Comparison of left atrial volume and function after linear ablation and after cardioversion for chronic atrial fibrillation

Several techniques for treatment of atrial fibrillation (AF) have been developed, including the direct placement of radiofrequency for lesions at open heart surgery. Detailed evaluation of left atrial (LA) function has not been performed after these procedures and has not been compared in patients with chronic AF. We compared the atrial function of patients with sustained sinus rhythm (SR) after linear ablation with a group who underwent direct-current cardioversion and a group of normal controls to investigate the measurable deleterious effects, if any, on atrial function after the surgical procedure. Twenty-one consecutive patients who had maintained SR for >6 months after a linear radiofrequency ablation (LRFA) procedure were studied. As control subjects, we examined 33 patients with chronic AF successfully restored to SR by cardioversion who maintained SR for >6 months and 42 age-matched normal subjects. LA function was decreased in both the LRFA and cardioverted AF groups compared with normal controls. The parameters of LA function, atrial fraction, LA ejection fraction, and the A' velocity were lowest in the LRFA group, intermediate in the cardioverted AF group, and highest in the normal controls (LA function: 15.8 +/- 10%, 26 +/- 10%, 33 +/- 7%; p = 0.0001; LA ejection fraction: 31 +13%, 41 +/- 12%, 51 +/- 9%; p = 0.0001; A' velocity: 4.2 +/- 1.4, 7.6 +/- 2.2, 9.5 +/- 1.9 cm/s; p = 0.0001). LA volumes were increased in the LRFA and cardioverted AF groups compared with normals (62.8 +/- 22 vs 70.6 +/- 17 vs 38.7 +/- 9.8 ml; p = 0.0001). Thus, although LA function is restored and maintained after LRFA has been performed during open heart surgery, LRFA use is associated with a measurable decrease in LA function over and above that found after conventional cardioversion.     

Clinical and echocardiographic characteristics of left atrial spontaneous echo contrast in sinus rhythm

OBJECTIVES

In this study we attempt to define the clinical and echocardiographic characteristics of patients with left atrial spontaneous echo contrast (LASEC) in sinus rhythm (NSR).

BACKGROUND

Left atrial spontaneous echo contrast in atrial fibrillation (AF) is associated with increased risk of thromboembolism. Little is known about its significance in NSR.

METHODS

We reviewed reports of 1,288 transesophageal echocardiogram (TEE) studies done with a 5 MHz probe. Patients with swirling LASEC who were in NSR during TEE were analyzed. We compared them with a control group of 45 age matched patients selected to have NSR, left atrium (LA) >4.0 cm but no SEC.

RESULTS

Spontaneous echo contrast in NSR was noted in 24 patients (2%) and formed our study group. All patients with SEC had enlarged LA, mean 5.6 cm ± 0.6 cm. There was a higher prevalence of cerebrovascular accident (CVA) in patients with SEC when compared with controls with no SEC, 83% versus 56%, p = 0.02. Patients with SEC had larger LA, 5.6 versus 4.9 cm, p < 0.0001 and lower mean peak left atrial appendage emptying velocity (LAAEV), 38 versus 56 cm/s, p = 0.001. Thirteen percent of patients with SEC had LA thrombus as compared with none in the control group, p = 0.02. By multivariate analysis, SEC in NSR was found to be associated with CVA, larger LA size and decreased mean LAAEV. Even after adjusting for LA size, patients with SEC had a higher prevalence of CVA than controls, p = 0.03.

CONCLUSIONS

Spontaneous echo contrast in NSR occurs in patients with significantly dilated LA and depressed atrial function. Left atrial thrombus is noted in 13% of such patients despite NSR. Spontaneous echo contrast in NSR is associated with a higher prevalence of CVA. Further, SEC is found to be an independent and more powerful correlate of CVA than reduced LAAEV or atrial size. These data indicate that LASEC in NSR is a prothombotic condition.     

Atrial myocardial deformation properties are temporarily reduced after cardioversion for atrial fibrillation and correlate well with left atrial appendage function.

