Determination of the optimal atrioventricular delay in DDD pacing. Comparison between echo and peak endocardial acceleration measurements.

The goal of this study was to compare two methods determining the optimal atrioventicular delay (AVD) in 19 patients implanted with the BEST-Living system for complete heart block. The definition of the optimal AVD was: the AVD with the echo method that provided the longest diastolic filling time without interruption of the A wave, and the AVD with the peak endocardial acceleration (PEA) method, corresponding to the knee of the PEA curve vs AV delay. The amplitude of the PEA was measured for every AVD programmed via an automatic scanner in steps of 60 to 300 ms (40 ms steps): in the VDD pacing mode with a low base rate, to obtain 100% sensed P waves; in DDD with a base rate = sinus rate + 20%, to obtain 100% paced P waves. Echocardiographic (Echo) measurement of the left ventricular filling time were performed in the same AV delay settings in VDD and DDD as the ones tested in the PEA method, which were manually programmed. The optimal AVDs obtained in DDD and those obtained in VDD were compared in the echo and the PEA tests by a paired Student's t-test. The optimal AVDs obtained by both Echo and by PEA were also compared by a paired Student's t-test in VDD and DDD. The r value of the correlation between the optimal AVDs obtained by Echo and those obtained by PEA was calculated. Similar values of optimal AVD were obtained with both methods. The optimal AVDs given by the Echo technique (179 +/- 25 ms in DDD and 124 +/- 18 ms in VDD) were slightly, but significantly shorter than the ones obtained with the PEA method (202 +/- 21 ms in DDD and 145 +/- 18 ms in VDD, P < 0.05). A highly significant difference between AVD VDD and AVD DDD was found with both methods (P < 0.001). The correlation between the AVDs obtained with the echo and the PEA methods was highly significant (r = 0.78, P < 0.01). Pacemaker software could be modified to determine automatically the optimal AVDs to be applied throughout the heart rate range.     

Ⅲ度房室传导阻滞患者行不同房室间期起搏对血流动力学及功能的影响

目的探讨Ⅲ度房室传导阻滞(AVB)患者不同房室间期(AVD)起搏对血流动力学及功能的影响。方法选择植入双腔起搏器的Ⅲ度AVB患者51例,按不同AVD分为前后4期:A期AVD为心房感知(SAV)90 ms、心室起搏(PAV)120 ms;B期为SAV 120 ms、PAV 150 ms;C期为SAV 150 ms、PAV 180 ms;D期为SAV 180 ms、PAV 210 ms。每期观察2个月,分别比较Ⅲ度AVB患者4期心电图QRS波时限和形态,血清氨基末端脑钠肽前体(NT-proBNP)水平及心脏超声左房内径(LAD)、左室收缩末期内径(LVDs)、左室舒张末期内径(LVDd)、室间隔厚度(IVST)、左室后壁厚度(LVPWT)、左室射血分数(LVEF)及二、三尖瓣返流等参数。结果Ⅲ度AVB患者行不同AVD起搏时LAD、LVDd、LVDs、IVST、LVPWT及LVEF无变化;而二尖瓣及三尖瓣返流随AVD的延长而依次减少;起搏QRS波时限A期较D期长(149.21±8.10 ms vs 145.27±6.94 ms,P<0.05);NT-proBNP随AVD的延长而减少(中位值分别为365.51,327.54,279.13和270.10 pg/ml)。结论Ⅲ度AVD患者不同AVD起搏对心脏血流动力学会产生影响,短期内对心脏的结构及功能影响不明显,选择起搏间期为SAV180 ms、PAV 210 ms时患者的获益最大。     

