起搏器更换时原心脏电极参数的变化及临床意义

目的　总结 18年来更换心脏起搏器时对电极参数测定结果 ,以判断电极能否继续使用提供临床经验。临床资料　 1986年 3月～ 2 0 0 3年 5月 ,38例在起搏器置入术及更换术时 ,用起搏器分析仪直接测量电极参数。心室电极在体内埋置时间为 4～ 11年 (平均 8.4年 )。置入时起搏阈值为 0 .6 4± 0 .37(0 .3～1.5 )V ,更换起搏器时起搏阈值为 1.78± 0 .73(1.0～ 3.6 )V ,更换起搏器时起搏阈值明显高于置入时的 2 .4 5倍 (P <0 .0 0 1) ,增加绝对值为 0 .1～ 2 .6V。置入时和更换时电极阻抗分别为 (6 47.5 2± 178.4 1) (35 0～980 )Ω和 (72 3.2 2± 10 3.30 ) (4 5 2～ 130 0 )Ω ,两者相比P >0 .0 5。本组更换新电极 6例 ,均为阈值明显升高 (>3.5V) ,或 /和电极阻抗过高或过低。结论　①本组电极置入后平均 8.4年 ,更换起搏器时 ,起搏阈值为 (1.78± 0 .73) (1.0～ 3.6 )V ,为置入时的 2 .4 5倍 ,但 30例 (80 % )的起搏阈值 <2 .5V。②起搏器更换时 ,原电极阻抗与首次置入时相比 ,总体上略有升高 ,但无统计学意义 ,近 90 %的电极阻抗在正常范围内 ,2例阻抗 >12 5 0Ω ,进行了电极更换。③更换起搏器时 ,电极参数如起搏阈值在 2 .5V以下 ,电极阻抗在 30 0～ 10 0 0V内 ,自主心律的R波振幅 >2 .5V ,原电极可继     

以异丙肾上腺素为“桥”完成起搏器依赖患者脉冲发生器更换

目的观察起搏器依赖患者以异丙肾上腺素为"桥"行脉冲发生器更换的可行性。方法术中起搏器依赖患者静滴异丙肾上腺素,诱发出内在节律后行脉冲发生器更换,不能诱发出内在节律者植入临时起搏电极,然后行脉冲发生器更换。结果自2009年至2014年,有17例符合起搏器依赖行脉冲发生器更换的患者。静滴异丙肾上腺素后,14例(82%)患者显露出内在节律,完成了脉冲发生器更换;3例(18%)未诱发出内在节律,植入临时起搏电极后完成脉冲发生器更换。在静滴异丙肾上腺素期间,患者血流动力学稳定,无不良反应。结论起搏器依赖患者,以异丙肾上腺素为"桥"行脉冲发生器更换是可行的,可以减少临时起搏电极植入。     

心室同步化治疗保留左室电极导引钢丝技术的初步探讨

目的 对比分析心室同步化治疗在保留左室电极导引钢丝前后的起搏参数,探讨该技术的有效性和可行性.方法 2009年6月-2012年6月收集左室电极植入困难患者8例,在保留左室电极导引钢丝前后分别测定起搏参数,包括起搏阈值、电极阻抗和膈肌刺激阈值,并在术后1、3、6和12个月进行门诊程控随访,在多普勒超声指引下进行参数优化.结果 保留钢丝前后的起搏阈值、电极阻抗和膈肌刺激阈值分别为(4.58±1.57)V比(2.12±1.35)V,(1 060±182)Ω比(640±213)Ω和(9.81±2.05)V比(5.64±2.97)V,保留钢丝明显降低起搏阈值、降低电极阻抗和膈肌刺激阈值,差异有统计学意义(P＜0.05).术后12个月随访,所有患者心力衰竭症状改善,左室电极起搏参数与保留钢丝后即刻差异无统计学意义(P＞0.05),2例患者在体位变动时有膈肌刺激.结论 心室同步化治疗时,保留左室电极导引钢丝能有效改善起搏参数,安全可行.远期随访,膈肌刺激和钢丝断裂的问题有待观察.     

