Coronary sinus electrode does not reduce atrial defibrillation thresholds

BACKGROUND: Atrial defibrillation can be achieved with a conventional dual-coil, active pectoral implantable cardioverter-defibrillator (ICD) lead system. Shocking vectors that incorporate an additional electrode in the CS have been used, but it is unclear if they improve atrial DFTs. OBJECTIVE: The objective of this prospective, randomized study was to determine if a coronary sinus (CS) electrode reduces atrial defibrillation thresholds (DFTs). METHODS: This was a prospective study of 36 patients undergoing initial ICD implant for standard indications. A defibrillation lead with superior vena cava (SVC) and right ventricular (RV) shocking coils was implanted in the RV. An active can emulator (Can) was placed in a pre-pectoral pocket. A lead with a 4 cm long shocking coil was placed in the CS. Atrial DFTs were determined in the following 3 shocking configurations in each patient, with the order of testing randomized: RV --> SVC + Can (Ventricular Triad), distal CS --> SVC + Can (Distal Atrial Triad), and proximal CS --> SVC + Can (Proximal Atrial Triad). RESULTS: The Proximal and Distal Atrial Triad configurations were both associated with significant reductions in peak current (p < 0.01), but this effect was offset by significant increases in shock impedance (p < 0.01), resulting in no net change in the peak voltage or DFT energy in comparison to the Ventricular Triad configuration (Ventricular Triad: 4.9 +/- 6.6 J, Proximal Atrial Triad: 3.3 +/- 4.1J, Distal Atrial Triad: 4.4 +/- 6.7 J, p > 0.2). CONCLUSION: Shocking vectors that incorporate a CS coil do not significantly improve atrial defibrillation efficacy. Since the Ventricular Triad shocking pathway provides reliable atrial and ventricular defibrillation, this configuration should be preferred for combined atrial and ventricular ICDs.     

阵发性房颤射频消融术后空白期内房性心律失常与房颤远期复发的关系

目的 探讨阵发性房颤射频消融术后3个月（“空白期”）内房性心律失常的发作趋势与远期复发的关系.方法 入选在我院接受首次环肺静脉电隔离射频消融术的阵发性房颤患者50例,并于术后3个月内每月行24h动态心电图检查,同时进行术后定期临床随访和监测12个月.根据术后第12个月体表心电图、24h动态心电图监测及临床随访结果,分为房颤复发组和无复发组,比较复发组患者与无复发组患者术后3个月内房性心律失常发生率及随着时间推移两组房性心律失常的发作趋势.结果 术后第12个月体表心电图及24h动态心电图统计结果显示,房颤复发率为36.0％（18/50）,所有心电图中出现快速型房性心律失常心电图为26.9％,其中房颤20.2％、房扑2.0％、房速4.7％;房性早搏20.1％;窦性心动过缓2.0％.复发组患者术后3个月内房性心律失常的发生率高于无复发组（41.1％比10.2％,P＜0.05）,复发组患者术后3个月内房性心律失常的发生率维持在较高水平（术后3个月分别为44.4％、41.8％、38.5％,P＞0.05）.无复发组患者术后3个月可出现房颤复发,随着时间推移房性心律失常的发生率呈降低趋势（术后3个月分别为18.7％、10.5％、4.4％,P＜0.01）.结论 早期复发不能代表消融失败和晚期复发,但早期房性心律失常发作频繁,则晚期房颤复发的危险性增加.     

Treatment of atrial fibrillation with an implantable atrial defibrillator--long term results.

OBJECTIVES: To evaluate the long-term outcome with an implantable atrial defibrillator (IAD) in patients with recurrent atrial fibrillation (AF). BACKGROUND: Maintenance of sinus rhythm using repeated internal cardioversion shocks has been shown to be effective and safe in short-term studies but long term follow-up is unknown. METHODS: Since 1995, 136 patients (30 women) with symptomatic, drug-refractory atrial fibrillation were implanted with an IAD (METRIX, InControl). This analysis was performed after a median of 40 (range 7-66) months after implantation. RESULTS: In 26 patients, the programmed mode was not documented during last follow-up, four patients had died. Of the remaining 106 patients (mean age 58+/-10, range 34 - 79 years), 39 were actively delivering therapy with the device, in 14 patients the device was used to monitor the arrhythmia but no shocks were delivered, and in 53 patients it was turned off or explanted. Increases in defibrillation thresholds (n=7), patient intolerance of multiple cardioversion shocks (n=15), and significant bradycardia requiring dual-chamber pacing (n=12) were the main reasons for discontinuation of therapy in addition to battery depletion (n=19). After explantation, efforts to maintain sinus rhythm were continued in 17 patients whereas rate control was attempted in 36 patients. CONCLUSIONS: A strategy of maintaining sinus rhythm long-term with an IAD is feasible in a proportion of patients. However, patient selection is critical, and technical improvements (i.e. higher shock energies, dual-chamber pacing and additional preventive and anti-tachycardia pacing algorithms) are required to increase the number of patients having long term benefit, and frequent arrhythmia recurrences and patient intolerance to repeated cardioversion shocks remain a major limitation.     

