双腔起搏器自动房室间期搜索功能的临床随访观察

目的 观察双腔起搏器自动房室间期搜索功能(AV Search)减少心室起搏的有效性及对血流动力学和快速房性心律失常的影响.方法 对两种DDD/R起搏器97例(有AV Search功能47例,无AV Search功能50例)患者术后半年内随访观察.结果 有AV Search功能组术后1、3、6个月右心室起搏百分比明显小于无AV Search功能组[(19.2±5.6)%vs(80.4±10.2)%,(17.8±6.6)%vs(75.3±9.5)%,(17.4±7.3)%VS[76.2±8.6]%,P<0.05].有AV Search功能组心脏指数、每搏量、左心室舒张末内径、左心房内径及患者心功能分级均无明显改善(P>0.05);而左心窒射血分数则高于无AV Search功能组(P<0.05).高频心房事件也显著减少((31±9)vs(49±11),P<0.05].结论 有AV Search功能DDD/R双腔起搏器在减少非必须的心室起搏,改善血流动力学,减少高频心房事件方面优于与无AV Search功能DDD/R起搏器.     

房室间期自动搜索功能起搏器对病窦综合征患者预后的影响

目的观察自动AV间期搜索功能双腔起搏器减少心室起搏的有效性及对心功能和快速房性心律失常的影响。方法 100例植入DDD/R起搏器的患者(有AV搜索功能50例,无AV搜索功能50例),术后1年内程控获取右室起搏百分比、高频心房事件、检查超声心动图及测试血浆心房利钠肽(ANP)值。结果有AV搜索功能组术后3,6,12个月右室起搏百分比明显小于无AV搜索功能组(18.7%±5.6%vs 82.4%±10.2%,19.8%±6.6%vs 77.3%±9.5%,18.4%±7.3%vs 79.2%±8.6%,P均<0.05)。有AV搜索功能组左室舒张末内径、左房内径、左室射血分数均明显改善(P均<0.05);ANP水平明显降低(203.10±28.20 pg/ml vs 298.80±31.50 pg/ml,P<0.05);高频心房事件也显著减少(18±9次vs 39±11次,P<0.05)。结论有AV搜索功能起搏器明显减少病窦综合征患者右室起搏比例,改善心功能,并减少高频心房事件。     

房室间期自动搜索功能对心室起搏及心功能的影响

目的 观察自动AV间期搜索功能双腔起搏器减少心室起搏和高频心房事件的效果及对心功能的影响.方法 60例置入DDD/R起搏器的患者（有AV搜索功能30例,无AV搜索功能30例）,术后1年内程控获取右室起搏百分比、高频心房事件,检查超声心动图,测试血浆利钠肽（BNP）值.结果 有AV搜索功能组术后6个月和12个月右室起搏百分比明显小于无AV搜索功能组[（21.2±6.0）％比（78.3±7.5）％,（19.1±6.5）％比（73.4±7.9）％,P均＜0.05）.AV搜索功能组左室射血分数、左室Tei指数均明显改善（0.57±0.03比0.53±0.05,0.48±0.15比0.68±0.20,P均＜0.05）;BNP水平明显降低[（75.2±34.5）pg/ml）比（37.0±16.4）pg/ml,P＜0.05];高频心房事件也显著减少[（42±10）次比（19±11）次,P＜0.05].结论 AV自动搜索功能起搏器可有效减少不必要的右室起搏及高频心房事件,改善血流动力学效应.     

双腔起搏器自动房室间期搜索功能的临床应用观察

目的观察双腔起搏器自动AV间期搜索功能(auto AV search)减少心室起搏的有效性及对心功能和快速房性心律失常的影响。方法43例植入具有自动AV间期搜索功能的双腔DDD(R)起搏器的患者,术后6个月内随机交叉关闭或打开AV search功能各3个月,分别在第一阶段(3个月末)、第二阶段(6个月末)程控获取心室起搏百分比(Vp)、高频心房事件及测试血浆BNP值。结果43例患者按计划完成随访,AV search关闭组心室起搏(VP)比例为78.0±10.3%,心房高频事件为58±15次,血浆脑钠肽(BNP)水平为333±30pg/ml;AVsearch打开组Vp比例为15.9±4.8%,心房高频事件为29±13次,BNP65±21 pg/ml,两者相比具有显著统计学差异(P<0.01)。结论双腔起搏器的auto AV search功能可有效减少非必须的心室起搏,促进自身心室激动。     

