Interatrial right-to-left conduction in patients with paroxysmal atrial fibrillation

Purpose  We wanted to illustrate the right-to-left impulse propagation routes during sinus in patients with paroxysmal atrial fibrillation (PAF), as alterations in conduction patterns have been linked to the pathogenesis of PAF, and as no large patient materials have been published. Methods  Patients underwent 3-D electroanatomical contact mapping prior to catheter ablation. The site of the earliest left atrial (LA) activation was determined. Results  Three different interatrial routes were identified, either as solitary pathways (36/50 patients, 72%) or in their combinations (14/50). Bachmann’s bundle (BB) was involved in the majority of the cases with solitary routes (25/36). More seldom, impulse propagation occurred near the oval fossa (FO) (7/36) or the coronary sinus ostium (4/36). In patients with combined routes, both the BB (10/14) and FO routes (11/14) were included in most cases. Conclusions  In PAF patients, LA can be activated during sinus rhythm through three distinct connections, either encompassing a single route or via any combination of these connections. In one third, the earliest LA activation occurs outside BB. The knowledge of the propagation patterns may give insight into the pathophysiology of PAF and into refining ablation therapy.     

阵发性心房颤动患者心房内阻滞的评价

目的对阵发性心房颤动(房颤)患者心房内阻滞的情况进行评价.方法入选78例阵发性房颤患者和8创无阵发性房颤的射频消融患者,电生理检查时分别放置高位右心房、希氏束、冠状静脉窦电极导管作起搏和标测用,在高位右心房进行S1S2程序刺激,S1刺激固定于500ms,S2从450ms开始,-10ms扫描,记录不同刺激时心房内和心房间传导时间及心房不应期.结果S1刺激时阵发性房颤组和对照组S1-AHB间期分别为(56.7±15.4)ms和(60.8±14.2)ms;S1-ACSd间期在两组分别为(110.2±24.3)ms和(107.5±25.6)ms;差异均无显著性(P＞0.05).S2刺激时,心房内传导时间最长延长1倍以上的患者在两组分别为15/78例和11/80例,心房间传导最长延长1倍以上的患者在两组间分别为13/78例和9/80例,两组间差异无显著性(P＞0.05).心房不应期在两组分别为(218.0±28.2)ms和(216.0±24.7)ms,两者间差异无显著性(P＞0.05).结论多数阵发性房颤患者无明显的心房内阻滞和不应期改变,传导时间延长也并非特异地发生在阵发性房颤组,提示心房内阻滞和不应期缩短在阵发性房颤的发生中的作用尚不明确.     

Prolonged atrial activity due to delayed conduction in the atrium of patients with paroxysmal atrial fibrillation

Summary We investigated the relationship between the duration of electrical atrial activity and intra-atrial conduction time to determine whether the prolonged atrial activity was due to delayed conduction in the human atrium. The study included 15 patients with paroxysmal atrial fibrillation (PAF) and 15 control patients. The duration of atrial electrical activity was measured by selecting a minimum electrographic amplitude of 50µV. In patients with PAF, the duration of atrial activity was prolonged in proportion to the delay of interatrial conduction time from the high right atrium to the coronary sinus as the coupling interval of premature extrastimuli was decreased. Both the fragmented atrial activity zone and the interatrial conduction delay zone were wider in patients with PAF than in control patients. It is concluded that assessment of the duration of atrial activity with a minimum amplitude of 50µV is useful in evaluating human atrial vulnerability since it reflects the atrial conduction delay in patients with PAF.     

Further evidence of localized posterior interatrial conduction delay in lone paroxysmal atrial fibrillation.

