Low-Energy Transvenous Cardioversion of Atrial Fibrillation Using a Single Atrial Lead System

Atrial Cardioversion Using a Single Atrial Lead System. Introduction: Clinical studies have shown that electrical conversion of atrial fibrillation (AF) is feasible with transvenous catheter electrodes at low energies. We developed a single atrial lead system that allows atrial pacing, sensing, and defibrillation to improve and facilitate this new therapeutic option. Methods and Results: The lead consists of a tripolar sensing, pacing, and defibrillation system. Two defibrillation coil electrodes are positioned on a stylet-guided lead. A ring electrode located between the two coils serves as the cathode for atrial sensing and pacing. We used this lead to cardiovert patients with acute or chronic AE. The distal coil was positioned in the coronary sinus, and the proximal coil and the ring electrode in the right atrium. R wave synchronized biphasic shocks were delivered between the two coils. Atrial signal detection and pacing were performed using the proximal coil and the ring electrode. Eight patients with acute AF (38 ± 9 min) and eight patients with chronic AF (6.6 ± 5 months) were included. The fluoroscopy time for lead placement was 3.5 ± 4.3 minutes. The atrial defibrillation threshold was 2.0 ± 1.4 J for patients with acute AE and 9.2 ± 5.9 J for patients with chronic AF (P < 0.01). The signal amplitude detected was 1.7 ± 1.1 mV during AF and 4.0 ± 2.9 mV after restoration of sinus rhythm (P < 0.001). Atrial pacing was feasible at a threshold of 4.4 ± 3.3 V (0.5-msec pulse width). Conclusions: Atrial signal detection, atrial pacing, and low-energy atrial defibrillation using this single atrial lead system is feasible in various clinical settings. Tbis system might lead to a simpler, less invasive approach for internal atrial cardioversion.     

Low-Energy Internal Cardioversion for Atrial Fibrillation Resistant to External Cardioversion

Internal Cardioversion. introduction : This report describes the electrical conversion of atrial fibrillation in two morbidly obese patients refractory to external cardioversion at 360 J.
Methods and Results : The two patients were lightly sedated and underwent placement of decapolar catheters in the coronary sinus and right atrial appendage. All ten electrodes of each decapolar catheter were electrically coupled, and defibrillation was attempted at successively increasing levels using a biphasic decaying exponential waveform generated by an external defibrillator. Both patients were returned to normal sinus rhythm using <10 J without complication.
Conclusion : Internal cardioversion is effective in restoration of sinus rhythm in some patients refractory to conventional forms of therapy     

Internal Cardioversion of Persistent Atrial Fibrillation Using Rectilinear Biphasic Waveform

Internal electrical cardioversion is currently used in patients with persistent atrial fibrillation resistant to external electrical cardioversion. In external cardioversion, biphasic waveforms have shown a greater efficacy than monomorphic waveforms. The present study aimed to test the safety and efficacy of rectilinear biphasic waveform in converting patients with persistent atrial fibrillation to sinus rhythm using internal electrical cardioversion, and to compare it with that of classical monophasic waveform. Twenty-seven consecutive patients with persistent AF received 31 internal cardioversions, using monophasic waveform in 11 (group I), and rectilinear biphasic waveform in 20 cases (group II). Baseline patients characteristics were similar in both groups. Multipolar catheters were positioned in the distal coronary sinus and in the high right atrium. Synchronised shocks were delivered using an escalating protocol of 2, 5, 10, 15, 20, 30, and 50 Joules. In group I, 1 patient was resistant to maximal energy (success rate 91%). The mean energy of the maximal shock was 18 ± 13 J. In group II, all patients were converted to sinus rhythm. The mean energy of the maximal shock was 9 ± 5 J (p < 0.01 vs. group I). No significant complications occurred. At 3 months follow-up, 45% of group I and 60% of group II patients remained in sinus rhythm (p = NS).We conclude that internal cardioversion using rectilinear biphasic waveform is feasible and safe, and requires less energy than classical monophasic waveforms.     

