Impact of acute atrial fibrillation termination and prolongation of atrial fibrillation cycle length on the outcome of ablation of persistent atrial fibrillation: A substudy of the STAR AF II trial.

BACKGROUND: Controversy exists about the impact of acute atrial fibrillation (AF) termination and prolongation of atrial fibrillation cycle length (AFCL) during ablation on long-term procedural outcome. OBJECTIVE: The purpose of this study was to analyze the influence of AF termination and AFCL prolongation on freedom from AF in patients from the STAR AF II (Substrate and Trigger Ablation for Reduction of Atrial Fibrillation Trial-Part II) trial. METHODS: Acute changes in AFCL and AF termination were collected during the index procedure of the STAR AF II trial and compared to recurrence of AF at 18 months. Recurrence was assessed by ECG, Holter (3, 6, 9, 12, 18 months), and weekly transtelephonic ECG monitoring for 18 months. RESULTS: AF terminated in 8% of the pulmonary vein isolation (PVI) arm, 45% in the PVI+complex electrogram arm, and 22% of the PVI+linear ablation arm (P <.001), but freedom from AF did not differ among the 3 groups (P = .15). Freedom from AF was significantly higher in patients who presented to the laboratory in sinus rhythm (SR) compared to those without AF termination (63% vs 44%, P = .007). Patients with AF termination had an intermediate outcome (53%) that was not significantly different from those in SR (P = .84) or those who did not terminate (P = .08). AF termination was a univariable predictor of success (P = .007), but by multivariable analysis, presence of early SR was the strongest predictor of success (hazard ratio 0.67, P = .004). Prolongation of AFCL was not predictive of 18-month freedom from AF. CONCLUSION: Acute AF termination and prolongation in AFCL did not consistently predict 18-month freedom from AF. Presence of SR before or early during the ablation was the strongest predictor of better outcome.

Treatment of macro-re-entrant atrial tachycardia based on electroanatomic mapping: identification and ablation of the mid-diastolic isthmus.

AIMS: This multicentre prospective study evaluated the ability of electroanatomic mapping (EAM) using a specific parameter setting to identify clearly the mid-diastolically activated isthmus (MDAI) and guide ablation of macro-re-entrant atrial tachycardia (MAT). METHODS AND RESULTS: Consecutive patients with MAT, different from typical isthmus-dependent atrial flutter, were enrolled. EAM was performed using a specific setting of the window of interest, calculated to identify the MDAI and guide ablation of this area. Sixty-five patients exhibiting 81 MATs (mean cycle length 308 +/- 68 ms) were considered. Thirty-two (49.2%) had previous heart surgery. In 79 of 81 morphologies (97.5%), EAM reconstructed 95.9 +/- 4.3% of the tachycardia circuit and identified the MDAI; 23 of the 79 morphologies (29.1%) were double-loop re-entry. Mapping of two morphologies was incomplete due to MAT termination after catheter bumping. In 73 of 79 mapped morphologies (92.4%), abolition of the MAT was obtained by 13.2 +/- 12.4 applications. During the 14 +/- 4 month follow-up, MAT recurred in 4 of the successfully treated patients (6.8%). CONCLUSION: EAM using a specific parameter setting proved highly effective at identifying the MDAI in MAT, even in patients with previous surgery and multiple re-entrant loops. Ablation of the MDAI yielded acute arrhythmia suppression with low rate of recurrence during follow-up.

Anatomical and electrophysiological approach to atrial fibrillation ablation: technical limitations.

OBJECTIVE: Pulmonary vein (PV) disconnection by radiofrequency (RF) catheter ablation has been reported to cure atrial fibrillation (AF). Different techniques have been proposed. The aim of this study was to evaluate the technical limitations of both anatomical and electrophysiological approaches. METHODS: A total of 110 PVs were ablated in 26 consecutive patients (23 male, 3 female, mean age 51 +/- 9.5 years) with paroxysmal (n = 19, 73%), persistent (n = 3, 12%) or permanent (n = 4, 15%) AF. Accurate reconstructions of the PV ostia were obtained using fluoroscopy, electrophysiology, and the CARTO mapping system. Electrophysiological mapping was attempted in all PVs by means of a decapolar circular catheter. RF ablation was performed in a single-blind fashion in order to anatomically create circumferential lines around each PV. Completeness of anatomically-guided, circumferential RF lesions around the PVs was established by the physician using the CARTO system, who was unaware of the decapolar circular catheter electrophysiological recordings of the PVs. If PV potentials persisted, RF delivery was targeted to the electrophysiological breakthroughs. RESULTS: All PV ostia were anatomically ablated by performing circumferential RF lesions. Among 110 PVs, 73 (66%) were fully mapped by use of circular catheters. After anatomical ablation, electrical disconnection was achieved in 44/73 PVs (60%). In the remaining 29 PVs (40%), a median of one RF pulse (mean 1.8 +/- 1.4) was necessary to achieve complete PV disconnection. Total procedure duration, fluoroscopy time, and RF delivery time were 232 +/- 29, 50 +/- 16 and 39 +/- 11 min, respectively. Pericardial effusion occurred in one patient after the procedure. After 10.5 +/- 6.4 months, 21 patients (81%) were in stable sinus rhythm and 13 of them (62%) discontinued all drugs after 6 months. Only 4 patients (15%) required two procedures. CONCLUSIONS: Electrical PV disconnection cannot be achieved in many PVs by means of a pure anatomical approach. On the other hand, electrophysiological mapping cannot be performed in many PVs owing to anatomical variations. An integrated approach might overcome these limitations.