Adenosine-guided pulmonary vein isolation versus conventional pulmonary vein isolation in patients undergoing atrial fibrillation ablation: An updated meta-analysis

Augmented wide area circumferential catheter ablation for reduction of atrial fibrillation recurrence (AWARE) trial: Design and rationale

BACKGROUND

Recurrence of atrial fibrillation (AF) after a pulmonary vein isolation procedure is often due to electrical reconnection of the pulmonary veins. Repeat ablation procedures may improve freedom from AF but are associated with increased risks and health care costs. A novel ablation strategy in which patients receive "augmented" ablation lesions has the potential to reduce the risk of AF recurrence.

OBJECTIVE

The Augmented Wide Area Circumferential Catheter Ablation for Reduction of Atrial Fibrillation Recurrence (AWARE) Trial was designed to evaluate whether an augmented wide-area circumferential antral (WACA) ablation strategy will result in fewer atrial arrhythmia recurrences in patients with symptomatic paroxysmal AF, compared with a conventional WACA strategy.

METHODS/DESIGN

The AWARE trial was a multicenter, prospective, randomized, open, blinded endpoint trial that has completed recruitment (ClinicalTrials.gov NCT02150902). Patients were randomly assigned (1:1) to either the control arm (single WACAlesion set) or the interventional arm (augmented- double WACA lesion set performed after the initial WACA). The primary outcome was atrial tachyarrhythmia (AA; atrial tachycardia [AT], atrial flutter [AFl] or AF) recurrence between days 91 and 365 post catheter ablation. Patient follow-up included 14-day continuous ambulatory ECG monitoring at 3, 6, and 12 months after catheter ablation. Three questionnaires were administered during the trial- the EuroQuol-5D (EQ-5D) quality of life scale, the Canadian Cardiovascular Society Severity of Atrial Fibrillation scale, and a patient satisfaction scale.

DISCUSSION

The AWARE trial was designed to evaluate whether a novel approach to catheter ablation reduced the risk of AA recurrence in patients with symptomatic paroxysmal AF.

[Catheter ablation of atrial fibrillation : Status quo]

Catheter ablation of atrial fibrillation (AF) is a standard part of treatment with respect to rhythm control. In this article, the authors provide a review of the state-of-the-art knowledge of AF catheter ablation including current indications, possible energy forms, procedural methods and endpoints as well as follow-up and further anticoagulation.

Long-term outcome of paroxysmal atrial fibrillation catheter ablation with and without pulmonary vein dormant conduction after adenosine challenge

OBJECTIVES

The prognostic significance of adenosine-mediated pulmonary vein (PV) dormant conduction is unclear. We prospectively followed patients with adenosine-mediated PV reconduction with a subsequent repeated ablation until there was no reconduction inducible with patients without reconduction after PV isolation.

METHOD AND RESULTS

Consecutive patients (n=179) with paroxysmal atrial fibrillation (AF) without prior catheter ablation (CA) were enlisted in the study. We used a point-by-point CA and general anesthesia in all patients. Twenty minutes after PV isolation we administered adenosine in a dose sufficient to produce an atrioventricular block. If a dormant conduction was present (n=54) we performed additional ablation until there was no adenosine mediated reconduction inducible. During 36 months of follow-up, all patients were examined for eight 7-day ECG recordings. There was no difference in arrhythmia recurrence rate between patients with and without dormant conduction (29.6 vs. 24.8% at 12 months, P=0.500; 31.5 vs. 30.4% at 36 months, P=1.000), for any echocardiographic parameter or any parameter of the ablation procedure.

CONCLUSION

The patients with dormant conduction after adenosine during catheter ablation of paroxysmal atrial fibrillation with complete elimination of the dormant conduction by additional extensive ablation have the same outcome in the long term as patients without a dormant conduction.

Adenosine as a Marker and Mediator of Cardiovascular Homeostasis: A Translational Perspective

Adenosine, a purine nucleoside, is produced broadly and implicated in the homeostasis of many cells and tissues. It signals predominantly via 4 purinergic adenosine receptors (ADORs) - ADORA1, ADORA2A, ADORA2B and ADOosine signaling, both through design as specific ADOR agonists and antagonists and as offtarget effects of existing anti-platelet medications. Despite this, adenosine has yet to be firmly established as either a therapeutic or a prognostic tool in clinical medicine to date. Herein, we provide a bench-to-bedside review of adenosine biology, highlighting the key considerations for further translational development of this proRA3 in addition to non-ADOR mediated effects. Through these signaling mechanisms, adenosine exerts effects on numerous cell types crucial to maintaining vascular homeostasis, especially following vascular injury. Both in vitro and in vivo models have provided considerable insights into adenosine signaling and identified targets for therapeutic intervention. Numerous pharmacologic agents have been developed that modulate adenmising molecule.

Adenosine triphosphate/adenosine guided pulmonary vein isolation does not improve the outcomes of ablation: a meta-analysis of randomized controlled trials

BACKGROUND

Successful pulmonary vein isolation (PVI) is the most reliable predictor of success after ablation in patients with atrial fibrillation (AF). Adenosine triphosphate (ATP) unmasks the dormant conduction and can be used to improve the effectiveness of PVI. The impact of ATP guided PVI on clinical outcomes is discordant in various randomized controlled trials (RCTs).

OBJECTIVES

To delineate the incremental benefit of ATP during PVI in patients with AF through a meta-analysis.

METHODS AND RESULTS

Database searches through January 2017 identified 5 RCTs (enrolling 2839 patients) comparing ATP guided PVI versus standard PVI (non-ATP). Four trials exclusively studied paroxysmal AF while one trial included both paroxysmal and non-paroxysmal AF patients. Baseline characteristics, dose of adenosine and ablation strategies were clearly identified among all the trials. The risk ratio (RR) for AF episodes lasting >30 s after 3-month blanking period was calculated with random effects meta-analysis and showed no difference at a median follow up of 12 months [RR: 1.02, 95 % Confidence interval (CI): 0.85 to 1.25; p = 0.82]. Similarly, the number of repeat ablation was similar in both groups [RR: 1.02, 95 % CI: 0.63, 1.56; p = 0.98].

CONCLUSIONS

ATP guided PVI does not decrease the recurrence of AF or the need for repeat ablation at 12 months.