心房肌复极的电整复性与阵发性心房颤动发生机制的实验研究

Objective Electrical restitution was believed to be a determinant responsible for the stability of heart rhythm. Although numerous studies focused on the role of action potential duration restitution (APDR) in the initiation and maintenance of ventricular fibrillation (VF), the relationship between atrial APDR and atrial fibrillation (AF) has not been fully understood. This study aims to investigate the characteristics of APDR of left atrium (LA) and right atrium (RA) in canines and the relevance to induction of AF. Methods Monophasic action potential (MAP) was recorded from LA and RA in 14 canines using the MAP recording-pacing combination catheter. APDR, plotted as action potential duration (APD) on the preceding diastolic interval (DI), was assessed by use of programmed stimulation with a single extrastimulus (S_1S_2) at LA and RA. Episodes of AF were recorded and analyzed. Results APD_(90) was significantly shorter in the LA than that in the RA [( 157.4 ± 43.5 ) ms vs. ( 170. 9 ± 37. 9)ms, P < 0. 05]. The mean slope of the APDR curve by S_1S_2 in the LA was significantly greater than that in the RA ( 1.3 ±0. 4 vs. 0. 9 ± 0. 3, P < 0. 05 ). The incidence of induced AF was significantly higher in the LA than in the RA (11/18 vs. 7/18, P < 0. 05). Conclusions The APDR and MAP characteristics are not uniform between atriums, which may be one of the important mechanisms responsible for the initiation of AF. Heterogeneity of APDR between LA and RA might create critical gradients or a dispersion of repolarization and subatrate for re-entrant arrhythmias and vulnerability to AF.     

阵发性心房颤动肌袖电隔离后复发病例的分析及再消融的体会(摘要)

目的 :结合 4例先后两次肺静脉电隔离成功治疗的阵发性心房颤动 (房颤 )患者 ,探讨导管射频消融肌袖电隔离治疗阵发性房颤后复发的机制 ,并对再次肌袖电隔离治疗的结果进行分析与评价。资料与方法 :对 4例进行肌袖电隔离治疗后复发的阵发性房颤患者 ,在Lasso标测导管指引下进行再次肌袖电隔离治疗。结果 :4例患者共对 14根靶静脉 (12根肺静脉和 2根腔静脉 )进行了射频消融治疗 ,较第一次消融的靶肺静脉数 (9根 )明显增多 ,隔离了除右下肺静脉外所有的肺静脉 ,其中 5根靶静脉恢复袖房传导 ,予以再次电隔离。电隔离一根靶静脉平均需进行 2 .9± 1.3次消融。术后平均随访 7.5± 5 .0 7(1-12 )个月 ,3例无房颤复发 ,1例发作次数明显减少。结论 :袖房传导的恢复及多异位灶起源可能是房颤复发的原因 ,对于阵发性房颤导管射频消融后复发病例 ,再次射频消融治疗是安全、有效的 ,有望彻底根治房颤     

心房肌的复极与阵发性房颤发生机制的实验研究

目的使用单相动作电位技术(MAP)对在体犬左、右心房肌的复极时间进行研究,以探讨阵发性心房颤动(房颤)发生与维持的潜在机制.     

应用多层螺旋计算机断层摄影术技术对比分析心房颤动及非心房颤动患者左心耳的形态学特征

目的探讨多层螺旋计算机断层摄影术(Multislice spiral CT,MSCT)对评价心房颤动(房颤)及非房颤患者左心耳形态学的临床应用价值.方法对入选的86例患者分为房颤组44例为拟行导管消融治疗的阵发性房颤患者,对照组42例为无房颤的患者.所有患者经MSCT肺静脉成像检查,进行三维容积重建.测量左心耳容积、左心耳口长短径直径、左心耳与冠状动脉左回旋支的关系、左心耳嵴的长度及宽度.结果房颤组患者左心房容积(119.8±33.4)ml、左心耳容积(10.1±4.8)ml、左心耳口面积(293.2±113.7)mm2、左心耳口长短径(24.3±5.3)mm、(15.6±4.4)mm均显著大于对照组,分别为(89.6±29.2)ml,(7.5±3.1)ml,(221.5±87.6)mm2,(20.8±3.8)mm及(13.0±3.3)mm,有极显著性差异(P＜0.005).房颤组患者左心耳口面积自54.0 mm2～502.4 mm2不等,对照组为111.0 mm2～566.6 mm2不等.而两组中左心耳嵴的长度及宽度、左心耳基部同冠状动脉左回旋支的距离没有显著差别.结论在房颤患者中,除了左心房的增大,左心耳容积及左心耳口面积也显著地增大,提示左心耳形态学的改变同房颤的发生密切相关.房颤患者左心耳口面积相差很大,术前评价左心耳口对选择封堵器及其型号很有帮助.另一方面,左心耳非常接近冠状动脉回旋支,基于左心耳基部消融时,应谨慎选择消融策略以避免损伤回旋支.MSCT可作为测量及评价左心房、左心耳相关指标,明确左心耳周围组织结构的有效检查手段.     

