Role of adenosine after antral pulmonary vein isolation of paroxysmal atrial fibrillation: A randomized controlled trial.

BACKGROUND: Adenosine can reveal dormant pulmonary vein (PV) conduction after PV isolation (PVI) in patients with paroxysmal atrial fibrillation (AF). However, the impact of elimination of adenosine-provoked dormant PV conduction after PVI has not been formally evaluated. OBJECTIVE: The purpose of this study was to determine whether ablation of PV reconnections unmasked by adenosine improves outcomes. METHODS: Patients with paroxysmal AF (n = 129) were randomized to receive either adenosine (n = 61) or no adenosine (n = 68) after PVI. Dormant conduction revealed by adenosine after PVI was ablated until all adenosine-mediated reconnections were eliminated. Thereafter, both groups received isoproterenol. RESULTS: Acute reconnection was seen in 23 patients (37%) in the adenosine group. There was a significant difference between the number of PVs reconnected if patients were given adenosine >60 minutes after initial PVI compared to those who received adenosine <60 minutes after initial PVI (3/32 [9.4%] vs 24/32 [75%], P <.0001). Patients who did not receive adenosine had more PV reconnections after isoproterenol infusion compared to patients in the adenosine group (17/68 [25.0%] vs 5/61 [8.2%], P = .018). There was no difference in the rate of AF recurrence in patients who received adenosine (24/61 [39%]) compared to control patients (23/68 [34%], log-rank P = .83). CONCLUSION: Adenosine can reveal dormant conduction in more than one-third of patients with paroxysmal AF undergoing PVI. However, adenosine administration, and additional ablation of the resultant connections, does not improve long-term outcomes compared to a protocol that includes isoproterenol infusion.

Temporal stability of the location of the esophagus in patients undergoing a repeat left atrial ablation procedure for atrial fibrillation or flutter.

BACKGROUND: The esophagus may be mobile during a left atrial (LA) ablation procedure for atrial fibrillation (AF). OBJECTIVE: The goal of the study was to determine whether the location of the esophagus is stable in patients undergoing a repeat LA ablation procedure. METHODS: Forty-two patients underwent repeat LA ablation a mean of 7 +/- 2 months after the initial procedure. Cinefluoroscopic images of the esophagus during a barium swallow were recorded and the course of the esophagus was tagged on the 3D map. The position of the esophagus at the index and repeat procedure were compared. RESULTS: At the index procedure, the esophagus was located near the left pulmonary veins (PVs) in 20 (48%), right PVs in 13 (31%), and at the mid LA in 9 (21%) patients. During the repeat procedure, the esophagus was found to be near the left PVs in 22 (52%), right PVs in 11 (26%), and at the mid LA in 9 patients (21%). In 35 of the 42 patients (83%), there was no change in the esophageal location, and in the remaining seven patients (17%), its position had shifted by > or =1 cm (range 1.0-4.0 cm). CONCLUSIONS: In more than 80% of patients presenting for a repeat LA ablation procedure, the esophagus is in the same position relative to the PVs as during the initial procedure. Therefore, if radiofrequency ablation at a particular location was limited by the position of the esophagus, safe ablation at that site is unlikely to be feasible during a repeat procedure.

Atrial tachycardia after circumferential pulmonary vein ablation of atrial fibrillation: mechanistic insights, results of catheter ablation, and risk factors for recurrence.

OBJECTIVES: The aim of this study was to determine the mechanism of atrial tachycardia (AT) that occurs after ablation of atrial fibrillation (AF). BACKGROUND: Patients who undergo catheter ablation of AF may develop AT during follow-up. METHODS: Seventy-eight patients underwent an ablation procedure for AT after circumferential pulmonary vein ablation (CPVA) for AF. The 3-dimensional maps from the AF and AT procedures were compared to determine whether AT arose from a prior ablation line. RESULTS: A total of 155 ATs were mapped, and the mechanism was re-entry in 137 (88%) and focal in 18 (12%). The most common left atrial (LA) ablation targets were the mitral isthmus, roof, and septum. The critical isthmus in 115 of the 120 LA re-entrant ATs (96%) traversed a prior ablation line, consistent with a gap-related mechanism. Catheter ablation was successful in 66 of the 78 patients (85%). After a mean follow-up of 13 +/- 10 months, 60 of the 78 patients (77%) were free of AT/AF without antiarrhythmic medications. Re-entrant septal AT was associated with recurrence (odds ratio 7.3; 95% confidence interval 1.5 to 36; p = 0.02), whereas PV isolation during the AT procedure was associated with a favorable outcome (odds ratio 0.17; 95% confidence interval 0.04 to 0.81; p = 0.03). CONCLUSIONS: Approximately 90% of ATs after CPVA are re-entrant, and nearly all are related to gaps in prior ablation lines. These findings suggest that the prevalence of these arrhythmias may be reduced by limiting the number of linear lesions, demonstration of linear block, and pulmonary vein disconnection during the initial AF procedure.