低位房间隔起搏与右心耳起搏的临床对比研究

目的 探讨低位房间隔起搏与右心耳起搏在植入操作时间、起搏参数方面的差异.方法 选取40例因窦房结功能障碍或成人获得性房室传导阻滞导致的缓慢型心律失常行起搏治疗的患者分为两组.其中,房间隔组20例,采用主动固定螺旋电极行低位房间隔起搏;右心耳组20例,采用被动固定翼状电极行右心耳起搏.对比两组电极植入操作时间,电极植入时、术后1个月、3个月的起搏参数（阈值和阻抗）.结果 房间隔组与右心耳组比较,心房电极植入操作时间和起搏参数在术中、术后1个月、3个月差异均无统计学意义（P＞0.05）.结论 低位房间隔起搏与右心耳起搏具有相似的电极植入操作时间以及相同的起搏参数,为临床起搏治疗的有效部位.     

不同部位起搏对阵发性心房颤动患者心房激动时间的影响

目的　比较右心耳 (RAA)、冠状窦远端 (DCS)、右心房双部位 (右心耳加冠状窦口 ,DSA)和双房 (右心耳加冠状窦远端 ,Bi A)起搏对阵发性心房颤动 (PAf)患者心房激动时间的影响。方法 2 2例接受心脏电生理评价试验的PAf患者在窦性心律下行心房不同部位起搏 ,同步记录 12导心电图 ,测量最大 P波时限。结果　与窦性 P波时限相比 ,RAA起搏明显延长 P波时限 (P<0 .0 1) ,DCS、DSA及 Bi A起搏则明显缩短 P波时限 (P<0 .0 1,P<0 .0 1,P<0 .0 1)。结论　 DCS、DSA及 Bi A起搏明显缩短心房激动时间 ,减少心房电活动的离散度 ,有利于 PAf的防治。     

Electrical characteristics of low atrial septum pacing compared with right atrial appendage pacing.

AIM: The study was designed to compare the electrical characteristics of atrial leads placed in the low atrial septum (LAS) with those placed in the right atrial appendage (RAA) associated with dual chamber pacing. METHODS: In 86 patients an active-fixation (St. Jude Medical's Tendril DX model 1388T) atrial lead was positioned in RAA and in 86 patients the same model atrial lead was placed in the LAS. Pacing thresholds, sensing thresholds, impedances and the Far Field paced R-Wave (FFRW) amplitude and timing were compared at 6 weeks and at 3 and 6 months. RESULTS: The pacing threshold did not differ between groups. Sensed voltage of the P-wave was higher in the LAS compared with the RAA at 3 and 6 months (P=0.004). Impedance was higher in the LAS at 6 weeks and 3 months (P=0.002) but this difference was no longer significant at 6 months (P=0.05). The atrial sensed FFRW voltage was significantly higher in the LAS position compared with the RAA at 3 and 6 months follow-up (P=0.0002). FFRW voltage>1 mV was seen in 87% of the RAA pacing group and in 94% of the LAS pacing group (P=ns). The time between the ventricular pacing stimulus and the sensed FFRW in the atrium, (V spike-FFRW) in RAA was longer than in LAS at all follow-up measurements (P=0.006). CONCLUSIONS: The electrical characteristics of LAS pacing makes this alternative position in the atrium safe and feasible. Though statistical differences were found in P-wave sensing (LAS higher voltage than in the RAA) and FFRW sensing was higher in the LAS compared with the RAA this did not interfere with the clinical applicability of the LAS as alternative pacing site.     

Coronary sinus pacing initiates counterclockwise atrial flutter while pacing from the low lateral right atrium initiates clockwise atrial flutter: Analysis of episodes of direct initiation of atrial flutter

