Comparison of the effects of AV nodal ablation versus AV nodal modification in patients with congestive heart failure and uncontrolled atrial fibrillation

Outcomes of Atrioventricular Node Ablation and Pacing in Patients with Heart Failure and Atrial Fibrillation: From Cardiac Resynchronization Therapy to His Bundle Pacing

Objective: To review the relevant literature on the use of atrioventricular node ablation and pacing in patients with heart failure and atrial fibrillation. Methods: APubMed/MEDLINE and SCOPUS search was performed in order to assess the clinical outcomes of atrioventricular node ablation and pacemaker implantation, as well as the complications that may occur. Results: Several clinical trials, observational analyses and meta-analyses have shown that the "pace and ablate" strategy not only improves symptoms but also can enhance cardiac performance in patients with heart failure and atrial fibrillation. Although this procedure is effective and safe, some complications may occur including worsening of heart failure, permanent fibrillation, arrhythmias and sudden death. Regarding pacemaker implantation, cardiac resynchronization therapy is shown to be the optimal choice compared to right ventricle apical pacing. His bundle pacing is a promising alternative to cardiac resynchronization therapy and has shown beneficial effects, while left bundle branch pacing is an innovative modality. Conclusions: Atrioventricular node ablation and pacemaker implantation is shown to have beneficial effects on clinical outcomes of patients with atrial fibrillation ± heart failure who do not respond or are intolerant to medical treatment. Cardiac resynchronization therapy is the treatment of choice and His bundle pacing seems to be an effective alternative way of pacing in these patients.

Quality of life in patients with atrial fibrillation: how to assess it and how to improve it

Atrial fibrillation (AF) is the most frequent cardiac rhythm disorder and presents a considerable public health burden that is likely to increase in the next decades due to the ageing population. Current management strategies focus on the heart rate and rhythm control, thromboembolism prevention, and treatment of underlying diseases. The concept of quality of life (QoL) has gained significant importance in recent years as an outcome measure in AF studies evaluating therapeutic interventions and as a relevant component of a comprehensive treatment plan. Quality of life is impaired in the majority of patients with AF, and both rate and rhythm control strategies show significant improvement in QoL measures in highly symptomatic patients. This article reviews generic and specialized instruments for measuring QoL in the context of AF, discusses their applications and limitations to integration in clinical practice, and addresses the potential of early therapy for improving QoL outcomes. The development and validation of new QoL assessment tools will have a central role in the advancement of therapies and treatment guidelines for AF.

Atrioventricular junction ablation and pacemaker implantation for heart failure associated with atrial fibrillation: potential issues and therapies in the setting of acute heart failure syndrome

Atrial fibrillation is the most common arrhythmia and is especially clinically important in patients with heart failure. Prolonged atrial fibrillation with high ventricular rate response may lead to development or worsening of left ventricular function. If adequate heart rate control cannot be obtained medically, often patients will undergo pacemaker implant and catheter ablation of the atrioventricular junction. This intervention can have profound effects on the course of heart failure. This article reviews the technique, complications, outcome data, and alternatives to this management strategy. The potential role of this therapeutic modality in those hospitalized with acute heart failure syndromes is discussed.

Pulmonary vein vestibule ablation for the control of atrial fibrillation in patients with impaired left ventricular function

INTRODUCTION

Congestive heart failure (CHF) and atrial fibrillation (AF) are frequently linked, and when associated produce additive deleterious effects. In this prospective study, the effects of catheter ablation for AF in patients with impaired left ventricular (LV) function are presented.

METHODS

Baseline data and clinical outcome have been prospectively collected in 105 consecutive patients who underwent pulmonary vein ablation for the control of AF. We evaluated 40 patients affected by LV dysfunction with ejection fraction (EF)<40% and compared them to the remaining 65 patients with normal ventricular function in terms of changes in LV function, maintenance of sinus rhythm, and quality of life during follow-up.

