左房异常与心房颤动的关系

目的探讨左房异常与心房颤动发生的关系。方法应用心电图和动态心电图进行,持续性房颤患者为A组,阵发性房颤、房扑患者为B组,仅有心电图P波增宽的患者为C组,A、B、C三组各40例。所有入选患者均经超声心动图检测左房大小,观察患者窦性心律时心电图P波时限、切迹和P波离散度,并分析与房颤发生的关系。结果房颤男性多于女性,年龄大于60岁者94例(占78.3%),三组中86.7%的患者存在器质性心脏病(104例)。心电图P波切迹明显、P波离散度大者快速房颤发生率高;超声心动图检测左房直径大者房颤发生率高,持续性房颤比阵发性房颤患者左房直径大(p<0.05)。结论左房扩大、房内阻滞及P波离散度增大的患者易发生房颤。     

Dual independent atrial tachycardias after ablation of chronic atrial fibrillation

We report the case of a 71-year-old man with two atrial tachycardias evolving simultaneously and independently in two dissociated regions after extensive ablation for chronic atrial fibrillation. One tachycardia was a focal tachycardia originating from the right inferior pulmonary vein and activating the posterior left atrium with a 2:1 conduction block, while the other tachycardia was an atrial flutter circulating around the tricuspid annulus, activating the right atrium and the anterior wall of the left atrium. These two atrial tachycardias were successfully ablated prior to restoration of sinus rhythm.     

Electrocardiographic differentiation of atrial flutter from atrial fibrillation by physicians

The purpose of this study was to determine the ability of physicians to differentiate atrial flutter from atrial fibrillation on a surface electrocardiogram (ECG). A questionnaire containing three 12-lead ECGs was mailed to 689 physicians, with multiple-choice questions asking whether the rhythm on each ECG was atrial flutter or atrial fibrillation. ECG 1 showed atrial fibrillation with prominent atrial activity (>0.2 mV) in lead V1; ECG 2 displayed atrial fibrillation with prominent atrial activity (>0.2 mV) in leads III and V1; and ECG 3 displayed atrial flutter. Overall, ECG1 was correctly identified as atrial fibrillation by 79% of physicians, ECG 2 was correctly identified as atrial fibrillation by 31%, and ECG 3 was correctly identified as atrial flutter by 90%. Cardiology fellows and cardiologists correctly identified ECG 1 more often than house officers and internists (95% vs 63%; P < or = .01). ECG 2 was correctly identified by 26% of cardiology fellows and cardiologists and by 37% of house officers and internists (P = .10). ECG 3 was correctly identified by 91% of cardiology fellows and cardiologists and by 82% of house officers and internists (P = .06). In conclusion, atrial fibrillation is frequently misdiagnosed as atrial flutter. Misdiagnosis of atrial fibrillation occurs more often when atrial activity is prominent on an ECG in more than one lead.     

Simultaneous occurrence of atrial fibrillation and atrial flutter

INTRODUCTION: Early reports suggested that some patients with "atrial fibrillation/flutter" might have atrial fibrillation in one atrium and atrial flutter in the other. However, more recent conceptions of atrial fibrillation/flutter postulate that the pattern is due to a relatively organized (type I) form of atrial fibrillation. We report the occurrence and ECG manifestations of simultaneous atrial fibrillation and flutter in patients undergoing attempted catheter ablation of atrial flutter. METHODS AND RESULTS: In patients undergoing radiofrequency ablation for atrial flutter, an attempt was made to entrain atrial flutter by pacing in the right atrium. The arrhythmias observed occurred following attempts at entrainment, or spontaneously in one case. Twelve transient episodes of simultaneous atrial fibrillation and flutter were observed in five patients. The atrial fibrillation was localized to all or a portion of one atrium, during which the other atrium maintained atrial flutter. In each case, the surface 12-lead ECG reflected the right atrial activation pattern. No patients had interatrial or intra-atrial conduction block during sinus rhythm, suggesting functional intra-atrial block as a mechanism for simultaneous atrial fibrillation/flutter. CONCLUSION: In certain patients, the occurrence of transient, simultaneous atrial fibrillation and flutter is possible. In contrast to prior studies in which it was suggested that left atrial or septal activation determines P wave morphology, the results of the present study show that P wave morphology is determined by right atrial activation. Functional interatrial block appears to be a likely mechanism for this phenomenon.     

