Atrial septal pacing in the prevention of paroxysmal atrial fibrillation refractory to antiarrhythmic drugs

BACKGROUND: Early reports have shown that pacing the atria at a site or sites other than the right atrial appendage may prevent atrial fibrillation. Our centre has shown that pacing the atrial septum reduces the duration of atrial activation which is an important determinant of predisposition to paroxysmal atrial fibrillation. Ablation of the atrioventricular (AV) node together with implantation of a pacemaker can control symptoms due to paroxysmal atrial fibrillation in patients in whom antiarrhythmic drugs have failed. The aim of this study was to investigate the effect of atrial septal pacing on patients who were candidates for AV node ablation. METHODS: Atrial septal pacemakers were implanted in 28 patients with symptomatic, paroxysmal atrial fibrillation that had been unresponsive to two or more antiarrhythmic drugs. Pacing was not indicated for any reason other than the anticipated need to proceed to AV node ablation. Change in symptoms was assessed by quality of life questionnaires and recurrence of atrial fibrillation was measured objectively by pacemaker interrogation and ambulatory electrocardiographic monitoring. RESULTS: Atrial septal pacing in combination with an antiarrhythmic agent resulted in a substantial subjective improvement in 19 patients (68%). Objective data confirmed similar findings; atrial fibrillation was completely or markedly reduced in 17 patients (60%). Six patients experienced a modest improvement in symptoms; in only four patients was it necessary to proceed to AV node ablation. CONCLUSIONS: Atrial septal pacing together with continuance of previously ineffective antiarrhythmic therapy may prevent or markedly reduce the frequency of paroxysmal atrial fibrillation and obviate the need to ablate the AV node.     

Chronic atrial fibrillation in patients with paroxysmal atrial fibrillation, atrioventricular node ablation and pacemakers: determinants and treatment.

AIMS: This study examined the factors associated with the development of chronic (or permanent) atrial fibrillation (AF) in patients who had undergone atrioventricular (AV) node ablation with permanent pacing because of paroxysmal AF. METHODS: A retrospective review of case notes of all 65 consecutive patients identified as having had paroxysmal atrial arrhythmias, AV node ablation and permanent pacemaker implantation was performed. Atrial rhythm was established from all pacing records and from the surface ECG. Treatment with anti-arrhythmic drugs and with warfarin was recorded. A multivariate analysis was undertaken, using atrial rhythm on final ECG and chronic AF as outcome measures. RESULTS: During a mean follow-up of 30 months, 42% of patients with paroxysmal AF had developed chronic AF. Multivariate analysis showed that increasing age, history of electrical cardioversion and VVI pacing all contributed to the development of chronic AF. 25/62 patients were taking warfarin, and four had had strokes (2.5%/year). CONCLUSION: The majority of patients with paroxysmal atrial arrhythmias treated with AV node ablation and pacing develop chronic AF eventually. Stroke remains a risk, particularly in those who develop chronic AF.     

Thromboembolism after atrioventricular node ablation and pacing: long term follow up

OBJECTIVE—To assess the incidence of arterial embolic events in patients with high rate, drug resistant, severely symptomatic paroxysmal and chronic atrial fibrillation who have undergone atrioventricular (AV) node ablation and permanent pacing.
DESIGN—Multicentre retrospective cohort study.
PATIENTS AND MANAGEMENT—From May 1987 to January 1997, AV node ablation was performed in 585 severely symptomatic patients (mean (SD) age 66 (11) years) with high rate, drug resistant paroxysmal atrial fibrillation (308) or chronic atrial fibrillation (277). Lone atrial fibrillation was present in 133 patients, while the remaining 452 suffered from dilated, ischaemic, or valvar heart disease. Patients underwent VVIR (454) or DDDR (131) pacemaker implantation, after AV node ablation. Antiplatelet agents were given to 202 patients, warfarin to 187 patients.
RESULTS—During a follow up of 33.6 (24.2) months, thromboembolic events were observed in 17 patients (3%); the actuarial occurrence rates of thromboembolism were 1.1%, 3%, 4.2%, and 7.4% after one, three, five, and seven years, respectively. Among five variables, univariate analysis showed that only the presence of chronic atrial fibrillation at the time of ablation (relative risk (RR) = 1.8, 95% confidence interval (CI) = 1.02 to 3.20, p = 0.04) and the need for warfarin treatment (RR = 1.6, 95% CI 1.00 to 2.71, p = 0.048) were associated with a significantly higher risk of occurrence of thromboembolic events. On multivariate analysis the only predictor of embolic events during the follow up was the presence of chronic atrial fibrillation.
CONCLUSIONS—Data from this large cohort of patients indicate a fairly low incidence (1.04% per year) of thromboembolic events after AV node ablation and pacing for drug refractory, high rate atrial fibrillation.