Introduction: Rapid atrial pacing in sinus rhythm may directly induce atrial flutter without provoking intervening atrial fibrillation, or initiate atrial flutter indirectly, by a conversion from an episode of transient atrial fibrillation provoked by rapid atrial pacing. The present study was performed to examine whether or not the direct induction of clockwise or counterclockwise atrial flutter was pacing-site (right or left atrium) dependent. Methods and Results: We analyzed the mode of direct induction of atrial flutter by rapid atrial pacing. In 46 patients with a history of atrial flutter, rapid atrial pacing with 3 to 20 stimuli (cycle LENGTH = 500 − 170 ms) was performed in sinus rhythm to induce atrial flutter from 3 atrial sites, including the high right atrium, the low lateral right atrium, and the proximal coronary sinus, while recording multiple intracardiac electrograms of the atria. Direct induction of atrial flutter by rapid atrial pacing was a rare phenomenon and was documented only 22 times in 15 patients: 3, 11, and 8 times during stimulation, respectively, from the high right atrium, low lateral right atrium, and the proximal coronary sinus. Counterclockwise atrial flutter (12 times) was more frequently induced with stimulation from the proximal coronary sinus than from the low lateral right atrium (8 vs 1, P = .0001); clockwise atrial flutter (10 times) was induced exclusively from the low lateral right atrium (P = .0001 for low lateral right atrium vs proximal coronary sinus, P = .011 for low lateral right atrium vs high right atrium). Conclusions: Direct induction of either counterclockwise or clockwise atrial flutter was definitively pacing-site dependent; low lateral right atrial pacing induced clockwise, while proximal coronary sinus pacing induced counterclockwise atrial flutter. Anatomic correlation between the flutter circuit and the atrial pacing site may play an important role in the inducibility of counterclockwise or clockwise atrial flutter.     

Atrial dysfunction and interatrial dyssynchrony predict atrial high rate episodes: insight into the distinct effects of right atrial appendage pacing

Atrial Dysfunction and Dyssynchrony Predict Atrial High Rate Episodes . Introduction: Right atrial (RA) appendage pacing may prolong atrial conduction time (ACT). This study aimed to investigate if RA appendage pacing can induce intra‐ and interatrial dyssynchrony and if atrial dysfunction and dyssynchrony can predict atrial high rate episodes (AHREs) in the first year after pacing. Methods and Results: Patients implanted with dual‐chamber pacemakers for symptomatic bradycardia were enrolled. Cumulative percentage of RA appendage pacing (Cum%AP) during 1‐year follow‐up and AHREs were recorded. Full Doppler echocardiography studies were performed before implantation and 1 year after pacing. ACT and peak atrial velocities (Sm‐la, Em‐la, Am‐la) were measured. One hundred ten patients (age 70.5 ± 11 years; 53 males) were recruited and completed 1‐year follow‐up. ACT of both RA and left atrial (LA) were more prolonged in patients with Cum%AP > 75% than those with <25%. Intra‐ and interatrial dyssynchrony was more obvious in patients with Cum%AP > 75% (22.3 ± 12.2 milliseconds vs 9.5 ± 6.2 milliseconds; 53.9 ± 29.7 milliseconds vs 19.7 ± 17.3 milliseconds; both P < 0.001). AHREs occurred in 29% of patients. Atrial pump function and interatrial dyssynchrony independently predicted AHREs in multivariate analysis. Receiver operating characteristic curve provided a cutoff value of Am‐la <5.3 cm/s, which predicted AHREs with a sensitivity of 71% and a specificity of 75% (area under the curve, 0.822; P < 0.001). Conclusion: RA appendage pacing causes atrial conduction delay with intra‐ and interatrial dyssynchrony. Atrial dysfunction and interatrial dyssynchrony are related to AHREs in the first year after pacing.     

Characteristics of right atrial activation during coronary sinus pacing

INTRODUCTION: Anatomic and electrical connections between the left atrium and right atrium (RA) have been described. The relationship between coronary sinus (CS) pacing site and RA activation has not been examined. METHODS AND RESULTS: Fifteen anesthetized swine underwent high-density noncontact mapping of the RA during pacing from up to five different sites within the CS. Isopotential mapping identified the site of earliest RA depolarization and the pattern of subsequent activation. Hearts were excised and endocardial dissection performed. Earliest RA activation occurred at the CS os with proximal CS pacing sites and at Bachmann's bundle at distal pacing sites. The mean depth at which a shift in earliest RA activation site occurred was 46 +/- 13 mm (range 21 to 63 mm). RA activation times following earliest activation at the CS and Bachmann's bundle were 40 +/- 4 msec and 51 +/- 6 msec (P < 0.002). Conduction delay or block was recorded at the lateral cavotricuspid isthmus, terminal crest, and tendon of Todaro. Latest RA activation always occurred in the high anterolateral atrium after ascending the anterolateral wall. The lateral RA was activated by the wavefront that traversed the posterior wall rather than by the wavefront crossing the cavotricuspid isthmus, even with earliest RA activation at the CS os. CONCLUSION: The site of earliest RA activation during CS pacing is dependent upon the pacing depth within the CS. In the porcine heart, areas of conduction delay influence RA activation patterns and timings. These findings may have implications for patients undergoing assessment of radiofrequency ablation of atrial flutter.     