双腔起搏器不同房室间期起搏对心功能影响的研究

探讨双腔起搏器不同房室间期 (AVD)起搏对即时心功能的影响 ,并观察根据即时心功能调定的最佳房室间期对CHF患者长期疗效的影响。用M型和B型超声心动图比较了 6例无心力衰竭DDD起搏者和 14例CHFDDD起搏患者 (其中 13例存在缓慢型心律失常 )不同AVD起搏时心功能参数的变化。 14例CHFDDD起搏患者常规起搏 3个月后随机分为常规起搏组 (7组 )和最佳房室间期起搏组 (7例 ) ,起搏 3个月后随访心功能 (NYHA分级 )和心室腔径的改变。结果 :CHF组和无心力衰竭组不同AVD起搏时各项心功能指标变化均无差异 (P >0 .0 5 ) ;常规起搏组和最佳AVD起搏组起搏 3个月后NYHA分级和心室腔径无显著变化 (P >0 .0 5 )。结论 :经调定的短AVDDDD起搏不能改善CHF患者的心功能和心室重构。不宜将双腔起搏器最佳AVD起搏作为CHF患者的常规非药物疗法 ,对因纠治心脏电学异常而安装DDD起搏器的CHF患者 ,在无其他证据之前仍宜采用常规AVD起搏     

CP13: OPTIMALIZATION OF AV INTERVAL (AVD) BY THE METHOD USING PULSE OXIMETRY SIGNAL AMPLITUDE CHANGES: EXPERIENCE FROM YEARS 1996-2002

PURPOSE: To optimize the AV delay in sequentially paced patients usinga method with beat-to-beat amplitude changes in the pulse oximetrysignal. PATIENTS AND METHOD: A total of 94 patients with dual chamber pacemakers (60 men)were studied. Patients with a pacemaker enabling to change AVDat constant RR intervals were included. The beat-to-beat changesin the pulse oximetry signal amplitude were produced by instantaneouschange of DDI to VVI mode from various AVD (50-250 ms). Theseamplitude drops served to calculate atrial contribution (AC).The oAVD corresponded to the maximal AC obtained. RESULTS: From the whole group, 58 patients had repeated examinationswithin a time range of an hour to a year to evaluate the stabilityof the oAVD and reproducibility of the relationship betweenindividual ACs and AVDs. A total of 193 evaluations were performed.Thecurve illustrating the dependence of ACs on AVDs was stablewith time. A total of 108 examinations produced clear resultsshowing an oAVD to be within the AVDs 100 and 250 ms. The remaininginvestigations either showed that the patient did not exhibitany changes in AC with regard to AVD between 100 and 250 ms(47 cases) or that the optimal AVD was even beyond the maximaltested AVD (38 cases). AV delays below 100 ms were unexceptionallydetrimental in all patients. In most (81) cases there was arise in ACs in AVDs between 50 and 175 ms but additional increasein AVDs produced no significant change in ACs. In patients withheart failure the oAVD was longer than in healthy patients (36cases). CONCLUSIONS: The described method enables to identify the optimal AV intervalin DDD paced patients non-invasively, rapidly and observer-independently.The optimal AVD is rather stable and does not seem to exhibitan intraindividual variation even within a long period of time.     

不同房室间期对双腔起搏左室收缩功能的影响

为探讨双腔起搏不同房室间期对左室收缩功能的影响及最佳房室间期 ,选择 18例置入DDD起搏器的病窦综合征患者 ,在DOO起搏方式下随机将房室 (AV)间期程控为 10 0 ,130 ,15 0 ,170 ,2 0 0ms,在超声心动图下观察左室收缩功能指标 ,每次测量间隔 5min以上。结果 :AV间期为 15 0ms时左室收缩功能最好 ,与AV间期为 10 0ms时相比 ,左室收缩功能明显改善。以心输出量 (CO)为标准 ,18例中有 9例AV间期在 15 0ms时CO最佳 ,5例在 2 0 0ms时CO最佳 ,3例在 170ms时CO最佳 ,1例在 130ms时CO最佳 ;以CO为标准 ,DOO起搏方式最佳AV间期为 16 6±2 4ms。结论 :双腔起搏的AV间期对左室收缩功能有重要的影响 ,以CO为标准 ,个体化地选择双腔起搏的最佳AV间期对改善患者的心脏功能有重要的意义。     

The effect of different atrioventricular delays on left atrium and left atrial appendage function in patients with DDD pacemaker