AIM: This study was conducted to evaluate whether left atrial strain and strain rate correlate well with transesophageal parameters of stunning after atrial fibrillation. METHODS AND RESULTS: Twenty-two consecutive patients with chronic atrial fibrillation >/=3 months and <1 year were enrolled in the study. Transthoracic (TTE) and transesophageal (TEE) echocardiography with color Doppler myocardial imaging were performed before, 1 day after and 10 days after successful cardioversion. Left atrial transthoracic strain (S) and strain rate (SR) from lateral, inferior and anterior atrial walls, left atrial appendage tissue velocities, strain and strain rate values were measured with offline analysis. Left atrial appendage emptying (LAAEV) and filling (LAAFV) velocities were obtained from transesophageal echocardiography. Left atrial transthoracic, and left atrial appendage strain and strain rates were significantly lower following 1 day after cardioversion (TTE S/SR, 5.0 +/- 2.8%/2.3 +/- 1.0; TEE (septal) S/SR, 7.6 +/- 3.6%/1.6 +/- 0.7). There was a good correlation between these parameters and LAAEV (LA systolic strain and LAAEV, r = 0.73, P = 0.007). Left atrial and LAA strain and strain rate values improved over time, and correlated well with LAAEV, measured 10 days after cardioversion. CONCLUSIONS: Transthoracic atrial and TEE LAA strain and strain rate, which are quantitative measures of atrial function, are reduced after cardioversion, and recover subsequently. The good correlation between LAA function and TTE strain and strain rate suggests that TTE atrial parameters may help determine duration of anticoagulation.     

Time course for resolution of left atrial appendage stunning after catheter ablation of chronic atrial flutter

OBJECTIVES: This study assessed the time course of resolution of left atrial appendage (LAA) stunning after catheter ablation of chronic atrial flutter (AFL). BACKGROUND: Although the presence of LAA stunning after ablation of chronic AFL calls for anticoagulation in the post-cardioversion period, limited information has been obtained, particularly regarding its duration. METHODS: Sixteen patients who underwent ablation of chronic, pure AFL were studied, only five of whom had structural heart disease and one of whom had a reduced left ventricular ejection fraction. The LAA emptying velocities (LAAEV) and left atrial spontaneous echo contrast (SEC) were assessed using transesophageal echocardiography before, within 24 h after, one week after, and two weeks after ablation. RESULTS: Within 24 h after ablation, the LAAEV decreased from 39 +/- 10 cm/s during AFL to 21 +/- 10 cm/s during sinus rhythm (p < 0.01), with eight patients (50%) having documented SEC. After one week, the LAAEV increased (39 +/- 17 cm/s, p < 0.01 vs. within 24 h) and SEC resolved in five of eight patients. After two weeks, the increase in LAAEV persisted (54 +/- 14 cm/s, p < 0.01 vs. 1 week) and SEC was no longer present in any of the patients. The numbers of patients with LAAEV >30 cm/s and absence of SEC were three within 24 h, 11 at one week, and 16 at two weeks after ablation. CONCLUSIONS: Patients with chronic, pure AFL and preserved left ventricular function who will undergo catheter ablation may not require anticoagulation therapy for more than two weeks after the procedure because of the presence of forceful mechanical LAA contractions and the absence of SEC.     

The left atrial function index: a rhythm independent marker of atrial function.