RESULTS

After a mean follow-up of 14+/-2 months, 87% of patients with impaired LV function and 92% of patients with normal ventricular function were in sinus rhythm, with or without antiarrhythmic therapy (P=NS). A significant improvement in LVEF and fractional shortening was documented in patients with CHF (33+/-2% vs 47+/-3%, and 19+/-4% vs 30+/-3%, P<0.01 for both comparisons). Evaluation of exercise capacity and quality of life documented better improvements in patients with CHF compared to patients without CHF.

CONCLUSIONS

Catheter ablation in patients with LV dysfunction is feasible, not associated with higher procedural complications, and provides a significant improvement in LV performance, symptoms, and quality of life during follow-up.

Changes in connexin 43, metalloproteinase and tissue inhibitor of metalloproteinase during tachycardia-induced cardiomyopathy in dogs

OBJECTIVE

To study changes in connexin, metalloproteinase and tissue inhibitor of metalloproteinase levels during tachycardia-induced cardiomyopathy (TIC).

METHODS

Canine models of TIC were established by rapid right atrial pacing at 350-400 beats per min for 8 weeks in 11 dogs, six dogs acted as a sham operation group. Echocardiography, left ventricular pressure and its first derivation with time (positive and negative maximum, dp/dtmax, -dp/dtmax), and intracardiac electrograms were recorded before and after rapid pacing at 1, 4 and 8 weeks. Data were acquired in sinus rhythm. Ultrastructural changes in left ventricular tissue were observed by transmission electron microscope. Connexin 43 (Cx43) levels in the left ventricular myocardium were measured by confocal laser microscopy. The relative abundance of matrix metalloproteinase (MMP-2) and tissue inhibitor of metalloproteinase (TIMP-2) were studied by immunoblotting.

RESULT AND CONCLUSIONS

(1) Ventricular dilatation and systolic dysfunction occurred after 1 week of rapid right atrial pacing. (2) There was structural damage to the myofibrils, mitochondria, and the sarcoplasmic reticulum with intercalated disk discontinuity. (3) Levels of Cx43 decreased significantly and gap junction remodelling occurred during TIC. (4) TIC may result from several mechanisms, such as ultrastructural changes or gap junction and matrix remodelling.

Changes in Metalloproteinase and Tissue Inhibitor of Metalloproteinase during Tachycardia-Induced Cardiomyopathy by Rapid Atrial Pacing in Dogs

BACKGROUND

It was the aim of this study to investigate the variation in metalloproteinase and tissue inhibitor of metalloproteinase (TIMP) connexin levels during tachycardia-induced cardiomyopathy (TIC).

METHODS

Canine models of TIC were established by rapid right atrial pacing at 350-400 beats per min for 8 weeks in 11 dogs, with another 6 dogs acting as sham operation group. Echocardiography, left ventricular pressure and its first derivation with time (positive and negative maximum, dp/dt(max) and -dp/dt(max)), as well as intracardiac electrograms were recorded before and after rapid pacing at 1, 4 and 8 weeks. Data were acquired in sinus rhythm. Ultrastructural changes in left ventricular tissue were observed by transmission electron microscope. The relative abundance of matrix metalloproteinase (MMP)-9 and TIMP-1 was studied by immunoblotting.

RESULTS

The following hemodynamic changes were detected after 8 weeks of rapid pacing: the TIC group had decreased dp/dt(max) (p < 0.05), the left ventricular relaxation time constant (tau) was prolonged (p < 0.05), both left ventricular end-diastolic volume and left ventricular end-systolic volume were decreased (p <0.05), left ventricular end-diastolic pressure was significantly increased (p <0.05), and -dp/dt(max) was significantly decreased (p <0.001) compared with the control group; no statistical differences in the left ventricular ejection fraction between weeks 1, 4 or 8 (p >0.05) were observed, but left ventricular ejection fraction was significantly decreased after 1 week of pacing (p < 0.05). The left ventricular end-diastolic volume was increased after 1 week of pacing compared with the control group (24.15 +/- 8.15 vs.11.19 +/- 4.41 ml; p <0.05), as shown by echocardiography. Compared with the control group, MMP-9 was significantly higher (0.217 +/- 2.16 E-02 vs. 0.314 +/- 5.263 E-02; p < 0.001), while TIMP-1 was decreased (0.230 +/- 8.944 E-02 vs. 0.120 +/- 9.258 E-03; p < 0.001).

