Long-term rhythm control of drug-refractory atrial fibrillation with "hybrid therapy" incorporating dual-site right atrial pacing, antiarrhythmic drugs, and right atrial ablation

We evaluated the long-term efficacy, safety, and applicability of a "hybrid" therapy strategy for rhythm control in atrial fibrillation (AF), incorporating dual-site right atrial pacing, antiarrhythmic drugs, and right atrial ablation. One hundred thirteen patients (paroxysmal AF [n = 70], persistent/permanent AF [n = 43]) with refractory symptomatic AF were treated with this strategy and followed for 1 to 81 months (mean 30 +/- 23). All-cause mortality, AF recurrences, and progression to permanent AF were monitored and recorded by implanted device data logs. There was no procedural mortality. Rhythm control was achieved in 90% of all patients at 3 and 5 years, with comparable efficacy in subpopulations with paroxysmal (98%), persistent, or permanent AF (87%, p >2). Overall survival was 84% at 3 years and 80% at 5 years, and was higher in patients with paroxysmal AF than in patients with persistent or permanent AF (86% vs 67% at 4 years, p <0.001). Patients with persistent or permanent AF had a greater need for cardioversion (p <0.004) and right atrial ablation (p <0.04) than patients with paroxysmal AF to achieve comparable rhythm control. A hybrid therapy strategy can provide safe and effective long-term rhythm control in patients with drug-refractory AF, and can be implemented in subpopulations presenting with paroxysmal, persistent, or permanent AF.     

Improved suppression of recurrent atrial fibrillation with dual-site right atrial pacing and antiarrhythmic drug therapy

OBJECTIVES: We compared the safety, tolerance and effectiveness of overdrive high right atrial (RA), dual-site RA and support (DDI or VDI) pacing (SP) in patients with symptomatic atrial fibrillation (AF) and bradycardias. BACKGROUND: Optimal pacing methods for AF prevention remain unclear. METHODS: Patients (n = 118) were randomized to each of three pacing modes in a crossover trial. RESULTS: Mode adherence was superior for dual-site RA (5.8 months) compared with SP (3.3 months; p < 0.001) and high RA pacing (4.7 months; p = 0.006). Adverse event-free survival improved with dual-site RA (p = 0.007 vs. SP) and was comparable to high RA (p = 0. 75). AF-free survival trended to improve with dual-site RA (hazard ratio [HR] 0.715, p = 0.07 vs. SP) but not high RA (HR = 0.71, p = 0.19) or when dual-site RA was compared with high RA (HR = 0.835, p = 0.175). Time-to-recurrence was longer in dual-site RA (1.77 months) compared with high RA (0.62 months, p < 0.09) or SP (0.44 months, p < 0.05). In antiarrhythmic drug-treated patients, dual-site RA reduced recurrence risk compared with SP (HR = 0.638, p = 0.011) and high RA (HR = 0.669, p = 0.06). In patients with < or =1 AF event/week, dual-site RA improved AF suppression (HR = 0.464, p = 0.004 vs. SP; HR = 0.623, p = 0.006 vs. high RA). Dual-site RA improved AF-free and mode survival (p < 0.03 vs. high RA, p < 0.001 vs. SP) and reduced asymptomatic AF (p < 0.01 vs. high RA). CONCLUSION: Dual-site RA is safe and better tolerated than high RA and SP. In patients on antiarrhythmics, dual-site RA prolonged and high RA trended to prolong time-to-recurrent AF compared with SP. Dual-site RA provides superior symptomatic and asymptomatic AF prevention compared with high RA in patients with symptomatic AF frequency of < or =1/week.     