经皮穿刺二尖瓣球囊扩张成形术后心房颤动复律的体会

对二尖瓣球囊扩张成形术后心房颤动（Ａｆ）同步直流电复律２０例患者的复律过程进行观察和随访，探讨复律的影响因素及窦性心律的维持。结果表明：复律时出现心律失常组的年龄（４３．４±３．１岁）、Ａｆ持续时间（５０．７±１６．８月）、心瓣膜病程（１６０．７±３０．２月）、左房内径（４８．２±７．３ｍｍ）等均高于未出现心律失常组（依次为：３４．７±４．５岁、２１．６±１０．２月、１０１．５±２３．５月、４２．１±４．５ｍｍ），Ｐ＜０．０５。经逐步回归分析发现复律放电能量与病人年龄、Ａｆ持续时间、转复时心率、左房内径等因素有关。复律时除应注意上述影响因素外，还应适当调整放电能量以使复律易于成功。对窦性心律的维持认为以口服胺碘酮效果较好     

An Update on Electrical Cardioversion of Atrial Fibrillation

Atrial fibrillation is the most frequently encountered sustained arrhythmia in clinical practice. Electrical cardioversion of atrial fibrillation using damped sine wave shocks has been a mainstay of therapy for nearly 4 decades; its limitation remains a failure rate that approaches 20%. Although several alternatives have been proposed, including delivering 720 J shocks using dual monophasic defibrillators, ibutilide pretreatment and internal cardioversion, each of these approaches has significant limitations, which preclude its routine use. Recent data demonstrate that routine use of biphasic shocks for cardioversion of atrial fibrillation is associated with a marked improvement in cardioversion efficacy and suggest that biphasic shocks may be the preferred method for the transthoracic electrical cardioversion of atrial fibrillation.     

Prospective Randomized Trial of External Versus Internal Transcatheter Cardioversion in Patients with Chronic Atrial Fibrillation

To evaluate the safety and long-term efficacy of internal transcatheter cardioversion, forty patients with chronic, lone atrial fibrillation were studied. The patients were randomised to internal transcatheter cardioversion or to conventional external cardioversion. In cases where the procedure was unsuccessful, cross-over to the alternate method was performed. Oral anticoagulation therapy was started three weeks prior to the procedure and was maintained for another three weeks following successful cardioversion.Sinus rhythm was restored in 16/18 patients (88%) in the internal cardioversion group, versus 9/22 patients (40%) in the external cardioversion group (p < 0.01). In addition, 8/13 (61%) patients who were crossed-over to internal cardioversion were successfully cardioverted to sinus rhythm. In contrast, both patients who were crossed-over to external cardioversion remained in atrial fibrillation.During a mean follow-up period of 23 months, 13 (39.3%) patients maintained sinus rhythm. Using the intention to treat principle, the recurrence rate was not statistically different between the two methods.It is concluded that internal cardioversion is more effective in acutely restoring sinus rhythm compared to external cardioversion. However, both methods have similar long-term recurrence rates.     

风湿性心脏瓣膜病并发心房颤动在围手术期的复律研究

探讨围手术期口服小剂量胺碘酮结合术中心脏表面直接电击复律在风湿性心脏瓣膜病并发心房颤动 (简称房颤 )患者围手术期复律中的应用价值。选取 30例病人 ,其中实验组 15例 ,围手术期应用胺碘酮 ,术中开放循环后 ,根据心脏自动复跳情况采用电击复律。对照组 15例 ,除不用胺碘酮外 ,其它处理同实验组。结果 :实验组开放循环后 ,有 3例自动恢复窦性心律 ,其余经电击除颤仅 1例房颤未能除去 ;对照组仅有 1例自动恢复窦性心律 ,且有 9例房颤未能最终除去。实验组即时、近期和远期窦律维持情况均明显高于对照组 (P <0 .0 0 1)。结论 :风湿性心脏瓣膜病并发的房颤在围手术期口服胺碘酮 ,并在术中给予心脏表面直接电击除颤 ,较传统复律方法复律效果好 ,且更为安全 ,可提高房颤的转复率 ,减少术后复发率。     