CONCLUSIONS

Ventricular dilatation and systolic dysfunction occurred after 1 week of rapid right atrial pacing. Enlarged and disarrayed fibers and mitochondria with disintegrated crystal and an anarchic pattern were observed. Additionally, moderate dilation of the rough endoplasmic reticulum and intercalated disk discontinuity were seen after 8 weeks of pacing, and MMP-9 was increased and TIMP-1 was decreased after the same time period.

Quality of life in patients with atrial fibrillation: a systematic review

The impact of atrial fibrillation (AF) on patients' quality of life (QoL) has yet to be fully elucidated in a systematic manner. This article examines QoL in "general" patients with AF as well as the effects that rate and/or rhythm-control interventions have on QoL. Patients with AF have significantly poorer QoL compared with healthy controls, the general population, and other patients with coronary heart disease. Studies examining rate or rhythm-control strategies alone demonstrate improved QoL after intervention. Three of the four large randomized control trials (STAF, PIAF, RACE) comparing rate versus rhythm control demonstrated a greater improvement in QoL in patients receiving rate control. However, the AFFIRM trial revealed a similar improvement in QoL for both rate and rhythm-control groups. The data, although frequently compromised by various methodologic weaknesses, suggest that patients with AF have impaired QoL, and that QoL can be significantly improved through rate or rhythm-control strategies.

Direct His-Bundle Pacing:. Present and Future

Direct His-bundle pacing (DHBP) produces rapid sequential multisite synchronous ventricular activation and, therefore, would be an ideal alternative to right ventricular apical (RVA) pacing. In 54 patients with cardiomyopathy, ejection fraction (EF) 0.23 +/- 0.11, persistent atrial fibrillation, and normal QRS < 120 ms. DHBP was attempted. This was successful in 39 patients. In seven patients, the effect of increasing heart rate on contractility (Treppe effect) was investigated. Twelve patients who also received a RVA lead underwent cardiopulmonary testing. After a mean follow-up of 42 months, 29 patients are still alive with EF improving from 0.23 +/- 0.11 to 0.33 +/- 0.15. Functional class improved from 3.5 to 2.2. DP/dt increased at each pacing site (P < 0.05) as the heart rate increased to 60, 100, and 120 beats/min. Rise in dP/dt by DHBP pacing at 120 beats/min was at least 170 +/- mmHg/s, greater than any other site in the ventricle (P < 0.05). Cardiopulmonary testing revealed longer exercise time (RVA 255 +/- 110 s) (His 280 +/- 104 s) (P < 0.05), higher O2 uptake (RVA 15 +/- 4 mL/kg per minute) (His 16 +/- 4 mL/kg minute) (P < 0.05), and later anaerobic threshold (RVA 126 +/- 71 s) (His 145 +/- 74 s) (P < 0.05) with DHBP compared to RVA pacing. Long-term DHBP is safe and effective in humans. DHBP is associated with a superior Treppe effect and increased cardiopulmonary reserve when compared to RVA pacing.

Pulmonary vein isolation for the treatment of atrial fibrillation in patients with impaired systolic function

OBJECTIVES

We aimed to determine the safety and efficacy of pulmonary vein isolation (PVI) in atrial fibrillation (AF) patients with impaired left ventricular (LV) systolic function.

BACKGROUND

To date, PVI has been performed primarily in patients with normal LV function. Yet, many AF patients have impaired LV systolic function. The outcomes of PVI in patients with impaired LV systolic function are unknown.

METHODS

We included 377 consecutive patients undergoing PVI between December 2000 and January 2003. Ninety-four patients had impaired LV function (ejection fraction [EF] <40%), and they comprised the study group. The control group was the remaining 283 patients who had a normal EF. End points included AF recurrence and changes in EF and quality of life (QoL).