Keywords: atrial fibrillation; embolism; atrioventricular node ablation; pacemaker implantation     

Determinants of development of permanent atrial fibrillation and its treatment.

We evaluated the rate of progression of permanent atrial fibrillation (AF) and identified clinical factors that predict this event in 63 consecutive patients who had undergone AV junctional ablation and DDDR pacemaker implantation for drug-refractory paroxysmal atrial fibrillation/ flutter. Immediately after ablation, anti-arrhythmic drugs were discontinued in all cases. Permanent AF was considered to have developed if AF was present on two consecutive 6-monthly examinations with no interim documented sinus rhythm. During a mean follow-up of 23 +/- 16 months, 22 (35%) of the 63 patients developed permanent AF. The actuarial estimate of progression of permanent AF was 22%, 40% and 56%, respectively, 1, 2 and 3 years after ablation. Age and underlying heart disease were independent predictors of progression of permanent AF. Only one (6%) of 16 patients with idiopathic AF had permanent AF (low risk group). Among the 47 patients with structural heart disease, permanent AF developed in 18 (62%) of the 29 who were aged >75 years or had >12 arrhythmic episodes per year and a symptom duration >4 years (high risk group), but only in three (17%) of the remaining 18 patients who did not (intermediate risk group). In conclusion, during a 3-year follow-up period, about half of the patients with a history of drug-refractory paroxysmal AF did not develop permanent AF after AV junctional ablation and dual-chamber pacemaker implantation, even in the absence of anti-arrhythmic drug therapy. Moreover, subgroups of patients whose risk of permanent AF progression differed were identified on the basis of simple baseline clinical variables. The results of this study form the necessary background for the correct management of patients after AV junction ablation and for the planning of future trials in this field.     

Radiofrequency Catheter Ablation Versus Modification of the AV Node for Control of Rapid Ventricular Response in Atrial Fibrillation

AV Node Modification vs Ablation in AF. Atrial fibrillation is a common arrhythmia, which is frequently difficult to control. Symptoms and ventricular dysfunction may be caused by a rapid ventricular response to atrial fibrillation. Radiofrequency catheter ablation techniques for ventricular rate control have been developed, including AV node modification and AV node ablation with pacemaker implantation. For both AV node modification and ablation, radiofrequency energy is applied via a 4-mm tipped electrode catheter. For AV node ablation radiofreqnency energy is applied near the compact AV node or His bundle via the right atrium, or occasionally at the His bundle via the left ventricle. For AV node modification radiofrequency energy is applied in the low middle or posterior septal right atrium near the tricuspid valve annulus. Both techniques can effectively control ventricular response to atrial fibrillation and the associated symptoms, although AV node modification is effective in only about 70% of patients compared to AV node ablation, which is effective in nearly 100%. In patients responding to AV node modification, maximal and mean ventricular response to atrial fibrillation is reduced by 25% to 35% chronically. Inadvertent AV block may occur during attempted AV node modification. It seems appropriate to attempt AV node modification prior to AV node ablation in patients with refractory atrial fibrillation and rapid ventricular response, in order to avoid the need for permanent pacemaker implantation. Although unproven, studies suggest that the mechanism by which AV node modification achieves ventricular rate control may he slow-pathway ablation in the low posterior septal right atrium.     