EnPulse起搏器自动化功能的临床研究

目的:通过对EnPulse起搏器安置患者的随访,了解心房及心室自动阈值管理、自动AV间期搜索等功能的安全性和有效性.方法:选取置入Enpluse E2D01起搏器患者15例,分别于起搏器置入后1个月及6个月时复查起搏器参数,包括起搏器最近1次自动测量的心房及心室起搏阈值,手动测量心房及心室起搏阈值,记录患者心室感知占心室总事件的比例,并记录由Search AV+所设定AV间期基础上的心室感知事件所占心室总事件的比例.结果:1个月及6个月随访时,手动测量心房及心室阈值与自动测量心房及心室阈值差异无统计学意义.术后病态窦房结综合征患者大部分心室事件为感知事件,其中绝大多数由search AV+功能参与.结论:EnPulse起搏器的自动AV搜索功能、心房及心室自动阈值管理是安全有效的.     

双腔起搏器最小化心室起搏功能的临床应用

目的探讨双腔起搏器的最小化心室起搏(MPV)功能减少心室起搏的有效性及对血流动力学及房颤发生率的影响。方法观察98例植入DDD/R起搏器患者(打开MPV功能组49例,关闭MPV功能组49例)术后3、6、12个月的随访结果。结果打开MPV功能起搏器组右室起搏百分比明显减少(P<0.05);打开MPV功能起搏器组房颤负荷百分比在术后6个月和12个月减少(P<0.05);两组在植入起搏器术前术后心脏指数、左室舒张末径、左房内径、左室射血分数比较均无统计学意义(P>0.05)。结论打开MPV功能起搏器组在减少不必要的右室起搏及减少房颤发生率方面均优于关闭MPV功能组。     

心脏起搏器自动化功能对老年患者心功能的影响

目的观察具有自动AV间期搜索和起搏模式策略自动化功能的双腔心脏起搏器对老年患者减少心室起搏的有效性。方法选择置入DDD/R型双腔心脏起搏器的老年病态窦房结综合征(SSS)患者123例,分为实验组66例,平均年龄(76.5±6.8)岁,置入具备自动AV间期搜索和模式策略功能的美敦力公司Adapta系列起搏器;对照组57例,平均年龄(73.1±7.4)岁,置入不具备上述2种功能的美敦力公司Sigma AED、MED系列起搏器。术后1年内随访,观察心功能(NYHA)、程控获取右心室起搏(VP)百分比、心脏彩色超声心动科进行左心房内径(LAD)、左心室舒张末内径(LVEDD)的测量,计算LVEF,抽血检测N末端前体钠尿肽(NT-proBNP)水平,并进行对比。结果与对照组比较,实验组术后1年VP百分比降低[(39.7±35.2)%vs(91.7±2.6)%,P=0.02],LVEDD、LAD、LVEF均明显改善,差异有统计学意义[(51.5±3.9)mmvs(53.9±3.6)mm,(38.2±2.6)mmvs(42.0±4.5)mm,(54.8±7.7)%vs(50.1±12.3)%,P<0.05,P<0.01),实验组术后1年NT-proBNP水平较对照组明显降低[(180.2±19.4)ng/Lvs(269.2±23.6)ng/L,P<0.01]。结论具有起搏自动AV间期搜索和模式策略自动化功能的双腔起搏器可减少老年SSS患者VP百分比,改善心功能。     

Kappa起搏器自动房室搜索功能对血流动力学的影响

目的:研究Kappa系列起搏器自动AV搜索功能对血流动力学的影响。方法:43例接受永久性心脏起搏器治疗的病人中Kappa起搏器组12例.普通DDD起搏器组31例。所有病人均于术前,术后3月行心脏彩超检查,比较两组病人左室射血分数(EF)差异,进行统计学分析。结果:Kappa起搏组EF值较普通DDD起搏组为高(P< 0.05)。结论:Kappa起搏组的自动AV搜索功能较普通DDD起搏组有更积极的血流动力学效果,能改善心脏功能。     

