔10根,心房侧壁6根)。起搏参数在电极导线置入15min后可达到理想值。术后7天及出院后1,3,6个月随访无电极导线脱位,起搏参数与置入时比较没有差异。结论使用主动固定电极进行心脏特殊部位起搏是可行和安全的。     

器械升级时原起搏导线及囊袋的处理

目的观察器械升级时原起搏导线及囊袋处理的方法、可行性和安全性。方法本组共11例患者,根据升级后所应用器械分为心脏再同步治疗（CRT）组及植入型心脏再同步治疗除颤器（CRT—D）组。CRT组5例患者,其中4例升级前为单腔起搏器（VVI）,1例为双腔起搏器（DDD）;CRT—D组6例,升级前分别为1例VVI、2例DDD、2例单腔植入型心律转复除颤器（ICD）及1例CRT。起搏器囊袋依患者情况而定,但CRT—D囊袋须往左侧胸部。结果常规起搏器升级为CRT者,除1例原双极心室导线各参数均符合更换时要求外,弃用其他单极心房、心室导线,重新植入新的双极导线。升级为CRT—D者,1例VVI起搏器,弃用原单极心室导线,植入ICD心室导线,同时植入双极心房起搏导线和左心室导线;2例双腔起搏器原心房导线均为单极,予弃用,重新植入双极心房导线,心室新植入ICD导线;2例原ICD导线均能续用;1例CRT升级仪需新债入ICD导线。起搏器衰袋除1例存右侧胸部外,余10例均在左侧胸部。结论器械的升级是安仝、可行的,对原起搏导线需评估后依不同情况分别作出相应的处理。     

右室双部位双心室同步起搏治疗心力衰竭一例

心房颤动伴Ⅲ度房室传导阻滞患者,接受VVI型人工心脏起搏器置入术后出现心力衰竭。在保留原起搏器及导线的情况下,新置入2根电极导线分别至右室,及左室侧后静脉,与DDD起搏器心室及心房接口连接,行右室双部位双室同步起搏,临床疗效可。     

经永存左上腔静脉植入起搏电极导线9例分析

目的:回顾性分析经永存左上腔静脉植入起搏电极导线患者的临床资料,为临床医生提供参考。方法 :本研究入选了2009～2019年在中国医学科学院阜外医院经永存左上腔静脉植入起搏电极导线的患者9例,其中男性2例,女性7例,平均年龄为(47±25)岁。分析患者基线特征、导线类型、导线植入成功率、术中起搏参数等。术后3个月和6个月常规随访,以后每6～12个月随访。测试起搏阈值、感知及导线阻抗等参数,并随访观察并发症发生情况。结果 :9例患者中3例合并先天性心脏病,7例患者为孤立性永存左上腔静脉,2例为双上腔静脉,其中1例患者因右侧锁骨下静脉闭塞,被迫经左上腔静脉植入起搏导线,另1例患者因右锁骨下静脉留置深静脉管,选择经左上腔静脉植入起搏导线。术中2例病态窦房结综合征患者心室导线植入失败,选择植入心房单腔起搏器;1例病窦综合征患者心房导线植入失败,选择植入心室单腔起搏器。随访期间,1例患者于术后2周发现心室导线脱位,选择经右侧重新植入,其余患者未见并发症。随访中位时间1.8(1.1,4.3)年,随访期间心房、心室导线参数稳定。结论:经永存左上腔静脉植入心房、心室起搏电极导线均存在一定难度,短期内存在导线脱位风险,但远期导线参数稳定。双上腔静脉患者应避免经永存左上腔静脉植入导线。     

起博电极导线脱位的临床探讨

报道6例起博器电极导线脱位，1例为VDD起博器，其余5例均为DDD起博器。共8根电极导线脱位，7根为电极导游动、1根呈微脱位。脱位后，2例再次发生晕厥、3例有明显症状，脱位电极导级均为双极电极导线。与以往电极导线脱位率相比，双极电极导线在临床中应用增多后引起的起博电极脱位率有所增高，约占同期起博器总数量的2%。这一现象应给予充分重视，并采取相应措施减少和预防其发生。     

Post-mortem evaluation of 415 pacemakers: in situ measurements and bench tests.

AIM: The hypothesis was that there is more undetected dysfunction of implanted pacemaker systems than that detected and corrected. This prompted a research project (sponsored by the German Research Foundation) to detect pacemaker abnormalities and evaluate their complications for patients, thus, proving or disproving the hypothesis. METHODS AND RESULTS: Four hundred and fifteen pacemakers of deceased patients were analyzed assessing their functionality by in situ measurements and bench tests including five measurements and one telemetric interrogation. Results were divided into four categories and statistically evaluated. Life-threatening abnormalities were found in 3.8%, potentially life-threatening in 3.7%, probably symptomatic, divided into atrial and ventricular problems, 13.3% and 2.8%, respectively, and premature exhaustion in 1.2%. Three of 179 bipolar ventricular leads and 2 of 131 bipolar atrial leads had insulation defects corresponding to 1.7% and 1.5%, respectively. The bipolar complication rate was 2.8 times higher than unipolar. CONCLUSION: The pacemaker patients investigated, living 4 years with their pacemaker on average, had a post-mortem evaluated complication rate of the category "life-threatening" of 3.8%. This result corresponds to an annual complication rate of 0.94% compared with a rate of only 0.39% in an earlier investigation.     