房室结慢径区域消融对迷走神经功能及心房颤动易感性的影响

Objective Atrioventricular node reentrant tachycardia (AVNRT) ablation may effect the vagal response,which is indicated by sinus tachycardia. On the other hand,atrial fibrillation (AF) ,which was found to be associated with vagal irmervation, often coexists with AVNRT. However,little is known about the im-pact of slow pathway ablation on local vagal innervation to atria. Methods In 11 dogs, bilateral cervical sympa-thovagal trunks were decentralized and metoprolol was given to block sympathetic effects. Linear lesion was per-formed from coronary sinus (CS) ostium to the middle area of Koch triangle. Atrial effective refractory period(ERP) ,vulnerability window (VW) of AF, and sinus rhythm cycle length (SCL) were measured at high fight atrium (HRA),low right atrium (LRA), distal (CSd) and proximal CS (CSp) at baseline with and without vagal stimulation before and after ablation. The histological study was also performed. Results (1) SCL during vagal stimulation remained unchanged before and after ablation(107±19)bpm vs (108±8) bpm (P > 0.05). (2) After ablation, ERP during vagal stimulation remained unchanged at HRA (55±34) ms vs (69 ±37) ms (P >0.05),and decreased slightly at CSd (42±32) ms vs (55±30) ms (P =0.08). However,at LRA and CSp,ERP was significantly decreased after ablation (19±21) ms vs (66±24) ms (P <0.001) ; and (7± 18) ms vs (46±24) ms (P < 0.001), respectively. (3) AF was difficult to be induced at baseline before and after ablation in all sites (VW close to 0). While during vagal stimulation, after ablation VW of AF significantly decreased at LRA (1±3) ms vs (49±36) ms (P < 0.005) and CSp (10±12) ms vs (45±34) ms (P < 0.05) ,decreased slightly at CSd after ablation (35±37) ms vs (57±28) ms (P =0.07) ,and remained un-changed at HRA (63±31) ms vs (63±25) ms (P > 0.05). (4) The altered architecture of individual gan-glia was histologically observed. Conclusions The decreased ERP shortening to vagal stimulation in CS and LRA induced by slow pathway ablation indicates that ablation in such area may result in the vagal dennervation in LRA and CS,thereby attenuating the susceptibility to vagal mediated AF. While unchanged SCL,ERP short-ening and VW to vagal stimulation in sinus node area and HRA indicate that slow pathway ablation did not change the vagal innervation to these sites.     

心房颤动射频消融术中经验性抗凝方案评价

目的 观察心房颤动(房颤)射频导管消融术中经验性抗凝活化凝血时间(ACT)达标情况及短期术后血栓并发症发生情况.方法 顺序入选2011年我院行射频导管消融治疗的阵发性或持续性房颤患者87例,术中均依据经验肝素抗凝(即首次穿刺房间隔后予负荷量肝素100 U/kg,术中每小时追加1000 U),术中定时监测ACT,如ACT≥250 s即为抗凝达标,ACT≥300 s则抗凝效果较好.观察ACT达标情况.随访终点:术后1个月脑卒中及严重出血情况(颅内出血、穿刺口血肿、皮肤黏膜出血).结果 87例患者测定ACT总体达标率为74.1％,未达标25.9％.ACT全程达标患者共45例,达标率为51.7％.术中术后无血栓及出血事件发生.结论 虽然房颤消融术中经验性抗凝多数患者可以全程达标抗凝,但仍有部分患者部分时间ACT未达到抗凝标准,存在潜在血栓及出血不良事件发生风险,建议遵循指南进行术中ACT监测指导抗凝.大体重的阵发性房颤患者,术中经验性抗凝不易达标,需要加强抗凝,提高达标率.     

通过体表心电图评价不同部位起搏时心脏整体复极离散的变化

目的观察心脏不同部位起搏时体表心电图评价心室肌复极指标的变化,了解不同部位起搏对心室肌整体复极离散的影响。方法 10只健康猪,分别在右心房(RA)、右心室心尖部心内膜(RVEndo)及左心室心外膜(LVEpi)起搏,记录并测量体表心电图12个导联的T波峰-末间期(Tpe)和QT间期,计算Tpe平均值(Tpe-AVE)、Tpe最大值(Tpe-MAX)以及QT间期离散度(QTd),比较不同部位起搏时上述各参数的差异,进一步评价不同起部位对心室整体复极离散的影响。结果 LVEpi、RA、RVEndo起搏时的QT间期分别为(328±24)ms、(295±13)ms、(304±17)ms,LVEpi起搏时的QT间期明显长于RA及RVEndo起搏时的QT间期(P<0.05),RA与RVEndo起搏时QT间期没有明显差别。LVEpi、RA、RVEndo起搏的QT离散度(QTd)分别为(33±6)ms、(17±3)ms、(18±3)ms,LVEpi起搏时的QTd明显大于RA及RVEndo起搏时的QTd(P>0.05),RA与RVEndo起搏时QTd没有明显差别(P>0.05)。RA起搏时Tpe-AVE及Tpe-MAX分别为49±6ms及58±8 ms,与RVEndo起搏相近(49±8)ms及(60±8)ms,P>0.05);LVEpi起搏时Tpe-AVE及Tpe-MAX明显增大(63±7)ms及(71±8)ms,与RA、RVEndo起搏时比较两者(P<0.05)。结论与RA及RVEndo起搏时比较,LVEpi起搏时的QT间期、QTd、Tpe-AVE及Tpe-MAX均明显增大,LVEpi起搏可能会增加心室整体复极离散。     