双腔起搏房室间期自动搜索功能对心室起搏及心功能的影响

选择30例接受具有自动AV间期搜索功能(auto AV search)的双腔DDD(R)起搏器治疗的病窦综合征患者。AV search打开时心室起搏(VP)比例,血浆脑钠肽(BNP)水平,左室Tei指数均较关闭时降低(P均<0.01),且血浆BNP水平、左室Tei指数与VP比例均存在较好的相关性(P均<0.05)。结论:双腔起搏器的auto AVsearch功能可有效减少非必须的右室起搏,促进自身心室激动,改善患者血流动力学效应。     

病态窦房结综合征患者房室全能型起搏不同房室间期对其心功能的影响

目的观察病态窦房结综合征患者在植入房室全能型(atrioventricular,DDD)起搏器后设置不同的房室(atrioventricular,AV)间期对其心功能的影响。方法收集南京医科大学附属淮安第一医院2013年至2014年行DDD起搏器治疗的病态窦房结综合征患者60例,通过AV间期150 ms、180 ms、240 ms将患者分为3组,每组20例。比较起搏器术前及不同随访时间的超声心动图指标、纽约心脏协会(New York Heart Association,NYHA)心功能分级、氨基末端脑钠肽前体(N-terminal pro-brain natriuretic peptide,NT-proBNP)、心室起搏比例情况。结果 3组患者在随访半年、1年、2年期间,150 ms组心室起搏比例最高(48.70%±8.44%、49.26%±8.86%、50.32%±7.67%),240 ms组最低(2.75%±1.29%、2.40%±1.27%、2.70%±9.23%)。3组随访期间左心房收缩末期内径(left atrial end diastolic dimension,LAESD)比较,差异无统计学意义(P0.05)。3组随访半年时的左心室舒张末期内径(left ventricular end diastolic dimension,LVEDD)、左心室射血分数(left ventricular ejection fraction,LVEF)、NYHA心功能分级、NT-proBNP比较,差异无统计学意义(P=0.068、0.206、0421、0.079);随访1年(P=0.004、0.020、0.035、0.001)、两年(P0.001、0.001、0.047、0.001)差异有统计学意义。将150 ms患者的AV间期程控为180 ms半年后随访,患者心室起搏比例降低(50.32%±7.67%vs. 9.89%±2.05%,P0.05),LVEDD缩小[(56.26±3.93)ms vs.(53.21±2.53)ms),P0.05],LVEF增加(46.05%±2.44%vs. 49.47%±3.66%,P0.05),NYHA心功能分级上升(2.33±0.69 vs. 1.67±0.57,P0.05)、NT-proBNP浓度下降[(551.37±28.31)pg/mL vs.(460.71±18.22)pg/mL,P0.05],差异有统计学意义。结论 DDD起搏器对患者心功能的影响与心室起搏比例、起搏时间有关,并且这种影响具有一定的可逆性。     

Randomized pilot study of a new atrial-based minimal ventricular pacing mode in dual-chamber implantable cardioverter-defibrillators