AIMS: Prolongation of interatrial conduction time has been reported in patients with paroxysmal atrial fibrillation (PAF). The study objective was to localize the region of the conduction delay in patients with lone PAF. METHODS AND RESULTS: Twenty-one patients with lone PAF and 23 patients with AV nodal re-entrant tachycardia ablation without history of PAF (control group) were recruited. Endocardial recordings were made during sinus rhythm and programmed atrial stimulation. The authors measured the interatrial conduction time, the 'right-sided' conduction time between the high lateral right atrium and the proximal coronary sinus (RA-CSp), and the 'left-sided' conduction time between the proximal and the distal coronary sinus (CSp-LA). During sinus rhythm, the interatrial conduction time was longer in the PAF group (103 +/- 19 vs 86 +/- 12 ms, P<0.01) due to delay of right-sided conduction (RA-CSp was 74 +/- 20 vs 56 +/- 10 ms, P<0.01). During programmed stimulation at the distal coronary sinus, the maximal RA-CSp time was also longer in the PAF group (110 +/- 47 vs 69 +/- 16 ms, P<0.05). No differences in CSp-LA time were observed. CONCLUSION: This study supports the role of posterior septal right atrial conduction disturbances in the genesis of lone PAF.     

Characterization of conduction recovery across left atrial linear lesions in patients with paroxysmal and persistent atrial fibrillation

Background: Left atrial (LA) linear lesions are effective in substrate modification for atrial fibrillation (AF). However, achievement of complete conduction block remains challenging and conduction recovery is commonly observed. The aim of the study was to investigate the localization of gap sites of recovered LA linear lesions.
Methods and Results: Forty-eight patients with paroxysmal (n = 26) and persistent/permanent (n = 22) AF underwent repeat ablation after pulmonary vein (PV) isolation and LA linear ablation at the LA roof and/or mitral isthmus due to recurrences of AF or flutter. In 35 patients, conduction through the mitral isthmus line (ML) had recovered whereas roof-line recovery was observed in 30 patients. The gaps within the ML were distributed to the junction between left inferior PV and left atrial appendage in 66%, the middle part of the ML in 20%, and in 8% to the endocardial aspect of the ML while only 6% of lines showed an epicardial site of recovery. The RL predominantly recovered close to the right superior PV (54%) and less frequently in the mid roof or close to the left PV (both 23%). Reablation of lines required significantly shorter RF durations (ML: 7.24 ± 5.55 minutes vs 24.08 ± 9.38 minutes, RL: 4.24 ± 2.34 minutes vs 11.54 ± 6.49 minutes; P = 0.0001). Patients with persistent/permanent AF demonstrated a significantly longer conduction delay circumventing the complete lines than patients with paroxysmal AF (228 ± 77 ms vs 164 ± 36 ms, P = 0.001).
Conclusions: Gaps in recovered LA lines were predominantly located close to the PVs where catheter stability is often difficult to achieve. Shorter RF durations are required for reablation of recovered linear lesions. Conduction times around complete LA lines are significantly longer in patients with persistent/permanent AF as compared to patients with paroxysmal AF.     

阵发性心房颤动患者心房复极离散度的研究

目的　通过记录阵发性心房颤动 (房颤 )患者心房单相动作电位 (MAP) ,分析心房复极离散度与房颤发生的关系。方法　特发性阵发性房颤患者与无自发房颤病史的阵发性室上性心动过速患者各 1 5例 ,均接受心内电生理检查和 /或导管射频消融治疗。两根 MAP电极于右心房共取 4～ 1 0个不同部位进行同步的窦性心律基础刺激 (S1)及期前刺激 S2 时的 MAP记录。测量、计算心房复极离散度(RTd)及动作电位时限和局部冲动时间的离散度 (APDd、ATd)。　结果　窦性心律时房颤组最大 RTd显著大于对照组 (1 2 3 .69± 54.67) ms比 (64 .2 5± 2 3 .2 9) ms,(P<0 .0 1 )。其差异主要来源于 APDd(1 1 5.0 0± 4 6.90 ) ms比 (57.56± 3 3 .57) ms,(P<0 .0 1 ) ,ATd差异无显著性。随 S1、S2 的加入 ,各组局部激动时间和离散度逐渐增大 ,而动作电位时限逐渐缩短 ,且房颤组的这种改变程度显著大于对照组。在S1时无房颤发生 ,加入期前刺激时 ,大多数房颤组患者均多次诱发出短阵房颤。其诱发率及次数均显著高于对照组。　结论　研究结果表明 ,MAP记录技术是临床观察、分析心房复极离散度及其在阵发性房颤中的作用的较佳方法。心房复极离散度的增加是阵发性房颤发生的重要因素。期前刺激时动作电位时限的缩短和离散以及传导障碍在     