RESULTS

Mean EF was 36% in our study group, compared with 54% in controls. After initial PVI, 73% of patients with impaired EF and 87% of patients with normal EF were free of AF recurrence at 14 +/- 6 months (p = 0.03). In the study group, there was a nonsignificant increase in EF of 4.6% and significant improvement in QoL. Complication rates were low and included a 1% risk of pulmonary vein stenosis.

CONCLUSIONS

Although the AF recurrence rate after initial PVI in impaired EF patients was higher than in normal EF subjects, nearly three-fourths of patients with impaired EF remained AF-free. Although our sample size was nonrandomized, our results suggest PVI may be a feasible therapeutic option in AF patients with impaired EF. Randomized studies with more patients and longer follow-up are warranted.

Some recent randomized clinical trials in the management of atrial fibrillation

It is not possible to review all the recent randomized clinical trials in management of atrial fibrillation. The author has chosen to select a few that illustrate key points. "Immediate" or "early" recurrence of atrial fibrillation after electrical cardioversion is an important part of inefficacy of drug therapy and more insight into the mechanisms of this phenomenon is needed. Two recent trials in which verapamil, a calcium channel blocker, and irbesartan, an angiotensin receptor blocking agent, added to a standard antiarrhythmic attenuated early recurrences of atrial fibrillation are of particular interest. Trials of drugs and pacing for maintenance of sinus rhythm continue to demonstrate only modest efficacy. Amiodarone, the most effective agent, is not markedly better and there are concerns about its adverse effect profile during long-term use. Other nonpharmacologic therapies have not yet been, but will need to be, evaluated in properly designed randomized clinical trials with clinically important end-points. The absence of a simple, highly effective treatment for the maintenance of sinus rhythm with few adverse effects has been part of the foundation for recent trials comparing the rate control strategy to the rhythm control strategy, particularly in the elderly patient. Six such trials have been completed and one is in progress. The data from these trials is quite consistent for the elderly patient with stroke risk factors and predominantly persistent atrial fibrillation: (1) any advantage for the rhythm control strategy remains unproven; (2) the rate control strategy has some clear advantages and should be considered more often as a primary approach in such patients; and (3) anticoagulation should not be discontinued in such high risk patients, even when it is felt that sinus rhythm has been maintained. Anticoagulation is under-utilized in this setting and alternatives to warfarin are badly needed. Trials in progress may be helpful in this regard. Finally, primary prevention of atrial fibrillation needs more attention. Recent randomized trials with trandolapril after myocardial infarction and physiologic pacing have given some insight into how this might be accomplished.

New approaches to atrial fibrillation management: a critical review of a rapidly evolving field

Atrial fibrillation (AF) is the most common cardiac arrhythmia, the prevalence of which is increasing with the aging of the population. Because of its clinical importance and the lack of highly satisfactory management approaches, AF is the subject of active clinical and research efforts. This paper reviews recent and on-going developments in pharmacological and non-drug management of AF. The ideal therapeutic goal for AF is the production and maintenance of sinus rhythm. Comparative studies suggest that available class I and III drugs have comparable and modest efficacy for sinus rhythm maintenance. Amiodarone, with actions of all antiarrhythmic classes, has recently been shown to have clearly superior efficacy compared with other available drugs. Newer agents are in development, but their advantages are as yet unclear and appear limited. A potentially interesting approach is the prescription of drugs upon the occurrence of an attack, rather than on a continuous basis. Recent insights into AF mechanisms may permit therapy to prevent development of the AF substrate. An alternative to sinus rhythm maintenance is a rate control approach, with no attempt to prevent AF. Drugs to effect rate control include digitalis, beta-blockers and calcium channel antagonists. Digitalis has limited value for control of exercise heart rate and for paroxysmal AF, but is particularly well suited for patients with concomitant AF and congestive heart failure. AV-nodal ablation and pacing is an effective alternative for rate control but leaves the patient pacemaker dependent. The relative merits of rate versus rhythm control are being evaluated in ongoing trials, preliminary results of which indicate no statistically significant differences in primary endpoints but highlight the risks of rhythm control therapy. In patients requiring pacemakers, physiological pacing (dual chamber devices or atrial pacing) has an advantage over purely ventricular pacemakers in AF prevention. Newer pacing modalities that produce more synchronised atrial activation, as well as pacemakers that prevent excessive atrial rate swings, show promise in AF prevention and may soon see wider use. The usefulness of automatic atrial defibrillators is presently limited by discomfort during shocks. Targeted destruction of pulmonary vein foci by radiofrequency catheter ablation suppresses paroxysmal AF. Efficacy in persistent AF is lower and still under study. Problems include potential recurrence in other veins and a small but nontrivial risk of pulmonary vein stenosis. Surgical division of the atria into zones with limited electrical connection, the MAZE procedure, is highly effective in AF prevention but is a major intervention that is not applicable to most patients. In conclusion, significant advances are being made in the management of patients with AF but much more work remains to be done.