Effectiveness of rhythm control in persistent or permanent atrial fibrillation with overdrive atrial pacing and antiarrhythmic drugs after linear right atrial catheter ablation

Right atrial (RA) maze procedures using linear catheter ablation have had limited efficacy in paroxysmal atrial fibrillation (AF). We hypothesized that "hybrid" therapy using overdrive atrial pacing and antiarrhythmic drugs can improve efficacy of catheter RA maze and expand its role to persistent or permanent AF. Catheter RA maze procedures were performed in 26 patients with persistent or permanent AF refractory to 4.5 +/- 2.1 antiarrhythmic drugs. Overdrive dual-site RA pacing (21 patients) or high RA pacing (5 patients) was continued (n = 11) or instituted periablation (n = 15). All patients continued receiving previously ineffective antiarrhythmic drugs. Freedom from permanent AF (rhythm control), symptomatic and/or asymptomatic AF recurrences, the safety of hybrid therapy, and overall survival were assessed. There was no procedure-related mortality or stroke. Rhythm control was achieved in 24 patients (92%) within 3 months. During long-term follow-up (6 to 49 months, mean 17 +/- 10), rhythm control was maintained in 20 patients (77%). Nine patients (35%) had no AF recurrences, whereas 11 patients maintained rhythm control with infrequent AF recurrences. Device datalogs at the study cut-off point demonstrated no AF events in 6 patients, nonsustained atrial tachycardia in 2 patients, and brief asymptomatic paroxysmal AF in 12 patients. Actuarial patient survival was 95% at 1 year and 74% at 2 years of follow-up. Thus, hybrid therapy utilizing catheter RA maze procedures with overdrive atrial pacing and antiarrhythmic drugs can be performed safely and can reestablish rhythm control in selected patients with refractory persistent or permanent AF.     

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.     

Prevention of recurrent atrial fibrillation with chronic dual-site right atrial pacing

Objectives. We investigated 1) the feasibility, safety and efficacy of multisite right atrial pacing for prevention of atrial fibrillation (AF); and 2) the ability of atrial pacing in single- and dual-site modes to increase arrhythmia-free intervals in patients with drug-refractory AF.Background. We recently developed and applied a novel technique of dual-site right atrial pacing in an unselected group of consecutive patients with AF requiring demand pacing. A prospective crossover study design was used to evaluate single- and dual-site right atrial pacing modes.Methods. The frequency of AF during the 3 months before pacemaker implantation was analyzed. Consecutive consenting patients underwent insertion of two atrial leads and one ventricular lead with a DDDR pulse generator. Patients were placed in a dual-site pacing mode for the first 3 months and subsequently mode switched to single site pacing for 3 months. Mode switching was repeated at 6-month intervals thereafter.Results. Atrial pacing resulted in a marked decline in AF recurrences (p < 0.001). During dual-site pacing with an optimal drug regimen, there was no AF recurrence in any patient compared with five recurrences in 12 patients during single-site pacing (p = 0.03). The mean (±SD) arrhythmia-free interval before pacing (14 ± 14 days) was prolonged with dual- (89 ± 7 days, p < 0.0001) and single-site pacing (76 ± 27 days, p < 0.0001). Symptomatic AF episodes showed a declining trend during dual- and single-site pacing compared with those during the preimplantation period (p = 0.10). Mean antiarrhythmic drug use for all classes declined from 4 ± 1.9 drugs before implantation to 1.5 ± 0.5 (p < 0.01) drugs after implantation. Twelve (80%) of 15 patients remained in atrial paced rhythm at 13 ± 3 months.Conclusions. We conclude that multisite right atrial pacing is feasible, effective and safe for long-term application. Atrial pacing significantly prolongs arrhythmia-free intervals in patients with drug-refractory paroxysmal AF. Dual-site right atrial pacing may offer additional benefits and should be considered either as the primary mode or in patients unresponsive to single-site pacing.     

Long-term outcome of patients with drug-refractory atrial flutter and fibrillation after single- and dual-site right atrial pacing for arrhythmia prevention

Objectives. An initial crossover study comparing dual- and single-site right atrial pacing was performed followed by a long-term efficacy and safety evaluation of dual-site right atrial pacing in patients with drug-refractory atrial fibrillation (AF). Also examined was the efficacy of two single-site right atrial pacing modes (high right atrium and coronary sinus ostium) and the long-term need for cardioversion, antithrombotic and antiarrhythmic drug therapies during dual-site atrial pacing.