左室电极导线植入不同冠状静脉分支血管与 左室起搏部位关系

目的探讨左室电极导线植入在不同冠状静脉分支血管与左室起搏部位的关系。方法回顾性分析自2011年1月至2015年12月在北部战区总医院因心力衰竭植入心脏再同步治疗起搏器或心脏再同步治疗除颤器的112例患者的临床资料。分析术中留取的左前斜45°及右前斜30°冠状静脉逆行造影影像,按冠状静脉分支走向将植入血管分为心大静脉、左室前侧静脉、左室侧静脉、左室后静脉、心中静脉。右前斜30°将左室起搏部位三等分为心尖部起搏、左室中部起搏和基底部起搏,并将心尖部起搏归类为左室心尖部组(n=22),左室中部和基底部起搏共同归类为左室非心尖部组(n=90)。分析两组植入冠状静脉各分支情况。结果 112例患者左室电极所植入各冠状静脉分支分别为心大静脉2例(1.8%)、左室前侧静脉9例(8.0%)、左室侧静脉85例(75.9%)、左室后静脉14例(12.5%)、心中静脉2例(1.8%)。其中,左室心尖组植入左室前侧静脉1例(4.5%)、左室侧静脉13例(59.1%)、左室后静脉8例(36.4%);左室非心尖组植入心大静脉2例(2.2%)、左室前侧静脉8例(8.9%)、左室侧静脉72例(80.0%)、左室后静脉6例(6.7%)、心中静脉2例(2.2%)。电极导线植入后静脉分支位于心尖部比例高达57.1%(8/14),植入侧静脉分支位于心尖部的比例仅15.3%(13/85);非心尖部起搏的患者植入靶血管大多数分布在左室侧静脉、左室前侧静脉。结论左室单极或双极电极导线植入左室后静脉更容易起搏心尖部。     

右心室起搏电极导线穿孔至左心室1例

<正>1临床资料患者男性,62岁。因"乏力,气短3年"入院。既往有明确的3度房室传导阻滞的病史3年,体型偏瘦,体质量45 kg。入院后,完善相关检查后行双腔永久起搏器植入(ST Jude Victory 5816),将右心室主动电极导线植入于室间隔(图1a,b)。术后2个月,患者主诉头晕再发、心率减慢来院就诊。心电图显示,右心室不起搏,右心房电极起搏感知良     

左心室四极与传统起搏导线起搏参数比较

目的比较左心室四极与传统单、双极起搏导线在心脏再同步治疗(CRT)中的起搏参数,探讨左心室四极起搏导线的优势。方法选择自2014年1月至2015年1月我院收治的18例行CRT心力衰竭(HF)患者,应用左心室四极导线与传统起搏导线,分析起搏参数包括:左心室起搏阈值、膈神经刺激(PNS)和心尖部起搏比例。结果本研究18例患者,应用左心室四极起搏导线均可避开高阈值左心室起搏。左心室四极起搏导线与单、双极起搏导线临床PNS发生率分别为5.6%、27.8%和11.1%。所有患者均无因PNS而行左心室导线重置。左心室四极起搏导线与传统单、双极左心室起搏导线比较,左心室心尖部起搏比例分别下降了44.4%和27.7%,差异有统计学意义(P<0.05)。结论左心室四极起搏导线可以有效解决因PNS而进行左心室导线重置及高阈值起搏问题,并降低了左心室心尖部起搏比例。     