NLR对阵发性和持续性心房颤动导管射频消融术后复发预测价值的比较

目的探讨中性粒细胞与淋巴细胞比值(NLR)对阵发性和持续性心房颤动(房颤)导管射频消融术后复发预测价值的比较。方法选取2014年6月至2016年6月于大连医科大学附属第一医院心内科首次行导管射频消融术的554例房颤患者为研究对象,其中阵发性房颤394例,持续性房颤160例。根据血常规结果计算NLR值。阵发性房颤行环肺静脉电隔离(CPVI),持续性房颤在CPVI基础上加行线性消融。房颤复发定义为消融3个月空白期后,发生的任何快速性房性心律失常,且持续时间≥30 s。结果平均随访(13.2±3.6)月,阵发性房颤87例(22.1%)复发,持续性房颤51例(31.9%)复发。在阵发性和持续性房颤中,复发组NLR均显著高于非复发组,差异有统计学意义(P0.05)。经多因素Cox回归和ROC曲线分析显示,NLR对持续性房颤患者消融术后复发的预测价值优于阵发性房颤患者[HR=2.421(95%CI:1.688～3.472),P0.05 vs. HR=2.071(95%CI:1.682～2.551), P0.05;AUC=0.721(95%CI:0.633～0.809),P0.05 vs. AUC=0.688(95%CI:0.625～0.751),P0.05]。在阵发性房颤中,NLR预测的最佳临界点为2.07。在持续性房颤中,NLR预测的最佳临界点为2.11。结论 NLR是阵发性和持续性房颤消融术后复发的独立预测因素,并且在持续性房颤中的预测价值优于阵发性房颤。当NLR≥2.07时阵发性房颤消融术后复发的概率明显增加;当NLR≥2.11时持续性房颤消融术后复发的概率明显增加。     

房室结慢径区域消融对迷走神经功能及心房颤动易感性的影响

Objective Atrioventricular node reentrant tachycardia (AVNRT) ablation may effect the vagal response,which is indicated by sinus tachycardia. On the other hand,atrial fibrillation (AF) ,which was found to be associated with vagal irmervation, often coexists with AVNRT. However,little is known about the im-pact of slow pathway ablation on local vagal innervation to atria. Methods In 11 dogs, bilateral cervical sympa-thovagal trunks were decentralized and metoprolol was given to block sympathetic effects. Linear lesion was per-formed from coronary sinus (CS) ostium to the middle area of Koch triangle. Atrial effective refractory period(ERP) ,vulnerability window (VW) of AF, and sinus rhythm cycle length (SCL) were measured at high fight atrium (HRA),low right atrium (LRA), distal (CSd) and proximal CS (CSp) at baseline with and without vagal stimulation before and after ablation. The histological study was also performed. Results (1) SCL during vagal stimulation remained unchanged before and after ablation(107±19)bpm vs (108±8) bpm (P > 0.05). (2) After ablation, ERP during vagal stimulation remained unchanged at HRA (55±34) ms vs (69 ±37) ms (P >0.05),and decreased slightly at CSd (42±32) ms vs (55±30) ms (P =0.08). However,at LRA and CSp,ERP was significantly decreased after ablation (19±21) ms vs (66±24) ms (P <0.001) ; and (7± 18) ms vs (46±24) ms (P < 0.001), respectively. (3) AF was difficult to be induced at baseline before and after ablation in all sites (VW close to 0). While during vagal stimulation, after ablation VW of AF significantly decreased at LRA (1±3) ms vs (49±36) ms (P < 0.005) and CSp (10±12) ms vs (45±34) ms (P < 0.05) ,decreased slightly at CSd after ablation (35±37) ms vs (57±28) ms (P =0.07) ,and remained un-changed at HRA (63±31) ms vs (63±25) ms (P > 0.05). (4) The altered architecture of individual gan-glia was histologically observed. Conclusions The decreased ERP shortening to vagal stimulation in CS and LRA induced by slow pathway ablation indicates that ablation in such area may result in the vagal dennervation in LRA and CS,thereby attenuating the susceptibility to vagal mediated AF. While unchanged SCL,ERP short-ening and VW to vagal stimulation in sinus node area and HRA indicate that slow pathway ablation did not change the vagal innervation to these sites.