Atrial pacemaker complex preserved radiofrequency maze procedure reducing the incidence of sick sinus syndrome in patients with atrial fibrillation

BACKGROUND: The Cox maze III procedure can effectively restore sinus rhythm in most patients with permanent atrial fibrillation (AF). However, previous studies have shown that the maze procedure results in significant sinus node dysfunction, and, consequently, a considerable number of patients required postoperative pacemaker implantation. HYPOTHESIS: This study investigates the hypothesis that the modification of the Cox III maze procedure, to avoid injuring the sinus node and the atrial physiologic pacemaker complex, will reduce the incidence of sick sinus syndrome following surgery. METHODS AND RESULTS: This study investigated 71 patients with permanent AF and mitral valve disease who were undergoing concomitant open-heart surgery. Most atrial incisions in the Cox maze III procedure were replaced with radiofrequency ablation, and the intercaval counterablation was moved posterolaterally to avoid injury to the sinus node and atrial pacemaker complex. At a mean (+/- SD) follow-up time of 46.5 +/- 24 months, 59 patients (83.1%) regained sinus rhythm without receiving antiarrhythmic drug therapy or undergoing electrical cardioversion. The transmitral atrial wave was observed in 44 patients (62%), and the transtricuspid atrial wave was also observed in 53 patients (74.6%). Late sinus node dysfunction developed in only two patients (2.8%), who received permanent pacemaker implantation. CONCLUSION: This modified radiofrequency maze procedure produces few patients with sick sinus syndrome and effectively restores sinus rhythm and atrial transport function in most patients with permanent AF undergoing concomitant open-heart surgery.     

New treatment options for stroke prevention in atrial fibrillation

Optional statement Atrial fibrillation (AF) is the most common arrhythmia requiring treatment. Its most devastating consequence is thromboembolic stroke. Therapy with warfarin is indicated in most patients, as it has been shown conclusively to reduce the risk of stroke. Aspirin is an inferior alternative except in certain low-risk patients or for patients with an absolute contraindication to warfarin. Guidelines have been published for the administration of antithrombotic therapy in AF, but many patients who are candidates for anticoagulation do not receive this therapy. Even as this therapy is under-utilized, the indication for anticoagulation is expanding. Indefinite continuation of anticoagulation should be considered in higher-risk patients despite the appearance that sinus rhythm has been restored because asymptomatic (or silent) AF occurs frequently. Newer agents that offer substantial benefit over warfarin are being developed and would enhance compliance with anticoagulation in AF if these novel therapies prove to be safe and equivalent to warfarin in efficacy.     

Pre- and post-cardioversion transesophageal echocardiography for brief anticoagulation therapy with enoxaparin in atrial fibrillation patients: a prospective study with a 1-year follow-up