心脏起搏器植入患者进行核磁共振扫描安全性研究

目的探讨植入核磁共振(MRI)兼容起搏器患者进行MRI扫描的安全性。方法选取自2013年1月至2017年10月于北部战区总医院植入MRI兼容起搏器并进行1. 5 T的MRI扫描的21例患者为研究对象。观察患者在核磁扫描前、扫描后即刻以及扫描后1、6、12个月的临床不良事件发生情况、起搏器系统稳定性及电极导线的参数变化情况。结果本组患者在MRI扫描过程中,无胸痛、心悸、胸闷、晕厥等不适症状,心电监测未监测到心律失常的发生,MRI扫描后复查的体表心电图与扫描前比较无变化。扫描后即刻程控仪测试脉冲发生器的工作情况,无误感知、超速起搏、脉冲发生器重置等异常现象发生,测试电池电量无损耗,扫描前、扫描后即刻以及扫描后1、6、12个月的电极导线参数未见明显异常变化(P>0. 05)。结论植入MRI兼容的起搏器患者进行1. 5 T的MRI扫描的安全性及稳定性均较好。     

左心室起搏部位与心脏再同步化治疗疗效关系研究

目的分析左心室电极导线(LVL)起搏部位与心脏再同步化治疗(CRT)疗效的关系。方法回顾性分析沈阳军区总医院早期因扩张型心肌病(DCM)行CRT治疗的82例患者的临床资料。根据左心室电极起搏的部位将患者分为心尖部组(n=15)和非心尖部组(n=67)。采用超声心动图测量两组患者的左心室射血分数(LVEF)、左室舒张末内径(LVEDD)。比较两组患者治疗前后的LVEF、LVEDD、QRS时限及美国纽约心功能分级(NYHA分级)变化情况。结果术后6个月,非心尖部组LVEF及LVEDD较术前及心尖部组均明显改善(P<0.05);心尖部组术前及术后6个月的LVEF、LVEDD比较,差异均无统计学意义(P>0.05)。非心尖部组术后QRS时限较术前明显缩窄,NYHA分级改善明显(P<0.05),与心尖部组比较,差异也有统计学意义(P<0.05);而心尖部组术后QRS时限、NYHA分级与术前比较,虽有改善,但差异无统计学意义(P>0.05)。结论左室电极导线起搏非心尖部较心尖部CRT疗效更佳,应尽量避免左室心尖部起搏。     

三腔起搏器囊袋感染电极拔除1例

三腔心脏起搏器(CRT)和植入型心律转复除颤器(ICD)显著的治疗效果已为人们所公认,随着起搏工程技术的飞速发展,起搏治疗的适应症也不断拓宽,尤其对于扩张型心肌病所致的心衰患者,特别是心电图ORS≥0.12s者,单纯药物治疗常常不能取得满意的效果,植入CRT能够取得较为满意的结果.此类患者一旦发生起搏系统感染,有效的治疗方法是将已被污染的电极导线取出体外[1],但由于左室电极置于冠状静脉窦内,血管壁薄,且易与血管发生粘连,给电极的拔出带来困难.     

希氏束起搏与普通起搏术中患者射线暴露的比较

目的 比较希氏束起搏（HBS）和右心室心尖起搏射线暴露的差异。方法 回顾性记录无锡市人民医院2018年8月至2020年1月并分析30例希氏束起搏患者（HIS组）的手术总体及各阶段皮肤表面累积入射剂量（CD）和透视时间,并与同期右心室心尖植入心室电极的双腔起搏器（RVA）的32例患者（RVA组）对比。结果 HIS组和RVA组的手术操作时间为（76.8±13.1）和（66.0±10.8）min（t=3.386,P<0.001）、透视时间为（698.2±113.7）和（293.3±63.9）s（t=14.709,P<0.001）、透视剂量为（391.3±70.0）和（162.3±40.5）mGy（t=13.694,P<0.001）;与右心室心尖电极植入过程相比,希氏束电极植入过程的透视时间[（501.2±112.3）和（103.4±30.6）s]及透视剂量[（279.9±65.0）和（57.3±13.8）mGy]明显增加（t=15.864,Z=-6.524,P<0.001）。结论 与右心室心尖起搏术相比,希氏束起搏手术时间更长,辐射剂量更大,需谨慎选择。     

Correlations of left ventricular diastolic parameters and heart rate: assessment through right ventricular pacing