OBJECTIVE: We hypothesized that a new minimal ventricular pacing mode (MVP) that provides AAI/R pacing with ventricular monitoring and back-up DDD/R pacing as needed during AV block (AVB) would significantly reduce cumulative percent ventricular pacing compared to DDD/R. BACKGROUND: Conventional DDD/R mode often results in high cumulative percent ventricular pacing that may adversely affect ventricular function and increase risk of heart failure and atrial fibrillation. METHODS: MVP was made operational in 30 patients with DDD/R implantable cardioverter-defibrillators (ICDs) and no history of AVB. Patients were randomized to one week each in DDD/R and MVP. Holter monitor recordings (ECG, intracardiac electrograms, and event markers) and device diagnostics were analyzed for cumulative % atrial paced (Cum%AP), cumulative percent ventricular pacing, and frequency and duration of DDD/R pacing back-up. Diaries were used to report symptoms. RESULTS: Age of the study population was 61 years +/- 12 years and 83% were male. Baseline PR interval was 204 ms +/- 32 ms and programmed AV intervals (DDD/R) were 200 ms +/- 50 ms (paced)/167 ms +/- 54 ms (sensed). Cum%AP was similar between MVP and DDD/R (47.9 +/- 37 vs 46.3 +/- 36). Cumulative percent ventricular pacing was significantly lower in MVP vs DDD/R (3.79 +/- 16.3 vs 80.6 +/- 33.8, P < .0001). Back-up DDD/R pacing during MVP operation due to transient AVB occurred in 10% of patients (9.3 +/- 7.4 [range 1-15] episodes/patient-day, duration 39.7 minutes +/- 156 minutes). Fifteen percent of AV intervals during MVP operation exceeded 300 ms. No significant symptoms were reported during MVP operation. CONCLUSIONS: MVP dramatically reduced cumulative percent ventricular pacing compared to DDD/R while maintaining AV synchrony and providing sensor-modulated atrial pacing support. Intermittent oscillations between MVP and DDD/R during transient AV block appeared safe and well tolerated.     

Current Concepts in Pacing 2010–2011: The Right and Wrong Way to Pace

Over five decades have passed since the first permanent cardiac pacemakers were introduced into clinical medicine. Evolving technology and falling costs have demanded adaptation to clinical practice and implantation trends and, with the advent of evidenced-based medicine, the specific roles and benefits of individual pacemaker technologies have never been so carefully scrutinized. Pacing mode choice continues to be a subject of great controversy, and there are great regional variations in practice. We believe that single chamber atrial pacing use (AAI/R) has become an anachronism that should generally be abandoned (obviously with rare exceptional cases) and be replaced by dual chamber pacemakers (DDD/R) equipped with modern pacing algorithms that minimize patient exposure to ventricular pacing. Also, in patients with atrioventricular (AV) block, randomized clinical trials have failed to show improvement in clinically relevant outcomes such as mortality, stroke, and heart failure, particularly in the elderly, which has led some to advocate that DDD/R devices should never be offered to elderly AV block patients. However, we believe that the elderly, like the young, come in many “shapes and sizes” and individualized medicine compels us to consider each pacemaker candidate as unique. Implanting DDD/R devices in chronologically older, yet physiologically younger, patients is justifiable and good medical practice. Where right ventricular (RV) pacing is necessary and unavoidable, physicians should consider routinely placing RV leads on the RV mid- or outflow tract septum because these location are as good, if not better, for patients than the current practice of RV apical lead placement. In patients with AV block and asymptomatic yet moderate to severely depressed left ventricular systolic function, primary cardiac resynchronization therapy (CRT) should be strongly considered. Compelling clinical trial evidence does not yet exist to indicate that CRT should be the standard of care in patients with AV block and intact left ventricular systolic function. Right ventricular septal lead placement remains a reasonable option.     

Sustained improvement in exercise tolerance following physiological cardiac pacing

Fifty-three patients have received ‘physiological’pacemakers,37 with atrioventricular (AV) block having atrial synchronousunits (VAT or VDD) implanted and the remaining 16 patients withboth AV block and sick sinus syndrome having ‘universal’(DDD) pacemakers. Effort tolerance was assessed by serial bicycleergometry and in 16 patients direct comparisons between ventricularpacing and atrial synchronous pacing could be made acutely.Physiological pacemakers were found to increase maximum efforttolerance by 43% compared to pre-pacing values (P<0.01).The increase was sustained over a mean of 33 months post pacing.The atrial synchronous mode increased maximum effort toleranceby 34% acutely compared to ventricular inhibited pacing. Dualchambered ‘physiological’ pacemakers represent asignificant therapeutic advance over standard ventricular inhibitedpacemakers.     

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.     