Background: Although it has been known that optimization of atrioventricular delay (AVD) has favorable effect on the left ventricular functions in patients with DDD pacemaker, the effect of different AVDs on left atrium (LA) and left atrial appendage (LAA) functions has not been exactly evaluated. The aim of the present study was to assess the effect of different AVDs on LA and LAA functions in DDD pacemaker implanted patients with atrioventricular block. Methods: Forty‐eight patients with DDD pacemaker were enrolled into the study. Patients were divided into two groups according to the echocardiographic diastolic function: Group I (normal diastolic function) and Group II (diastolic dysfunction). LAA emptying velocity on pulsed wave Doppler and LAA late systolic wave velocity by using tissue Doppler were recorded. Patients were paced for five successive continuous pacing periods of 10 minutes duration using five selective AVDs (80–250 ms). Results: Significant effect on LA and LAA functions has not been observed by the setting of AVD in Group I. However, when the AVD was gradually shortened form 150 ms to 80 ms, LA and LAA functions gradually decreased in Group II patients. When AVD increased to 200 ms, LA and LAA functions were improved. Further increase in AVD resulted in decreased LA and LAA functions. Conclusion: Setting of AVD has not significant effect on the LA and LAA functions in patients with normal diastolic function, but moderate prolongation of AVD in physiological limits improved LA and LAA functions in DDD pacemaker implanted patients with diastolic dysfunction. (Echocardiography 2011;28:626‐632)     

Preimplantation echo Doppler evaluation of VVI versus DDD pacing

This study was carried out to select before permanent pacemaker implantation patients with complete atrioventricular block (CHB) who would benefit best from DDD pacing, and to determine the optimal atrioventricular delay (AVD) for each of those patients. This was achieved with the aid of Doppler echocardiography. The effect of different AVDs on both the systolic and diastolic function of the normal and failing heart was also delineated in this study. METHODS: Thirty patients with CHB and normal sinoatrial function were selected, with no age or sex predilection. These patients were categorized into three equal groups: groups A, B, and C with normal left ventricular (LV) systolic and diastolic function, LV diastolic dysfunction, and LV systolic dysfunction, respectively. For each patient, systolic and diastolic function was calculated utilizing echo Doppler during CHB, temporary VDD pacing with different AVDs, and temporary VVI pacing with a rate matching that during VDD mode. Temporary VDD mode of pacing was performed utilizing a temporary bipolar ventricular lead for ventricular pacing and an esophageal lead for atrial sensing to trigger ventricular pacing. RESULTS: Qualitatively the most obvious change in the pattern of LV filling as AVD is increased in the three groups, is the earlier occurrence of active atrial filling A wave due to progressive approximation of the ECG P wave toward the previous QRS. As the AV interval is increased, the following changes occur: (a) A wave occurs progressively earlier with superimposition onto the early filling E wave resulting in a progressive increase in its velocity (VA), its FVI, and its percent atrial contribution (%AC); (b) the three times diastolic filling time (DFT), mitral valve opening to Q wave (MVO-Q), and closure (Q-MVC) progressively shorten; (c) since DFT decreases, less passive filling occurs early during diastole, thus E.FVI decrease with longer AV intervals; (d) the ratios VE/VA and FVI E/A decrease subsequently to the previous described changes. Compared to CHB, percent ejection fraction (% EF) was not significantly changed during VVI pacing. Percent EF increased significantly during VDD in comparison to VVI pacing modes. Percent EF was highest at optimal AVD and decreased as this AVD increased or decreased. The cardiac output (CO) increment during VDD in comparison to VVI pacing modes differed much among the three groups. In group A, a 10.29% increase in CO was seen when comparing VDD pacing (with optimal AVD) with that of VII one; in group B, this increment was much greater and reached 29.48%; in group C it reached 23.68%.(ABSTRACT TRUNCATED AT 400 WORDS)     

Therapeutic optimization of atrioventricular delay in cardiosurgical ICU patients by noninvasive cardiac output measurements versus pulse contour analysis