冠状静脉窦口起搏对心房激动时间影响及方法学探讨

目的观察冠状静脉窦口起搏对心房激动时间的影响，并探讨该部位起搏的方法学。方法包括两部分，首先对20例射频消融的患者行心内电生理检查，术中分别给予高位右心房（HRA）、冠状静脉窦口（CS9-10）、左心房游离壁（CS1-2）起搏，记录刺激信号至腔内电图最远A波为心房激动时间；HRA至CS1-2的AA间期作为左、右心房间激动时间差，同时测量体表心电图最长P波时限。第二部分研究在可控弯导丝系统的辅助下将心房主动电极导线固定在冠状静脉窦口，比较冠状静脉窦口起搏与HRA起搏的起搏参数及起搏后体表心电图P波时限。结果冠状静脉窦口起搏时P波时限、心房激动时间及左、右心房激动时间差较窦性心律下、高位右心房及左心房游离壁起搏时均明显缩短。两组患者术中及术后起搏参数差异无统计学意义，冠状静脉窦口起搏患者体表心电图P波宽度明显缩短。结论冠状静脉窦口起搏时心房激动时间明显缩短，左、右心房间激动时间差最短。采用可控弯导丝系统的辅助可实现冠状静脉窦口起搏。     

Prevention of paroxysmal atrial fibrillation in patients with sinus bradycardia: role of right atrial linear ablation and pacing site

INTRODUCTION: Right atrial linear lesions (RALL), either alone or in combination with antiarrhythmic drug therapy, may modify the substrate for maintenance of atrial fibrillation (AF). The aim of this prospective randomized study was to determine whether RALL provides additional benefit to right atrial appendage pacing (RAAP) and/or interatrial septum pacing (IASP) and drug therapy in patients with symptomatic paroxysmal AF and sinus bradycardia requiring permanent atrial pacing. METHODS AND RESULTS: Sixty-four patients (33 men and 31 women, mean age 73 +/- 10 years) completed the 6-month follow-up. Patients were randomized to either RALL (n = 33) or non-right atrial linear lesions (NRALL), and then to either IASP (n = 32) or RAAP (n = 32). Fifteen RALL patients were paced at the IAS and 18 at the RAA. Seventeen NRALL patients were paced at the IAS and 14 at the RAA. No statistical difference was observed with regard to the mean atrial tachyarrhythmia (AT) burden between NRALL (84 +/- 169 min/day) and RALL patients (202 +/- 219 min/day). Mean AT burden was significantly lower in the IASP group (70 +/- 150 min/day) than in RAAP group (219 +/- 317 min/day; P < 0.016). In the RALL group, the mean AT burden was 99 +/- 180 min/day in the IASP patients and 288 +/- 372 min/day in the RAAP patients (P < 0.046). In the NRALL group, no statistical difference in the mean AT burden was observed between IASP patients (46 +/- 117 min/day) and RAAP patients (130 +/- 211 min/day). CONCLUSION: The results of the present study indicate that RALL did not provide any additional therapeutic benefit to combined antiarrhythmic drug therapy and septal or nonseptal atrial pacing in patients with sinus bradycardia and paroxysmal AF.     