Predictors of atrial rhythm after atrioventricular node ablation for the treatment of paroxysmal atrial arrhythmias

OBJECTIVE: To assess the natural history of the atrial rhythm of patients with paroxysmal atrial arrhythmias undergoing atrioventricular node ablation and permanent pacemaker implantation. DESIGN AND SETTING: A retrospective cohort study of consecutive patients identified from the pacemaker database and electrophysiology records of a tertiary referral hospital. PATIENTS: 62 consecutive patients with paroxysmal atrial arrhythmias undergoing atrioventricular node ablation and permanent pacemaker implantation between 1988 and July 1996. MAIN OUTCOME MEASURES: (1) Atrial rhythm on final follow up ECG, classified as either ordered (sinus rhythm or atrial pacing) or disordered (atrial fibrillation, atrial flutter or atrial tachycardia). (2) Chronic atrial fibrillation, defined as a disordered rhythm on two consecutive ECGs (or throughout a 24 hour Holter recording) with no ordered rhythm subsequently documented. RESULTS: Survival analysis showed that 75% of patients progressed to chronic atrial fibrillation by 2584 days (86 months). On multiple logistic regression analysis a history of electrical cardioversion, increasing patient age, and VVI pacing were associated with the development of chronic atrial fibrillation. A history of electrical cardioversion and increasing patient age were associated with a disordered atrial rhythm on the final follow up ECG. CONCLUSIONS: Patients with paroxysmal atrial arrhythmias are at high risk of developing chronic atrial fibrillation. A history of direct current cardioversion.     

射频消融并植入心脏起搏器对房颤患者生活质量及心功能的影响

目的:研究射频消融阻断房室传导同时植入永久性人工心脏起搏器对老年心房颤动(房颤)患者生活质量及心室结构和功能的影响。方法:2005年1月至2007年2月,7例老年房颤患者在长征医院接受射频消融阻断房室传导同时植入永久性人工心脏起搏器。术前及术后随访平均(7.7±4.9)月时进行生活质量问卷调查及心脏超声检查。结果:患者术后心悸、气短、头晕、胸痛评分较术前显著增加,分别提高120%、104%、94%和25%(P均0.01);总生活质量评分显著改善(P0.01)。与术前相比,7例患者术后室间隔舒张末期厚度(IVSTd)[(11.6±2.3)mm∶(9.1±1.4)mm]、室间隔收缩末期厚度(IVSTs)[(17.1±5.1)mm∶(11.8±1.2)mm]、左心室后壁舒张末期厚度(LVPWTd)[(11.0±2.1)mm∶(9.1±1.4)mm]、左心室后壁收缩末期厚度(LVPWTs)[(16.3±1.9)mm∶(12.2±0.8)mm]显著减小(P均0.05)。3例植入房室全能型起搏器(DDD)的患者,术前后左室射血分无明显变化。心室按需型起搏器。6名患者术后左室收缩末期内径(LVEDs)较术前显著增大[(30.0±6.4)mm∶(34.0±6.4)mm,P=0.01]。无起搏失灵、起搏电极脱位、囊袋感染及起搏综合征等并发症。结论:对于症状严重、药物疗效差或不能耐受药物治疗的老年心房颤动患者,射频消融阻断房室传导同时植入永久性人工心脏起搏器能显著减轻症状,提高生活质量。     

Deterioration of left ventricular function following atrio-ventricular node ablation and right ventricular apical pacing in patients with permanent atrial fibrillation.

AIMS: Transcatheter radiofrequency ablation of the atrio-ventricular (AV) node followed by ventricular pacing has been shown to improve symptoms and quality of life of patients with atrial fibrillation (AF). It is assumed that function improves, but this has been less well demonstrated. The aim of this study was to assess the long-term effect of AV node ablation and ventricular pacing on left ventricular ejection fraction (LVEF) in patients with permanent AF. METHODS AND RESULTS: All 12 patients studied had permanent AF for at least 12 months (mean age 70 years, range 41 to 78). LVEF was determined 6 days and 3 months after AV node ablation by radionuclide ventriculography, at a paced rate of 80 beats . min (-1). Cardiac dimensions were measured by means of transthoracic echocardiography. No major changes in pharmacological therapy were made during 3 months follow-up period. LVEF showed a significant deterioration after 3 months follow-up period for the group (47.5 +/- 14.4%; 6 days after ablation vs 43.2 +/- 13.7%; 3 months after ablation, P < 0.05). There were no significant differences in left ventricular cavity dimensions directly after AV node ablation and 3 months later (LVEDD 51.2 +/- 10.7 mm vs 52.6 +/- 8.6 mm, P = NS: LVESD: 36.1 +/- 14.2 mm vs 36.6 +/- 9.7 mm, P = NS). Left atrial size did not show reduction 3 months after AV node ablation (50.8 +/- 13.6 mm vs 51.0 +/- 14.1 mm, P = NS). CONCLUSION: The restoration of a regular ventricular rhythm following AV node ablation for patients in permanent AF does not result in improvement in left ventricular function.     