Chemoreflexsensitivity among patients with paroxysmal atrial fibrillation

Atrial fibrillation is the most common cardiac arrhythmia with typical complications of thromboembolisms. The autonomic nervous system is an important factor for the initiation of arrhythmias. A vagally or adrenergically hyperfunction could cause the initiation of paroxysmal atrial fibrillation (PAF). METHOD: We measured the chemoreflexsensitivity (CHRS) among 110 patients to determine a disturbed autonomic function as risk factor for PAF. We examined 45 patients with PAF (group A), 45 patients with sinus rhythm (group B) and 20 young volunteers (group C). The ratio between the difference of RR intervals in ECG and venous pO(2) was measured for the determination of CHRS. The margin of the CHRS was 3 ms/mmHg. RESULTS: Patients of group A had a significantly lower CHRS compared to group B (1.56+/-1.46 vs 6.29+/-3.71 ms/mmHg, p<0.0008) or group C (1.56+/-1.46 vs 6.35+/-4.29 ms/ mmHg, p<0.0003). A significant difference between group B and C could not be observed (6.29+/-3.71 vs. 6.35+/-4.29 ms/mmHg, p = n.s.). A specificity of 74% and a sensitivity of 71% was achieved for identifying patients with PAF by using a margin of 3 ms/mmHg for the CHRS. CONCLUSIONS: An analysis of CHRS seems to be an appropriate method to demonstrate a neurovegetative imbalance which might be one possible trigger mechanism of PAF. The predictive power has to be examined by prospective investigations of a larger patient population.     

Cholesterol paradox in patients with paroxysmal atrial fibrillation

Hypercholesterolemia is a major risk factor for coronary heart disease (CHD), but the associations among lipids, lipoproteins and paroxysmal atrial fibrillation (PAF) have not yet been reported. The associations among lipids, lipoproteins and PAF were examined in a case-control study, in which cases and controls were defined as those with/without definite ECG-detectable PAF, respectively. CHD patients were excluded from the study. The mean values of serum total cholesterol (TC), triglyceride (TG) and high density lipoprotein-cholesterol (HDL-C), after adjusting for age and gender, in patients with PAF were lower than those in patients without PAF (175 +/- 4 mg/dl vs. 190 +/- 3 mg/dl, 104 +/- 7 mg/dl vs. 123 +/- 6 mg/dl, 46.0 +/- 1.7 mg/dl vs. 51.8 +/- 1.4 mg/dl, respectively), as assessed by an analysis of covariance. After controlling for age and gender, TC, TG and HDL-C (all in quartiles) were inversely and linearly (p < 0.05) associated with the percentage of patients with PAF, as assessed by a multiple logistic regression analysis. The associations between TC or TG and PAF varied with the HDL-C level: significant when HDL-C was low (p < 0.05), but not when HDL-C was high. The odds ratio (relative risk of PAF) for patients with both low TC or TG and low HDL-C was 4.08 (95% CI: 1.81-9.57) times or 9. 40 (3.25-32.0) times higher (p < 0.01) than that for patients with high TC or TG and high HDL-C, respectively. In conclusion, low serum levels of TC and TG were found in PAF patients, while reduced HDL-C may cause PAF. Hypolipoproteinemia including low HDL-C may affect atrial vulnerability and cause atrial fibrillation.     

First-degree atrioventricular block in patients with atrial fibrillation and atrial flutter: the prevalence of intra-atrial conduction delay

Journal of Interventional Cardiac Electrophysiology - PR interval prolongation &gt;?200&nbsp;ms resulting in the diagnosis of first-degree atrioventricular block (AVB1) is caused by a...     