静脉地尔硫治疗快速房颤、房扑的疗效分析

为检验静脉地尔硫艹卓控制房颤、房扑心室率的有效性和安全性，对４７例快速房颤、房扑患者一次静脉注射０．２５ｍｇ／ｋｇ地尔硫艹卓后以５ｍｇ／ｈ～１０ｍｇ／ｈ微泵维持，平均起效时间５．２±２．７ｍｉｎ，总有效率９３．６％，心功能较用药前明显改善（Ｐ＜０．０５），对血压无明显影响，副作用发生率为１０．６％，均不严重。结果提示地尔硫艹卓是一种能迅速、安全、有效控制房颤、房扑患者心室率的药物     

Importance of right and left atrial dilation and linear ablation for perpetuation of sustained atrial fibrillation

INTRODUCTION: Atrial dilation associated with increasing atrial pressure plays an apparent role in the development of atrial fibrillation (AF). We characterized a new model of separate and biatrial dilation in the Langendorff-perfused rabbit heart. The aim of this study was to examine if sustained AF in this model (1) would be inducible by separate right atrial (RA) and left atrial (LA) dilation; (2) would be reproducibly inducible at the same pressure level; and (3) could be suppressed by RA, LA, or biatrial ablation. METHODS AND RESULTS: Intra-atrial pressure was increased stepwise in the RA (n = 13), LA (n = 12), or both atria (n = 25) until sustained AF could be induced or a pressure of 20 cm H2O was reached. The stimulation protocol was repeated once in RA and LA dilation (n = 9) and three times in biatrial dilation (n = 7). Then, RA orifices (superior and inferior caval veins, tricuspid valve annulus, and foramen ovale) or LA orifices (pulmonary veins, mitral valve annulus, and foramen ovale) were connected by radiofrequency (RF) lesions. Sustained AF was rendered inducible in 100% of hearts with biatrial dilation, but in only 92% of hearts with RA dilation and 67% with LA dilation. Inducibility of sustained AF was reproducible. Under biatrial dilation, not RA ablation (0/10 hearts; P = NS) but LA ablation (4/11 hearts; P < 0.05) and biatrial ablation (16/21; P < 0.01) reduced the inducibility of sustained AF. CONCLUSION: The inducibility of sustained AF due to increased intra-atrial pressure differs between the RA and LA. LA and biatrial lesions, not RA RF lesions, reduce the ability to perpetuate sustained AF.     

Effect of gender on atrial electrophysiologic changes induced by rapid atrial pacing and elevation of atrial pressure

INTRODUCTION: The incidence of atrial fibrillation is greater in men than in women, but the reasons for this gender difference are unclear. The purpose of this study was to evaluate the effects of gender on the atrial electrophysiologic effects of rapid atrial pacing and an increase in atrial pressure. METHODS AND RESULTS: Right atrial pressure and effective refractory period (ERP) were measured during sinus rhythm and during atrial and simultaneous AV pacing at a cycle length of 300 msec in 10 premenopausal women, 11 postmenopausal women, and 24 men. The postmenopausal women were significantly older than the premenopausal women (61 +/- 8 years vs 34 +/- 10 years; P < 0.01). During sinus rhythm, mean atrial ERP in premenopausal women was shorter (211 +/- 19 msec) than in postmenopausal women and age-matched men (242 +/- 18 msec and 246 +/- 34 msec, respectively; P < 0.05). Atrial ERPs in all patients shortened significantly during atrial and simultaneous AV pacing. However, the degree of shortening during atrial pacing (43 +/- 8 msec vs 70 +/- 20 msec and 74 +/- 21 msec; P < 0.05) and during simultaneous AV pacing (48 +/- 16 msec vs 91 +/- 27 msec and 84 +/- 26 msec; P < 0.05) was significantly less in premenopausal women than in postmenopausal women or age-matched men. CONCLUSION: The results of this study demonstrate a significant gender difference in atrial electrophysiologic changes in response to rapid atrial pacing and an increase in atrial pressure. The effect of menopause on the observed changes suggests that the gender differences may be mediated by the effects of estrogen on atrial electrophysiologic properties.     