经胸体外直流电复律治疗心房颤动的进展

虽然心房颤动的治疗已取得很大的进展,经胸体外直流电复律仍然是临床上常用的治疗心房颤动的方法,它高效、安全,近年来,为使其效率进一步提高,现就采取的一些改进措施进行综述。包括:(1)电极板的位置、数量:多数研究证实前-后位置复律优于前-前(侧)位置,表现在复律的成功率高、用电量低上;还可应用X线透视以优化电极板的位置,使其尽可能包绕心房肌,以此来提高复律成功率;另外,同时应用2台体外除颤器的更高能量的电复律对那些标准能量复律无作用的心房颤动患者有效,并且同样安全。(2)输出波形为双相波形时对心房颤动的转复具有比单相波形更高的效率,要求的电量更低,且同样对心肌无损害。(3)首次放电量较高,如≥150 J时复律的成功率高。(4)除了抗心律失常药物,近几年新出现的一些药物如血管紧张素转换酶抑制剂、血管紧张素Ⅱ受体拮抗剂以及他汀类药物也可影响心房颤动体外电复律的效果。     

Maintenance of Sinus Rhythm after Cardioversion of Atrial Fibrillation in Patients with Lone Atrial Fibrillation and Patients with Hypertension

Background: The success rate and prognosis of cardioversion of atrial fibrillation (AF) in patients with organic heart disease is well known. In contrast, little data exist about cardioversion success and maintenance of sinus rhythm (SR) in patients with lone AF and in patients with hypertension as the only underlying cardiovascular disease. Methods: In a prospective cardioversion registry 148 of 181 patients (81.8%) with lone AF (age 58 ± 13 years, duration of AF 7.6 ± 19 weeks) and 120 of 148 patients (81.1%) with hypertension (age 62 ± 10 years, duration of AF 6.6 ± 21 weeks) had successful cardioversion and were followed for 7.7 ± 1.9 months. Results: At follow-up, 120 patients (81.1%) with lone AF were in SR, and 18 of these patients had had repeated cardioversion during follow-up (AF total recurrence rate 31.1%). In stepwise regression analysis, the number of previous cardioversions was predictive of rhythm at follow-up (P = 0.0453). Rhythm at follow-up did not differ between patients who were or were not on antiarrhythmic drugs. At follow-up 96 patients (80%) with hypertension were in SR, and 9 of these had had repeated cardioversion during follow-up (AF total recurrence rate 27.5%). As in lone AF, the recurrence rate of AF did not differ between patients with or without antiarrhythmic drug treatment, and in multivariate regression analysis, the number of previous cardioversions was the only clinical predictor of rhythm at follow-up (P = 0.0284). Conclusions: Even in patients with such benign conditions as lone AF or hypertension as the only underlying disease, the prognosis of cardioversion in terms of maintenance of SR is poor. Future studies of rhythm control versus rate control need to include not only patients with organic heart disease but also patients with lone AF and patients with hypertension, since the long-term benefits of these two strategies remain unclear even in these subsets of patients.     