Cholesterol lowering and coronary artery disease: mechanisms of risk reduction

OBJECTIVE: To assess the effect of atrioventricular node ablation and implantation of a dual chamber, mode switching pacemaker on quality of life, exercise capacity, and left ventricular systolic function in patients with drug refractory paroxysmal atrial fibrillation. PATIENTS: 18 consecutive patients with drug refractory paroxysmal atrial fibrillation. METHODS: Quality of life was assessed before and after the procedure using the psychological general wellbeing index (PGWB), the McMaster health index (MHI), and a visual analogue scale for cardiac symptoms. Nine of the patients also underwent symptom limited exercise tests and echocardiography to assess left ventricular systolic function. RESULTS: The procedure allowed a reduction in antiarrhythmic drug treatment (p < 0.01). PGWB and symptom scores improved (p < 0.01) but the MHI score did not change. Left ventricular systolic function and exercise capacity were unchanged. CONCLUSIONS: Atrioventricular node ablation and implantation of a DDDR/MS pacemaker is effective treatment for refractory paroxysmal atrial fibrillation, producing improved quality of life while allowing a reduction in drug burden. The popularity of the treatment is justified, but further studies are needed to determine optimum timing of intervention.     

病态窦房结综合征合并阵发性心房颤动的射频消融治疗

目的探讨病态窦房结综合征患者合并阵发性房颤的射频消融治疗效果。方法 7例病态窦房结综合征合并阵发性房颤患者,术前动态心电图诊断为病态窦房结综合征,24小时内有数次停搏及多次阵发房颤发作,其中有5例患者停搏均发生在房颤终止时,2例停搏与房颤发作无明显关联。接受环肺静脉前庭电隔离术。术后动态心电图随访。结果该7例患者,有2例房颤复发,1例再次接受手术并成功,1例拒绝再次手术。动态心电图提示有4例(考虑为快慢综合征)心动过缓明显好转,2例(考虑为慢快综合征)房颤发作明显减少但是心动过缓无改善,接受心脏永久起搏器置入治疗。此7例患者术前与术后1个月最大心率、最小心率、平均心率比较,最小心率、平均心率术后较术前增加,最大心率术后较术前无明显变化。结论快慢型病态窦房结综合征合并阵发性房颤患者对房颤射频消融治疗效果较好,大部分患者术后心动过缓明显改善,而不需要置入心脏永久起搏器。     

Ablate and pace for drug refractory paroxysmal atrial fibrillation. Is ablation necessary?

BACKGROUND: Atrio-ventricular junctional ablation with pacemaker insertion has been shown to improve quality of life in patients with drug refractory paroxysmal atrial fibrillation. It is unknown whether this improvement is secondary to the ablation procedure or to the pacemaker mode utilised. To investigate this we reviewed our experience of implanting a dual chamber rate responsive pacemaker with mode switching (DDDR/MS) alone on quality of life in this patient group. METHODS AND RESULTS: Over a 1-year period, 19 patients (mean age 62+/-9 years, 13 female) with drug refractory paroxysmal atrial fibrillation (mean duration of symptoms 8.7+/-7 years, failed 3.1+/-0.9 anti-arrhythmic drugs, amiodarone in 15) were recruited. Quality of life was assessed at baseline and after 1 month using a cardiac specific questionnaire, the modified Karolinska questionnaire. The mean score for all patients significantly improved by 39% at follow up (baseline 59+/-24, 1 month 36+/-24, P=0.001). Individually 15 patients (79%) had an improvement in their score, whilst for 13 patients (68%) their symptoms were sufficiently improved after pacing that ablation was not required. The benefit was maintained to a mean follow up of 12+/-5 months (score 31+/-20, P<0.001). Six patients remained symptomatic after pacing and requested further treatment. Benefit was unrelated to symptoms at baseline or the number and total duration of paroxysmal atrial fibrillation episodes recorded on pacemaker Holter. CONCLUSIONS: Patients with drug refractory paroxysmal atrial fibrillation, DDDR/MS pacing alone can improve quality of life without concurrent atrio-ventricular junctional ablation in a significant proportion of patients.     