Tachycardia-induced cardiomyopathy

Systolic dysfunction associated with chronic tachyarrhythmias, known as tachycardia-induced cardiomyopathy, is a reversible form of heart failure characterized by left ventricular dilatation that is usually reversible once the tachyarrhythmia is controlled. Its development is related to both atrial and ventricular arrhythmias. The diagnosis is usually made following observation of a marked improvement in systolic function after normalization of heart rate. Clinicians should be aware that patients with unexplained systolic dysfunction may have tachycardia-induced cardiomyopathy, and that controlling the arrhythmia may result in improvement and even complete normalization of systolic function.

Atrial fibrillation: treatment rationale and clinical utility of nonpharmacologic therapies

Atrial fibrillation (AF) is the most common sustained cardiac dysrhythmia requiring therapy. Nonpharmacologic therapies for the treatment of AF, namely, catheter ablation, cardiac pacing, internal defibrillation, and dysrhythmia surgery are playing an increasingly important role in the overall management of AF. Although usually prescribed when traditional pharmacologic therapy is not effective, not tolerated, or contraindicated, these therapies are rapidly assuming a more prominent role as they mature. These modern therapies for AF, offering the promise of prevention and cure of AF, potential elimination from the sequelae of AF, and significant improvements in quality of life, are increasingly becoming more frequent in clinical practice. Further investigation is needed to determine which therapy is ideally suited for an individual patient and the impact of these varying therapies on morbidity and mortality.

Tachycardia-related cardiomyopathy: a common cause of ventricular dysfunction in patients with atrial fibrillation referred for atrioventricular ablation

OBJECTIVE

To determine the frequency of tachycardia-related cardiomyopathy in patients with atrial fibrillation and systolic dysfunction referred for atrioventricular node ablation.

PATIENTS AND METHODS

This prospective multicenter cohort study was conducted at 16 tertiary care centers. The ejection fraction was measured before and 3 and 12 months after atrioventricular node ablation. Patients with reduced systolic function (ejection fraction < or = 45%) before atrioventricular ablation were included in this study. Patients whose ejection fraction increased by at least 15 percentage points and to higher than 45% were considered to have tachycardia-related cardiomyopathy.

RESULTS

Of 63 patients with systolic dysfunction, 48 had at least 1 adequate follow-up echocardiographic study. Sixteen (25%) of the 63 had marked improvement in the ejection fraction (mean +/- SD change, 27 +/- 8 percentage points) to a value higher than 45% after ablation.

CONCLUSIONS

Tachycardia-related cardiomyopathy is common in patients with atrial fibrillation and systolic dysfunction referred for atrioventricular node ablation. This diagnosis should be considered in all patients in whom systolic dysfunction occurs subsequent to or concomitant with onset of atrial fibrillation.

Clinical outcomes after ablation and pacing therapy for atrial fibrillation : a meta-analysis

BACKGROUND

Radiofrequency ablation of the atrioventricular node and permanent pacing are used for symptomatic relief in patients with medically refractory atrial fibrillation. In this study, meta-analysis was used to clarify clinical outcomes and survival after ablation and pacing therapy using data from the published literature.