Interference by cellular phones with permanent implanted pacemakers: an update.

AIMS: The aim of this study was to test pacemakers with feedthru filters for interference with a digital cellular telephone. METHODS: The study comprised 100 patients having their first pacemaker implantation between January 2001 and May 2003. A GSM-standard cellular phone was tested in the standby, dialing and operating mode against 23 single-chamber and 77 dual-chamber pacemakers. Continuous surface electrocardiograms, intracardiac electrograms, and marker channels were recorded when calls were made by a land phone to the cellular phone. RESULTS: In 2 patients we observed pacing inhibition with the cellular phone positioned directly above the pacemaker pocket. The unipolar and bipolar ventricular sensitivity setting was 0.25 mV in one dual-chamber pacemaker, and when we changed the sensitivity to 0.50 mV and higher no interference could be detected. The second inhibition occurred in a single-chamber pacemaker with unipolar and bipolar ventricular sensitivity setting of 0.5 mV, where a sensitivity change to 1.0 mV eliminated the interference. CONCLUSION: Anticipating a correct setting of ventricular sensitivity, currently available pacemakers equipped with feedthru filters do not show any interference with cellular phones. Since interference was only observed with sensitivity settings below 0.50 mV, we recommend that permanent programming of ventricular sensitivity should be set at 2.0 mV and higher.     

Latest generation of unipolar and bipolar steroid eluting leads: long-term comparison of electrical performance in atrium and ventricles.

One hundred and seventy-three patients, mean age 74 years permanently paced with 123 atrial (53 unipolar, 70 bipolar) and 143 ventricular (73 unipolar, 70 bipolar) pacing leads were included in this study. The pacing leads were recent generation low surface area steroid eluting leads from one manufacturer: leads with silicone and polyurethane insulation were studied, and they were combined with generations of one pacemaker family from the same manufacturer permitting identical measurements to be made over a follow-up of 2 years. Pacing threshold was measured using pulse duration at a fixed voltage of 1.5 V: peak to peak P and R wave amplitude and pacing impedance at 2.5 V and 0.5 ms were all measured using the manufacturer's standard programmer. Although many significant differences, in the parameters measures, existed between atrium and ventricle and unipolar and bipolar configurations, none was felt to be of clinical significance. These data permit the physician to choose the lead type with regard to sensing performance and long-term lead integrity.     

Uni- and bipolar pacing threshold measurements with capturecontrol, a new automatic pacemaker function for capture verification. Comparison of the automatic and the manual pacing threshold measurement

It is mandatory in pacemaker patients to determine the pacing threshold at each follow-up visit. To facilitate the pacing threshold measurements, complete automatic pacemaker tests are being developed. A new pacemaker algorithm for automatic capture verification (Capturecontrol) detects the presence of the evoked response signal 70-100 ms after the pacing pulse. The aim of this study was to determine the uni- and bipolar pacing thresholds using this automatic pacemaker function and compare them with the manually determined threshold. The study included 14 patients with the DDD pacemaker Logos (Biotronik) connected to the high-ohmic ventricular pacing lead Synox SX 60-BP (Biotronik). At predischarge and 8, 14, 20 and 26 weeks after implantation the uni- and bipolar pacing thresholds were assessed manually and with the automatic pacemaker function at 0.4 ms duration. Mean pacing thresholds determined with the automatic pacemaker function were not different from the manually measured values. This applied to uni- and bipolar pacing. Seventy percent of all unipolar and 67% of all bipolar measurements had no deviation. A deviation of 0.1 V between manual and automatic threshold measurement was observed in 25% (unipolar) and 28% (bipolar), respectively. A 0.2-volt difference occurred in 3% in the unipolar measurements. Deviations >/=0.3 V were found in 2% of all unipolar and in 5% of all bipolar measurements. In conclusion, automatic pacing threshold measurements using the Capturecontrol algorithm were similar compared to the manually determined thresholds. The excellent agreement between the two methods was observed for bipolar as well as unipolar pacing and on condition that all patients had a high-ohmic ventricular pacing lead. Therefore, fewer requirements are necessary for Capturecontrol than for presently available systems. Such pacemaker functions can help to speed up the measurements during follow-up visits.     