非瓣膜病心房颤动病人电复律前后左心房功能变化研究

目的评价经食道超声心动图(TEE)对非瓣膜病心房颤动(房颤)病人电复律前后左心房功能变化.方法选择房颤持续2周以上的非瓣膜疾病病人18例,其中原发性高血压6例,扩张型心肌病6例,脑血栓4例,缺血性心肌病2例.应用TEE确定左心房内无血栓后行电复律,转为窦性心律者测定左心耳血流最大速度及流速积分,肺静脉血流最大速度及流速积分、二尖瓣血流最大速度、流速积分及减速时间.结果左心耳排空速度于复律后显著减少,有显著性差异(P＜0.05),排空指数增加(P＞0.05),电复律后肺静脉收缩期、舒张期最大流速及其流速积分比值无显著差异(P＞0.05),收缩期最大流速积分在左、右肺静脉均有显著差异(P均＜0.05).复律前后舒张期最大流速积分在右肺静脉有显著性差异(P＜0.05),左肺静脉差异不显著(P＞0.05).二尖瓣血流E波最大速度及E波与A波比值(E/A)增加.结论适合的抗凝治疗及TEE确认心房内无附壁血栓后进行电复律治疗,安全又无并发症.TEE能评价房颤病人电复律后的左心房功能变化.电复律后心房的电活动及机械活动均微弱,能引起左心房功能不全及栓塞,所以心房功能完全恢复前均有必要进行抗凝治疗.     

Cardioversion Related Thromboembolism: Value of Transesophageal Echocardiography to Guide Cardioversion in Patients with Atrial Fibrillation

The aim of this article is to review two recent investigations of the value of transesophageal echocardiography to guide direct current cardioversion in different patient populations. In the Ludwigshafener Observational Cardioversion Study (LOCS) a TEE was performed prior to electrical cardioversion in patients with atrial fibrillation who had been receiving oral anticoagulation adjusted to an international normalized ratio of 2 to 3 for at least three weeks. In contrast, the ACUTE study investigated the value of transesophageal echocardiography in patients with atrial fibrillation in whom long-term oral anticoagulants had not been initiated in comparison to standard anticoagulation therapy. Furthermore, the following questions in respect to anticoagulation therapy are addressed: (1) how should patients be approached for pharmacological or spontaneous conversion; (2) how to treat emergency situations, (3) what is the importance of the postcardioversion period and long-term anticoagulation therapy; and (4) what is the role of low molecular weight heparin in the pericardioversion period.     

P Wave Amplitude and Duration may Predict Immediate Recurrence of Atrial Fibrillation After Internal Cardioversion

Background: Although internal cardioversion (IC) for atrial fibrillation (AF) is effective at restoring sinus rhythm, immediate recurrence (IR) of AF after IC is a major and largely unpredictable clinical problem. The purpose of the study was to determine the role of P wave duration and amplitude in prediction of IR of AF after IC. Forty‐five consecutive patients undergoing IC for chronic AF were evaluated. Material and Methods: After successful IC, 1‐minute ECG recording was obtained in all patients. P wave duration and amplitude in Lead II and V₁ were measured using computer. Forty patients (88%) had successful IC. Thirteen patients experienced IR of AF within 1 minute of restoring sinus rhythm. Results and Conclusion: As a result, the incidence of IR of AF after IC was higher in the patients with shorter P wave amplitude (for lead II P < 0.01 , for V₁P < 0.01 ) and larger P wave duration (for lead II P < 0.01 , for V₁P < 0.05 ).     

口服奎尼丁转复心房颤动的临床分析

应用口服奎尼丁转复心房颤动（AF）393例次，评价其效果、安全性、血药浓度的意义及相关因素对转复的影响。奎尼了用量第1日每次0．2g，每2h1次，共5次。如未能转复逐日每次递增0．1g，至第3日仍未转复逐停药。有47例测了血药浓度。393例次AF中324例次（82．4％）转复成功，平均转复时间为13．7±5．1（2～42）h。高血压病、冠心病、心肌病及孤立性AF的转复率较风湿性心脏病者为高（93．8％、88．9％、88.9％、95.7％vs76.4％，P＜0．05）。AF持续时间＜6个月者转复率高于6～12及＞12个月者（88．2％vs69．2％、56．3％，P＜0．01）。左房内径＜50mm者转复率高于≥50mm者（89．7％vs72．0％，P＜0.05）。有效见药浓度为1．5～6．0ng／ml。未发现与奎尼丁有关的严重副作用。表明口服奎尼丁转复AF的成功率高，严重不良反应的发生率低，其仍不失为治疗AF的一种较好方法。     

