Report of a study group on ablate and pace therapy for paroxysmal atrial fibrillation. Barcelona Discussion Group. Working Group on Arrhythmias of the European Society of Cardiology

Long-term outcomes after radiofrequency catheter ablation of the atrioventricular node: The experience of a Portuguese tertiary center

INTRODUCTION

In patients with supraventricular arrhythmias and high ventricular rate, unresponsive to rate and rhythm control therapy or catheter ablation, atrioventricular (AV) node ablation may be performed.

OBJECTIVES

To assess long-term outcomes after AV node ablation and to analyze predictors of adverse events.

METHODS

We performed a detailed retrospective analysis of all patients who underwent AV node ablation between February 1997 and February 2019, in a single Portuguese tertiary center.

RESULTS

A total of 123 patients, mean age 69±9 years and 52% male, underwent AV node ablation. Most of them presented atrial fibrillation at baseline (65%). During a median follow-up of 8.5 years (interquartile range 3.8-11.8), patients improved heart failure (HF) functional class (NYHA class III-IV 46% versus 13%, p=0.001), and there were reductions in hospitalizations due to HF (0.98±1.3 versus 0.28±0.8, p=0.001) and emergency department (ED) visits (1.1±1 versus 0.17±0.7, p=0.0001). There were no device-related complications. Despite permanent pacemaker stimulation, left ventricular ejection fraction did not worsen (47±13% vs. 47%±12, p=0.63). Twenty-eight patients died (23%). The number of ED visits due to HF before AV node ablation was an independent predictor of the composite adverse outcome (OR 1.8, 95% CI 1.24-2.61, p=0.002).

CONCLUSIONS

Despite pacemaker dependency, the clinical benefit of AV node ablation persisted at long-term follow-up. The number of ED visits due to HF before AV node ablation was an independent predictor of the composite adverse outcome. AV node ablation should probably be considered earlier in the treatment of patients with supraventricular arrhythmias and HF, especially in cases that are unsuitable for selective ablation of the specific arrhythmia.

An approach to ablate and pace:AV junction ablation and pacemaker implantation performed concurrently from the same venous access site

BACKGROUND

Atrioventricular junction (AVJ) ablation combined with permanent pacemaker implantation (the "ablate and pace" approach) remains an acceptable alternative treatment strategy for symptomatic, drug-refractory atrial fibrillation (AF) with rapid ventricular response. This case series describes the feasibility and safety of catheter ablation of the AVJ via a superior vena caval approach performed during concurrent dual-chamber pacemaker implantation.

METHODS

A total of 17 consecutive patients with symptomatic, drug-refractory, paroxysmal AF underwent combined AVJ ablation and dual-chamber pacemaker implantation procedure using a left axillary venous approach. Two separate introducer sheaths were placed into the axillary vein. The first sheath was used for implantation of the pacemaker ventricular lead, which was then connected to the pulse generator. Subsequently, a standard ablation catheter was introduced through the second axillary venous sheath and used for radiofrequency (RF) ablation of the AVJ. After successful ablation, the catheter was withdrawn and the pacemaker atrial lead was advanced through that same sheath and implanted in the right atrium.

RESULTS

Catheter ablation of the AVJ was successfully achieved in all patients. The median number of RF applications required to achieve complete AV block was three (range 1-10). In one patient, AV conduction recovered within the first hour after completion of the procedure, and AVJ ablation was then performed using the conventional femoral venous approach. There were no procedural complications.

CONCLUSION

Catheter ablation of the AVJ can be performed successfully and safely via a superior vena caval approach in patients undergoing concurrent dual-chamber pacemaker implantation.

Total Atrioventricular Nodal Ablation Increases Atrial Fibrillation Burden in Patients with Paroxysmal Atrial Fibrillation Despite Continuation of Antiarrhythmic Drug Therapy

INTRODUCTION

Total atrioventricular nodal (TAVN) ablation and pacing is an accepted and safe treatment for patients with drug-refractory paroxysmal atrial fibrillation (AF). Many patients develop permanent AF within the first 6 months after TAVN ablation. This usually is ascribed to the cessation of antiarrhythmic drug therapy. We hypothesized that TAVN ablation itself creates an atrial substrate prone to AF.