BACKGROUND: In patients with atrial fibrillation (AF) eligible for electrical cardioversion (C), the guided approach with transesophageal echocardiography (TEE) allows to avoid the 3 weeks of recommended precardioversion anticoagulation therapy. However, after sinus rhythm restoration, at least other 4 weeks of oral anticoagulation therapy are indicated, due to the postcardioversion thromboembolic risk related to left atrial (LA) and left atrial appendage (LAA) stunning. The aim of this study was to prospectively assess the effectiveness and the safety of anticoagulation therapy discontinuation 7 days after C using low-molecular-weight heparins (LMWH) in a selected group of patients who underwent a pre-C and 7 days post-C TEE evaluation. METHODS: One hundred one patients (74 patients with nonvalvular AF and 27 patients with atrial flutter lasting >48 h and history of AF) were enrolled into the study. Two patients refused the TEE, therefore, in 99/101, we performed a first TEE and, within 24 h, a C if there were no LAA thrombi, complex aortic plaques or severe spontaneous echocontrast. After C and 7 days of home-administered enoxaparin, a second TEE was carried out. In the absence of any new thrombi, severe spontaneous echocontrast and/or low emptying velocity of LAA, the therapy with enoxaparin was stopped; otherwise, anticoagulation therapy with enoxaparin was overlapped with oral anticoagulation and continued for at least 3 weeks. All patients were clinically followed at 1, 6 and 12 months after C. RESULTS: Sinus rhythm was restored in 68/99 patients after successful C. The second TEE was carried out in 53 patients. At 1 month follow-up, no thromboembolic events were recorded either in patients at risk who had continued the oral anticoagulant therapy for at least 3 weeks or in those who suspended LMWH after 7 days post-C TEE. Between the 2nd and 12th month, three ischemic strokes occurred, all in the group of patients who had anticoagulation therapy for at least 3 weeks and had shown LAA velocity <25 cm/s at first or second TEE. No thromboembolic events were recorded in patients with normal LAA velocity; conversely, among the patients who had shown low LAA velocity at either TEE, three suffered from ischemic stroke. In two of these three patients, low LAA velocity was detected only at post-C TEE. CONCLUSIONS: A brief anticoagulation therapy using LMWH appears to be safe and feasible. The 7 days post-C TEE can well-define patients without LAA stunning at low thromboembolic risk, who may take advantage of an early interruption of enoxaparin as an alternative to long oral anticoagulation. The LAA stunning, even in the absence of other thromboembolic risk factors, could select a group of patients at high risk who should continue oral anticoagulation indefinitely or until signs of LAA dysfunction disappear.     

Prevalence of left atrial chamber and appendage thrombi in patients with atrial flutter and its clinical significance

OBJECTIVES: The study was done to assess the prevalence of left atrial (LA) chamber and appendage thrombi in patients with atrial flutter (AFl) scheduled for electrophysiologic study (EPS), to evaluate the prevalence of thromboembolic complications after transesophageal echocardiographic (TEE)-guided restoration of sinus rhythm and to evaluate clinical risk factors for a thrombogenic milieu. BACKGROUND: Recent studies showed controversial results on the prevalence of atrial thrombi and the risk of thromboembolism after restoring sinus rhythm in patients with AFl. METHODS: Between 1995 and 1999, patients with AFl who were scheduled for EPS were included in the study. After transesophageal assessment of the left atrial appendage and exclusion of thrombi, an effective anticoagulation was initiated and patients underwent EPS within 24 h. RESULTS: We performed 202 EPSs (radiofrequency catheter ablation, n = 122; overdrive stimulation, n = 64; electrical cardioversion, n = 16) in 139 consecutive patients with AFl. Fifteen patients with a thrombogenic milieu were identified. All of them had paroxysmal atrial fibrillation (AF). Transesophageal echocardiography revealed LA thrombi in two cases (1%). After EPS no thromboembolic complications were observed. Diabetes mellitus, arterial hypertension and a decreased left ventricular ejection fraction were found to be independent risk factors associated with a thrombogenic milieu. CONCLUSIONS: The findings of a low prevalence of LA appendage thrombi (1%) in patients with AFl and a close correlation between a history of previous embolism and paroxysmal AF support the current guidelines that patients with pure AFl do not require anticoagulation therapy, whereas patients with AFl and paroxysmal AF should receive anticoagulation therapy. In addition, the presence of clinical risk factors should alert the physician to an increased likelihood for a thrombogenic milieu.     

Influence of atrial fibrillation on the morbido-mortality of patients on hemodialysis