BACKGROUND: Optimizing atrioventricular (AV) delay improves cardiac output and postoperative outcome. Impedance cardiography (ICG) is a non-invasive method for CO measurement. This study evaluates the ability of two ICG methods to determine the optimal AV delay (OAVD) and to compare ICG with invasive PICCO measurements. METHODS: In 14 cardiosurgical ICU patients (age 70.4 +/- 12.0 yrs) with temporary pacing wires, OAVD was determined by pulse contour analysis (PICCO) and ICG (conventional ICG [CI] and electrical velocimetry [EV] ICG monitors). Cardiac output (CO) and stroke volume (SV) were measured during DDD pacing with AVD varying from 70 to 270 ms in 20-ms increments. RESULTS: Measured OAV showed a linear correlation between PICCO and ICG: CI (r = 0.82, P < 0.0002) and EV (r = 0.84, P < 0.0002). The mean OAVD deviation between PICCO and ICG was 15.7 +/- 21.0 ms (CI) and 17.1 +/- 20.5 ms (EV). Hemodynamic parameters (SV increase OAVD against worst case) improved significantly (+ 11.7 +/- 7.2 %, P < 0.0001). CONCLUSION: Inappropriate selection of AVD can compromise the hemodynamic situation of cardiosurgical patients. As it is totally noninvasive, ICG is a reliable and effective tool for tailoring AVD. Both systems (CI and EV) offer valid OAV determination.     

Severe atrioventricular decoupling, uncoupling, and ventriculoatrial coupling during enhanced atrial pacing: incidence, mechanisms, and implications for minimizing right ventricular pacing in ICD patients

Background: Enhanced AAI/R pacing minimizes right ventricular pacing but may permit or induce AV decoupling (AV‐DC) due to unrestricted AV intervals (AVIs). The purpose of this study was to characterize and quantify AVI behavior in a randomized trial of enhanced AAI/R pacing in ICD patients. Methods: One hundred twenty‐one patients in the Marquis ICD MVP? Study, a randomized 1‐month crossover comparison of cumulative% ventricular pacing (Cum%VP) in enhanced AAIR (MVP) vs DDD/R, were analyzed. AV‐DC was defined as ≥40% AVIs >300 ms; VA coupling (VA‐C) was defined as%V‐atrial pace (AP) intervals <300 ms. Dynamic AVI behavior and increases in Cum%VP due to AV block (AV uncoupling, AV‐UC) were characterized using Holters with real‐time ICD telemetry. Results: AV‐DC occurred in 17 (14%) of patients. Baseline PR, amiodarone, nighttime, lower rate >60 beats/min, rate response, and Cum%AP were associated with longer AVIs. Logistic regression identified baseline PR (odds ratio [OR]= 1.024, 95% confidence interval [CI] 1.007–1.042; P = 0.005), and Cum%AP (OR = 1.089, 95% CI 1.027–1.154; P = 0.004) as predictors of AV‐DC. AV‐DC was associated with ≈10‐fold increases in both Cum%VP (13.6 ± 28.3% vs 1.2 ± 3.9%; P = 0.023) due to transient AV‐UC) and VA‐C (6.0 ± 17.5% vs 0.5 ± 1.2%, P = 0.028). AV coupling (<40% AVIs >300 ms) was preserved in 104 (86%) patients. Conclusions: AV‐DC, VA‐C, and AV‐UC may be worsened or induced by enhanced AAI/R pacing. Conservative programming of lower rate and rate response should reduce the risk of AV‐DC by reducing Cum%AP.     

双腔起搏房室延迟优化对心功能及神经内分泌因子的影响

观察双腔起搏不同房室延迟(AVD)对即刻心功能的影响,并探讨以优化的AVD起搏对心功能及神经内分泌因子的影响。用SwanGanz导管和彩色多谱勒心脏超声仪分别测定20例心功能ⅡⅢ级患者不同AVD起搏时心功能参数的变化,将心排血量(CO)最大的和/或平均肺毛细血管楔嵌压(MPCWP)下降最明显的AVD定为优化AVD。其后,所有患者分别进行8周常规AVD及8周优化AVD起搏,分别在8周结束时对患者进行心脏B超测试及测定血浆内皮素(ET)、心钠素(ANP)、肾素活性(PRA)、血管紧张素Ⅱ(AngⅡ)、醛固酮(ALD)。结果:根据心导管及心脏B超测量的优化AVD分别为134±13ms及131±12ms。优化AVD组较常规AVD组对左室收缩功能指标有改善,但未达有统计学显著性差异。左室舒张功能指标在优化AVD组较常规AVD组明显改善。神经内分泌因子在优化AVD组较常规AVD组明显减低。结论:优化AVD起搏对心力衰竭患者远期心功能有改善作用,能明显降低有关神经内分泌因子。     