METHODS AND RESULTS

Patients participating in the Atrial Pacing Periablation for Paroxysmal Atrial Fibrillation (PA3) study who remained on stable antiarrhythmic drug therapy throughout follow-up were included in this analysis. AF burden and the development of persistent AF in the preablation period were compared to two consecutive postablation periods. Echocardiographic changes also were evaluated. Twenty-two patients remained on stable drug therapy (9 men and 13 women, age 59 +/- 3 years). One patient developed persistent AF preablation compared to 10 postablation (P < 0.05). AF burden preablation was 3.0 +/- 1.2 hours/day and increased to 10.4 +/- 2.2 hours/day and 11.8 +/- 2.3 hours/day in the two postablation follow-up periods (P < 0.05). In patients with fractional shortening (FS) >30% prior to ablation, FS decreased significantly from 39.4% +/- 1.3% to 36.4%+/- 1.7% (P < 0.05). In contrast, in patients with a FS < or =30% prior to ablation, FS increased from 27% +/- 0.8% to 33.6 +/- 1.7% (P < 0.05).

CONCLUSION

TAVN ablation increases AF burden and facilitates the development of persistent AF in patients with paroxysmal AF despite the continuation of antiarrhythmic drugs. Loss of AV and/or interventricular synchrony may lead to altered cardiac hemodynamics resulting in atrial stretch and increasing AF burden.

Sick sinus syndrome

Sinus-node dysfunction is common in the elderly and, in most cases, does not cause any symptoms. Despite the high number of laboratory investigations, most diagnoses of sinus-node dysfunction are made by 12-lead electrocardiography, which shows severe sinus bradycardia, sinus arrest, or sinoatrial block. Continuous electrocardiographic monitoring, exercise testing, and electrophysiologic investigations (including pharmacologic interventions to cause complete autonomic blockade) are sometimes useful in detecting transient or latent sinus-node abnormalities. The term sick sinus syndrome should be reserved for patients with symptomatic sinus-node dysfunction. Sick sinus syndrome has a protean presentation with variable degrees of clinical severity. Symptoms are often intermittent, changeable, and unpredictable. Because these symptoms can be observed in several other diseases, none are specific to sick sinus syndrome. Owing to the nonspecific nature of its symptoms, sick sinus syndrome can be diagnosed only when clear electrocardiographic signs corroborate symptoms. In the absence of a demonstrable link between signs and symptoms, a diagnosis can be presumed only when signs of severe sinus dysfunction are present and when every other possible cause of symptoms has been excluded carefully. Sinus-node dysfunction frequently is associated with diseases of the autonomic nervous system, and autonomic reflexes play a major role in the genesis of syncope. Survival does not seem to be affected by sick sinus syndrome. Atrioventricular block, chronic atrial fibrillation, and systemic embolism are major pathologic conditions that affect the outcome of the syndrome. Treatment should be aimed at controlling morbidity and relieving symptoms. Cardiac pacing is the most powerful therapy; physiologic pacing (atrial or dual-chamber) has been shown definitively to be superior to ventricular pacing.

Ablate and pace: palliating the symptoms?

Atrioventricular (AV) junction ablation (producing AV block) followed by pacemaker implantation is the most common nonpharmacologic treatment for patients affected by atrial fibrillation (AF) not controlled by antiarrhythmic drugs. In expert hands, the efficacy of producing complete AV block is usually >95% if a sequential right- and left-side approach is used; regression of AV block late after ablation (which requires a second procedure on a different day) occurs in <5% of cases. The clinical efficacy of ablate and pace therapy in controlling arrhythmic symptoms and improving overall quality of life is well established for patients with paroxysmal AF, although not yet for patients with persistent and permanent AF, owing to the lack of sufficient clinical studies. Ablation and pacing is clinically unsuccessful in a minority of cases. There have been little data available on long-term effects of this treatment on cardiac performance, morbidity, and survival. Although concern has arisen from some case reports, no evidence of adverse effect has ever been shown in controlled trials. Ablation and pacing does not seem to increase thromboembolic risk. We estimate that in Europe, about 396,000 patients with paroxysmal AF not controlled by drug therapy could therefore be candidates for ablate and pace therapy. Permanent forms of AF are even more frequent, but it is unknown how many are refractory to drug therapy. The recommended pacing mode is DDDR with mode switching for paroxysmal/persistent AF and VVIR for permanent AF.