不同部位心房起搏对植入双腔起搏器患者术后发生心房颤动的影响

目的]研究高位房间隔起搏(HASP)和右心耳起搏(RAAP)对心房电活动及心房结构的影响,评估HASP的安全性及临床有效性。[方法]回顾分析2013年1月—2017年1月于哈尔滨医科大学附属第二医院心内科行双腔起搏器植入的病态窦房结综合征患者142例,根据患者心房起搏电极植入的部位分为两组:HASP组100例,RAAP组42例。分别记录术前和术后P波时限、P波离散度、左心房大小及心房电极起搏参数(起搏阈值、感知、阻抗),并进行回顾性分析和对比研究。[结果]入选的142例患者的性别、年龄、既往疾病、吸烟饮酒史等因素无明显差异。RAAP组术前P波时限为(128.03±17.11) ms,术后为(144.82±21.37) ms;HASP组术前P波时限为(125.48±13.20) ms,术后为(102.08±15.23) ms;两组术后P波时限相比有统计学差异(P＜0.001)。RAAP组术前P波离散度为(27.33±10.12) ms,术后为(18.64±6.59) ms;HASP组术前P波离散度为(27.12±8.58)ms,术后为(18.89±4.85)ms;两组间P波离散度虽无明显差异(P＝0.47),但两组P波离散度术后较术前均减小。RAAP组与HASP组左心房内径无明显差异(34.07±5.71比32.48±4.19,P＝0.10)。HASP组起搏参数稳定,无额外并发症。植入起搏器1年后程控随访时发现,RAAP组患者发生心房颤动的比例为16.7%,而HASP组仅为4.0%,两组间有统计学差异(P＝0.015)。程控随访2年,RAAP组患者发生心房颤动的比例为28.6%,HASP组为17.0%,两组间无统计学差异。[结论]HASP是一种安全可行的起搏方式,可以明显缩短P波时限,有机会减少患者发生心房颤动的风险。     

右心室不同位点起搏对QRS时限的影响

目的 观察右心室不同起搏位点的QRS时限,为临床导线放置提供参考依据.方法 选择216例符合Ⅰ类或Ⅱa类起搏器植入适应证的患者,在放置心室导线过程中,分别在右心室心尖部、流入道、中位间隔部、高位间隔部和流出道等不同位点起搏右心室,记录起搏时的体表心电图,比较不同位点QRS时限和形态的差异.结果 与基础心电图QRS波比较,所有右心室起搏部位心电图QRS时限均明显增宽(P＜0.001)；以心尖部起搏QRS时限增宽(168±16) ms,其次为流入道(166±15) ms和流出道(165±15) ms；三者比较差异无统计学意义(P＞0.05).间隔部起搏QRS时限明显缩短(P＜0.001),且QRS波形态和电轴正常.中间隔部最短(139± 19) ms,高位间隔部次之(153±14) ms,二者相比差异有统计学意义(P＜0.01).结论 在所有右心室起搏位点中,中间隔部起搏QRS时限最窄,且形态和电轴正常.中间隔部可能是右心室最理想起搏选择位点.     

The electromechanical effects of pacing at different sites within the right atrium.

AIMS: To compare high right atrium (HRA) with right atrial appendage (RAA) pacing with respect to atrial electromechanical function. METHODS: Eleven patients undergoing elective electrophysiological studies were studied in order directly to compare atrial conduction acutely associated with HRA and RAA pacing. Twenty-five patients with chronically implanted, active fixation leads in the HRA were compared with an age and sex matched group of 25 patients with chronically implanted, passive fixation leads in the RAA. For both studies recordings were taken in sinus rhythm then repeated when paced. Measured time intervals were intra- and interatrial activation times. P wave duration and time to onset of atrial systolic blood flow. RESULTS: Right atrial pacing, when compared with sinus rhythm, significantly prolongs the interatrial activation time, the P wave duration and the time to onset of right and left atrial blood flow irrespective of site paced. Comparing the RAA group with the HRA group, there were no statistical differences for any of the measured parameters. CONCLUSION: High right atrial free wall or the right atrial appendage pacing, when compared with sinus rhythm, is significantly detrimental to atrial electromechanical function. There is, however, no demonstrable difference between the two sites.     

Septal atrial pacing for the prevention of atrial fibrillation.