AIMS: This study evaluates a simple echocardiographic rhythm independent expression of left atrial (LA) function, 'the left atrial function index' (LAFI). BACKGROUND: Quantitation of LA function is challenging and often established parameters including peak A are limited to sinus rhythm (SR). We hypothesized that atrial function could be characterized independent of rhythm by combining analogues of LA volume, reservoir function and LV stroke volume. METHODS: Seventy-two patients with chronic atrial fibrillation (CAF) were followed for six months post cardioversion (CV). Thirty-seven age matched healthy subjects were controls. The LAFI = LAEF x LVOT-VTI/LAESVI (LAEF = LA emptying fraction, LAESVI = maximal LA volume indexed to BSA, LVOT-VTI = outflow tract velocity time integral). RESULTS: The LAFI pre-CV in the CAF group was depressed vs controls (0.10 +/- 0.05 vs 0.54 +/- 0.17; P = 0.0001). Post-CV, LAFI was lower in persistent AF than in those restored to SR (AF vs SR: 0.08 +/- 0.03 vs 0.15 +/- 0.08; P = 0.0001), improved progressively in SR and was unchanged when AF persisted. CONCLUSION: The LAFI, a simple, rhythm independent expression of atrial function, appears sensitive to differences between individuals in AF and those restored to SR and justifies clinical and investigative applications.     

Serial evaluation of left atrial dimension after cardioversion for atrial fibrillation and relation to atrial function

The size of the left atrium is usually increased during atrial fibrillation (AF). The aim of the present study was to evaluate changes in left atrial (LA) dimension after cardioversion for AF, and the relation between LA dimension and atrial function. The initial study population included 171 consecutive patients. Patients who had spontaneous cardioversion to sinus rhythm (56 patients) were compared with patients who had random cardio-version with drugs (50 patients) or direct-current (DC) shock (50 patients). Echocardiographic evaluations included LA size and volume. LA passive and active emptying volumes were calculated, and LA function was assessed. Atrial stunning was observed in 18 patients reverted with DC shock and in 7 patients reverted with drugs. The left atrium was dilated in all patients during AF (48 +/- 5 mm). The size of the left atrium decreased after restoration of sinus rhythm in all patients with spontaneous reversion to sinus rhythm, in 73% of patients reverted with drugs, and in 50% of patients reverted with DC shock. The comparison between patients with a normal mechanical atrial function and patients with reduced atrial function showed that a higher atrial ejection force was associated with a more marked reduction in LA size after restoration of sinus rhythm. A relation between LA volumes and atrial ejection force was observed in the group of patients with depressed atrial mechanical function (r = -0.78; p <0.001). The active emptying fraction was lower, although not significantly, in this group, whereas the conduit volume was increased. Thus, a depressed atrial mechanical function after cardioversion for AF was associated with a persistence of LA dilation.     

心房颤动复律前后左房结构和功能变化的超声心动图研究

目的应用超声心动图观察心房颤动(简称房颤)患者复律前后左房结构和功能的变化。方法选择房颤患者20例,按心脏复律的方式分为直流电复律组7例,药物复律组13例,分别于复律前、复律后第1天、第3天、第7天、第1个月时应用超声心动图测定左房内径和容积,记录二尖瓣血流频谱A峰流速(VA)、A峰速度时间积分(A-VTI)、心房充盈分数(AFF)和左房射血力(LAEF)。分析左房内径、容积变化与左房收缩功能的关系。应用心房肌超声组织定征技术在左房后壁心肌和心包处测量背向散射积分值(IBS)及背向散射积分周期变异幅度(CVIB)评价心肌组织的声学特征。结果房颤时所有患者均存在左房扩大,而恢复窦性心律后直流电复律组和药物复律组的左房上下径均显著降低(P<0.05或0.01)。恢复窦性心律后第1天、第3天直流电复律与药物复律组比较,左房最大和最小容积显著增大(P<0.05或0.01),VA、A-VTI、AFF和LAEF明显降低。房颤时左房心肌标化IBS较健康对照组增大,而CVIB则降低(P均<0.01),直流电复律组恢复窦性心律后第1天、第3天左房心肌标化IBS及CVIB与房颤时比较无差异(P>0.05),而药物复律组左房IBS%与房颤时和直流电复律组比较显著降低,CVIB则显著增大。恢复窦性心律后第7天、第1个月时,两组左房IBS%与房颤时比较均显著降低,CVIB显著增大(P均<0.01),两组无差异。结论两种复律方式成功复律后随时间推移均可改善房颤患者的左房结构重构和功能。     