This study evaluated the correlations between left ventricular (LV) diastolic parameters assessed by equilibrium radionuclide angiography (ERNA) and heart rate (HR) through right ventricular pacing. Twelve patients with a permanent right ventricular apex pacemaker were included. Serial ERNA studies were performed under 6 sets of pacing cycle length (heart rate=52, 62, 72, 82, 92, 104 beats/min) for each patient. The left ventricular ejection fraction was 49.9%±3.1 under pacing HR of 52 bpm and 43.8 %±3.1 % under pacing HR of 104 bpm. The peak filling rate (PFR) increased very significantly with HR (r=0.98, P < 0.001). When the relative changes of end-diastolic volume were taken into account, the correlation between PFR and HR remained significant (r=0.94, P <0.001). The absolute time to PFR (TPFR) did not significantly change with HR, but the ratio of TPFR to cycle length strongly correlated with HR. Our study clearly demonstrates that the PFR assessed by ERNA increases and the TPFR occupies an increasing proportion of the cycle length as HR increases. Therefore, LV diastolic parameters should be normalized for HR in clinical applications. In particular, HR changes should be considered when LV diastolic parameters are used for the assessment of therapeutic interventions. Offprint requests to: Z.-X. He     

The availability of task-specific feedback does not affect 20 km time trial cycling performance or test-retest reliability in trained cyclists

ObjectivesThis study examined the influence of the availability of task-specific feedback on 20 km time trial (20TT) cycling performance and test-retest reliability.DesignThirty trained, club-level cyclists completed two 20TT’s on different days, with (feedback, FB) or without (no-feedback, NFB) task-specific feedback (i.e., power output, cadence, gear and heart rate [HR]). Elapsed distance was provided in both conditions.MethodsDuring trials, ergometer variables and HR were continuously recorded, and a rating of perceived exertion (RPE) was collected every 2 km. Data were analysed using linear mixed-effects models in a Bayesian framework, and Cohen’s d was calculated for standardised differences. The reliability of finish time and mean power output (PO) was determined via multiple indices, including intraclass correlations (ICC).ResultsPerformance, pacing behaviour, and RPE were not statistically different between conditions. The posterior mean difference [95% credible interval] between TT1 and TT2 for FB and NFB was 10 s [−5, 25] and −2 s [−17, 14], respectively. In TT2, HR was statistically higher (∼8 b min⁻¹) in FB compared to NFB after 13 km (d = 2.08–2.25). However, this result was explained by differences in maximal HR. Finish time (FB: ICC =  0.99; NFB: ICC = 0.99) and mean power output (FB: ICC = 0.99; NFB: ICC = 0.99) in each condition were substantially reliable.ConclusionsThe availability of task-specific information did not affect 20TT performance or reliability. Except for elapsed distance, task-specific feedback should be withheld from trained cyclists when evaluating interventions that may affect performance, to prevent participants from recalling previous performance settings.     

Development of an MRI-compatible catheter for pacing the heart: Initial in vitro and in vivo results

An MRI-compatible catheter was developed for pacing the heart during MRI imaging. The device was tested in vitro and in vivo in 10 animal experiments, using spin-echo, gradient-echo, and echo-planar MRI sequences. Images were of good quality in all sequences. Pacing was effective without induced arrhythmias. Therefore, pacing the heart during MRI is feasible and seems to be safe when using dedicated hardware.     

Effect of expertise on pacing strategies and sprint performance in batsmen

Objectives

To assess whether the absence of a known endpoint, at the beginning of repeated-sprint bouts between the wickets, affects how skilled compared to less skilled batsmen pace themselves.

The reproducibility of 10 and 20 km time trial cycling performance in recreational cyclists,runners and team sport athletes

Objectives

This study aimed to determine the reliability of 10 and 20 km cycling time trial (TT) performance on the Velotron Pro in recreational cyclists, runners and intermittent-sprint based team sport athletes, with and without a familiarisation.