Evaluation of Atrial Refractoriness and Atrial Fibrillation Inducibility Immediately after Internal Cardioversion in Patients with Chronic Persistent Atrial Fibrillation

Summary. Objective: To prospectively evaluate right atrial refractoriness and sustained atrial fibrillation (AF) inducibility at programmed electrical stimulation in two groups of patient: a series of patients with chronic persistent AF, studied immediately after successful low energy internal atrial cardioversion, and a group of control patients without history of supraventricular arrhythmias.Patients: Nineteen patients with chronic persistent AF (mean AF duration 11 ± 10 months, range 2–61 months) submitted to successful internal low energy atrial cardioversion in fully conscious state and 11 control patients without history of supraventricular arrhythmias.Methods: An electrophysiological evaluation was performed to measure atrial refractoriness and AF inducibility, by delivering single atrial extrastimuli in high right atrium, at decremental coupling, during spontaneous sinus rhythm and after 8 beats at 600, 500, 400 and 330 ms cycle length. If sustained AF was induced the protocol was terminated.Results: During programmed atrial stimulation sustained AF was induced in 8 out 19 (42%) of the AF patients but in none of the control group. Atrial effective refractory period was significantly shorter in AF patients compared to controls both at basic cycle length, at 600 ms, 500 ms and 400 ms cycle length, meanwhile no statistically significant differences were found at 330 ms cycle length. An altered relationship between atrial effective refractory period and cycle length was found in AF patients compared to controls: the slope of linear correlation slope was significantly lower in AF group than in controls (0.04 ± 0.07 vs 0.17 ± 0.10, p < 0.002).Conclusions: Marked abnormalities of atrial refractoriness and of its heart rate relationship are observed after internal cardioversion of chronic persistent AF in humans and these abnormalities are associated with an high vulnerability to AF. These observations may explain the high risk of AF recurrences in the early phases following successful cardioversion. In this scenario antiarrhythmic drug therapy seems to be mandatory for reducing arrhythmia relapses.     

复律后左心房功能恢复与心房颤动持续时间相关性的临床研究

目的:应用心肌组织多普勒技术结合M型超声、脉冲血流多普勒和心尖搏动图评价心房颤动(房颤)复律后心房功能的变化及其相关因素。方法:正常对照组20例,房颤复律患者34例。根据房颤持续时间分成短期房颤组(n=18)和长期房颤组(n=16),于复律后1小时、1天、1周和1个月行超声检查。采用心肌组织多普勒技术测量二尖瓣环侧壁心房收缩期心肌组织运动峰速(Am)和舒张早期运动峰速(Em)并计算Am/Em比值,M型超声测量瓣环侧壁舒张晚期心肌最大运动幅度(DAD)和舒张早期最大运动幅度(DED)并计算DAD/DED比值,脉冲血流多普勒测量心房收缩期跨瓣血流最大流速(A)和心室舒张早期血流最大流速(E)并计算A/E比值,心尖搏动图记录心房收缩压力波。并筛选出与复律后1小时、1天、1周左心房心肌组织运动速度有关的临床变量。结果:复律后1小时、1天、1周与Am相关的临床变量均为房颤持续时间。左心房功能与房颤持续时间的关系:复律后1小时及1天,Am、Am/Em,A/E,DAD、DAD/DED在两房颤组均低于正常对照组(P<0.05);长期房颤组低于短期房颤组(P<0.05);复律后1周,长期房颤组仍低于正常对照组和短期房颤组(P<0.05);短期房颤组与正常对照组无差异(P>0.05)。复律后1个月,除长期房颤组DAD/DED仍低于正常对照组(P<0.05),其余指标3组间无差异(P>0.05)。复律后左心房顿抑仅发生于长期房颤组,其发生率于1小时为43.8%,1天为25%,1周为12.5%。结论:房颤复律后左心房功能的恢复及左心房顿抑的发生与房颤持续时间有明显相关性。