心房颤动患者复律前后左心房功能变化的超声研究

目的　探讨心房颤动 ( AF )复律后左心房功能变化的特点。方法　选择 AF病人 96例 ,按心脏节律转复的方式分为自发性复律 ( A)组 2 4例 ,药物复律 ( B)组 40例及直流电复律 ( C)组 3 2例 ;分别应用超声心动图测定其左心房内径和容积 ,计算左心房主动和被动排空容积 ,并评价左心房功能。结果　AF时所有病人的左心房扩大 ,而恢复窦性心律后 A、B及 C组左心房内径降低者分别为 10 0 %、74%及 5 2 %。 62例左心房机械功能正常患者与 3 4例左心房功能降低患者比较有更强的左心房射血力 ( LAEF ) ,这与复律后左心房内径降低有关。左心房功能异常( L AEF<7达因 )患者左心房内径和容积分别与左心房射血力呈负相关 ( r=-0 .72和 -0 .76,P<0 .0 0 1)。左心房主动排空分数降低而管道容积却增加。结论　心房颤动复律后 ,左心房机械功能的延迟恢复与持续存在的的左心房扩大有关     

Effect of radiofrequency ablation on atrial mechanical function in patients with atrial flutter.

Atrial stunning, as assessed by left atrial appendage emptying and increased spontaneous echo contrast, is known to occur following direct-current cardioversion of atrial fibrillation (AF) and atrial flutter (AFI). Little is known on atrial mechanical function and the time course of atrial recovery following radiofrequency ablation of AFI. Fourteen patients undergoing radiofrequency ablation of persistent typical counterclockwise AFI were enrolled. Two-dimensional and pulse Doppler transesophageal echocardiography (TEE) were performed before ablation and immediately following restoration of sinus rhythm. Left atrial spontaneous echo contrast grades, left atrial appendage emptying fractions, and peak left atrial appendage emptying velocities were measured. Transthoracic echocardiography (TTE) was performed immediately after ablation, then repeated after 1 day, 1 week, and 6 weeks to measure peak transmitral velocities and percent atrial contribution to ventricular filling. Left atrial appendage emptying velocities decreased significantly following AFI termination (44 +/- 23 cm/s before ablation vs 25 +/- 14 cm/s after ablation, p = 0.01). Left atrial appendage emptying fractions also decreased significantly (0.48 +/- 0.1 preablation vs 0.34 +/- 0.17 postablation, p = 0.02). New spontaneous echo contrast developed in 4 patients (29%) after ablation. Four patients had complete atrial standstill after ablation, and 1 patient developed a new left atrial appendage thrombus. The percent atrial contribution to ventricular filling recovered progressively over 6 weeks with significant improvement in peak transmitral velocities at day 7. Thus, atrial stunning occurs after catheter ablation of AFI and may lead to rapid formation of thrombus in the left atrial appendage. Significant improvement in left atrial function occurs in 7 days.     

Effect of radiofrequency catheter ablation for atrial fibrillation on left atrial cavity size

Left atrial (LA) remodeling is associated with atrial fibrillation (AF). Radiofrequency catheter ablation offers a good treatment option for AF, with reasonable long-term results. The purpose of the present study was to assess whether LA reverse remodeling occurs after successful catheter ablation. Fifty-seven consecutive patients (45 men; age 53 +/- 8 years) with symptomatic drug-refractory AF were treated with radiofrequency catheter ablation. The patients were divided into 2 groups on the basis of AF recurrence as determined by Holter monitoring and 12-lead electrocardiographic findings at 6 weeks and 3 months of follow-up (sinus rhythm [SR] group, no recurrence; AF group, AF recurrence). At baseline and 3 months of follow-up, 2-dimensional echocardiography was performed to assess LA size and dimensions. Furthermore, LA volumes were measured at end-systole and end-diastole. After 3 months, 39 of 57 patients (68%) maintained SR. At 3 months of follow-up, the LA anteroposterior diameter showed a significant reduction in the SR group (4.5+/- 0.3 vs 4.2 +/- 0.2 cm, p <0.01), and an additional increase was observed in the AF group (4.5+/- 0.3 vs 4.8 +/- 0.3 cm, p <0.05). Furthermore, the LA end-systolic and end-diastolic volumes decreased significantly in the SR group from baseline to follow-up (59 +/- 12 vs 50 +/- 11 ml, p <0.01, and 37 +/- 9 vs 31 +/- 7 ml, p <0.01, respectively). However, a tendency toward an increase in LA volumes was observed in the AF group. In conclusion, the results of this study have demonstrated that LA reverse remodeling occurs after successful radiofrequency catheter ablation for AF.     