Acute effects of left atrial radiofrequency ablation on atrial fibrillation

INTRODUCTION: Acutely, when left atrial ablation is performed during atrial fibrillation (AF), the AF may persist and require cardioversion, or it may convert to sinus rhythm or to atrial tachycardia/flutter. The prevalence of these acute outcomes has not been described. METHODS AND RESULTS: Left atrial ablation, usually including encirclement of the pulmonary veins, was performed during AF in 144 patients with drug-refractory AF. Conversion to sinus rhythm occurred in 19 patients (13%), to left atrial tachycardia in 6 (4%), and to atrial flutter in 6 (4%). In the 6 patients with a focal atrial tachycardia, the mean cycle length was 294 +/- 45 ms. The tachycardia arose in the left atrial roof in 3 patients, the left atrial appendage in 2, and the anterior left atrium in 1. In 3 of 6 patients, the focal atrial tachycardia originated in an area that displayed a relatively short cycle length during AF. In 6 patients, AF converted to macroreentrant atrial flutter with a mean cycle length of 253 +/- 47 ms, involving the mitral isthmus in 5 patients and the septum in 1 patient. All atrial tachycardias and flutters were successfully ablated with 1 to 15 applications of radiofrequency energy. CONCLUSION: When left atrial ablation is performed during AF, the AF may convert to atrial tachycardia or flutter in approximately 10% of patients. Focal atrial tachycardias that occur during ablation of AF may be attributable to driving mechanisms that persist after AF has been eliminated, whereas atrial flutter results from incomplete ablation lines.     

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.     

动态心房超速起搏预防阵发性房颤

目的观察动态心房超速起搏预防阵发性房颤的临床疗效和安全性。方法选择病态窦房结综合症伴阵发性房颤,并需植入永久起搏器的患者8例,分别植入具有动态心房起搏功能的起搏器,PacessetterTrilogy23643例,VitatronSelectionTM900E5例;随访6个月,前3个月不打开动态心房起搏功能,后3个月打开动态心房起搏功能,根据起搏器记录到的模式转换次数和持续时间来判断其预防房颤发作的疗效。结果打开动态心房起搏功能前后,患者房颤发作的次数分别为2437±956次/月和472±135次/月(P<0.05);模式转换持续时间分别为173±105小时/月和48±25小时/月(P<0.05);房颤负荷分别为33±8%和10±7%(P<0.05)。结论动态心房超速起搏,是阵发性房颤预防治疗的有效和安全的方法之一。     

Termination of persistent atrial fibrillation during left atrial mapping

Termination of Persistent AF During Mapping. Complex fractionated atrial electrograms (CFAEs) may represent critical areas for the maintenance of atrial fibrillation (AF). While AF organization and termination have been reported with CFAE ablation, no reports of arrhythmia termination during left atrial mapping exist. We report a case of reproducible AF termination with catheter pressure at a site of CFAE remote from the site of AF. (J Cardiovasc Electrophysiol, Vol. 22, pp. 1171‐1173, October 2011)     

Right atrial vegetation in left ventricular-right atrial communication

We report a case of right-sided endocarditis with left ventricular-right atrial communication in which right atrial vegetation was demonstrated by two-dimensional echocardiography. The present case demonstrates that the right atrial vegetation in ventricular septal defect is suggestive of left ventricular-right atrial communication.     

立体心电图分析阵发性房颤患者心房的电生理特性

目的应用立体心电图(three-dimensional electrocardiogram,3D-ECG)分析阵发性房颤患者心房传导时间、心房除极角度和振幅的变化。方法入选在住院的阵发性房颤患者13例,对照组患者15例。分别应用立体心电图仪记录窦律下的立体心电图,分析后比较两组患者心房传导时间,P波除极振幅及角度。同时记录患者入院时超声心动图中左心房内径数值进行比较。结果两组患者比较左心房内径无显著差异。阵发性房颤组与对照组心房传导时间分别为123.75±11.67msvs.111.39±13.52ms,两组比较有显著性差异(p<0.05)。而在心房除极角度、振幅上,两组无显著差异。与对照组比较,阵发性房颤组患者P环初始部的运行方向与泪点疏密程度无明显变化,但在P环中间至终末部分,P环运行方向及泪点疏密出现明显变化,并且可看到明显的曲折、弯曲。但在除极末20ms的振幅,房颤患者较对照组明显降低(0.05±0.013mvvs.0.036±0.014mv,p<0.05),除极末30ms、40ms处两组振幅无显著差异。结论阵发性房颤患者可以出现心房传导时间延长、心房除极末振幅的改变和立体三维P环运行方向及泪点疏密程...     