BACKGROUND: The consequences of atrial fibrillation (AF) on morbido-mortality of patients on hemodialysis have not been fully explored. The objective of this study was to determine the prevalence of AF in patients on hemodialysis and to evaluate its influence on the development of thromboembolic phenomena (TEP). METHODS: The incidence of AF in 190 patients in our hemodialysis program was assessed, and the patients were followed up for 1 year. Pertinent demographic and biochemical parameters were entered into univariate and multivariate statistical analyses to evaluate associations with overall mortality and TEP such as cerebrovascular accident, transitory ischemic accident, or peripheral embolism. RESULTS: In 13.6% of patients, AF was found; 9.4% of these were of the permanent type. In the multivariate analysis, only increased age was associated with a higher probability of having arrhythmia (odds ratio, 1.10; 95% confidence interval, 1.03-1.17; P =.003). During follow-up, 23% of the patients with AF died compared with 6% of those in sinus rhythm (P <.05), although AF did not appear to be an independent predictive factor for death. Thirty-five percent of the patients with AF and 4% with sinus rhythm had TEP (P <.01). In the multivariate analysis, AF was identified as the only independent predictor for TEP (odds ratio, 8; 95% CI, 2.3-27; P =.0008). CONCLUSIONS: AF is a frequent arrhythmia in patients on hemodialysis, and approximately 1 in 3 hemodialysis patients with AF had thromboembolic complications within 1 year of follow-up. These findings suggest that the consensus contraindication of prophylactic anticoagulation therapy for this group of patients may need to be redefined.     

埋藏式心脏转复除颤器治疗患者的心房颤动回顾性分析

回顾性分析埋藏式心脏转复除颤器(ICD)治疗患者中心房颤动(AF)的发生率,评价AF对ICD治疗患者再次住院、不适当放电治疗和总死亡率的影响。182例ICD置入患者,随访48±17个月,用存活率回归分析等相关统计方法,对AF组和窦律(SR)组再住院率、不适当放电治疗和总死亡率等进行比较。结果:两组在室性心律失常再发生率和再住院率上无明显差异(P>0.05)。存活率分析,AF组患者较SR组患者低(P=0.038)。ICD治疗患者,新的AF发生率为8.43%。在AF组中,ICD治疗前有AF病史的患者其不适当放电治疗发生率为25%,而新出现AF病史的患者,不适当放电治疗发生率为64.3%(P<0.05)。结论:ICD治疗后,新发现的AF患者有更高的不适当放电治疗危险。有AF病史的患者,3年存活率比一直为窦性节律的患者低。     

持续性心房颤动射频消融术中不同抗凝方案与围术期血栓事件的关系

目的探讨持续性心房颤动（房颤）患者经导管射频消融术中不同抗凝方案与围术期血栓事件的关系。方法2004年7月至2007年10月连续收治行导管射频消融治疗的持续性房颤145例。所有患者术前均口服华法林抗凝,使国际标准化比率（INR）控制在2．0—3．0至少1个月。消融前停用华法林并用低分子肝素替代抗凝。2004年7月至2006年1月消融的患者（组Ⅰ）64例,完成房间隔穿刺后,静脉给予普通肝素5000U;2006年2月至2007年10月消融的患者（组Ⅱ）81例,完成房间隔穿刺后根据患者体重予以肝素（100U／kg）,两组患者消融术中每小时均追加肝素1000U。消融后行低分子肝素抗凝3d并口服华法林治疗至少3个月。结果组Ⅰ有4例患者于围术期出现血栓形成或血栓栓塞;组Ⅱ1例持续性房颤患者因消融后第3天自行停用华法林出现短暂性脑缺血发作,其余严格抗凝的患者均未出现血栓事件。组Ⅰ与组Ⅱ消融术前后达到抗凝要求的持续性房颤患者血栓事件发生率差异有统计学意义（4／64对0／80,P=0．037）。结论消融中根据患者体重调整抗凝强度可以显著减少持续性房颤患者围术期血栓事件并发症的发生。     

Cardioversion under the guidance of transesophageal echochardiograhy in persistent atrial fibrillation: results with low molecular weight heparin