Effect of left atrial circumferential ablation for atrial fibrillation on left atrial transport function

BACKGROUND: The effects of left atrial (LA) circumferential ablation on LA function in patients with atrial fibrillation (AF) have not been well described. OBJECTIVES: The purpose of this study was to determine the effect of LA circumferential ablation on LA function. METHODS: Gated, multiphase, dynamic contrast-enhanced computed tomographic (CT) scans of the chest with three-dimensional reconstructions of the heart were used to calculate the LA ejection fraction (EF) in 36 patients with paroxysmal (n = 27) or chronic (n = 9) AF (mean age 55 +/- 11 years) and in 10 control subjects with no history of AF. Because CT scans had to be acquired during sinus rhythm, a CT scan was available both before and after (mean 5 +/- 1 months) LA circumferential ablation (LACA) in only 10 patients. A single CT scan was acquired in 8 patients before and in 18 patients after LACA ablation. Radiofrequency catheter ablation was performed using an 8-mm-tip catheter to encircle the pulmonary veins, with additional lines along the mitral isthmus and the roof. RESULTS: In patients with paroxysmal AF, LA EF was lower after than before LACA (21% +/- 8% vs 32 +/- 13%, P = .003). LA EF after LA catheter ablation was similar among patients with paroxysmal AF and those with chronic AF (21% +/- 8% vs 23 +/- 13%, P = .7). However, LA EF after LA catheter ablation was lower in all patients with AF than in control subjects (21% +/- 10% vs 47% +/- 5%, P < .001). CONCLUSION: During medium-term follow-up, restoration of sinus rhythm by LACA results in partial return of LA function in patients with chronic AF. However, in patients with paroxysmal AF, LA catheter ablation results in decreased LA function. Whether the impairment in LA function is severe enough to predispose to LA thrombi despite elimination of AF remains to be determined.     

Prognostic predictors of sinus rhythm control by amiodarone and electrical cardioversion in patients undergoing percutaneous transluminal mitral valvuloplasty for rheumatic atrial fibrillation.

BACKGROUND: Conversion to sinus rhythm (SR) is rarely attempted in patients with rheumatic atrial fibrillation (AF) because the length of AF duration and the dilation of left atrium (LA) make maintenance of SR difficult. In this study, predictors of the successful maintenance of SR with amiodarone and electrical cardioversion in rheumatic AF patients receiving percutaneous transluminal mitral valvuloplasty (PTMV) were identified. METHODS AND RESULTS: This study included 23 consecutive patients undergoing PTMV for rheumatic AF (6 men, 53+/-11 years; AF duration 25 +/-24 months; LA diameter 44+/-6 mm; mitral valve area (MV) 1.1+/-0.2 cm(2)). Electrical cardioversion was required for the successful conversion to SR in all patients regardless of whether they had received amiodarone (400 mg/day) 2 months before PTMV (n=8) or 2 months after (n=15). After cardioversion, all patients received amiodarone 200 mg/day. With a follow-up period of 35+/-8 months, 14 patients (61%) remained in SR. A greater reduction in LA size (-4+/-3 mm vs 1+/-1 mm; p=0.004) and an greater increase in MV area (0.8+/-0.4 cm(2) vs 0.5+/-0.2 cm(2); p=0.01) by PTMV, not AF duration, were found to be the independent predictors for patients with successful maintenance of SR as compared with patients with recurrence of AF. CONCLUSION: In rheumatic AF patients receiving PTMV, the successful maintenance of SR with amiodarone and electrical cardioversion can be predicted by the degree to which LA size is reduced and MV area is increased.     