心房起搏脉冲传导延迟患者AV问期的优化

目的探讨心房起搏至心房除极波时间延迟患者设置起搏的房室间期（PAV）的方法及远期心房起搏的有效性。方法分析2005年1月至2012年12月我院起搏器植入后发生心房起搏至心房除极波时间延迟≥lOOms的患者10例,病窦综合征（SSS）患者的房室间期设置为最大值,并最大限度开启房室问期滞后功能;对房室传导阻滞（AVB）患者设置PAV的值为：140～180ms＋心房起搏至心房除极波延迟时间,不开启AV滞后。结果经1个月至7年随访,5例SSS患者心室起搏比例〈10％,3例SSS患者心室起搏比例30％。50％,Holter显示心室起搏时为假性融合波,l例SSS患者及1例AVB患者为心室起搏心律,起搏比例〉99％,保证了房室问期的生理性。10例患者心房起搏阈值均〈1．5／0．4ms,未发生心房起搏阈值增高及失夺获。结论心房起搏至心房除极波时间延迟患者远期的心房起搏夺获是安全的;设置起搏器PAV间期要将心房起搏至心房除极波延迟时间计算其中,程控随访中应注意观察程控仪中监护图的心房波,房室传导阻滞患者可延长房室间期后观察心房波,部分患者因监护导联显示不清,需要通过12导联心电图进行观察,避免心房起搏至心房除极波延迟病例被遗漏．导致增加心室起搏及非生理性的房室间期。     

Should we use the rate-adaptive AV delay in cardiac resynchronization therapy-pacing?

AIMS: Recommendations for programming the rate-adaptive AV delay in CRT. METHODS AND RESULTS: In cases of continual biventricular pacing, the optimal AV delay in CRT (AVD(opt)) is the net effect of the pacemaker-related interatrial conduction time (IACT), duration of the left-atrial electromechanical action (LA-EAC(long)), and the duration of the left-ventricular latency period (S(V)-EAC(short)). It can be calculated by AVD(opt) = IACT+LA-EAC(long)-S(V)-EAC(short). We measured these three components in 20 CRT-ICD patients during rest and submaximal ergo metric exercise (71 +/- 9 W) resulting in a 22.5 +/- 9.6 bpm rate increase. IACT and S(V)-EAC(short) did not reveal significant differences. LA-EAC(long), however, varied significantly by -10.7 +/- 16.1 ms (P = 0.008) during exercise. In contrast to AVD(optVDD), there was a significant difference in AVD(optDDD) of -8.8 +/- 14.5 ms (P = 0.014) between the resting and submaximal exercise conditions. In DDD pacing, AVD(opt) was shortened by 2.6 ms/10 bpm. CONCLUSION: In consideration of the findings of the studies performed to date, the rate-adaptive AV delay should be deactivated.     

Haemodynamic benefit of a rate-adapted A-V delay in dual chamber pacing

In dual chamber pacing, an improvement of exercise capacityis expected when the atrial refractory period is shortened,because the 2/1 point is increased. This objective can be achievedby greatly reducing atrio-ventricular delay (AVD) on exercise.Are such variations (up to 100–120 ms) detrimental froma haemodynamic standpoint? This study was performed to analysethis particular aspect of DDD pacing. Three DDD pacing modes,differing by their AVDs (fixed 200 ms AVD, fixed 150 ms AVD,and rate-adapted AVD) were tested in random order, with a haemodynamicprotocol including ten patients with chronic atrio-ventricular(A-V) block. For the rate-adapted AVD pacing mode, AVD was reducedby 20 ms every 10beats min^–1 increment (from 220 ms at90 beats min^–1 to 100 ms at 150 beats min^–1). Pacingrate was increased from 90 to 150 beats min^–1 by incrementsof 10 beats min^–1 every 5 min. Cardiac performance was significantly improved with the rate-adaptedAVD above the two fixed AVDs, despite a large A VD variation.When A VD was rate adapted, cardiac index, stroke volume indexand left ventricular systolic work index were generally higherand pulmonary capillary wedge pressure, pulmonary arterial pressureand systemic vascular resistances were generally lower, especiallyat 120, 130 and 140 beats min^–1. Comparing the two fixedAVDs, 200 AVD improved cardiac function more at lower heartrates, whereas 150 AVD improved cardiac function more at higherheart rates. Despite its limitations, this study demonstratesthat the potential benefits of reducing AVD with increasingheart rates should be twofold in dual chamber pacing:

1. haemodynamic,optimizing cardiac performance on exercise forall heart rates,especially in cases of organic heart disease;
2. electrophysiologic,permitting a sufficiently rapid maximaltracking rate in caseswith long post-ventricular atrial refractoryperiods, allowinga satisfactory level of exercise.

     

双腔起搏器不同房室延迟对左心房功能的影响

目的：探讨双腔起搏器不同房室延迟（AVD）起搏时对左心房功能的影响。方法：选择植入双腔起搏器的40例患者,分为舒张功能正常组（20例）和舒张功能不全组（20例）。应用实时三平面应变率成像分别测算两组患者在不同AVD时左心房心肌在收缩期、舒张早期和舒张晚期平均峰值应变率（SRs、SRe和SRa）。结果：在舒张功能正常组,不同AVD起搏对左心房功能的影响不显著（P〉0．05）。在舒张功能不全组：①AVD自80ms开始增至250ms时,SRa随AVD的延长相应增大,在AVD为200ms时达到最大,达峰值后又逐渐下降,AVD为150ms、200ms时SRa和LAEF较AVD为80ms、100ms、250ms时明显升高[SRa：（-2．87±0．50）S-1、（-3．14±0．44）S-1,比（-2．35±0．53）S-1、（-2．55±0．52）S、（-2．55±0．49）S-1,LAEF：（46．00±3．67）％、（51．22±3．33）％比（37．99±3．56）％、（39．64±3．08）％、（43．78±3．83）％,P〈0．05];②当AVD为80ms、250ms时,SRs增大,SRe减小;AVD为200ms时SRs明显低于AVD为80ms时[（3．02±0．56）S。比（3．27±0．62）S-1,P〈0．05]。结论：不同房室延迟对舒张功能正常患者左心房功能的影响不明显,但对于单纯舒张功能不全的患者,适当延长房室延迟更有利于左心房的功能,改善血流动力学。     

Interatrial conduction measured during biventricular pacemaker implantation accurately predicts optimal paced atrioventricular intervals

Background: Optimizing atrioventricular (AV) delay during biventricular (BiV) pacemaker implantation can require substantial resources. Hence, a simpler method is desirable. We hypothesized that interatrial conduction time (IACT), measured at the time of BiV device implant, could be a surrogate value for the optimal AV delay.
Objective: This study determined the relationship between paced IACT and the optimal paced AV delay (PAV), as determined by echocardiography.
Methods: Consecutive subjects (N = 25; age = 66 ± 10 years; M/F: 17/8) undergoing BiV pacemaker implantation and in sinus rhythm were included. Cannulation of the coronary sinus (CS) was at the operator's discretion. A quadripolar electrophysiology catheter was inserted via the guiding sheath into the inferiolateral CS to measure left atrial depolarization. The IACT was calculated as the interval between right atrial stimulation artifact and earliest deflection on the coronary sinus catheter electrogram. Subsequently, during atrial pacing the PAV was determined using transmitral pulsed wave Doppler echocardiography (iterative method). The relationship between paced IACT and PAV was then determined.
Results: The mean ± SD paced IACT and PAV were 126 ± 25 msec and 157 ± 23 msec, respectively. There was a strong positive correlation between the paced IACT and PAV (r = 0.73, P < 0.001). The equation describing the relationship was PAV = 0.68 * (IACT + 104) msec.
Conclusions: The paced IACT has a strong correlation with the echo derived optimal PAV. This method may be used to program PAV intervals without need for echocardiography in patients undergoing BiV pacemaker implantation.     