Immediate impairment of left ventricular mechanical performance and force-frequency relation by rate-responsive dual-chamber, but not atrial pacing: Implications from intraventricular isovolumic relaxation flow

BACKGROUND: Despite the maintenance of atrioventricular (AV) synchrony, the detrimental effect of left ventricular asynchronization on mechanical performance and intraventricular flow by nonphysiologic right ventricular apical pacing in dual-chamber pacing, with and without rate adaptation, is not clear. METHOD: Twenty-seven consecutive patients receiving permanent pacemakers for symptomatic bradyarrhythmias (18 with DDD and 9 with AAI mode pacemakers) were evaluated with standard and tissue Doppler echocardiography before and 24 h after pacemaker implantation. The rate-response effect of pacing was studied by programmed rate with increments of 20, from 60 to 100/min. RESULTS: Color M-mode echocardiography demonstrated that much more DDD patients developed new biphasic intraventricular flow during isovolumic relaxation period than AAI patients (13/18 versus 0/9, P<0.001). In DDD patients, the ventricular relaxation represented by mitral annulus velocity in early diastole significantly attenuated (before vs. after DDDR, 8.5+/-2.8 vs. 5.2+/-1.2 cm/s, P<0.05), and also the mitral flow propagation velocity (33+/-11 vs. 25+/-5 cm/s, P<0.01). The myocardial performance index increased after DDD (0.70+/-0.15 vs. 0.79+/-0.24, P<0.05) but not after AAI (0.61+/-0.1 vs. 0.59+/-0.08, P=NS). For both pacing groups, the accelerated pacing rate prolonged the isovolumic relaxation time and shortened the diastole period (P<0.001). However, only DDD patients had a decreased mitral flow propagation velocity (P=0.026) and an attenuated force-frequency relation in programmed rate acceleration. CONCLUSION: Despite the AV synchrony, right ventricular apical pacing immediately attenuates the left ventricular contraction and relaxation performance, which deteriorated further and suppressed the physiologically positive force-frequency relation after accelerated pacing rate.     

Multicenter, prospective, randomized safety and efficacy study of a new atrial-based managed ventricular pacing mode (MVP) in dual chamber ICDs

BACKGROUND: Ventricular desynchronization caused by right ventricular pacing may impair ventricular function and increase risk of heart failure (CHF), atrial fibrillation (AF), and death. Conventional DDD/R mode often results in high cumulative percentage ventricular pacing (Cum%VP). We hypothesized that a new managed ventricular pacing mode (MVP) would safely provide AAI/R pacing with ventricular monitoring and DDD/R during AV block (AVB) and reduce Cum%VP compared to DDD/R. METHODS: MVP RAMware was downloaded in 181 patients with Marquis DR ICDs. Patients were initially randomized to either MVP or DDD/R for 1 month, then crossed over to the opposite mode for 1 month. ICD diagnostics were analyzed for cumulative percentage atrial pacing (Cum%AP), Cum%VP, and duration of DDD/R pacing for spontaneous AVB. RESULTS: Baseline characteristics included age 66 +/- 12 years, EF 36 +/- 14%, and NYHA Class II-III 36%. Baseline PR interval was 190 +/- 53 msec and programmed AV intervals (DDD/R) were 216 +/- 50 (paced)/189 +/- 53 (sensed) msec. Mean Cum%VP was significantly lower in MVP versus DDD/R (4.1 +/- 16.3 vs 73.8 +/- 32.5, P < 0.0001). The median absolute and relative reductions in Cum%VP during MVP were 85.0 and 99.9, respectively. Mean Cum%AP was not different between MVP versus DDD/R (48.7 +/- 38.5 vs 47.3 +/- 38.4, P = 0.83). During MVP overall time spent in AAI/R was 89.6% (intrinsic conduction), DDD/R 6.7% (intermittent AVB), and DDI/R 3.7% (AF). No adverse events were attributed to MVP. CONCLUSIONS: MVP safely achieves functional atrial pacing by limiting ventricular pacing to periods of intermittent AVB and AF in ICD patients, significantly reducing Cum%VP compared to DDD/R. MVP is a universal pacing mode that adapts to AVB and AF, providing both atrial pacing and ventricular pacing support when needed.