BACKGROUND: Transesophageal echocardiography (TEE) guided cardioversion to restoration of sinus rhythm is a therapeutic option in patients with atrial fibrillation (AF). Anticoagulation at the time of and after cardioversion is necessary to prevent formation of new thrombus during atrial stunning period. We aimed to evaluate the efficacy and safety to TEE guided cardioversion with low molecular weight heparin (LMWH) in patients with atrial fibrillation. METHODS: We followed up 208 patients with persistent AF (mean age: 65.5+/-10.2 years) who were attempted TEE guided cardioversion. LMWH were used as an anticoagulant and warfarin therapy was continued. RESULTS: Cardioversion were performed in 183 patients. Sinus rhythm restored in 144 patients (78.7%). Mean follow up duration was 155 days. No cardiac death occurred. In the early follow up period (within 30 day) one thromboembolic event (0.54%) occurred in a patient who was cardioverted. Two patients who had not been cardioverted because of left atrial thrombus presented embolic stroke, one in early and another in late follow up period. All embolic complications occurred in patients who had been taking warfarin and whose INR level was subtherapeutic at the time of stroke. Sinus rhythm was maintained in 64% and total hemorrhagic complications occurred in 4.8% of the patients in long-term follow-up. CONCLUSION: TEE guided cardioversion with a short-term anticoagulation protocol using low molecular weight heparin is a safe and effective method in restoring and maintaining sinus rhythm and enables us to make earlier cardioversion in atrial fibrillation.     

Pharmacologic management of atrial fibrillation in the elderly: Rate control,rhythm control,and anticoagulation

Atrial fibrillation (AF) is the most prevalent major arrhythmia in the elderly. It may lead to significant morbidity and mortality through both primary cardiac effects and thromboembolic complications. It is controversial how aggressive physicians should be in their efforts to maintain normal sinus rhythm. Clearly, elderly patients with hemodynamic impairment or other symptoms of AF should undergo attempts to convert AF and maintain normal sinus rhythm, by means of cardioversion and initiation of antiarrhythmic medications. In patients left in AF, rate control with atrioventricular nodalslowing agents is appropriate. The use of anticoagulation in the elderly is often complicated by concerns about excessive bleeding or falls in this population; however, evidence strongly supports the need for anticoagulation with close monitoring even in the extreme elderly. Because of the high prevalence of asymptomatic AF and the high burden of thromboembolism in the elderly, even patients ostensibly maintained in normal sinus rhythm should continue systemic anticoagulation in the absence of contraindications.     

Mortality after cardiac surgery with or without microwave ablation in patients with permanent atrial fibrillation

BACKGROUND AND AIM OF THE STUDY: The surgical treatment of atrial fibrillation (AF) by Cox and other ablation methods shows a 50-90% conversion rate to sinus rhythm. However, to date no study has addressed the influence of ablation on the mortality rate. METHODS: The perioperative and postoperative mortalities of 210 consecutive patients with permanent AF was investigated for up to two years after cardiac surgery with (n = 111) or without (n = 99) endocardial microwave ablation within the framework of a prospective register study. All patients were followed up. RESULTS: In the ablation group, one patient (0.9%) died perioperatively, seven died during the first year of follow up (6.3%), and nine in the second year of follow up (8.1%). In the control group, five patients died perioperatively (5.1%), 12 died in the first year of follow up (12.1%), and 22 in the second year of follow up (22.2%). During the two-year follow up period, significantly more patients died in the control group than in the ablation group (Log-Rank test: p = 0.0051). CONCLUSION: The results of this register study showed that among patients with permanent AF who underwent cardiac surgery with ablation, mortality was significantly lower than in those who underwent comparable surgery but without ablation. The marked difference in mortality was essentially based on the typical clinical consequences of AF (e.g. thromboembolic complications, cardiac arrhythmias and bleeding complications due to anticoagulation therapy), which occurred less often in the ablation group.     