双腔起搏器置入患者最佳房室延迟不同设置方法的临床研究

对不同最佳房室延迟(OAVD)设置方法进行比较,探讨OAVD设置的简单、实用的方法。选择36例置入双腔起搏器的患者,设置不同的AVD,于超声心动图下记录左室射血分数(EF)、舒张期二尖瓣返流、A波结束至二尖瓣完全关闭的时间间期(Time1)、最早出现舒张期二尖瓣返流的AVD(临界AVD),并通过同步心电图测定QT间期(QTI)、QT离散度(QTD)及QRS波群时间(QRSI)。将各指标预测的OAVD与OAVD(EF最大时的AVD)进行比较。结果:①心功能正常者心房起搏或心房感知时在AVD为170ms或140~160ms时EF达到最大,且与OAVD时EF相比差异均无显著性;心功能不全者在AVD为130~140ms时EF达到最大,但与OAVD时EF相比差异有显著性。②三种心电图指标预测的OAVD与OAVD比较差异均无显著性,其预测的OAVD在心功能不全患者与OAVD显著相关。③预测OAVD、AVD=200或180ms时预测的OAVD与OAVD比较差异均无显著性。结论:在实际工作中,可通过下述简单方法设置OAVD:OAVD=200ms(或180ms)减去200ms(或180ms)时Time1,以提高随访效率。     

The optimized V-V interval determined by interventricular conduction times versus invasive measurement by LVdP/dtMAX

Introduction: We compared the calculated optimal V‐V interval derived from intracardiac electrograms (IEGM) with the optimized V‐V interval determined by invasive measurement of LVdP/dt_MAX. Methods and Results: Thirty‐two patients with heart failure (six females, ages 68 ± 7.8 years) had a CRT device implanted. After implantation of the atrial, right and a left ventricular lead, the optimal V‐V interval was calculated using the QuickOpt? formula (St. Jude Medical, Sylmar, CA, USA) applied to the respective IEGM recordings (V‐V_IEGM), and also determined by invasive measurement of LVdP/dt_MAX (V‐V_dP/dt). The optimal V‐V_IEGM and V‐V_dP/dt intervals were 52.7 ± 18 ms and 24.0 ± 33 ms, respectively (P = 0.017), without correlation between the two. The baseline LVdP/dt_MAX was 748 ± 191 mmHg/s. The mean value of LVdP/dt_MAX at invasive optimization was 947 ± 198 mmHg/s, and at the calculated optimal V‐V_IEGM interval 920 ± 191 mmHg/s (P < 0.0001). In spite of this significant difference, there was a good correlation between both methods (R = 0.991, P < 0.0001). However, a similarly good correlation existed between the maximum value of LVdP/dt_MAX and LVdP/dt_MAX at a fixed V‐V interval of 0 ms (R = 0.993, P < 0.0001), or LVdP/dt_MAX at a randomly selected V‐V interval between 0 and +80 ms (R = 0.991, P < 0.0001). Conclusion: Optimizing the V‐V interval with the IEGM method does not yield better hemodynamic results than simultaneous BiV pacing. Although a good correlation between LVdP/dt_MAX determined with V‐V_IEGM and V‐V_dP/dt can be constructed, there is no correlation with the optimal settings of V‐V interval in the individual patient.     

