Determining the Optimal Dose of Adenosine for Unmasking Dormant Pulmonary Vein Conduction Following Atrial Fibrillation Ablation: Electrophysiological and Hemodynamic Assessment. DORMANT-AF Study.

INTRODUCTION: ELECTROPHYSIOLOGICAL AND HEMODYNAMIC ASSESSMENT. DORMANT-AF STUDY: The significance of adenosine induced dormant pulmonary vein (PV) conduction in atrial fibrillation (AF) ablation remains controversial. The optimal dose of adenosine to determine dormant PV conduction is yet to be systematically explored. METHODS AND RESULTS: ELECTROPHYSIOLOGICAL AND HEMODYNAMIC ASSESSMENT. DORMANT-AF STUDY: Consecutive patients undergoing index AF ablation received 3 adenosine doses (12, 18, and 24 mg) in a randomized blinded order, immediately after pulmonary vein isolation (PVI). Electrophysiological (PR prolongation, AV block (AVB) and PV reconnection) and hemodynamic (BP) parameters were measured. A total, 339 doses (113/dose) assessed 191 PVs in 50 patients (66% male, 72% PAF, 52% hypertensive). Dormant PV conduction occurred in 28% of patients (16.5% [32] of PVs). All cases were associated with AVB (AVB: PV reconnection vs. no PV reconnection 100% vs. 83%, P = 0.007). AVB occurred more frequently at 24 mg versus 12 mg (92% vs. 82%, P = 0.019) but not versus 18 mg (91%, P = 0.62). AVB duration progressed between 12 mg (12.0 ± 8.9 seconds), 18 mg (16.1 ± 9.1 seconds, P = 0.001), and 24 mg (19.0 ± 9.3 seconds, P < 0.001) doses. MBP fell further at 24 mg (ΔMBP: 27 ± 12 mmHg) and 18 mg (26 ± 13 mmHg) doses compared to 12 mg (22 ± 10 mmHg vs., P < 0.001). A significant reduction in AVB in patients >110 kg (65% vs. 91% in 70-110 kg group, P < 0.001) in response to adenosine was seen. CONCLUSION: ELECTROPHYSIOLOGICAL AND HEMODYNAMIC ASSESSMENT. DORMANT-AF STUDY: An adenosine dose producing AVB is required to unmask dormant PV conduction. AVB is significantly reduced in patients >110 kg. Weight and dosing variability may in part explain the conflicting results of studies evaluating the clinical utility of adenosine in PVI.

Pulmonary vein activity does not predict the outcome of catheter ablation for persistent atrial fibrillation: A long-term multicenter prospective study.

BACKGROUND: Pulmonary vein (PV) isolation (PVI) remains the cornerstone of catheter ablation (CA) in persistent atrial fibrillation (AF) (PeAF), although less successful than for paroxysmal AF. Whether rapid or fibrillatory (PV AF) PV firing may identify patients with PeAF more likely to benefit from a PV-based ablation approach is unclear. OBJECTIVE: The purpose of this study was to determine the relationship between the PV cycle length (PVCL) and the PV AF outcome after CA. METHODS: Before ablation, the multipolar catheter was placed in each PV and the left atrial appendage (LAA) for 100 consecutive cycles. The presence of PV AF, the average PVCL of all 4 veins (PV4VAverage), the fastest vein average (PVFVAverage), the fastest cycle length (PVFast) both individually and relative to the average LAA cycle length were calculated. The ablation strategy included PVI and posterior wall isolation with a minimum of 12 months follow-up. RESULTS: A total of 123 patients underwent CA (age 62 ± 9.1 years; CHA2DS2-VASC score 1.6 ± 1.1; left ventricular ejection fraction 48% ± 13%; left atrial area 31 ± 8.7 cm2; AF duration 16 ± 17 months). PVI was achieved in 100% of patients. Multiprocedure success (MPS; freedom from AF/atrial tachycardia episodes lasting >30 seconds) was achieved in 76% of patients at 24 ± 8.1 months of follow-up after 1.2 ± 0.4 procedures. PV activity was not associated with MPS either absolutely (PV4VAverage [MPS no vs yes: 178 ± 27 ms vs 177 ± 24 ms; P = .92], PVFVAverage [P = .69], or PVFast [P = .82]) or as a ratio relative to the LAA cycle length (PV4VAverage/LAA 1.05 ± 0.11 vs 1.06 ± 0.21; P = .87). The presence of PV AF (31% vs 47%; P = .13) did not predict MPS. CONCLUSION: The rapidity of PV firing or presence of fibrillation within the PV was not predictive of outcome of CA for PeAF. PV activity does not identify patients most likely to benefit from a PV-based ablation strategy.