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.     

Massive right atrial myxoma

Right atrial myxomas are uncommon and are often detected incidentally in asymptomatic individuals. We describe a case of a massive right atrial myxoma that was suspected following an abnormal right heart border on a chest X-ray and an abnormal 12 lead electrocardiogram.     

Pacing therapy for atrial tachyarrhythmias

The use of pacing techniques for the treatment of atrial tachyarrhythmias has been advocated for more than 30 years. Although it has played a beneficial role in the management of paroxysmal supraventricular tachycardia (PSVT) in drug-refractory patients, tachycardia acceleration and development of atrial fibrillation has been the major drawback. With the availability of radiofrequency catheter ablation therapy, the use of implantable antitachycardia devices for PSVT is currently negligible. From retrospective and small control studies it has been shown that atrial or dual-chamber pacing in patients with sick sinus syndrome has been associated with a lower incidence of paroxysmal atrial flutter or fibrillation than in those who received a ventricular pacemaker. Furthermore, recent studies have reported the potential benefit of reducing frequency of paroxysmal atrial flutter and fibrillation with multisite atrial pacing. As a result, there is a resurgence of research interest in antitachycardia pacing for prevention of atrial tachyarrhythmias. This paper briefly describes the basic aspects of antitachycardia pacing, reviews the data on the use of implantable antitachycardia devices for PSVT and the selection of patients, and assesses the current status of research on atrial pacing for prevention of paroxysmal atrial flutter and fibrillation.     

Effects of simultaneous atrioventricular pacing on atrial refractoriness and atrial fibrillation inducibility: role of atrial mechanoelectrical feedback

INTRODUCTION: The purpose of this study was to evaluate the effects of an acute increase in atrial pressure on refractoriness (mechanoelectrical feedback) and the vulnerability to atrial fibrillation (AF) and to investigate the effects of autonomic blockade and verapamil on mechanoelectrical feedback in humans. METHODS AND RESULTS: Right atrial pressure and effective refractory period (ERP) at the right atrial appendage (RAA) and high right atrial septum were measured during sinus rhythm, and during atrial and simultaneous AV pacing at a cycle length of 300 msec, either in the absence (n = 25) or presence (n = 22) of pharmacologic autonomic blockade. In another 15 patients, the protocol was performed before and after infusion of verapamil 0.15 mg/kg. In the absence of autonomic blockade, AV pacing resulted in a higher mean right atrial pressure (11.7 +/- 3.3 vs 4.3 +/- 3.0 mmHg, P < 0.001) and a shorter atrial RAA ERP (144 +/- 23 msec vs 161 +/- 21 msec; P < 0.001) compared with atrial pacing; AF was induced more often during AV pacing (87%) than during atrial pacing (20%) and was related directly to the right atrial pressure (r = 0.39, P = 0.004) and indirectly to the RAA ERP (r = -0.42, P < 0.001). The susceptibility to sustained AF was greatly enhanced by autonomic blockade. Verapamil markedly attenuated the shortening of ERP and the propensity for AF that occurred during simultaneous AV pacing. CONCLUSION: An acute increase in atrial pressure during tachycardia is associated with shortening of atrial refractoriness and a propensity for AF, i.e., atrial mechanoelectrical feedback, which may be enhanced by autonomic blockade and attenuated by calcium channel blockade.     

心房粘液瘤对心房除极的影响

为探讨心房粘液瘤对心房激动过程的影响,对19例左心房粘液瘤和2例右心房粘液瘤的VCG高倍P环(1mV=360mm)进行测量,结果显示不同部位粘液瘤对心房激动的影响不同,VCGP环亦不同.左心房粘液瘤P环时限延长,除左心房肥大外,较容易判断出双侧心有肥大、房内传导阻滞.右心房粘液瘤P环时限正常,仅表现右心房肥大.VCG上放大的P环能比ECG上P波更敏感地反映出心房异常活动的电变化.