Methods. Thirty consecutive patients with drug-refractory symptomatic AF and documented primary or drug-induced bradycardia were implanted with a dual chamber rate-responsive pacemaker and two atrial leads. Single-site atrial pacing was performed at the high right atrium or the coronary sinus ostium. Continuous atrial pacing was maintained.

Results. Mean arrhythmia-free intervals increased from 9 ± 10 days in the control period preceding implant to 143 ± 110 days (p < 0.0001) in single-site right atrial pacing and 195 ± 96 days in dual-site right atrial pacing (p < 0.005 versus single-site pacing and p < 0.0001 versus control). Dual-site right atrial pacing significantly increased the proportion of patients free of AF recurrence (89%) as compared to single-site right atrial pacing (62%, p = 0.02). High right atrial pacing and coronary sinus ostial pacing had similar efficacy for AF prevention. Effective rhythm control was achieved in 86% of patients during dual right atrial pacing. Seventy-eight percent of patients at 1 year and 56% at 3 years remained free of symptomatic AF. The need for cardioversion was reduced after pacemaker implant (p < 0.05) and antithrombotic therapy was reduced (p < 0.06) without any thromboembolic event. Coronary sinus ostial lead dislodgement was not observed after discharge.

Conclusions. Atrial pacing in combination with antiarrhythmic drugs eliminates or markedly reduces recurrent AF. Prevention of AF is enhanced by dual-site right atrial pacing. High right atrial and coronary sinus ostial pacing do not differ in efficacy. Dual-site right atrial pacing is safe, achieves long-term rhythm control in most patients, decreases the need for cardioversion, and antithrombotic therapy can be selectively reduced.     

Catheter ablation of atrial fibrillation versus atrioventricular junction ablation plus pacing therapy for elderly patients with medically refractory paroxysmal atrial fibrillation

BACKGROUND: Catheter ablation of atrial fibrillation (AF) has become another nonpharmacologic therapeutic option for medically refractory paroxysmal AF. Whether this method is better than atrioventricular (AV) junction ablation plus pacing therapy is unknown. The purpose of this study was to compare the very long-term (longer than 4 years) clinical outcomes of the 2 methods in elderly patients (>65 years old) with medically refractory paroxysmal AF. METHODS: From January 1995 to December 2001, 71 elderly patients with medically refractory paroxysmal AF were included; group 1 included 32 patients with successful AV junction ablation plus pacing therapy and group 2, 37 patients with successful catheter ablation of AF. RESULTS: After a mean follow-up of more than 52 months, the AF was better controlled in the group 1 patients than group 2 (100% vs 81%, P = 0.013), however, they had a significantly higher incidence of persistent AF (69% vs 8%, P < 0.001) and heart failure (53% vs 24%, P = 0.001). Furthermore, the incidence of ischemic stroke and cardiac death was similar between the 2 groups. Compared with the preablation values, a significant increase in the NYHA functional class (1.7 +/- 0.9 vs 1.4 +/- 0.7, P = 0.01) and significant decrease in the left ventricular ejection fraction (44 +/- 8% vs 51 +/- 10%, P = 0.01) were noted in the group 1 patients, but not in the group 2 patients. CONCLUSIONS: Although AV junction ablation plus pacing therapy better controlled the AF in elderly patients with medically refractory paroxysmal AF, that method was associated with a higher incidence of persistent AF and heart failure than catheter ablation of AF in the very long-term follow-up.     