AIMS: Atrial fibrillation (AF) produces significant morbidity and mortality. The current method of permanent pacing of the right atrium (RA) may cause delayed interatrial conduction and predispose to AF. We hypothesized that atrial septal pacing would reduce AF compared with high RA pacing. METHODS AND RESULTS: The patients were randomized into two groups. After randomization, patients received a dual-chamber rate-responsive device capable of mode-switching with advanced telemetry features. Devices were programmed in a standardized manner. To be eligible, the patients were required to have a conventional indication for a permanent pacemaker and recurrent paroxysmal AF. Group 1 was paced from high RA and Group 2 was paced from the atrial septum. Analysis of 43 patients who have completed 6 months of follow-up and 22 patients who completed 12 months of follow-up showed no significant differences in the number of mode-switching episodes or in AF burden between groups (P = NS by Mann-Whitney) although there was a trend for less AF with septal pacing. There were no differences in thresholds, sensing, or lead impedance. Lead parameters remained stable over time and there were no displacements of the electrodes after implantation. No patient experienced lead-related complications. A significant variability in AF burden was noted in this patient population. CONCLUSIONS: Implantation of an atrial-active fixation lead on the atrial septum is safe and feasible. However, this study showed no significant difference between septal pacing and high atrial pacing, using the endpoints of AF duration and number of AF episodes.     

不同部位心房起搏对心房电活动的影响

目的 观察右心耳及房间隔起搏对心房电活动的影响。方法 对DDD永久起搏器安置术109例（右心耳电极72例、房间隔电极37例）术前、术后分别描记体表12导联心电图，测量右心耳及房间隔起搏前后最长P波时间（Pmax）及P波离散度（Pd）。结果 右心耳起搏方式，Pmax及Pd较术前明显增加，而房间隔起搏方式Pmax及Pd较术前显著减少（P均〈0．05）。结论 房间隔起搏方式使心房电活动较稳定，有助于预防房性心律失常。     

Arterial thromboembolism in patients with sick sinus syndrome: prediction from pacing mode, atrial fibrillation, and echocardiographic findings

OBJECTIVE: To evaluate whether thromboembolism in sick sinus syndrome can be predicted by pacing mode, atrial fibrillation, or echocardiographic findings. METHODS: Patients were randomised to single chamber atrial (n = 110) or ventricular (n = 115) pacing. They were divided into subgroups with and without brady-tachy syndrome at time of randomisation. The occurrence of atrial fibrillation and thromboembolism during follow up were investigated and compared with echocardiographic findings. RESULTS: The annual risk of thromboembolism was 5.8% in patients with brady-tachy syndrome randomised to ventricular pacing, 3.2% in patients without brady-tachy syndrome randomised to ventricular pacing, 3% in patients with brady-tachy syndrome randomised to atrial pacing, and 1.5% in patients without brady-tachy syndrome randomised to atrial pacing. In atrial paced patients without brady-tachy syndrome at randomisation and without atrial fibrillation during follow up, the annual risk of thromboembolism was 1.4%. Left atrial size measured by M mode echocardiography was of no value in predicting thromboembolism. CONCLUSIONS: Arterial thromboembolism in patients with sick sinus syndrome is very common and is associated primarily with brady-tachy syndrome at randomisation and with ventricular pacing. The risk of thromboembolism is small in atrial paced patients in whom atrial fibrillation has never been documented.     

房间隔起搏对病窦综合征并阵发性心房颤动的影响

目的探讨房间隔起搏(ASP)对病窦综合征(SSS)合并阵发性心房颤动(PAF)的影响。方法 12例SSS合并PAF行DDD(房间隔部)起搏,术前查常规心电图、24h动态心电图(DCG)及超声心动图,测量最长P波时限(Pmax)、最短P波时限(Pmin),计算P波离散度(Pd),观察PAF发作例数、发作次数及持续时间,测量左房直径等,术后1周内、3个月及1年时复查心电图、DCG及超声心动图,并统计起搏心搏比例。结果与起搏前窦性心律心电图比较,ASP后1年内Pmax和Pd均较术前明显缩短(P均0.05)。ASP1周内,PAF发作例数、发作次数及持续时间明显减少(P均0.05);但随着时间延长,PAF发作例数、发作次数及持续时间有增多趋势;术后发现再发心房颤动者均有基础病,且已转变为持续心房颤动者心房直径明显大于非持续心房颤动及窦性心律者,但与起搏心搏比例无关;术后左房直径有缩小趋势。结论 ASP能明显缩短Pmax及Pd,可以预防和治疗PAF,降低PAF的发生率,但有基础心脏病、心房直径增大者远期疗效不佳。     