Impact of atrial fibrillation duration on postcardioversion recurrence

BACKGROUND: "Begetting," a mechanistic tenet of atrial fibrillation (AF), stipulates that the rate of recurrence of AF after cardioversion is proportional to the preceding arrhythmia duration. However, recent reports suggest that, for brief durations, the incidence of early recurrence of AF (ERAF) is inversely proportional to duration. These reports were based on potentially biased data. OBJECTIVES: We performed a prospective study to examine the impact of AF duration on postcardioversion recurrence. METHODS: Forty-four patients underwent placement of an implantable cardioverter-defibrillator (ICD) capable of delivering patient-elicited AF cardioversion shocks. Subsequently, in the ambulatory setting, the timing of shocks in relationship to perceived AF onset was randomly assigned within individuals to early (as soon as possible) or delayed (1 day later). RESULTS: During a follow-up averaging 199 days per patient, a total of 61 AF episodes among 17 patients occurred for which a patient-elicited cardioversion shock was delivered. Twenty-three shocks were delivered using early protocol (mean 6.8 hours after AF onset), and 38 shocks were delivered using delayed protocol (mean 34.7 hours after AF onset). The incidence of ERAF was significantly lower using the delayed protocol. CONCLUSION: A strategy of approximately 24-hour delay in cardioversion shock timing decreased the incidence of ERAF, relative to a shock delivered within a few hours of AF onset. This observation has important mechanistic and therapeutic implications.     

Electrical atrial fibrillation induction affects the characteristics of induced arrhythmia

Several methods are being used to induce atrial fibrillation (AF) in experimental investigations, which may affect the electrophysiologic parameters of the induced arrhythmia. The aim of our study was the investigation of temporal characteristics of AF during and after electrical induction.Direct current and high-frequency stimulation was used for induction in bipolar biatrial, right and left atrial appendage configurations in 6 dogs. Atrial and ventricular electrical activity was recorded near the bundle of His. Seven statistical parameters were calculated to analyze the temporal characteristics of electrical activity of both chambers.The induction method affected 5 atrial and no ventricular electrophysiologic parameters during stimulation, and the effect disappeared after ceasing induction, during the induced transient or persistent AF.Electrical stimulation affects the properties of the induced arrhythmia during the induction; thus, the investigation of AF is recommended only after ceasing the induction to avoid bias.     

心房颤动病人转律前AFW的临床应用

目的:为帮助选择可以成功转律的心房颤动患者,研究转律前心房颤动病人房颤波谱分析(a spectra analysissystem for atrial fibrillation waves,AFW)的价值。方法:所有病人在转律前均行AFW研究,成功转律的患者为A组,转律不成功的患者为B组,对两组进行比较研究。结果;当房颤小波的峰频率F_(0 max),F_(1 max),F_(2 max),P4明显减少,而对应的主导心房周长MACL0,MACL1,MACL2明显的延长时.特别是F_(0 max)<3、51±O.17Hz.MACL0>315±15.09ms,P4<3.21±0.63pw时转律的成功率较高(p均<0.01)。结论:AFW信号分析技术中F_(0 max_,MACL0,P4是指导临床医师成功进行房颤转律的较好指标。     

Reduced apelin levels in lone atrial fibrillation.