Sinus node-atrioventricular node isolation: long-term results with the "corridor" operation for atrial fibrillation

The "corridor" operation is designed to restore sinus rhythm to patients with atrial fibrillation by electrically isolating the sinus node, a band of atrial tissue and the atrioventricular (AV) node from the remaining atrial tissue. Nine patients with drug-refractory atrial fibrillation underwent this operation; four patients had chronic atrial fibrillation and five had paroxysmal atrial fibrillation; the mean duration of symptoms was 12 +/- 8 years. Patient ages ranged from 25 to 68 years (mean 48 +/- 12). At preoperative electrophysiologic study, no patient had evidence of an accessory AV pathway or AV node reentry. Sinus node recovery time could not be determined in five patients because of recurrent atrial fibrillation during or before programmed stimulation. At operation the corridor of atrial tissue connecting the sinus and AV nodes was successfully isolated from the remaining left and right atrial tissue in all patients. One patient required early reoperation for recurrent atrial fibrillation before hospital discharge. At the predischarge electrophysiologic study, the corridor remained isolated in all patients except for one patient who had intermittent conduction between the corridor and excluded right atrium. One patient had nonsustained atrial fibrillation and one had atrial tachycardia evident in the corridor. Atypical AV node reentry of uncertain significance was induced in one other patient. Over a total follow-up of 191 patient months (mean 21 +/- 20), seven patients remained free of atrial fibrillation. Two patients had recurrent atrial fibrillation, which in one patient was effectively controlled by a single antiarrhythmic agent. A permanent pacemaker was implanted in four patients for sinus node dysfunction.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ventricular Performance and Quality of Life in Patients Who Underwent Radiofrequency AV Junction Ablation and Permanent Pacemaker Implantation Due to Medically Refractory Atrial Tachyarrhythmias

In patients with drug refractory atrial tachyarrhythmias and previous failed attempts of ablation of the arrhythmia substrate, radiofrequency (RF) modulation or ablation of the atrioventricular (AV) junction is an alternative procedure.Aim of this study was to assess the efficacy and long term results of RF AV junction ablation in conjunction with permanent pacemaker implantation, in the management of patients with drug resistant atrial tachyarrhythmias.Methods: Between 4/92 and 1/97, 46 patients (30 male, 16 female, 67&plusmn;12 years) underwent RF AV junction ablation because of paroxysmal atrial fibrillation (24 patients), chronic atrial fibrillation (13 patients), atrial flutter (5 patients) and atrial tachycardia (4 patients). The underlying heart disease was dilated cardiomyopathy (16), ischemic heart disease (9), hypertensive heart disease (6), hypertrophic cardiomyopathy (3), atrial septal defect (2) and non structural heart disease (10). The duration of symptoms was 6.4&plusmn;3.5 years at a maximal heart rate 169&plusmn;24 bpm. The hospital admissions in the last 12 months were 8.2&plusmn;3 per patient. The failed antiarrhythmic drugs were 3.5&plusmn;2.1. The functional NYHA class was 2.7&plusmn;0.6. Patients with atrial flutter and atrial tachycardia had previous failed attempts of RF ablation of the arrhythmia substrate. Thirty patients had a compromised left ventricular systolic function with LVEF below 50% (mean 34&plusmn;9%). AV junction ablation was achieved in all patients after 4&plusmn;2.5 RF applications. Post ablation, the selected pacing mode was DDD-R for the 33 patients with paroxysmal atrial tachyarrhythmias and VVI-R for the 13 pts with chronic atrial fibrillation. The dual chamber pacemakers implanted had the option of automatic mode switch.Results: During the follow-up period of 28&plusmn;13 months (6–47), AV conduction recovered in 1 patient. Antiarrhythmic treatment was necessary in only 7 patients. Post ablation the new functional NYHA class was 1.4&plusmn;0.8 (p &lt; 0.001). Post ablation hospital admissions, including ordinary pacemaker follow-up visits, were 4&plusmn;1 per patient per year (p &lt; 0.001). Six months after the procedure the LVEF of the study population was increased from 42&plusmn;16% to 50&plusmn;14% (p &equals; NS). In the 30 patients with heart failure the LVEF was significantly increased to 46&plusmn;8% (p &lt; 0.05). Symptomatic relief or significant improvement was observed in all patients as showed by the answers given in a customized questionnaire before and after the procedure.Conclusions: In patients with drug refractory atrial tachyarrhythmias, RF AV junction ablation and permanent pacemaker implantation is an alternative therapy with excellent long term results in terms of arrhythmia control, ventricular performance and quality of life.     