Disparate activation of the coronary sinus and inferior left atrium during atrial tachycardia after persistent atrial fibrillation ablation: prevalence, pitfalls, and impact on mapping

Partial Coronary Sinus Disconnection During Atrial Tachycardia . Introduction: Persistent atrial fibrillation (AF) ablation may lead to partial disconnection of the coronary sinus (CS). As a result, disparate activation sequences of the local CS versus contiguous left atrium (LA) may be observed during atrial tachycardia (AT). We aimed to evaluate the prevalence of this phenomenon and its impact on activation mapping. Methods: AT occurring after persistent AF ablation were investigated in 74 consecutive patients. Partial CS disconnection during AT was suspected when double potentials with disparate activation sequences were observed on the CS catheter. Endocardial mapping facing CS bipoles was performed to differentiate LA far‐field from local CS potentials. Results: A total of 149 ATs were observed. Disparate LA–CS activations were apparent in 20 ATs after magnifying the recording scale (13%). The most common pattern (90%) was distal to proximal endocardial LA activation against proximal to distal CS activation, the latter involving the whole CS or its distal part. Perimitral macroreentry was more common when disparate LA–CS activations were observed (67% vs 29%; P = 0.002). Partial CS disconnection also resulted in “pseudo” mitral isthmus (MI) block during LA appendage pacing in 20% of patients as local CS activation was proximal to distal despite distal to proximal activation of the contiguous LA. Conclusion: Careful analysis of CS recordings during AT following persistent AF ablation often reveals disparate patterns of activation. Recognizing when endocardial LA activation occurs in the opposite direction to the more obvious local CS signals is critical to avoid misleading interpretations during mapping of AT and evaluation of MI block. (J Cardiovasc Electrophysiol, Vol. 23, pp. 697‐707, July 2012)     

Differences in pacing from the atrial appendage and the lateral atrial free wall on left ventricular filling and haemodynamics during DDD pacing.

INTRODUCTION: Atrioventricular sequential pacing involves stimulation from electrodes in the right atrium, generally the atrial appendage (RAA) and the right ventricular apex. The appendage, however, may be unsuitable if a stable position cannot be achieved. The aim of this study was to assess the haemodynamic consequences of different atrial stimulation sites during DDD pacing. METHODS: In 12 consecutive patients (mean age 67 +/- 7 years) who underwent DDD pacemaker implantation, an additional temporary bipolar pacing electrode was positioned on the right atrial free wall. Pacing was performed alternating from the two locations at 85, 100 and 120 beats per minute (bpm). Paced atrioventricular delay was set at 180 ms. Cardiac output and mitral inflow measurements were performed using Doppler echocardiography. RESULTS: Pacing at 85 and 100 bpm resulted in a significantly higher A-peak velocity from the RAA compared with the right atrial free wall. Cardiac index was consistently higher from the RAA location (2.4 +/- 1.2 vs 2.1 +/- 0.91. min-1 m-2 at 85 bpm, 2.71 +/- 1.4 vs 2.35 +/- 1.11. min-1 m-2 at 100 bpm and 2.94 +/- 1.5 vs 2.61 +/- 1.41. min-1 m-2 at 120 bpm, P < 0.05). CONCLUSION: Stimulation from the RAA was superior to stimulation from the right atrial free wall with respect to left ventricular filling and cardiac output. Compared with stimulation from the right atrial free wall, RAA pacing resulted in an increase of 10-15% in cardiac output.     

No evidence of automatic atrial overdrive pacing efficacy on reduction of paroxysmal atrial fibrillation.