AIMS: Apelin is an endogenous peptide hormone that appears to have a physiological role in counter-regulation of the angiotensin and vasopressin systems. This peptide has been reported to be down-regulated in subjects with acute heart failure, but has not been studied in other cardiovascular conditions. We studied apelin levels in 73 subjects with lone atrial fibrillation (AF). METHODS AND RESULTS: Study subjects had electrocardiographic evidence of paroxysmal or chronic AF and a structurally normal heart on echocardiography. Subjects were excluded if they had a history of coronary artery disease, rheumatic heart disease, cardiomyopathy, significant valvular disease, hyperthyroidism, or antecedent hypertension. Controls were recruited from a healthy outpatient population. Plasma apelin levels were determined using a commercially available immunoassay. Seventy-three subjects with lone AF and 73 healthy controls were enrolled and studied. Mean levels of apelin were significantly lower in subjects with lone AF when compared with controls (307 vs. 648 pg/mL, P<0.00005). CONCLUSION: Reduced apelin levels were observed in this homogenous population of lone AF subjects and may represent an underlying diathesis predisposing to this common arrhythmia.     

非瓣膜病心房颤动对左心房大小的影响

目的　研究非瓣膜病心房颤动对左心房大小及左心室结构和功能的影响 ,探讨心房颤动与左心房扩大之间的因果关系。方法　选择 32 9例非瓣膜病心房颤动患者 ,根据心房颤动类型及心房颤动发作时间分组 ,比较各组间超声心动图参数。结果　心房颤动发作 1～ 3年组和 3年以上组左心房内径 ( L AD)均大于 1年以下组 ( P<0 .0 5 ,P<0 .0 1) ,而 3年以上组 L AD又大于 1～ 3年组 ( P<0 .0 5 ) ,3年以上组左心室舒张末期内径 ( L VED)大于 1年以下组 ( P<0 .0 5 ) ;持续性心房颤动组 L AD和 L VED均明显大于阵发性心房颤动组 ( P<0 .0 1) ;而持续性心房颤动患者心房颤动发作 3年以上组 L AD大于 1年以下组及 1～ 3年组 ( P<0 .0 1,P<0 .0 5 )。结论　心房颤动本身可引起左心房扩大 ,且左心房扩大常发生在心房颤动持续以后 ,因此转复心房颤动应尽早进行 ;心房颤动对左心室结构及功能也有一定影响 ,且持续性心房颤动的影响较大。     

递进式个体化心房基质消融治疗心房颤动

目的 以肺静脉电学隔离为终点的心房颤动（房颤）消融术式的疗效难以令人满意。本研究旨在探索规范化的递进式个体化心房基质改良消融术治疗房颤的方法。方法 124例患者（男性96例,女性28例）,年龄27-76（53．6±8．7）岁。其中92例为阵发性房颤,32例为持续性／永久性房颤。若无自发房颤则在心房进行持续递增的快速刺激（频率200—600次／min）诱发房颤。均在非接触式标测观察房颤时心房激动情况,将最常激动部位做为房颤基质进行改良消融,并根据消融后重复等电位标测的结果作出递进式调整,直至房颤被终止不再被诱发。结果 在既不隔离肺静脉也不寻求碎裂电位的情况下,87．1％（108／124）的房颤消融转复为窦性心律,其余被转为非典型心房扑动（房扑）或房性心动过速（房速）。可将消融灶分为3种类型,其中以7字形的A型线性消融最关键,71．6％的阵发性房颤可被A型消融终止且不再被诱发,而68．8％的持续性／永久性房颤则需通过B型消融终止。随访（21．6±5．3）个月,90．3％（112／124）的患者不服药亦无房颤发生。其余9．7％（12／124）的患者有顽固性非典型房扑／房速,其中仅1．6％（2／124）的患者伴有阵发性房颤。结论 递进式的心房基质消融术可以将房颤有效地转复为窦性心律,并有满意的远期疗效。此种术式简单易行有望在NavX和Carto标测下复制。     

西地兰对老年阵发性房颤复律效果与左心功能的关系

目的明确老年阵发性心房纤颤（ＰＡｆ）患者发作间歇期的心功能状态与西地兰复律效果的关系，为选择复律适应证提供依据。方法对６５例原发病为冠心病（ＣＨＤ）、高血压（ＨＰＴ）及不明原因（ＩＤＰ）的老年ＰＡｆ患者，使用西地兰复律，并用超声心动图检测发作间歇期心功能，分析两者的关系。结果（１）有效组原发病以ＣＨＤ及ＣＨＤ伴ＨＰＴ为主，大多兼有左室收缩功能障碍（ＳＩ），推测西地兰的正性肌力作用参与了ＰＡｆ伴ＳＩ患者的复律机制。（２）无效组原发病以ＨＰＴ为主，大多兼有左室舒张功能障碍（ＤＩ）。（３）老年有效组中有少数单纯ＤＩ及心功能正常者，推测西地兰的迷走神经兴奋作用可能参与了ＰＡｆ伴ＤＩ患者的复律机制。结论ＣＨＤ伴ＳＩ为西地兰复律的良好适应证，ＨＰＴ伴ＤＩ者不适用西地兰复律     