Atrial fibrillation in the elderly

Opinion statement Atrial fibrillation (AF) is the most common sustained arrhythmia in adults, and its incidence and prevalence increase progressively with age. As a result, AF-associated morbidity and mortality increase with age. Therefore, because even asymptomatic AF markedly increases the risk of stroke and other embolic events, aggressive treatment is warranted in order to avoid the potentially devastating sequelae of this condition. Goals for the treatment of AF in the elderly population should primarily focus on alleviation of symptoms and prevention of strokes, while minimizing potential toxic effects of polypharmacy. Rate control should be optimized with atrioventricular (AV) nodal-blocking agents. The decision of anticoagulation should be individualized for each patient, balancing the risk of stroke against the risk for major bleeding complications. In elderly patients without symptoms, rate control and anticoagulation is the preferred method of treatment. Antiarrhythmic therapy to maintain sinus rhythm is generally reserved for patients with significant symptoms attributable to AF. However, simply maintaining sinus rhythm has not been proven to decrease stroke risk; therefore, longterm anticoagulation is recommended even in patients who are in sinus rhythm on antiarrhythmic drugs. AV nodal ablation with implantation of a pacemaker is a safe and excellent method of rate control for elderly patients who do not respond adequately to pharmacotherapy. Other invasive procedures, such as pulmonary vein isolation and Cox-Maze operations, are associated with high risks of complications in the elderly and are generally not recommended. Postoperative AF is common in the elderly population, and its development in high-risk patients should be anticipated and promptly treated to avoid potential hemodynamic compromise and prolonged hospitalization.     

Implication from Randomized Trials of Rate and Rhythm Controls on Management of Patients with Persistent Atrial Fibrillation

Recently, several randomized trials were published on the issue of rate or rhythm control for patients with atrial fibrillation (AF). Patients were typically minor symptomatic, relatively old, with age above 70, presenting with a recurrence of AF and suffering from only mild to moderate underlying heart disease. The main outcome of these trials is that rate control is not inferior to rhythm control for the management of patients with AF concerning morbidity and mortality. Also patients' quality of life did not differ significantly in follow‐up in these trials. However, rhythm control is not redundant in the treatment of AF. Focus is now on subgroups of patients who could still have benefit being in sinus rhythm. For severely symptomatic patients, patients presenting with the first episode of AF and probably those with severe congestive heart failure, to restore and maintain sinus rhythm should still be the goal. With the failure of antiarrhythmic therapy, nonpharmacological approaches such as pulmonary vein isolation can be performed. Another finding of the randomized trials is that being in sinus rhythm does not prevent from the occurrence of thromboembolic complications. This means that for patients with AF, with risk factors for thromboembolic events, adequate anticoagulant therapy is indicated irrespective of the current heart rhythm. As with antiarrhythmic therapy, the search for new and safer anticoagulant therapy is underway. This review will focus on the key aspects we have learned from the randomized trials on rate and rhythm controls for patients with AF.     

Superior left atrial approach to the mitral valve: incidence of postoperative arrhythmia

BACKGROUND AND AIM OF THE STUDY: The superior left atrial approach to mitral surgery involves exposure of the mitral valve through a longitudinal, craniocaudally orientated incision in the roof of the left atrium. The study aim was to evaluate the incidence of postoperative arrhythmias following this procedure. METHODS: Fifty-nine patients underwent either mitral valve repair (n = 20), mitral valve replacement (n = 26) or an associated procedure (n = 13), including aortic valve replacement, coronary artery bypass grafting and atrial septal defect closure. Eight patients had undergone previous surgery on the mitral valve. Patients were classified according to their preoperative rhythm: sinus rhythm (SR), paroxysmal or chronic atrial fibrillation (AF), or permanent pacing. Changes in cardiac rhythm were evaluated postoperatively, after four weeks, and at late follow up (mean 23.8 months). RESULTS: Preoperatively, 24 patients had shown SR, 10 had paroxysmal AF, 24 had chronic AF, and one patient had permanent pacing. At the time of discharge, SR was recorded in 18 patients who had SR preoperatively, in seven who had paroxysmal AF preoperatively, and in one patient who had chronic AF preoperatively. At follow up, SR was seen in 19 patients with preoperative SR, in seven with paroxysmal AF preoperatively, and in two with chronic AF preoperatively. Four patients received permanent pacemakers postoperatively due to total heart block or bradycardia. CONCLUSION: The superior left atrial approach to mitral valve surgery appears to be safe as it maintains the sinus rhythm in a high proportion of patients postoperatively. In addition, it is not normally prone to technical complications.     