Catheter ablation or modulation of the AV node

The ablate and pace strategy may be considered a viable therapy in the palliative management of patients with medically refractory highly symptomatic atrial fibrillation (AF). The overall success rate is approaching 100%, the inhospital course is usually event free, and the procedure is a relatively safe therapeutic option. There is no doubt that one of the major findings after atrioventricular (AV) node ablation is the significant reduction of cardiac symptoms and health care use, while exercise tolerance and quality of life significantly improved after the procedure. It is also well accepted that catheter ablation and pacemaker (PM) implantation are usually associated with significant improvement in left ventricular ejection fraction, particularly in patient with AF and reduced systolic function at baseline. On the other hand, AV node ablation seems unlikely to have a negative effect on long term survival. The mortality rate in some reports have raised concerns about excess deaths (mainly sudden deaths) attributable to AV node ablation and pacing therapy. These findings are not confirmed by recent data.Modulation of the AV node has been more recently introduced in the clinical practice in order to avoid permanent complete AV block and lifetime PM dependency. AV node modulation procedure is effective in 70% of cases. The short duration of following periods does not allow to draw definitive conclusions concerning the potential evolution of AV node conduction disorders.Both AV node ablation and AV node modulation, when successful, are effective means to improve quality of life and cardiac performance in patients with medically refractory AF. The exact place of these procedures is, today, a matter of debate which is more controversial in patients with paroxysmal AF than with uncontrolled permanent AF.     

The Ablate and Pace Trial: A Prospective Study of Catheter Ablation of the AV Conduction System and Permanent Pacemaker Implantation for Treatment of Atrial Fibrillation

Background: The Ablate and Pace Trial (APT) prospectively assessed the effects of catheter ablation of the AV conduction system and permanent pacemaker implantation on health-related quality of life, survival, exercise capacity, and ventricular function in 156 patients with symptomatic atrial fibrillation. Methods: All patients referred for catheter ablation and permanent pacemaker implantation because of medically-refractory atrial fibrillation at 16 centers were screened for enrollment in a prospective registry. Baseline assessment prior to ablation included measurement of quality of life, including the Health Status Questionnaire, the Quality of Life Index and the Symptom Checklist: Frequency and Severity. Exercise capacity was assessed with metabolic treadmill exercise testing and ventricular function was quantitated with echocardiography. The quality of life instruments, exercise capacity, and echocardiography were repeated at 3 and 12 months after catheter ablation. Results: The APT population included 90 men and 66 women (66.1 ± 11.5 years of age) with either chronic (n = 70), recurrent (n = 31), or paroxysmal atrial fibrillation (n = 55). Structural heart disease was present in 78.2% of patients. Successful ablation of AV conduction was achieved in 155 of 156 patients (99.4%). Survival at 1 year was 85.3%, with 5 of 23 deaths being sudden cardiac deaths. Survival over the first year of follow-up was significantly lower for patients with a baseline left ventricular ejection fraction (LVEF) <0.45 (0.73) than for patients with a LVEF 0.45 (0.88, p = 0.03). The NYHA functional class improved from 2.1 at baseline to 1.8 at 3 months and 1.9 at 12 months of followup (p = 0.0001). Significant improvement in quality of life scores were noted for all 8 subscales of the Health Status Questionnaire, for the overall rating of the Quality of Life Index, the Health and Function subscales; Arrhythmia-related symptoms were markedly reduced as measured by the Symptom Checklist: Frequency and Severity scale. The mean LVEF improved from 0.50 ± 0.20 at baseline to 0.54 ± 0.20 at 3 months (p = 0.03). The LVEF 12 months after ablation was 0.52 ± 0.20, not statistically different from baseline. Individuals with reduced systolic function at baseline had the greatest improvement, from LVEF 0.31 ± 0.20 at baseline to 0.41 ± 0.20 at 3 months and 0.41 ± 0.30 at 12 months (p = 0.0001). There were no significant changes in treadmill exercise duration (10.0 ± 4.3 min at baseline and 11.6 ± 3.6 min at 12 months) or VO_2max (1467 ± 681 ml O₂ min baseline and 1629 ± 739 ml O₂ min at 12 months). Conclusions: Catheter ablation of the AV conduction system and permanent pacemaker implantation were associated with improved quality of life and left ventricular function in this population of highly symptomatic patients with atrial fibrillation refractory to medical therapy.     