AIMS: Paroxysmal atrial fibrillation (PAF) is frequently encountered in pacemaker patients, most commonly in sick sinus syndrome. The combination of site-specific pacing in conjunction with an overdrive algorithm combined with antiarrhythmic drugs on the incidence of PAF in patients with a conventional indication for pacing is unknown. METHODS AND RESULTS: Patients with pacemaker indication and PAF received a DDDR-pacemaker, which included an automatic atrial overdrive (AO) algorithm. The atrial lead was implanted in either the right atrial appendage (RAA) (n = 83) or the right low-atrial septum (LAS) (n = 94). The algorithm was switched on or off in a 3 month, single blind crossover design and antiarrhythmic drugs were kept stable. A control group of 96 patients (LAS, n = 14; RAA, n = 84) without PAF served as controls to assess any proarrhythmic effect of overdrive pacing. Atrial fibrillation (AF) burden defined as cumulative time in mode switch was not reduced during automatic AO from either the RAA or from the LAS. The reduction was not effective both for AF of short (<24 h) and long (> or =24 h) duration. There was no atrial proarrhythmia induced by the overdrive algorithm in the control group. CONCLUSIONS: We could not demonstrate a reduction of AF burden defined as cumulative time in AF by the AO algorithm, in patients who are paced for standard indications and PAF, neither from the RAA nor from the LAS.     

右心室间隔部起搏和右心室心尖部起搏对血流动力学的影响

目的:比较右心室间隔部(RVS)起搏和右心室心尖部(RVA)起搏对血流动力学的影响。方法:20 例置入DDD起搏器的患者,随机均分为2组,RVS组行RVS起搏,RVA组行RVA起搏;对比观察术前与术后心电图QRS波宽度和形态;比较2组术前和术后6个月随访的左室射血分数(LVEF)、心脏指数(CI)、每搏量 (SV)、二尖瓣血流E峰和A峰最大充盈速度比值(E／A)差异。结果:RVA组起搏心电图Ⅱ导联QRS时限度显著长于RVS组[(0．19±0．02)s:(0．12±0．02)s,P<0．01];术前2组LVEF、CI、SV和E／A均差异无统计学意义。与术前相比,RVA组6个月随访的LVEF、CI、SV和E／A均显著降低[(60．7±5．9)％:(54．8±6．4)％, (2．78±0．31):(2．49±0．26),(81．5±10．0):(68．6±12．5),(1．70±0．48):(1．20±0．39),均P<0．05], RVS组无明显变化[(62．7±6,4)％:(61．14±5．8)％,(2．74±0．33):(2．76±0．25),(82．2±9．2):(78．7±11． 5),(1．62±0．49):(1．61±0．40),均P>0．05]。6个月随访RVS组LVEF、CISV、SV、E／A均显著高于RVA 组(均P<0．05)。结论:RVA起搏扰乱了双心室电同步,导致血流动力学恶化,RVS起搏则尽可能地保证了双心室正常电激动和机械收缩顺序,对血流动力学无不良影响。     

Comparison of spontaneous atrial fibrillation electrogram potentials with the P-wave electrogram amplitude in dual chamber pacing with unipolar atrial sensing.

AIMS: Although bipolar sensing is recommended and desirable in patients with dual chamber pacemakers (DDD) and intermittent atrial fibrillation (AF) it is a clinical reality that some patients who are given unipolar atrial leads without a prior history of AF may develop intermittent AF during follow-up. It was therefore the purpose of this prospective study to compare the electrogram amplitudes of AF potentials with sinus rhythm P-wave potentials as a relevant factor for appropriate mode switching in dual chamber pacing with unipolar atrial sensing. METHODS AND RESULTS: Forty-two patients with dual chamber pacemakers, unipolar atrial leads and intermittent AF were studied. Aside from measuring the P-wave potential, it was possible in 14 patients (4 women, 10 men; mean age: 61.8 (+/- 13.3) years) additionally to document spontaneous AF electrogram potentials using pacemaker telemetry. A prospective survey study was performed including a 6 month follow-up period with an outpatient clinic visit every 2-3 weeks. The mean P-wave electrogram amplitude was 3.4 (+/- 1.8) mV (range: 1.4-7.4) compared with the mean amplitude during AF of 2.04 (+/- 1.26) mV (range: 0.8-5.2 mV) indicating a significant attenuation of 40% during AF (P < 0.0001). A linear correlation regression analysis revealed that there was a significant correlation between the P-wave and the AF amplitude (P < 0.0001), with a correlation coefficient of r = 0.867. CONCLUSION: Once it is known that a substantial reduction exists in electrogram amplitude, compared with the P wave electrogram potential, an estimate can be made of whether AF potentials will be sensed, if the programming of atrial sensitivity is congruent with the P-wave characteristics and the presence or absence of myopotential triggering.