Atrial structural remodelling and restoration of atrial contraction after linear ablation for atrial fibrillation.

AIMS: We determined late atrial function following a surgical linear endocardial radiofrequency (RF) ablation procedure that aimed to restore and maintain sinus rhythm (SR) in atrial fibrillation (AF). We tested the hypothesis that successful restoration of SR is accompanied by measurable mechanical atrial function that is at normal or near normal levels. METHODS: Forty-seven patients who underwent the surgical RF procedure at least 6 months previously (median 2.86 years; range: 0.6-4.2 years) were studied using an array of echocardiographic variables. Two patient groups (SR restored [RF-SR], persistent AF [RF-AF]) and an age matched control group were studied. Among the echocardiographic variables measured were left atrial (LA) size and volume, LA active fractional emptying and mitral annular displacement corresponding to atrial contraction (A' velocity) by Doppler tissue imaging. RESULTS: At long term follow up 29/47of patients who underwent the RF procedure were in SR with atrial contraction present echocardiographically. Of the patients initially restored to SR, the proportion remaining in SR at 3 years was 79% (SE 9%). The atrial-emptying fraction was reduced in comparison to that seen in normal controls (27+/-14% vs 46+/-10%). The A' velocity was decreased in the surgical RF cohort vs controls (4.4+/-1.3 vs 9.7+/-1.7cm/s; P=0.0001). Despite LA size preoperatively being similar in both surgical groups, atrial size decreased in those in whom SR was restored (48.6+/-7.6 vs 44.8+/-4.7mm; P=0.0001) but increased in those in whom AF persisted (48.2+/-8.1mm vs 52.3+/-7.8mm; P=0.0001). CONCLUSION: The radial pattern of linear radiofrequency ablation used in the present study resulted in restoration of SR and atrial function. Procedural success was independent of preoperative atrial size. Restoration of SR results in 'reverse' atrial remodelling and improved atrial function. However atrial function remains modestly impaired, either due to the ablation lesions or pre-existing atrial disease.     

厄贝沙坦对高血压病并阵发性心房颤动患者左房功能的影响

目的观察厄贝沙坦对高血压病并阵发性心房颤动(简称房颤)患者左房功能的影响,探讨其对房颤预防及治疗的作用。方法104例高血压病合并阵发性房颤患者随机分治疗组和对照组。两组均给予基础降压治疗,治疗组除给予基础治疗外加用厄贝沙坦。3个月后通过超声心动图观察左房功能。结果治疗后两组左房各项指标均明显改善,其中左房上下径、左房最大容积改善程度治疗组较对照组大(32.47±7.38 mm vs 38.47±6.47 mm;18.45±3.67 mm vs 30.56±3.68 mm,P<0.05或0.01)。治疗组的房颤发生次数显著低于对照组(1.2±0.36次vs2.1±0.42次,P<0.01)。结论厄贝沙坦能改善高血压病并阵发性房颤患者左房功能,降低房颤发生次数。     

Prognostic value of plasma soluble CD40 ligand in patients with chronic non-valvular atrial fibrillation.