左旋氨氯地平对阵发性房颤并高血压患者房颤的影响

目的观察左旋氨氯地平对阵发性房颤并高血压患者P波离散度（Pd）、左房内径、高敏C反应蛋白（hs—CRP）水平、房颤发作情况的影响。方法将阵发性房颤并高血压患者100例随机分为治疗组（50例）和对照组（50例）。降压药物治疗组给予左旋氨氯地平,对照组给予坎地沙坦,随访1年,观察治疗前后Pd、左房内径、hs—CRP水平及房颤发作情况。结果至随访结束,在长期应用胺碘酮的患者中,对照组房颤复发17例,占81．0％,治疗组房颤复发22例,占95．7％,两组之间差异无统计学意义（x^2=1．122,P〉0．05）。未长期应用胺碘酮的患者,对照组、治疗组在7-12个月时房颤发作次数均较治疗前减少（t=2．823,P〈0．01;t=2．655,P〈0．05）,但两组之间差异无统计学意义（t=0．594,P〉0．05）。与治疗前比较,对照组、治疗组的Pd、左房内径、hs—CRP均降低（t=4．025-13．546,P〈0．01）,治疗后两组之间Pd、左房内径、hs—CRP比较,差异无统计学意义（t=1．234-1．514,P〉0．05）。结论左旋氨氯地平可减少阵发性房颤并高血压患者房颤的复发,降低Pd、左房内径和hs—CRP水平,其效果与坎地沙坦没有差异。     

莫雷西嗪对阵发性心房颤动的疗效评价

目的 评估莫雷西嗪治疗阵发性心房颤动(房颤)患者的有效性和不良反应以及其对房颤负荷的影响.方法 入选阵发性房颤患者212例,给莫雷西嗪单药干预,并随访观察治疗1、6、12个月后房颤的再发情况、负荷量和不良反应.结果 服用莫雷西嗪1、6、12个月房颤再发率仅34％、32％、35％;用药前与用药后1、6、12个月平均心率,最大心率和最小心率均无明显变化,房颤负荷均有明显下降,并未见死亡和恶性室性心律失常.结论 莫雷西嗪可以作为预防、治疗阵发性房颤发作的选择药物之一.     

Dispersion of atrial repolarization in patients with paroxysmal atrial fibrillation.

To study the role of the dispersion of atrial repolarization (DAR) in the genesis of atrial fibrillation (AF), monophasic action potentials (MAP) were recorded simultaneously from a catheter at the high lateral right atrium (HLRA) and a catheter moving around the high, middle and low lateral right atrium (RA) the high, anterior and posterior septal RA and the RA appendage in 15 patients with paroxysmal AF and 15 patients with atrioventricular nodal re-entry tachycardia (AVNRT) or concealed Wolff-Parkinson-White syndrome (WPW) without history of AF. After recordings during sinus rhythm (SR), MAPs were recorded during programmed stimulation (PS) via the HLRA catheter at a drive cycle length (CL) of 500 ms. Thus, MAPs were recorded simultaneously from 2 sites at a time and sequentially from 4 to 12 sites during SR, drive pacing and PS. Taking the MAP at the HLRA as reference, the dispersion of repolarization time (dispersion of RT) and its two components, the dispersions of activation time (dispersion of AT) and MAP duration (dispersion of MAP duration) among the 4 to 12 sites were calculated and taken as parameters of DAR. RESULTS: During SR and PS, the maximal dispersion of RT was significantly greater in AF than in control patients, 113+/-49 ms vs 50+/-28 ms (P<0.001) and 114+/-56 vs 70+/-43 ms (P<0.05) respectively. The increased dispersion of RT in the AF group was caused by increases in both dispersion of MAP duration and dispersion of AT. CONCLUSION: During SR and PS, DAR increased in patients with paroxysmal AF due to increases in dispersion of MAP duration and dispersion of AT, which suggests the involvement of both repolarization and conduction disturbances in the development of paroxysmal AF.     