静脉注射胺碘酮治疗快速心房纤颤的临床观察

目的:观察静脉注射胺碘酮对心房纤颤并快速心室率(简称快速型房颤)患者的临床疗效。方法:对34例新发快速型房颤患者,10 min静脉推注胺碘酮150 mg,观察10 min,未转为窦性心律者再次于10 min内推注150 mg,仍未转复者则以0.5~1.0 mg/min静脉滴注24 h,转为窦性心律者则随时终止滴注。观察房颤转复、心室率控制情况及不良反应,同时比较老年组(18例)和非老年组(16例)有何不同。结果:34例患者在24 h内均转为窦性心律。两组患者用药后30 min,1 h,6 h,24 h心室率分别为(96.00±8.39)次/min与(98.00±8.35)次/min,(88.13±9.98)次/min与(86.47±8.68)次/min,(84.88±10.19)次/min与(82.88±8.25)次/min,(74.88±9.80)次/min与(78.88±7.80)次/min,较用药前的(138.58±9.15)次/min与(130.36±8.26)次/min明显下降(P<0.01),但两组间用药前、后无显著差异。无严重心律失常发生,未诱发或加重心功能不全。结论:静脉应用胺碘酮治疗快速型房颤安全有效,老年人用药剂量不减。     

血管紧张素Ⅱ受体拮抗剂、胺碘酮联用对预防心房颤动的影响

目的观察厄贝沙坦联用胺碘酮在持续性心房颤动转复后维持窦性心律的作用及对左心房功能的影响。方法98例持续性心房颤动(持续超过7d)患者,药物或电复律后随机分为两组,Ⅰ组50例给予胺碘酮0.2g,1次/d;Ⅱ组48例给予厄贝沙坦150mg,1次/d,胺碘酮0.2g,1次/d;两组均连服6个月。分别于治疗后第1周、2周、1个月、2个月、4个月及6个月复查心电图或动态心电图,观察心房颤动复发情况;复律后次日及6个月后做超声心动图(UCG)检查,观察左心房功能变化。结果共87例完成治疗。随访6个月,心房颤动复发Ⅰ组为34.9%(15/43),Ⅱ组为13.6%(6/44),两组比较差异有统计学意义(P<0.05),Ⅱ组复律后次日及治疗6个月后,超声测量左心房内径由(42±12)mm缩小为(34±11)mm,治疗前与治疗6个月后比较差异有统计学意义(P<0.01),而Ⅰ组上述指标比较差异无统计学意义(P>0.05)。结论厄贝沙坦联用胺碘酮在持续性心房颤动转复后维持窦性心律,较单用胺碘酮更有效,长期服用厄贝沙坦可逆转左心房扩大,降低左心房压,有利于消除心房颤动复发的基础。     

心房颤动中的室率控制和节律控制策略

目的 室率控制和节律控制是临床治疗心房颤动(房颤)的两种基本策略.为了进一步比较两种治疗策略在不同人群中的获益,该研究入选了10个前瞻性随机临床研究进行荟萃分析.方法 以房颤、室率控制、节律控制、随机对照试验为检索词,对MEDLINE、The Cochrane Library、The Clinical Trials 和中国维普期刊数据库进行系统检索,检索截止时间为2010年5月31日.结果 该研究总入选人群7876例,3932例分布在室率控制组,3944例分布在节律控制组.结果显示,在总体年龄中,室率控制组的住院率明显低于节律控制组(17.56％与22.98％,OR:0.37,95％ CI:0.19～0.71);而在平均年龄＜65岁的亚组人群中,室率控制组的总病死率(3.6％与1.9％,OR:1.89,95％CI:1.01～3.53)和进行性加重的心力衰竭事件(2.3％与0.3％,OR:5.6,95％ CI:1.44～21.69)明显高于节律控制组.而对于血栓栓塞事件和出血事件,在总体人群和亚组人群中,两组之间差异无统计学意义.结论研究结果提示,对于相对年轻的房颤患者,节律控制策略可能优于室率控制策略.     