What is the real atrial fibrillation burden after catheter ablation of atrial fibrillation? A prospective rhythm analysis in pacemaker patients with continuous atrial monitoring.

AIMS: Rhythm follow-up after catheter ablation of atrial fibrillation (AF ablation) is mainly based on Holter electrocardiogramm (ECG), tele-ECG or on patients symptoms. However, studies using 7-day Holter or tele-ECG follow-up revealed a significant number of asymptomatic recurrences. Thus, the aim of this study was to analyse continuous atrial recordings in pacemaker patients with an incorporated Holter function before and after AF ablation in order to determine all AF recurrences and thereby the 'real' success rates. METHODS AND RESULTS: The study comprised 37 patients (64.6 +/- 10 years) with prior pacemaker/implantable cardioverter defibrillator (ICD) implantation including an atrial Holter function referred for AF ablation. Holter data were obtained and correlated to patients' symptoms before and every 3-month after AF ablation. AF recurrence was defined as an atrial high frequency episode of less than 330 ms (180 b.p.m.) lasting longer than 30 s. The ablation procedure consisted of pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (PAF, n = 20) and additional substrate modification aiming arrhythmia termination in patients with persistent or inducible AF after PVI as well as in patients with a history of long-lasting persistent AF (PersAF, n = 17). The mean atrial Holter monitoring period was 7.4 +/- 3.3 months before and 13.5 +/- 4.2 months after ablation with an overall AF burden of 33.7% prior to ablation. During follow-up, AF burden decreased from 17.3-0.65% (P = 0.001) in PAF patients and from 57.4 to 13.9% (P = 0.024) in patients with PersAF. Complete AF freedom was observed in 85% (17 patients) of PAF patients and 59% (10 patients) in patients with PersAF. The absence of symptoms correlated well with documented freedom of AF. CONCLUSION: In the present study we could show, that freedom from AF can be achieved by catheter ablation in a high percentage of patients even with PersAF. Continuous atrial monitoring reveals AF ablation success rates comparable with those assessed by clinical evaluation. Symptomatic freedom of AF correlated well with the actual freedom of AF at least in this highly symptomatic patient cohort.     

Sudden death after radiofrequency ablation of the atrioventricular node in patients with atrial fibrillation

OBJECTIVES: We evaluated the incidence and predictors of sudden death after atrioventricular (AV) node ablation and pacemaker implantation. BACKGROUND: Sudden death may occur after radiofrequency catheter ablation of the AV node and pacemaker implantation in patients with atrial fibrillation (AF). Whether it is related to the procedure or to pre-existing heart disease remains unclear. METHODS: All patients who had radiofrequency catheter ablation of the AV node and pacemaker implantation for rate control of medically refractory AF were identified retrospectively and observed prospectively. All patients with sudden death after ablation were identified. The relationship between the procedure and sudden death was defined on the basis of the time between the two as "likely," "possibly" or "unlikely." RESULTS: Of 334 consecutive patients with AF who underwent AV node ablation, nine had sudden death after the ablation. Four patients (1.2%) had sudden death likely related to the procedure: in 3 patients, arrest occurred within 48 h after the procedure; in one patient, arrest occurred four days after the procedure. In three other patients (0.9%), sudden death was possibly related to the procedure because the event occurred within three months afterward. The remaining two deaths were unrelated to the procedure. Diabetes, New York Heart Association functional class (>or=II), preprocedure ventricular arrhythmia, mitral or aortic stenosis, aortic regurgitation and chronic obstructive pulmonary disease were independent predictors for sudden death. CONCLUSIONS: Sudden death likely or possibly related to catheter ablation occurred in 7 of 334 patients (2.1%). Risk of sudden death is highest within two days after the procedure.     

The presence of contractile reserve has no predictive value for the evolution of left ventricular function following atrio-ventricular node ablation in patients with permanent atrial fibrillation.