Assessment of right ventricular oxidative metabolism by PET in patients with idiopathic dilated cardiomyopathy undergoing cardiac resynchronisation therapy

Purpose Right ventricular (RV) performance is known to have prognostic value in patients with congestive heart failure (CHF). Cardiac resynchronisation therapy (CRT) has been found to enhance left ventricular (LV) energetics and metabolic reserve in patients with heart failure. The interplay between the LV and RV may play an important role in CRT response. The purpose of the study was to investigate RV oxidative metabolism, metabolic reserve and the effects of CRT in patients with CHF and left bundle brach block. In addition, the role of the RV in the response to CRT was evaluated.Methods Ten patients with idiopathic dilated cardiomyopathy who had undergone implantation of a biventricular pacemaker 8±5 months earlier were studied under two conditions: CRT ON and after CRT had been switched OFF for 24 h. Oxidative metabolism was measured using [¹¹C]acetate positron emission tomography (K_mono). The measurements were performed at rest and during dobutamine-induced stress (5 g/kg per minute). LV performance and interventricular mechanical delay (interventricular asynchrony) were measured using echocardiography.Results CRT had no effect on RV K_mono at rest (ON: 0.052±0.014, OFF: 0.047±0.018, NS). Dobutamine-induced stress increased RV K_mono significantly under both conditions but oxidative metabolism was more enhanced when CRT was ON (0.076±0.026 vs 0.065±0.027, p=0.003). CRT shortened interventricular delay significantly (45±33 vs 19±35 ms, p=0.05). In five patients the response to CRT was striking (32% increase in mean LV stroke volume, range 18–36%), while in the other five patients no response was observed (mean change +2%, range –6% to +4%). RV K_mono and LV stroke volume response to CRT correlated inversely (r=–0.66, p=0.034). None of the other measured parameters, including all LV parameters and electromechanical parameters, were associated with the response to CRT. In responders, RV K_mono with CRT OFF was significantly lower than in non-responders (0.036±0.01 vs 0.058±0.02, p=0.047).Conclusion CRT appears to enhance RV oxidative metabolism and metabolic reserve during stress. Patients responding to CRT appear to have lower RV oxidative metabolism at rest, suggesting that the RV plays a significant role in the response to CRT.     

不同部位起搏对缓慢性心律失常患者的疗效及对其LV相关指标和CQQC评分的影响初步评估

目的 探讨不同部位放置起搏器对缓慢性心律失常患者的疗效及对其左心室(left ventricular,LV)功能和患者生活质量的影响。方法 选取2020年1月-2021年12月海安市人民医院收治的83例缓慢性心律失常的患者,根据永久性起搏器植入的部位分为两组。其中研究组患者43例,采用右心室间隔植入心脏永久性起搏器治疗;对照组患者40例,则采用右心室心尖部植入心脏永久性起搏器治疗,比较两组患者的心功能情况、临床疗效、生活质量等差异。结果 植入术后研究组的左心室射血分数(left ventricular ejection fraction,LVEF)高于对照组,左心室舒张末期内径(left ventricular end diastolic dimension,LVEDD)和左心室收缩末期内径(left ventricular end-systolic dimension, LVESD)均低于对照组（P＜0.05）。植入术后研究组的心室机械收缩同步性指标及心肌受损相关指标低于对照组（P＜0.05）。植入术后两组的心脏不良事件发生率比较无差异（P＞0.05）。植入术后两组的生活质量均较术前升高,且研究组更高（P＜0.05）。结论 右心室间隔起搏可更为显著的改善缓慢性心律失常患者的心功能情况,同时不增加术后的并发症发生率,最终改善患者的生活质量。     

Migration of epicardial pacemaker leads.

The implantation of permanent pacemakers often gives rise to complications. Migration of leads, an unusual complication, occurred in two of our patients with epicardial pacemakers. In one case lead fracture and sussequent displacement due to heart action occurred after an automobile accident. In the second case looping and migration of the wire occurred within a day after implantation although the lead continued to function properly for six months. The probable cause of migration in this patient was excess slack.