心房颤动导管消融与药物治疗效果的比较研究

目的比较心房颤动(房颤)导管消融治疗与药物治疗的治疗效果。方法连续入选644例房颤患者,获取基线特征,应用倾向评分方法进行匹配分组,获得两组不同治疗策略的入选人群(257例),进行为期约18个月的随访,通过Cox比例风险模型比较导管消融和药物治疗对房颤患者一级终点房颤复发事件以及二级终点因心力衰竭住院率、血栓栓塞事件、累积生存率及生活质量改善的影响。结果 (1)无房颤复发终点:导管消融术组优于抗心律失常药物治疗组(HR:3.12,95%CI:1.93~5.03,P<0.01)。(2)因心力衰竭住院率:导管消融术组与抗心律失常药物治疗组差异无统计学意义(HR:1.14,95%CI:0.67~1.94,P=0.34)。(3)血栓栓塞事件发生率:在导管消融术组和抗心律失常药物治疗组间差异无统计学意义(HR:0.98,95%CI:0.44~2.20,P=0.38)。(4)累积生存率:两组间差异无统计学意义(HR:1.05,95%CI:0.33~3.32,P=0.73)。(5)生活质量评分:抗心律失常药物组生活质量无明显改善,而导管消融术组仅对精神方面评分有显著改善(随访3个月和12个月均为P=0.04)。结论导管消融治疗与药物治疗相比,房颤复发率更低,并可以改善精神方面的生活质量,但未能降低因心力衰竭住院率和血栓栓塞事件发生的风险,两种治疗手段的累积生存率差异无统计学意义。     

Left ventricular mechanics during right ventricular apical or left ventricular-based pacing in patients with chronic atrial fibrillation after atrioventricular junction ablation

OBJECTIVES: The aim of the study was to evaluate whether left ventricular (LV) mechanics are better under LV-based pacing than under right ventricular (RV) apical pacing in patients with permanent atrial fibrillation (AF) after atrioventricular junction (AVJ) ablation. BACKGROUND: "Ablate and pace" is an acceptable therapy for drug-refractory AF. However, the RV apical stimulation commonly used seems to interfere with the beneficial hemodynamic effect of regularization of heart rhythm. METHODS: The study included 12 patients (5 men, mean age 62 +/- 8.3 years), 6 with impaired and 6 with normal LV systolic function. All of them had a biventricular pacemaker system implanted and underwent atrioventricular node ablation for drug-refractory chronic AF. Using a conductance catheter, we analyzed LV pressure-volume loops during routine coronary angiography in order to evaluate short-term changes in LV mechanics during RV apical and LV-based (LV free wall or biventricular) pacing. RESULTS: Compared with RV pacing, LV-based pacing significantly improved the indexes of LV systolic function (i.e., end-systolic pressure and volume, cardiac index, stroke work, preload recruitable stroke work, maximal rate of rise of LV pressure [dP/dt(max)], LV ejection fraction, and end-systolic elastance). The LV diastolic filling indexes, end-diastolic pressure and volume, were better during LV-based pacing, whereas LV diastolic function indexes, -dP/dt(max), passive diastolic chamber stiffness, and time constant of LV isovolumic relaxation showed no clear change. CONCLUSIONS: In the short term, LV-based pacing is superior to RV apical pacing in terms of contractile function and LV filling after AVJ ablation for drug-refractory AF.     

No incremental benefit of multisite atrial pacing compared with right atrial pacing in patients with drug refractory paroxysmal atrial fibrillation

