A mesh-type flexible tip catheter vs a contact force catheter for catheter ablation of atrial fibrillation: A prospective nonrandomized 1:1 matched study

Late recurrence of atrial fibrillation 5 years after catheter ablation: predictors and outcome

AIMS

Atrial fibrillation (AF) is a chronic progressive disease that continuously recurs even after successful AF catheter ablation (AFCA). We explored the mechanism of long-term recurrence by comparing patient characteristics and redo-ablation findings.

METHODS AND RESULTS

Among the 4248 patients who underwent a de novo AFCA and protocol-based rhythm follow-up at a single centre, we enrolled 1417 patients [71.7% male, aged 60.0 (52.0-67.0) years, 57.9% paroxysmal AF] who experienced clinical recurrences (CRs), and divided them according to the period of recurrence: within one year (n = 645), 1-2 years (n = 339), 2-5 years (n = 308), and after 5 years (CR>5 yr, n = 125). We also compared the redo-mapping and ablation outcomes of 198 patients. In patients with CR>5 yr, the proportion of paroxysmal AF was higher (P = 0.031); however, the left atrial (LA) volume (quantified by computed tomography, P = 0.003), LA voltage (P = 0.003), frequency of early recurrence (P < 0.001), and use of post-procedure anti-arrhythmic drugs (P < 0.001) were lower. A CR>5 yr was independently associated with a low LA volume [odds ratio (OR) 0.99 (0.98-1.00), P = 0.035], low LA voltage [OR 0.61 (0.38-0.94), P = 0.032], and lower early recurrence [OR 0.40 (0.23-0.67), P < 0.001]. Extra-pulmonary vein triggers during repeat procedures were significantly greater in patients with a CR>5 yr, despite no difference in the de novo protocol (P for trend 0.003). The rhythm outcomes of repeat ablation procedures did not differ according to the timing of the CR (log-rank P = 0.330).

CONCLUSIONS

Patients with a later CR exhibited a smaller LA volume, lower LA voltage, and higher extra-pulmonary vein triggers during the repeat procedure, suggesting AF progression.

Detailed investigation of the lesion formation with a novel contact force sensing catheter with a mesh-shaped irrigation tip

Background

Recently, a novel contact force (CF) sensing catheter with mesh-shaped irrigation tip (TactiFlex SE, Abbott) was invented and is expected to be useful for safe and effective radiofrequency ablation. However, this catheter's detailed characteristics of the lesion formation are unknown.

Methods

With an in vitro model, TactiFlex SE and its predecessor, FlexAbility SE, were used. A cross-sectional analysis of 60 s lesions (combination of various energy power settings [30, 40, and 50 W], and CFs [10, 30, and 50 g]) and longitudinal analysis (combination of various powers [40 or 50 W], CFs [10, 30, and 50 g] and ablation times [10, 20, 30, 40, 50, and 60 s]) of both catheters were analyzed and compared.

Results

One hundred eighty RF lesions were created in protocol 1 and 300 in protocol 2. The lesion formation, impedance changes, and steam pops characteristics were similar between the two catheters. Higher CFs were related to higher incidences of steam pops. A nonlinear, time-dependent increase in the lesion depth and diameter was observed for all power and CF settings, and linear, positive correlations between the RF delivery time and lesion volume were observed for all power settings. Compared with 40 W, a 50 W ablation created greater lesions. Longer durations with higher CF settings had a higher steam pop incidence.

Conclusions

The lesion formation and incidence of steam pops with TactiFlex SE and FlexAbility SE were similar. A 40 or 50 W ablation with careful CF control not to exceed 30 g in addition to monitoring impedance drops was required to safely create transmural lesions.

Efficacy and Safety of High-Power Short-Duration Radiofrequency Catheter Ablation of Atrial Fibrillation

Introduction: Whereas, high-power short-duration (HPSD) radiofrequency (RF) ablation is generally used in atrial fibrillation (AF) catheter ablation (CA), its efficacy, safety, and influence on autonomic function have not been well established in a large population. This study compared HPSD-AFCA and conventional power (ConvP)-AFCA in propensity score matched-population.

Methods: In 3,045 consecutive patients who underwent AFCA, this study included 1,260 patients (73.9% male, 59 ± 10 years old, 58.2% paroxysmal type) after propensity score matching: 315 in 50~60W HPSD group vs. 945 in the ConvP group. This study investigated the procedural factors, complication rate, rhythm status, and 3-month heart rate variability (HRV) between the two groups and subgroups.

Results: Procedure time was considerably short in the HPSD group (135 min in HPSD vs. 181 min in ConvP, p < 0.001) compared to ConvP group, but there was no significant difference in the complication rate (2.9% in HPSD vs. 3.7% in ConvP, p = 0.477) and the 3-month HRV between the two groups. At the one-year follow-up, there was no significant difference in rhythm outcomes between the two groups (Overall, Log-rank p = 0.885; anti-arrhythmic drug free, Log-rank p = 0.673). These efficacy and safety outcomes were consistently similar irrespective of the AF type or ablation lesion set. The Cox regression analysis showed that the left atrium volume index estimated by computed tomography (HR 1.01 [1.00–1.02]), p = 0.003) and extra-pulmonary vein triggers (HR 1.59 [1.03–2.44], p = 0.036) were independently associated with one-year clinical recurrence, whereas the HPSD ablation was not (HR 1.03 [0.73–1.44], p = 0.887).

Conclusion: HPSD-AFCA notably reduced the procedure time with similar rhythm outcomes, complication rate, and influence on autonomic function as ConvP-AFCA, irrespective of the AF type or ablation lesion set.