METHODS AND RESULTS

We used 21 studies with a total of 1181 patients in the meta-analysis. All patients had medically refractory atrial tachyarrhythmias, primarily atrial fibrillation (97%). Nineteen measures of clinical outcome, encompassing quality of life, ventricular function, exercise duration, and healthcare use, were derived from the studies. The meta-analysis demonstrated significant improvement after ablation and pacing therapy in all outcome measures except fractional shortening, which demonstrated a trend toward improvement (P=0.08). Ejection fraction did show significant improvement (P<0.001). The calculated 1-year total and sudden death mortality rates after ablation and pacing therapy were 6.3% and 2.0%, respectively.

CONCLUSIONS

Ablation and pacing therapy improves a broad range of clinical outcomes for patients with medically refractory atrial fibrillation. The calculated 1-year mortality rates after this therapy are low and comparable with medical therapy.

Permanent, direct His-bundle pacing: a novel approach to cardiac pacing in patients with normal His-Purkinje activation

BACKGROUND

Direct His-bundle pacing (DHBP) produces synchronous ventricular depolarization and improved cardiac function relative to apical pacing. Although it has been performed transiently in the electrophysiology laboratory and persistently in open-chested canines, permanent DHBP in humans has not been achieved.

METHODS AND RESULTS

A total of 18 patients aged 69+/-10 years who had a history of chronic atrial fibrillation, dilated cardiomyopathy, and normal activation (ie, QRS< or =120 ms) were screened for permanent DHBP using an electrophysiology catheter. In 14 patients, the His bundle could be reliably stimulated. Of these 14, permanent DHBP using a fixed screw-in lead was successful in 12 patients. Radiofrequency atrioventricular node ablation was performed in patients exhibiting a fast ventricular response. All patients received single-chamber rate-responsive pacemakers. Acute pacing thresholds were 2.4+/-1.0 V at a pulse duration of 0.5 ms. Lead complications included exit block requiring reoperative adjustment and gross lead dislodgment. Echocardiographic improvement in heart function was shown by reductions in the left ventricular end-diastolic dimension from 59+/-8 to 52+/-6 mm (P</=0.01) and in the end-systolic dimension from 51+/-10 to 43+/-8 mm (P<0.01), with an accompanying increase in fractional shortening from 14+/-7% to 20+/-10% (P=0.05). The left ventricular ejection fraction improved from 20+/-9% to 31+/-11% (P<0. 01), and the cardiothoracic ratio decreased from 0.61+/-0.06 to 0. 57+/-0.07 (P<0.01). Despite DHBP, 2 patients died at 8 and 36 months. Conclusions-Permanent DHBP is feasible in select patients who have chronic atrial fibrillation and dilated cardiomyopathy. Long-term, DHBP results in a reduction of left ventricular dimensions and improved cardiac function.

Pacing for patients with congestive heart failure and dilated cardiomyopathy

Considerable evidence has now accumulated that permanent pacing may provide symptomatic benefit for at least some patients with CHF. Recently, the most promising results with left ventricular or biventricular pacing have been obtained. The data for improvement in survival with pacing is less compelling. The mortality of CHF associated with systolic dysfunction of the left ventricle remains high and arrhythmic deaths are frequent. Clinical trials such as the Sudden Cardiac Death Heart Failure Trial (SCD-HeFT) are currently underway to investigate the role of the implantable defibrillator in patients with heart failure. The development and general availability of ICDs with biventricular pacing capability may play an increasingly important role in the overall therapeutic plan for this group of patients to allow for optimization of functional status with pacing and protection from sudden cardiac death with defibrillation.

The AFFIRM trial: main trial and substudies-what can We expect?