Mending the rhythm does not improve prognosis in patients with persistent atrial fibrillation: a subanalysis of the RACE study.

AIMS: To compare outcome of AF patients with effective rhythm control with patients treated with rate control. METHODS AND RESULTS: Out of the 266 AF patients randomized to rhythm control in the RACE study, 49 patients turned to long-term sinus rhythm and were continuously treated with oral anticoagulation. The incidence of the primary endpoint in these patients was compared to that in 178 patients out of the initial 256 rate-control patients of RACE who were in AF and using oral anticoagulation continuously. Baseline characteristics of both groups were not different. After a mean follow-up of 2.3+/-0.6 years, the primary endpoint (a composite of cardiovascular mortality, heart failure, thrombo-embolic complications (TECs), bleeding, serious adverse effects of antiarrhythmic drugs and pacemaker implants) was 22.4% in the rhythm-control group vs. 15.2% in the rate-control group. Multivariable regression analysis indicated coronary artery disease, heart failure, and digitalis as independent risk indicators of cardiovascular morbidity and mortality. Chronic sinus rhythm did not matter. CONCLUSION: Among patients who remained on warfarin, those who mostly were maintained in sinus rhythm under a rhythm-control strategy did not have a superior prognosis compared to those who remained in AF under a rate-control strategy.     

Facilitating Electrical Cardioversion of Persistant Atrial Fibrillation by Antiarrhythmic Drugs: Update on Clinical Trial Results

Results from clinical trials suggest that antiarrhythmic drugs (AD) can facilitate electrical cardioversion (EC) for persistent atrial fibrillation (AF) (duration >48 hours, no spontaneous termination) by suppression of immediate reinitiation of AF following the procedure. Class IC agents may increase the atrial defibrillation threshold (DFT) by significantly reducing the availability of Na+-channel for depolarization. In contrast, class III agents may decrease the atrial DFT by markedly prolonging atrial refractoriness. Among all AD, ibutilide and amoidarone have been shown to be most effective in enhancing the acute outcome of EC.In patients who are over 65 years of age at high risks of stroke (e.g., atherosclerotic cardiovascular disease, diabetes, hypertension, previous thromboembolism, etc.), the rhythm control strategy offers no survival advantage over the rate control strategy and frequently subjects patients to serious adverse effects of AD therapy. It can not be overemphasized that adequate anticoagulation (INR 2.0-3.0) with warfarin is needed regardless of whichever strategy is chosen unless there are contraindications. On the other hand, in patients who are under 65 years of age without structural heart disease or other risk factors of stroke, rhythm control can be the treatment of choice. Specifically, if a patient has failed EC alone or if the patient has characteristics (e.g., duration of AF >6 months, left atrium >50 mm, etc.) that EC could fail, AD may be given before the procedure to facilitate EC. In the subgroup of patients who are symptomatic with hypertrophic cardiomyopathy and severe diastolic dysfunction requiring maintenance of sinus rhythm to have sufficient ventricular function for optimization of cardiac output, an aggressive approach for rhythm control with amiodarone along with adequate anticoagulation with warfarin should be encouraged.     

Antithrombotic therapy in native heart valve disease

In establishing the indication for anticoagulation of patients with native heart valve disease, those with thromboembolic events and/or atrial fibrillation (AF) must be distinguished from patients with sinus rhythm. Anticoagulation should be started as a matter of principle in patients with thromboembolic events and/or AF who do not undergo valve replacement. However, a more differentiated procedure is mandatory for patients with sinus rhythm. If the left atrium is enlarged, spontaneous echo contrast is detected, and/or there is no atrial contraction and/or reduced left ventricular pump function (e.g., in patients with mitral valve stenosis), then anticoagulation with a target INR of 2.5 is indicated, even in those with sinus rhythm. Whereas rheumatic mitral valve stenosis predominates in developing countries, aortic stenosis (AS) predominates in developing countries. These AS patients mainly suffer microemboli that often determine the prognosis in patients with calcification of the mitral annulus. Anticoagulation is not recommended in calcific microemboli. If there are simultaneous atherothrombotic plaques of the aortic arch > 5 mm in size owing to an often more complex cardiovascular risk profile, then warfarin treatment is indicated. Mitral valve prolapse (MVP), patient foramen ovale and atrial septal aneurysm are potential sources of embolism that may cause stroke. On their own, these congenital lesions do not entail an indication for anticoagulation. This applies in particular to patients with MVP in whom secondary prevention of stroke can be attained with 100 mg aspirin.     