双腔起搏器不同房室延迟时心功能及QT间期的变化

观察DDD起搏不同房室延迟 (AVD)时心功能与体表心电图QT间期的变化 ,探讨根据心电图QT间期优化AVD的可行性。选择 19例完全性房室阻滞置入DDD永久人工心脏起搏器患者 ,男 10例 ,女 9例 ,年龄 6 6 .79±15 .5 2岁 ,采用彩色多普勒超声心动图测量不同AVD起搏时每搏输出量 (SV)、心排量 (CO)、左室收缩末期内径和舒张末期内径 (LVESd/LVEDd)、左室射血分数 (LVEF)等 ,同时单盲测量不同AVD起搏时 12导联心电图QT间期。心房起搏频率预设为 75次 /分 ,AVD自 90ms起以 30ms步长依次递增至 2 4 0ms。结果 :随着AVD的递增 ,心功能和QT间期随之改善和延长 ,达峰值后又逐渐下降。超声心功能最佳时所对应的AVD与QT间期最长时所对应的AVD无显著差异 (15 8.80± 13.6 4msvs 16 3.30± 30 .4 1ms;P >0 .0 5 ) ;QT间期最长时所对应的心功能各参数与最佳超声心功能各参数相似 (CO :6 .2 9± 1.75L/minvs 6 .5 0± 1.5 4L/min ;SV :87.37± 17.0 9ml/bpmvs91.4 7± 16 .2 5ml/bpm ;LVEF :0 .6 6± 0 .11vs0 .6 7± 0 .11;P均 >0 .0 5 ) ;QT与CO、SV呈显著正相关 (相关系数分别为0 .70 ,0 .6 7,P <0 .0 5 ,0 .0 0 1)。结论 :AVD对心功能有明显影响 ;QT间期随不同AVD时心功能变化而发生变化 ;通过测量体表心电图QT间期可优化     

How can the rate-adaptive atrioventricular delay be programmed in atrioventricular block pacing?

AIM: To optimize recommendations for programming of the rate-adaptive atrioventricular (AV) delay. METHODS AND RESULTS: Optimal AV delay (AVD(opt)) is the net effect of the pacemaker-related interatrial conduction time (IACT), duration of the left-atrial electromechanical action (LA-EAC(long)) and duration of left-ventricular latency (S(V)-EAC(short)). It can be calculated by AVD(opt) = IACT + LA-EAC(long)-S(V)-EAC(short). We measured these three components in 20 DDD pacemaker patients (EF >45%) with the third degree AV block (AVB) at rest and submaximal ergometric exercise load of 71 +/- 9 W which resulted in a 31.5 +/- 9.9 bpm rate increase. Between exercise and rest, the components of and the final AVD(opt) showed no significant differences. Interatrial conduction time in VDD and DDD pacing varied by 2.3 +/- 8.4 ms and 1.4 +/- 8.8 ms, respectively, S(V)-EAC(short) changed by -2.6 +/- 21.8 ms and AVD(opt) by -3.5 +/- 33.3 ms and -4.3 +/- 37.8 ms in VDD and DDD operation, respectively. The greatest variation was of LA-EAC(long) by -8.4 +/- 32.7 ms. Linear regressions of the rate-dependent variations (Deltaf) in VDD operation yielded DeltaIACT(f) = 0.04Deltaf + 0.95 ms, DeltaLA-EAC(long) = -0.59Deltaf + 10.1 ms, and DeltaS(V) - EAC(short) = 0.14Deltaf -7.2 ms which resulted in DeltaAVD(opt) = -0.69Deltaf + 18.2 ms. CONCLUSION: A recommendation for programming of rate-adaptive AV delay in AV block patients cannot be given.     

Long-term follow-up of atrioventricular delay optimization in patients with biventricular pacing.

BACKGROUND: Atrioventricular (AV) delay optimization may be important in patients with biventricular pacing and the optimal AV delay can be predicted using Doppler echocardiography and the formula: optimal AV delay = AV delay-the interval between the end of A wave and complete closure of the mitral valve when the AV delay is set at slightly prolonged AV delay. METHODS AND RESULTS: In the present study the efficacy of this method was evaluated in 5 patients (67.4+/-8.0 (SD) years old) with biventricular pacing. Cardiac output (CO) and diastolic filling time were measured by Doppler echocardiography. When the AV delay was set at the predicted optimal AV delay -25 ms, the predicted optimal AV delay (133+/-66 ms) and predicted optimal AV delay + 25 ms, the respective CO were 4.5+/-0.9, 5.3+/-1.0, 4.8+/-1.0 L/min (p<0.05, ANOVA) and the diastolic filling times were 364 +/-100, 373+/-105, 335+/-84 ms (p<0.05, ANOVA). Congestive heart failure improved from New York Heart Association class 3.6+/-0.5 to 1.4+/-0.5 (p<0.001). CONCLUSIONS: AV delay optimization is important in patients with biventricular pacing and can be easily achieved by the new method.