AIMS: We aimed to clarify whether determination of levels of soluble CD40 ligand (sCD40L) could predict subsequent thrombo-embolic events in patients with non-valvular atrial fibrillation (NVAF). METHODS AND RESULTS: Forty-four consecutive outpatients (mean age: 58 +/- 6 years, 20 male) with chronic NVAF who were not receiving aspirin and had no thrombus or spontaneous echo contrast (SEC) on left atrium (LA) or left atrial appendage (LAA) were included in the study. The patients had no history of an embolic event and were followed up 24 +/- 2 months for thrombo-embolic events. sCD40L was determined at the enrollment. All patients were evaluated by means of SEC and thrombus formation by transoesophageal echocardiography at the end of follow-up period. Twelve (27%) patients had SEC and 2 (5%) patients had thrombus on LAA. Ischaemic stroke occurred in 2 (4.5%) patients and transient ischaemic attack developed in 4 (9%) patients during follow-up. sCD40L was significantly higher in patients with LASEC (0.41 +/- 0.05 vs. 0.16 +/- 0.04 ng/mL, P = 0.02) and embolic events (0.74 +/- 0.05 vs. 0.19 +/- 0.03 ng/mL, P = 0.001) than in those without. sCD40L levels were significantly related to the LASEC grade (R = 0.377, P = 0.02). In multivariable analysis, while independent variables for SEC or thrombus formation were LA diameter, sCD40L levels, and the duration of AF, independent variables for cerebrovascular events were the existence of SEC or thrombus formation on LAA, and sCD40L level. CONCLUSION: Plasma sCD40L may prospectively predict stroke in AF. sCD40L may provide useful marker to identify patients at high thrombo-embolic risk with NVAF.     

High-density activation mapping of fractionated electrograms in the atria of patients with paroxysmal atrial fibrillation

BACKGROUND: Areas of complex fractionated atrial electrograms (CFAEs) have been implicated in the atrial substrate of atrial fibrillation (AF). The mechanisms underlying CFAE in humans are not well investigated. OBJECTIVES: The purpose of this study was to investigate the regional activation pattern associated with CFAE using a high-density contact mapping catheter. METHODS: Twenty patients with paroxysmal AF were mapped using a high-density multielectrode catheter. CFAE were mapped at 10 different sites (left atrium [LA]: inferior, posterior, roof, septum, anterior, lateral; right atrium [RA]: anterior, lateral, posterior, septum). Local atrial fibrillation cycle length (AFCL) was measured immediately before and after the occurrence of CFAE, and the longest electrogram duration (CFAEmax) was assessed. RESULTS: Longer electrogram durations were recorded in the LA compared with the RA (CFAEmax 118 +/- 21 ms vs 104 +/- 23 ms, P = .001). AFCL significantly shortened before the occurrence of CFAEmax compared with baseline (LA: 174 +/- 32 ms vs 186 +/- 32 ms, P = .0001; RA: 177 +/- 31 ms vs 188 +/- 31 ms, P = .0001) and returned to baseline afterwards. AFCL shortened by >or=10 ms in 91% of mapped sites. Two different local activation patterns were associated with occurrence of CFAEmax: a nearly simultaneous activation in all spines in 84% indicating passive activation, and a nonsimultaneous activation sequence suggesting local complex activation or reentry. CONCLUSION: Fractionated atrial electrograms during AF demonstrate dynamic changes that are dependent on regional AFCL. Shortening of AFCL precedes the development of CFAE; thus, cycle length is a major determinant of fractionation during AF. High-density mapping in AF may help to differentiate passive activation of CFAE from CFAE associated with an active component of the AF process.     

A comparison of P-wave duration and dispersion in patients with short-term and long-term atrial fibrillation

This study compared P-wave duration and dispersion (PD) in patients with short-term (48 hours) atrial fibrillation (AF) after cardioversion. We studied 96 consecutive patients with short-term (group A; n:51, age: 61 +/- 11 years) and long-term AF (group B; n:45, age: 64 +/- 10 years). P-wave measurements were calculated from 12-lead electrocardiogram. There was no difference related to clinical characteristics. Left atrial dimension was significantly higher in group B (P =.003). P maximum (124 +/- 12 vs. 113 +/- 11 ms, P =.001) and PD (57 +/- 8 vs. 49 +/- 9 ms, P =.001) were also significantly longer in group B compared with group A, but P minimum did not. In univariate analysis, PD were related to AF duration (P =.002) and left atrial size (P =.02). This relation remained in multivariate analysis (P =.01, P =.02, respectively). P maximum >112 ms and PD >47 ms had accuracy values of 74% and 83% respectively for separating group B. Our results suggest that P wave duration and dispersion is prolonged in patients with long-term AF compared to short-term AF.     