AIMS: Transcatheter ablation of the atrio-ventricular (AV) node followed by ventricular pacing has been shown to improve symptoms and quality of life (QOL) of patients with permanent atrial fibrillation (AF). In a considerable number of patients, cardiac function deteriorates after AV node ablation. We aimed to determine whether the absence of contractile reserve assessed by low dose dobutamine stress echocardiography (LDDSE) could identify those patients whose left ventricular (LV) function deteriorates after AV node ablation. METHODS: All 25 patients studied had permanent AF for at least 12 months. LVEF was determined 6 days and 3 months after AV node ablation by radionuclide ventriculography (RNV), at a paced rate of 80 beats/min. Deterioration in cardiac function was defined as a decrease in LVEF>5%. LDSE was performed in all patients before and after ablation. The presence of contractile reserve was defined as an improvement in regional function of >or=1 grade at low dose dobutamine in at least 4 segments. QOL measurements were taken using Minnesota, NHBP and MPWB questionnaires. RESULTS: LVEF showed no improvement in the overall group (52.8+/-11.1% vs. 51.8+/-9.8%, p=NS). QOL showed significant improvement in all questionnaires (Minnesota: 4.1+/-2.1 vs. 2.5+/-2, p=0.001; NHBP: 54.8+/-43.3 vs. 34.2+/-34.3, p=0.002; MPWB: 22.2+/-4.6 vs. 19.4+/-6.2, p=0.03). There was no significant difference in change of LVEF between patients with and without contractile reserve (-0.4+/-8.7 vs. 1.6+/-11.3, p=NS). However, patients with a preserved LVEF at baseline showed more frequently a reduced LVEF after AV node ablation (62.2+/-10.4% vs. 47.5+/-7.6%, p=0.001). CONCLUSIONS: (1) The absence of contractile reserve does not predict deterioration of cardiac function after AV node ablation. (2) AV node ablation results in a significant improvement in QOL, which is not necessarily associated with improvement of LVEF. (3) Higher baseline LVEF predicts deterioration of cardiac function. These data suggest that although AV node ablation is an excellent way of controlling symptoms, it should be avoided in patients with normal LV function.     

超声引导下实施射频消融房室结安置VVI起搏器初步探讨

探索经胸心脏超声引导心内射频消融房室结的可行性和安全性。对11例持续/永久性心房颤动/心房扑动拟行房室结消融加VVI起搏,在经胸心脏彩超引导下,采取多切面观察、导管运动中观察,密切结合心内电生理定位,尝试左锁骨下静脉永久起搏导管和右股静脉消融导管的心内定位和靶点消融。以出现稳定的房室分离判为消融成功。结果:11例房室结消融及VVI起搏均顺利完成,手术时间70～180min,放电期间超声切面可见能量释放征,消融后靶点区心内膜回声明显增强。手术成功率100%,随访期内患者恢复良好。结论:经胸切面超声引导射频消融房室结安置VVI起搏安全、简便、可行、经济。     

Left ventricular-based cardiac stimulation post AV nodal ablation evaluation (the PAVE study)

BACKGROUND: Chronic right ventricular pacing has been reported to promote cardiac dyssynchrony. The PAVE trial prospectively compared chronic biventricular pacing to right ventricular pacing in patients undergoing ablation of the AV node for management of atrial fibrillation with rapid ventricular rates. METHODS AND RESULTS: One hundred and eighty-four patients requiring AV node ablation were randomized to receive a biventricular pacing system (n = 103) or a right ventricular pacing system (n = 81). The study endpoints were change in the 6-minute hallway walk test, quality of life, and left ventricular ejection fraction. Patient characteristics were similar (64% male; age: 69 +/- 10 years, ejection fraction: 0.46 +/- 0.16; 83%, NYHA Class II or III). At 6 months postablation, patients treated with cardiac resynchronization had a significant improvement in 6-minute walk distance, (31%) above baseline (82.9 +/- 94.7 m), compared to patients receiving right ventricular pacing, (24%) above baseline (61.2 +/- 90.0 m) (P = 0.04). There were no significant differences in the quality-of-life parameters. At 6 months postablation, the ejection fraction in the biventricular group (0.46 +/- 0.13) was significantly greater in comparison to patients receiving right ventricular pacing (0.41 +/- 0.13, P = 0.03). Patients with an ejection fraction 相似文献