OBJECTIVE—To evaluate the incremental antifibrillatory effect of multisite atrial pacing compared with right atrial pacing in patients with drug refractory paroxysmal atrial fibrillation paced for arrhythmia prevention alone.
METHODS—In 20 of these patients (mean (SD) age 64 (8) years; 14 female, six male), a single blinded randomised crossover study was performed to investigate the incremental benefit of one month of multisite atrial pacing compared with one month of right atrial pacing. Outcomes included the number of episodes of paroxysmal atrial fibrillation, their total duration obtained from pacemaker Holter memory, and quality of life using a cardiac specific questionnaire (the modified Karolinska questionnaire).
RESULTS—Comparing right atrial with multisite atrial pacing, there was no significant change in either the number of paroxysmal atrial fibrillation episodes (mean (SD): right atrial pacing 77 (98) episodes v multisite pacing 52 (78) episodes, NS) or their total duration (right atrial, 4.8 (5.4) days v multisite, 6.3 (9.8) days, NS). Quality of life scores compared with baseline status were equally improved by either pacing strategy (mean percentage improvement: right atrial, 38%, p = 0.003; multisite, 44%, p = 0.003). There was no significant difference in life scores comparing the two pacing modes.
CONCLUSIONS—Multisite atrial pacing has no incremental antiarrhythmic effect compared with right atrial pacing in patients paced for drug refractory paroxysmal atrial fibrillation. Quality of life is equally improved with either pacing strategy, with no differences between them.


Keywords: multisite atrial pacing; atrial fibrillation; pacing     

Evaluation of biatrial pacing, right atrial pacing, and no pacing in patients with drug refractory atrial fibrillation.

It has been suggested biatrial pacing may prevent the recurrence of atrial fibrillation (AF). To further evaluate this hypothesis, we performed a randomized, single-blinded study in 19 patients with drug refractory AF. The study compared biatrial pacing with conventional right atrial (RA) pacing and a control period of inhibited pacing. The pacing modes utilized were DDD with a base rate of 70 beats/min for biatrial and RA pace (with and without biatrial resynchronization, respectively) and 40 beats/min for the control period. The duration of each pacing mode was 3 months. The number of AF episodes and their duration were obtained from pacemaker Holter memory (Chorus RM ELA Medical). Comparison of the control period (n = 11) with either pacing strategy showed a significant decrease in the total duration of AF (control 27 +/- 35 days, biatrial 8 +/- 15 days p = 0.02, RA 11 +/- 27 days p = 0.04). However, there was no effect on the number of AF episodes (control 79 +/- 108, biatrial 36 +/- 75 p = 0.32, RA 41 +/- 80 p = 0.11). The total percentage of atrial pacing also significantly increased when the control period (6 +/- 9%) was compared with both RA pace (62 +/- 33%, p = 0.008) and biatrial pace (63 +/- 31, p = 0.003). When biatrial pacing was compared with RA pace (n = 19), there was no significant difference in either the duration of AF (biatrial 16 +/- 26 days vs RA 19 +/- 31 days, p = 0.7) or the number of AF episodes (biatrial 56 +/- 91 vs RA 87 +/- 106, p = 0.34). In conclusion, pacing (either type) at a base rate of 70 beats/min has an antifibrillatory effect when compared with inhibited pacing at 40 beats/min. No additional benefit of biatrial pacing over right atrial pacing was demonstrated in this study.     

Rhythm control for management of patients with atrial fibrillation: balancing the use of antiarrhythmic drugs and catheter ablation

Antiarrhythmic drug (AAD) therapy may be beneficial for patients with symptoms attributable to atrial fibrillation despite adequate rate control. The limited long-term efficacy of AAD and the relatively large proportion of patients discontinuing therapy because of side effects led to the development of nonpharmacological therapies to achieve rhythm control. Pressing questions remain about the effect of ablation therapy on long-term patient outcomes. Based on recent clinical trials and meta-analyses, ablation appears more effective and possibly safer than AAD for long-term maintenance of sinus rhythm in selected patients, but the evidence is insufficient to recommend ablation in preference to drug therapy as the first AAD therapy for the majority of patients in whom a rhythm control strategy is justified. Herein, we review the most current evidence supporting the use of AAD and catheter ablation in atrial fibrillation.     

Left atrial volume and dominant frequency of atrial fibrillation in patients undergoing catheter ablation of persistent atrial fibrillation

Background  

Prior studies have suggested that left atrial (LA) volume and frequency of atrial fibrillation (AF) are associated with suboptimal outcomes in patients undergoing catheter ablation of AF. However, the interaction of these factors and their relative impact on outcome are not clear.