Intermittent pacemaker dysfunction caused by digital mobile telephones

Objectives. This study was designed to evaluate possible interactions between digital mobile telephones and implanted pacemakers.Background. Electromagnetic fields may interfere with normal pacemaker function. Development of bipolar sensing leads and modern noise filtering techniques have lessened this problem. However, it remains unclear whether these features also protect from high frequency noise arising from digital cellular phones.Methods. In 39 patients with an implanted pacemaker 14 dual-chamber [DDD], 8 atrial-synchronized ventricular-inhabited [VDD(R)] and 17 ventricular-inhibited [VVI(R)] pacemarkers), four mobile phones with different levels of power output (2 and 8 W) were tested in the standby, dialing and operating mode. During continuous electrocardiographic monitoring, 672 tests were performed in each mode with the phones positioned over the pulse generator, the atrial and the ventricular electrode tip. The tests were carried out at different sensitivity settings and, where possible, in the unipolar and bipolar pacing modes as well.Results. In 7 (18%) of 39 patients, a reproducible interference was induced during 26 (3.9%) of 672 tests with the operating phones in close proximity (<10 cm) to the pacemaker. In 22 dual-chamber (14 DDD, 8 VDD) pacemakers, atrial triggering occurred in 7 (2.8%) of 248 and ventricular inhibition in 5 (2.8%) of 176 tests. In 17 VVI(R) systems, pacemaker inhibition was induced in 14 (5.6%) of 248 tests. Interference was more likely to occur at high power output of the phone and at maximal sensitivity of the pacemakers (maximal vs. nominal sensitivity, 6% vs. 1.8% positive test results, p = 0.009). When the bipolar and unipolar pacing modes were compared in the same patients, ventricular inhibition was induced early in the unipolar mode (12.5% positive test results, p = 0.0003).Conclusions. Digital mobile phones in close proximity to implanted pacemakers may cause intermittent pacemaker dysfunction with inappropriate ventricular tracking and potentially dangerous pacemaker inhibitions.     

Epicardial Versus Endocardial Pacemakers in the Pediatric Population: A Comparative Inquiry

Background: Most children in need of cardiac pacemakers remain dependent on the function of the permanent from childhood to adulthood. We sought to evaluate and compare the function between epicardial and endocardial pacemakers in pediatric groups with different conditions. Methods: Between 2012 and 2018, this single-canter study evaluated 44 pediatric patients with indications for epicardial or endocardial pacemakers. Results: The 2 groups, at a median age of 5 (0.1–16) years, were compared concerning the characteristics of the leads used (n = 80: bipolar, unipolar, steroid-eluting, and non–steroid-eluting), survival data, and complications. The reason for pacemaker implantation was congenital complete heart block in 11 (25%) cases and postoperative heart block in 33 (75%) cases. The commonest congenital heart disease accompanied by postoperative block was the ventricular septal defect. In the endocardial lead group, the mean ventricular pacing threshold immediately after the implantation and during the follow-up was less than that in the epicardial lead group (0.75 vs. 0.81 V; P = 0.01 and 0.8 vs. 2.4 V; P = 0.001). During the follow-up, the mean battery longevity was better in the endocardial group (last visit: 6.7 endocardial vs. 3.3 years epicardial). Lead failure was commoner in the epicardial pacemaker, and chronic high-pacing threshold pattern was seen in 14 patients in this group. After 3 years, freedom from lead failure was 94% and 63% in the endocardial and epicardial leads. Conclusions: Pacemakers with endocardial bipolar steroid-eluting leads showed better lead characteristics regarding survival and battery longevity than epicardial pacemakers without these lead characteristics. An appropriate pacemaker type should be selected based on the patient’s condition.     

Problems of artificial pacemaker therapy

Four hundred and sixty-seven cases with implantation of an artificial pacemaker were studied. The postoperative survival rate was 63% for 15 years. Seventy-two percent of type III patients of the sick sinus syndrome were free from postoperative thromboembolism and the lowest of the three types of the sick sinus syndrome. Comparing postoperative physical activity, cardiothoracic ratio and exercise tolerance time, physiological pacing was superior to ventricular pacing in hemodynamic effects and clinical symptoms. In a hundred cases of physiological pacing, complications and problems of physiological pacing were discussed. Atrial sensing failure and over-sensing were observed in seven and two cases respectively. A low amplitude of atrial potential and use of unipolar atrial leads were considered to be the main causes of these complications. Bipolar lead should be used as the atrial lead to avoid such complications, because the atrial potential by bipolar leads is not less than that by unipolar leads. Atrial sensing may be more sensitive without electromagnetic interference. The fixed A-V delay time whenever the atrium is sensed or paced, often results in a ventricular fusion beat and hemodynamic change on every beat, according to the interval of atrial and ventricular contractions. The A-V delay time should be changed in accordance with atrial sensing or pacing.