Transesophageal echocardiography (TEE) in atrial fibrillation

Transesophageal echocardiography has given new insight into the pathogenesis of the thromboembolic sequelae of AF and expanded the available therapeutic options. Studies to date indicate that TEE-guided cardioversion is a safe and reasonable approach when the clinical situation warrants prompt restoration of sinus rhythm. Whether widespread use of this strategy offers further benefit remains to be established, although there are theoretical advantages to such an approach. The potential for earlier cardioversion using a TEE-guided approach may facilitate the achievement and maintenance of sinus rhythm. In the long term, earlier restoration of sinus rhythm prevents adverse atrial remodeling, lowers embolic risk, and may improve cardiac performance and functional status. Thromboembolic sequelae (either cardioversion-related or as a result of chronic AF) remain the most devastating complications of AF. Every attempt to minimize this risk should be pursued aggressively. Information gathered from TEE has helped to elucidate the mechanisms responsible for postcardioversion embolism and has emphasized the importance of anticoagulation during and after the restoration of sinus rhythm. TEE also has the potential to further risk stratify patients with AF. Ultimately, a subset of patients may be identified who require more intense anticoagulation (i.e., those with dense SEC or thrombus, or persistent thrombus after prolonged anticoagulation) or in whom cardioversion may be deferred entirely. Likewise, TEE also may prove to be useful in identifying patients with a low-clinical risk profile who may be treated with aspirin alone and patients in whom warfarin may be superior. The results of the ACUTE study should help to further define the role of TEE in the management of patients with AF. Additional clinical studies are needed to address some of the issues that have been raised and to allow for optimal use of TEE in this patient population.     

冲洗式射频消融迷宫手术治疗不同病因永久性心房颤动的疗效比较

目的分析和比较我院冲洗式射频消融迷宫手术治疗不同病因永久性心房颤动（房颤）的疗效。方法：收集我院201 1年1月1日-2012年12月31日外科冲洗式射频消融迷宫手术治疗永久性房颤502例病例资料进行分析。根据病因（手术方式）不同分为两组：瓣膜置换并发冲洗式射频消融迷宫手术（瓣膜病组）406例;非瓣膜置换并发冲洗式射频消融迷宫手术（非瓣膜病组）96例。分别于术中心脏复跳、术后1周、3个月和6个月行超声心动图及心电图检查,观察左房、左室大小及窦性心律维持情况。结果：两组术后各时点心脏转复率均无显著差异,两组左房内径均较术前显著缩小。就全部患者而言,术中心脏转为窦性心律者为358例,转复率为71．3％;术后1周为376例,转复率为74．9％;术后3个月为347例,转复率为69．1％。术后6个月为339例,转复率为67．5％。总体手术死亡3例,2例死于低心排,1例死于恶性心律失常（室颤）,手术死亡率为0．6％。结论：冲洗式射频消融迷宫手术治疗不同病因永久性房颤的疗效没有显著差异,疗效均较好。     

Association between atrial fibrillation and appropriate implantable cardioverter defibrillator therapy: results from a prospective study