左房机械功能对持续性心房颤动电复律术后疗效的影响

目的探讨左房机械功能对持续性心房颤动(简称房颤)电复律术后疗效影响。方法选择30例持续性房颤成功电复律患者,应用超声心动图测定其电复律术后48 h静息时窦性心律(简称窦律)下最大二尖瓣口面积、A波速度峰值(PMA),E波速度峰值(PME),计算左房射血力,测量左房内径,随访2个月,分析左房机械功能指标与持续性房颤电复律术后复发的关系。结果有11例(36.7%)患者电复律术后2个月复发,复发组左房射血力较窦律维持组明显下降[(8.5±2.4)×10-5N vs(11.4±3.6)×10-5N,P=0.020〗;复发组6例左房机械功能低下,较窦律维持组(5例)显著升高(54.5%vs 26.3%,χ2=4.9,P=0.042)。而复发组左房内径有增大的趋势(37.3±4.1mm vs 34.4±4.2 mm,P=0.077)。结论左房机械功能低下是持续性房颤电复律术后近期复发的危险因素。     

Effect of inotropic stimulation on left atrial appendage function in atrial myopathy of chronic atrial fibrillation

Atrial fibrillation (AF) leads to remodeling of the left atrium (LA) and left atrial appendage (LAA), resulting in atrial myopathy. Reduced LA and LAA function in chronic AF leads to thrombus formation and spontaneous echo contrast (SEC). The effect of inotropic stimulation on LAA function in patients with chronic AF is unknown. LAA emptying velocity (LAAEV) and maximal LAA area at baseline and after dobutamine were measured by transesophageal echocardiography in 14 subjects in normal sinus rhythm (NSR) and 6 subjects in AF. SEC in the LA was assessed before and after dobutamine. LAAEV increased significantly in both groups. However, the LAAEV at peak dobutamine in patients with AF remained significantly lower than the baseline LAAEV in patients who were in NSR (P = 0.009). Maximal LAA area decreased significantly with dobutamine in both groups, but LAA area at peak dose of dobutamine in patients with AF remained greater than baseline area in those in NSR (P = 0.01). Despite the increase in LAAEV, SEC improved in only two of five patients. We conclude that during AF, the LAA responds to inotropic stimulation with only a modest improvement in function.     

非瓣膜性心房颤动患者C反应蛋白与左心房自发显影的关系

目的探讨高敏C反应蛋白(hs-CRP)与非瓣膜性心房颤动(房颤)患者左心房自发显影(LASEC)的关系。方法连续入选自2018年1月1日至6月30日于首都医科大学附属北京安贞医院心内科病房首次行射频消融术的非瓣膜性房颤患者490例,根据术前经食管超声心动图检查结果将研究人群分为无LASEC组(n=338)和LASEC组(n=152)。采用胶乳增强免疫比浊法测定hs-CRP;用单因素及多因素logistic分析探讨非瓣膜性房颤患者hs-CRP与LASEC的相关性。结果490例患者中有152例(31%)检测到LASEC。LASEC组的年龄、房颤类型、既往栓塞事件、纤维蛋白原定量、D-二聚体、左心房前后径及CHA2DS2VASc评分与无LASEC组比较,差异均有统计学意义(P均<0.05),LASEC组hs-CRP水平明显高于无LASEC组[3.16(1.30,5.23)mg/L比0.67(0.37,1.48)mg/L,P<0.001]。多因素logistic回归分析发现hs-CRP(OR=1.136,95%CI 1.060~1.217,P<0.001)和D-二聚体(OR=1.040,95%CI 1.011~1.070,P=0.007)是LASEC的独立相关因素。结论hs-CRP升高是非瓣膜性房颤患者LASEC的独立相关因素,炎症反应可能参与非瓣膜性房颤血栓前状态的形成。