Gender-related differences in catheter ablation of atrial fibrillation.

AIMS: Women have an increased risk for atrial fibrillation (AF)-related complications and there is evidence towards a reduced efficacy of the rhythm control strategy than men. A catheter-based strategy is therefore widely attractive, but the impact of gender on catheter ablation (CA) of AF remains undefined. METHODS AND RESULTS: We included 221 consecutive patients (150 men) who underwent CA of drug-refractory AF. Gender differences in clinical presentation and outcomes were compared. Women were older (P = 0.002), had a longer history of AF (P = 0.04), and were more likely to have hypertension (P = 0.04). Moreover, a concomitant valvular heart disease tended to be more common in women (32.4 vs. 23.3%; P = 0.28) and left atrium dimensions were significantly larger (P = 0.003). However, acute success rate and complications rate were similar between genders. After 22.5 +/- 11.8 months of follow-up, the overall freedom from arrhythmia recurrences was similar (83.1 vs. 82.7% in men), and a similar improvement in SF-36 quality of life scores was achieved in both groups. CONCLUSION: Women are referred for AF ablation later with a more complex clinical pre-operative presentation. Despite this higher risk profile in women, no differences were detected in clinical outcomes. Our findings indicate that CA of AF appears to be safe and effective in women as in men.     

房颤与房扑的射频消融治疗研究

目的 探讨房颤与房扑之间的相互关系，寻找房颤的射频治疗方法。方法 对40例阵发性房颤患者进行了电生理标测及射频消融。结果 40例中有6例患者发生房扑，行右房峡部消融，1例行Halo电极标测示峡部双向阻滞，随访12－30个月房颤消失或次数明显减少。结论 房颤与房扑为两种密切相关的心律失常，消融右房峡部可能对部分房颤患者起到治疗作用。     

Impact of volume status on the incidence of atrial fibrillation following aortic arch repair

We evaluated the volume status of patients undergoing aortic arch repair to determine the impact of fluid balance on risk of postoperative atrial fibrillation (AF). From 1993, 445 patients who underwent total aortic arch repair were enrolled in this study. Patients who had AF preoperatively or died within the 10th postoperative day (POD) were excluded. Volumes administered (input) and eliminated (output) through all routes were recorded, and fluid balance (input minus output) was calculated intraoperatively, on the day of surgery, and PODs 1–2. The incidence of new onset of AF was 53.9% (240/445). Total input on POD 1 was greater in patients developing AF than in those not developing it (3 372 ± 90 vs 3 012 ± 79; P = 0.0036), as was net fluid balance on POD 1 as well (−806 ± 84 vs −558 ± 90; P = 0.050). Blood transfusion volume was greater in patients developing AF than in those not developing it on POD 1 (1 285 ± 89 vs 927 ± 74; P = 0.003) and POD 2 (405 ± 53 vs 227 ± 47; P = 0.015). Increased input volume and net fluid balance on POD 1 are associated with an increased risk of postoperative AF in patients undergoing aortic arch surgery.     

胺碘酮或氯沙坦及两者合用对急性心房颤动患者心房重构的干预

目的:采用人工心脏起搏的方法制备家兔急性心房颤动模型,分别探讨胺碘酮与氯沙坦对心房颤动导致心房重构的不同干预效果.方法:40只家兔随机分为0.9%氯化钠溶液组(对照组)、胺碘酮组、氯沙坦组、合用组,分别灌胃给药1周,以600次/min的频率起搏心房8 h,并分别于起搏前、起搏后0.5、1、2、4、6、8 h及停止起搏后10、20、30 min重复测定心房有效不应期(AERP).结果:①经过8 h快速起搏后对照组AERP200(100.63±7.5)ms和AERP150(95.01±6.2)ms均较起搏前明显缩短(均P＜0.01),AERP200较AERP150缩短更为明显(P＜0.05),胺碘酮组、氯沙坦组及合用组快速起搏前后AERP无显著变化.②停止快速起搏后,对照组AERP逐渐恢复,AERP200和AERP150在10 min内基本恢复至起搏前的95.78%和96.76%,30 min内基本恢复至起搏前的99.07%和99.39%.结论:短期快速心房起搏可致心房电重构;胺碘酮和氯沙坦可以逆转心房电重构.