INTRODUCTION: Atrial fibrillation (AF) is associated with significant morbidity and mortality that may be related to hemodynamic impairment, thromboembolic events, or enhanced electrical instability of the ventricular myocardium. There is, however, a lack of data concerning the association of AF and ventricular tachyarrhythmias. METHODS AND RESULTS: Consecutive patients with indication for an implantable cardioverter defibrillator (ICD) were classified for the presence or absence of persistent AF at the time of device implantation. Incidence of device therapy, stored electrograms, and clinical events during follow-up were evaluated prospectively. Two hundred fifty patients were included. During follow-up (20+/-14 months), patients in AF experienced appropriate device therapy for recurrent ventricular arrhythmias more frequently compared with patients in sinus rhythm (SR) (63% vs 38%, P = 0.01). On multivariate analysis, AF was an independent predictor of appropriate ICD therapy (relative risk 1.8; 95% confidence interval [CI] 1.2 to 2.9) and inappropriate device therapy (relative risk 2.3; 95% CI 1.2 to 4.5). Predefined clinical events (cluster endpoint: death, syncope, and hospitalizations) were observed more frequently in AF than in SR patients (55% vs 31%, P = 0.01). Analysis of device-stored electrograms revealed a higher incidence of short-long-short cycles preceding ventricular arrhythmias in AF compared with SR patients (50% vs 16%, P = 0.002). Baseline heart rate preceding ventricular arrhythmias did not differ between the two groups. CONCLUSION: AF is an independent predictor of recurrent ventricular arrhythmias in ICD recipients. The underlying electrophysiologic mechanism seems to be irregular rather than rapid ventricular activation, with a high incidence of short-long-short sequences preceding ventricular tachyarrhythmias in AF patients.     

A study of platelet activation in paroxysmal, persistent and permanent atrial fibrillation.

We hypothesized that the 'residual' thromboembolic risk in therapeutically anticoagulated patients undergoing cardioversion could potentially be related to abnormal haemorheology and platelet activation. To test this hypothesis, we firstly investigated the role of haemorheology and platelet activation in patients with paroxysmal and persistent atrial fibrillation (AF), who were compared with healthy controls and patients with permanent AF. Second, we compared these indices in patients with persistent AF, before and after successful cardioversion. We measured indices of haemorheology (haematocrit, plasma viscosity, and fibrinogen), fibrin D-dimer (an index of thrombogenesis and fibrin turnover) and platelet activation (as assessed by platelet aggregation and plasma levels of beta-thromboglobulin, and soluble P-selectin) in 29 patients with paroxysmal AF, 87 patients with permanent AF and 29 healthy controls in sinus rhythm. The effects of cardioversion were studied in 20 patients with persistent AF, who maintained sinus rhythm at 2 months follow-up. Plasma levels of beta-thromboglobulin (P = 0.03) and fibrin D-dimer (P = 0.001) were higher in patients with AF, when compared with controls; the highest levels were seen in those with permanent AF (Tukey's test, < 0.05). Plasma viscosity was significantly higher in the patients with paroxysmal AF compared with healthy controls (P = 0.02). Plasma soluble P-selectin levels and platelet aggregation responses to all four platelet agonists (adenosine diphosphate, collagen, epinephrine and thrombin) in patients with paroxysmal AF and permanent AF were similar to controls. Plasma fibrinogen, viscosity and other markers of platelet activation (including platelet aggregation) were not significantly different in patients with paroxysmal AF, during episodes of AF and sinus rhythm (P = not significant), although mean haematocrit was significantly higher during the episodes of AF compared with episodes of sinus rhythm (P = 0.03). Among the patients with persistent AF who remained in sinus rhythm at 2 months following successful cardioversion, there was a significant decrease in the plasma levels of soluble P-selectin at 2 weeks and 2 months, when compared with baseline (pre-cardioversion) levels (P < 0.001). Haemorheology and platelet aggregation response to agonists did not change significantly, except for a transient increase in platelet aggregation response to collagen at 2 weeks (P = 0.045). In conclusion. abnormal haemostatic and platelet activation in patients with permanent AF are not consistently observed in patients with paroxysmal and persistent AF. Abnormal haemorheology appears to play an important role in patients with paroxysmal AF, especially during the paroxysms of AF. Cardioversion of persistent AF to sinus rhythm appears to decrease the platelet activation, but whether this translates into a beneficial reduction in thromboembolic risk requires further study.