Statin treatment for patients with paroxysmal atrial fibrillation

Recent clinical evidence and animal experiments support the belief that statins have beneficial effects on cardiovascular outcomes and prevention of atrial fibrillation (AF). We investigated whether the use of statins reduces the mortality, morbidity, and recurrence rate of AF in patients with paroxysmal AF. A post hoc analysis of the Japanese Rhythm Management Trial for Atrial Fibrillation (J-RHYTHM) study was conducted.Of the 823 patients with paroxysmal AF in the J-RHYTHM study, 101 (12.3%) were receiving a statin at baseline. Patients taking statins were older and more likely to have hypertension, dyslipidemia, coronary artery disease, and ischemic stroke compared to patients not taking statins. During a mean follow-up period of 19.3 months, 40 patients (5.5%) reached the primary endpoint (a composite of all-cause death, stroke, systemic embolism, major bleeding, and hospitalization for heart failure) and 140 patients (19.4%) experienced a recurrence of AF. Multivariate Cox proportional-hazard regression analysis revealed statin use was not associated with improved mortality and morbidity (hazard ratio [HR] 0.409, 95% confidence interval [CI] 0.113-1.482), or a decreased risk of AF recurrence (HR 0.662, 95% CI 0.299-1.466).This analysis provides evidence that statin use did not affect clinical outcomes in patients with paroxysmal AF and emphasizes the need for randomized clinical trials defining more clearly the role of statins in treating AF.     

Prevalence and characteristics of continuous electrical activity in patients with paroxysmal and persistent atrial fibrillation

Background: Complex fractionated atrial electrograms (CFAEs) may play a role in the genesis of atrial fibrillation (AF). One type of CFAE is continuous electrical activity (CEA). The prevalence and characteristics of CEA in patients with paroxysmal and persistent AF are unclear.
Methods and Results: In 44 patients (age = 59 ± 8 years) with paroxysmal (25) or persistent (19) AF, bipolar electrograms were systematically recorded for ≥5 seconds at 24 left atrial (LA) sites, including 8 antral sites, and 2 sites within the coronary sinus (CS). CEA was defined as continuous depolarization for > 1 second with no isoelectric interval. CEA was recorded at the LA septum (79%), antrum (66%), posterior (68%) and anterior walls (67%), roof (66%), base of the LA appendage (61%), inferior wall (61%), posterior mitral annulus (48%), CS (41%), and in the LA appendage (14%). Antral CEA was equally prevalent in patients with paroxysmal (63%) and persistent AF (70%, P = 0.12). In patients with paroxysmal AF, the prevalence of CEA was similar among antral and nonantral LA sites, except for the LA appendage. However, in patients with persistent AF, CEA was more prevalent at the nonantral (80%) than antral sites (70%, P = 0.03). CEA at nonantral sites except the CS was more prevalent in persistent than in paroxysmal AF (80% vs 57%, P < 0.001). The mean duration of intermittent episodes of CEA was longer in persistent than in paroxysmal AF (P < 0.001).
Conclusions: The higher prevalence and duration of CEA at nonantral sites in persistent than in paroxysmal AF is consistent with a greater contribution of LA reentrant mechanisms in persistent AF. However, the high prevalence of CEA at nonantral sites in paroxysmal atrial fibrillation (PAF) suggests that CEA alone is a nonspecific marker of appropriate target sites for ablation of AF. The characteristics of CEA that most accurately identify drivers of AF remain to be determined.     

Left atrial function and ventricular filling in hypertensive patients with paroxysmal atrial fibrillation

