Value of adenosine test to reveal dormant conduction or adenosine-induced atrial fibrillation after pulmonary vein isolation

Electrophysiological Findings in Patients with Early Recurrence During Blanking Period Following Atrial Fibrillation Ablation

BACKGROUND

Atrial tachyarrhythmias (ATa) during the blanking period (BP) may predict late recurrences of arrhythmia. This study evaluates the outcomes of redo procedures during BP in patients with early recurrence after catheter ablation (CA) for atrial fibrillation (AF).

METHODS

This retrospective study included patients undergoing redo procedures within 3 months of their initial CA due to severely symptomatic ATa episodes. Baseline data, medications, and procedural details of initial and redo CAs were analyzed from medical records.

RESULTS

Among 64 patients, 37 underwent cryoballoon (CB) and 27 underwent radiofrequency (RF) ablation. In the CB group, additional low-voltage areas beyond pulmonary veins, cavo tricuspid isthmus (CTI)-dependent flutter (27%), and left atrial reentrant tachycardia (30%) were common. Pulmonary vein reconnection was observed in 43%. In the RF group, left atrial macro/micro reentrant tachycardia (63%), CTI-dependent flutter (22%), and pulmonary vein reconnection (33%) were common causes of symptomatic ATas. After 12 months, 85.9% of patients (n = 55) were free from ATa following redo procedures.

CONCLUSION

Symptomatic ATas during BP often stem from substrates unrelated to the initial ablation, particularly in CB and pulmonary vein isolation-only RF groups. These findings suggest the need to reevaluate BP definitions, as select patients may benefit from early redo procedures to enhance long-term outcomes.

Validation Strategy for Pulmonary Vein Isolation in Patients With Paroxysmal Atrial Fibrillation in Long-Term Maintaining Sinus Rhythm: A Randomized Controlled Study

Background: Data comparing the outcomes of loose versus rigorous validation strategies for pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (PAF) are limited. We aimed to prospectively assess the effectiveness of loose versus rigorous validation for PVI in patients with PAF with a maintained sinus rhythm. Methods: Patients (n = 117) with PAF were randomized to receive either loose validation (n = 59) or rigorous validation (n = 58) after PVI. The presence of dormant conduction in loose validation was assessed only by adenosine administration followed by isoproterenol infusion. The complete absence of pulmonary vein (PV) potentials in rigorous validation was confirmed by the combination of the Lasso catheter with isoproterenol plus adenosine. Dormant conduction, revealed by validation after PVI, was ablated until all reconnections were eliminated. Results: The procedure time in the rigorous validation group was greater than that in the loose validation group (161.3 ± 52.7 min vs. 142.5 ± 37.6 min, p=0.03, respectively). After successful PVI, the detection of dormant PV reconnections in the rigorous validation group was significantly greater than that in the loose validation group (69.0% vs. 37.3%, p=0.001). However, after reisolation of the sites of dormant PV conduction, the postablation recurrence rates in 1.3 years were similar between the groups (79.2% vs. 83.6%, p=0.67). Conclusion: Rigorous validation can reveal dormant conduction in more than two-thirds of patients with PAF undergoing PVI. However, rigorous validation and additional ablation of the resulting connections do not improve long-term outcomes when a protocol that includes electrophysiological confirmation and pharmacological validation is used.

Adenosine plasma level in patients with paroxysmal or persistent atrial fibrillation and normal heart during ablation procedure and/or cardioversion

The mechanism of atrial fibrillation (AF) in patients with normal heart remains unclear. While exogenous adenosine can trigger AF, nothing is known about the behavior of endogenous adenosine plasma level (APL) at the onset of AF and during ablation procedure. Ninety-one patients (68 with paroxysmal AF: 40 males, 66 ± 16 years; 23 with persistent AF: 14 males, 69 ± 11 years) and 18 controls were included. Among paroxysmal patients: i) medical therapy alone was performed in 45 cases and ablation procedure in 23. AF was spontaneously resolutive in 6 cases; ii) 23 underwent ablation procedure and blood was collected simultaneously in a brachial vein and in the left atrium; 17 were spontaneously in sinus rhythm while 6 were in sinus rhythm after direct current cardioversion. Among persistent patients: i) in 17 patients, blood samples were collected in a brachial vein before and after direct current cardioversion; ii) in 6 patients, blood samples were collected simultaneously in a brachial vein and in left atrium before and after cardioversion during ablation procedure. CV-APL was higher in patients with persistent AF vs patients with paroxysmal AF (median [range]: 0.9[0.6-1.1] vs 0.7[0.4-1.1] μM; p < 0.001). In patients with paroxysmal AF, LA-APL increased during the AF episode (0.95[0.85-1.4] vs 2.7[1.5-7] μM; p = 0.03) and normalized in sinus rhythm after DCCV. In patients with persistent AF, LA-APL was higher than CV-APL (1.2[0.7-1.8] vs 0.9[0.6-1.1] μM; p < 0.001), and both normalized in sinus rhythm (CV-APL: 0.8[0.6-1.1] vs 0.75[0.4-1] μM; p = 0.03), (LA-APL: 1.95[1.3-3] vs 1[0.5-1.15] μM; p = 0.03). The occurrence of AF is associated with a strong increase of APL in the atrium. The cause of this increase needs further investigations.