The clinical categorization of patients who present with atrial fibrillation is a major determinant of the most appropriate strategy for rhythm management. For those patients with recurrent atrial fibrillation that has not become permanent the two available strategies are rhythm control and anticoagulation or rate control and anticoagulation. There is no clear evidence that one of these strategies is superior to the other. In the AFFIRM trial these two strategies are being compared to one another in a randomized trial. Patients are randomly assigned to one of the two strategies and the treating physician then uses therapies from an approved menu as clinically indicated. Both pharmacologic and nonpharmacologic therapies are used. An overview of the main study protocol is presented. The primary endpoint is total mortality but there are a number of clinically important secondary endpoints. Several substudies will explore important ancillary questions and some of these are also described. At this time over 3000 patients have been enrolled and the planned enrollment is 4300. Enrollment will end late in 1999 and the last patient enrolled will be followed for two years. The AFFIRM Trial will provide important information concerning the management of atrial fibrillation in a large portion of the patients who have this arrhythmia.

Pacing in congestive heart failure

Despite the major advances in medical drug therapy, heart failure remains a syndrome associated with high mortality and morbidity. Biventricular or left ventricular (LV) short atrioventricular (AV) delay pacing is being tested in congestive heart failure patients with left bundle branch block. The aim is to resynchronise the dyscoordinate LV contraction. A number of studies are underway, but it is clear that while some patients respond remarkably, this is highly variable. Accurate identification of patients likely to benefit will be crucial. The mechanism of benefit is unclear. A greater understanding of the physiological consequences of pacing will be necessary to accurately identify these patients.

Catheter-ablative techniques for the treatment of atrial fibrillation

Atrial fibrillation is the most commonly encountered arrhythmia in clinical practice and is associated with significant morbidity and mortality. Pharmacologic therapy, although useful for rate control, has proven much less effective in the long term maintenance of sinus rhythm. The utility of implantable atrial defibrillators or pacing to prevent atrial fibrillation remains largely untested. This article describes four catheter-based therapies for atrial fibrillation: His ablation, atrioventricular nodal modification, the Maze procedure, and the ablation of pulmonary vein foci which initiate the arrhythmia. Whereas the first two procedures are largely palliative and recommended for patients with symptomatic, drug-refractory atrial fibrillation, the latter two offer the potential for a curative intervention.

Radiofrequency ablation of atrioventricular junction and pacemaker implantation versus modulation of atrioventricular conduction in drug refractory atrial fibrillation

Modulation of atrioventricular (AV) node conduction and radiofrequency ablation of AV junction are alternative approaches to control ventricular rate in drug refractory atrial fibrillation (AF). In 2 centers, 120 patients were treated either with AV junction ablation (center 1, group 1, 60 patients [30 men, aged 64 +/- 11 years], paroxysmal AF in 24 patients) or with modulation (group 2, 60 patients [32 men, aged 58 +/- 12 years], paroxysmal AF in 43 patients). In group 1, complete AV block was achieved in all patients. In group 2, the procedure was performed in sinus rhythm (30 patients), prolonging the Wenckebach cycle length from 328 +/- 85 to 466 +/- 80 ms (p <0.01) or during AF (30 patients), decreasing ventricular rate from 178 +/- 35 to 96 +/- 35 beats/min (p <0.01), and to <100 beats/min in 17 patients (61%). Complete AV block was induced in 9 of 60 patients (15%). In groups 1 and 2, at a follow-up of 27 +/- 7 and 26 +/- 6 months, there were 2 deaths (1 cardiac, 1 sudden death) and 1 death for end-stage heart failure, respectively. Hospital readmissions decreased from 3.2 to 0.2 and from 4.2 to 0.2/year; late AF recurrences at of >120 beats/min were documented in 6% and 12%, respectively. Symptom score analysis including effort and rest dyspnea, exercise intolerance, weakness, and palpitation showed a significant improvement in both treatment groups, when acutely effective, in patients with paroxysmal and/or chronic AF. In conclusion, ablation of the AV junction shows a higher acute success rate compared with modulation of the AV node conduction in patients with drug refractory AF. Depending on the acute success, both approaches therefore were similarly effective in achieving long-term ventricular rate control and symptom score improvement.