Objectives. We evaluated left atrial dimensions and function, as well as left ventricular structure and filling, in hypertensive patients with paroxysmal atrial fibrillation.Background. In hypertensive patients, left atrial dilation and enhanced volume transport may facilitate arrhythmias.Methods. Left ventricular two-dimensional and M-mode echocardiograms and pulsed Doppler echocardiography of transmitral flow were performed in 17 consecutive primary hypertensive patients with paroxysmal atrial fibrillation (group EHf) and in 34 patients with high blood pressure without this arrhythmia (group EH). Seventeen normal subjects (group N) were also investigated. Groups were matched for age and gender.Results. The EH and EHf groups had similar systolic arterial pressures ([mean ± SD] group EH 185 ± 27, group EHf 173 ± 25 mm Hg, p = NS) and left ventricular mass index (group EH 154 ± 55, group EHf 131 ± 57.8 g/m², p = NS), and their M-mode left ventricular systolic wall stress and fractional shortening were comparable to those of normal subjects. M-mode left atrial maximal (group N 37.8 ± 6, group EH 37.9 ± 4.6, group EHf 44.6 ± 6.7 mm, p < 0.05 for group EHf vs. groups N and EH) and minimal diameters and the diameter preceding atrial contraction (group N 31 ± 3.6, group EH 34.5 ± 5, group EHf 40.4 ± 6.9 mm, p < 0.001 for group EHf vs. group N; p < 0.05 for group EHf vs. group EH) were greater in group EHf than in group EH and group N subjects, whereas only the latter diameter was increased in group EH (p < 0.05 vs. group N), so that left atrial fractional shortening was higher than normal only in group EH (group N 10.8 ± 4.4%, group EH 14.6 ± 5.5%, group EHf 9.3 ± 5.3%; group EH vs. group N, p < 0.05; group EHf vs. group EH, p < 0.05). The pulsed Doppler ratio of early to late transmitral flow rates (E and A wave velocity/time integrals × mitral annulus area) was lower than normal in group EH (group N 2.9 ± 2.2, group EH 1.75 ± 0.8, group EHf 2.8 ± 0.8; group EH vs. group N, p < 0.05; group EHf vs. group EH, p < 0.001; group EHf vs. group N, p = NS) and was “normalised” in group EHf, early flow being increased in this group (group N 42 ± 13, group EH 39 ± 29, group EHf 60 ± 17 ml; group EHf vs. group N, p < 0.05; group EHf vs. group EH, p < 0.05).Conclusions. These results suggest that the occurrence of paroxysmal atrial fibrillation in hypertension is associated with enlargement of the left atrium, depression of its contractile function and “normalization” of the pattern of left ventricular filling and is independent of left ventricular hypertrophy and systolic wall stress. The mechanisms linking these variables remain undefined.     

Electroanatomic characteristics of atrial premature beats triggering atrial fibrillation in patients with persistent versus paroxysmal atrial fibrillation

APBs in Persistent Versus Paroxysmal AF. BACKGROUND: Although the electrical disconnection between the left atrium (LA) and pulmonary veins (PVs) by radiofrequency catheter ablation has been proven to be effective in controlling atrial fibrillation (AF), the recurrence rate is higher in patients with persistent AF (PeAF) than with paroxysmal AF (PAF). We hypothesized that the origin of the atrial premature beats (APBs) that trigger AF and the pattern of their breakthrough into the LA differ between PAF and PeAF. METHODS: We mapped 75 APBs (53 APBs triggering AF, 22 isolated APBs) from the LA and PVs in 26 patients with AF (age: 49.5 +/- 9.6, males: 23, PAF = 17, PeAF = 9), using a noncontact endocardial mapping (NCM) system. The location of the preferential conduction (PC) sites and their conduction velocity (CV) were compared. RESULTS: In patients with PeAF, the earliest activation (EA) site and exit of the PC were more frequently located on the LA side of the LA-PV junction as compared with PAF (P < 0.001). Eighty-one percent of the PCs were located in the area between the left and right superior PVs. The incidence of PCs was similar between the PeAF and PAF patients (P = NS). PCs were more commonly found with APBs inducing AF (63.3%) than with those not inducing AF (35.2%, P = 0.01). The CV of the PC was slower for PeAF than PAF (P < 0.001). The CV in the LA during sinus rhythm was also slower for PeAF than PAF (P < 0.01). CONCLUSION: PeAF was more frequently triggered by APBs from the LA side of the LA-PV junction than PAF and resulted in slower conduction than did PAF. These findings may help explain the higher potential for recurrence after electrical PV isolation in patients with PeAF.