Comparison between linear and focal ablation of complex fractionated atrial electrograms in patients with non-paroxysmal atrial fibrillation: a prospective randomized trial.

AIMS: Findings regarding efficacy of substrate modification for non-paroxysmal atrial fibrillation (AF) are inconsistent. We prospectively compared clinical outcomes of complex fractionated atrial electrogram (CFAE)-guided focal ablation (CFA) and CFAE-guided linear ablation (CLA) in patients with non-paroxysmal AF. METHODS AND RESULTS: We randomized 150 patients with non-paroxysmal AF into CFA and CLA groups in a 1:1 ratio. Complex fractionated atrial electrogram distribution was evaluated using an automated algorithm of a three-dimensional mapping system. After pulmonary vein isolation (PVI), CFAE-guided ablation was performed in the left atrium and then in the right atrium (RA). When compared with conventional CFA, CLA was performed based on conventional lines, with additional lines. Atrial fibrillation was not induced after PVI alone or with cavotricuspid isthmus ablation in 20.7% of patients. To achieve the endpoint, additional CFAE-guided RA ablation was required in 42.7% and 36.0% of patients undergoing CFA and CLA, respectively (P = 0.403). Atrial fibrillation was terminated during CFAE-guided ablation in 72.9% and 75.0% of patients undergoing CFA and CLA, respectively (P = 0.792). Termination of atrial tachycardia (AT) or non-inducibility of AF/AT was achieved in 61.3% and 68.0% of patients undergoing CFA and CLA, respectively (P = 0.393). The CLA group showed decreased 1-year freedom from AF/AT recurrence (60.0%, CFA vs. 47.3%, CLA; log rank P = 0.085), but no significant difference throughout the follow-up (22.2 ± 21.0 months) (67.1%, CFA vs. 68.9%, CLA; log rank P = 0.298). CONCLUSION: Long-term efficacy of CFAE-guided ablation was unaffected by the ablation technique in patients with non-paroxysmal AF.

Long-Term Clinical Comparison of Procedural End Points After Pulmonary Vein Isolation in Paroxysmal Atrial Fibrillation: Elimination of Nonpulmonary Vein Triggers Versus Noninducibility.

BACKGROUND: Pulmonary vein isolation (PVI) is effective for maintenance of sinus rhythm in 50% to 75% of patients with paroxysmal atrial fibrillation, and it is not uncommon for patients to require additional ablation after PVI. We prospectively evaluated the relative effectiveness of 2 post-PVI ablation strategies in paroxysmal atrial fibrillation. METHODS AND RESULTS: A total of 500 patients (mean age, 55.7±11.0 years; 74.6% male) were randomly assigned to undergo ablation by 2 different strategies after PVI: (1) elimination of non-PV triggers (group A, n=250) or (2) stepwise substrate modification including complex fractionated atrial electrogram or linear ablation until noninducibility of atrial tachyarrhythmia was achieved (group B, n=250). During a median follow-up of 26.0 months, 75 (32.2%) patients experienced at least 1 episode of recurrent atrial tachyarrhythmia after the single procedure in group A compared with 105 (43.8%) patients in group B (P value in log-rank test of Kaplan-Meier analysis: 0.012). Competing risk analysis showed that the cumulative incidence of atrial tachycardia was significantly higher in group B compared with group A (P=0.007). With the exception of total ablation time, there were no significant differences in fluoroscopic time or procedure-related complications between the 2 groups. CONCLUSIONS: Elimination of triggers as an end point of ablation in patients with paroxysmal atrial fibrillation decreased long-term recurrence of atrial tachyarrhythmia compared with a noninducibility approach achieved by additional empirical ablation. The post-PVI trigger test is thus a better end point of ablation for paroxysmal atrial fibrillation.

Atrial fibrillation cycle length as a predictor for the extent of substrate ablation.

AIMS: Atrial fibrillation (AF) cycle length (CL) has been demonstrated to be one of the predictors for termination during ablation for AF. We evaluated the AF CL gradient between right atrium (RA) and left atrium (LA) and their mean AF CL in predicting the extent of substrate ablation. METHODS AND RESULTS: One-hundred and thirty-six patients undergoing first ablation for persistent AF were studied. Stepwise ablation, sequentially in the following order: pulmonary veins (PV), LA, and RA, was performed to achieve AF termination. Stepwise ablation terminated AF in 110 patients (81%). In the AF termination group, AF was terminated by PV isolation (PVI) (Group P), PVI plus LA ablation (Group L), and PVI plus LA plus RA ablation (Group R) in 14 patients (13%), 49 patients (44%), and 47 patients (43%), respectively. Group R had much shorter mean AF CL than Group L (156 ± 18 vs. 174 ± 24 ms, P < 0.001) and mean AF CL in Group L was much shorter than Group P (174 ± 24 vs. 209 ± 36 ms, P = 0.004). The RA to LA AF CL gradient was not significantly different between left-side ablation (Group P + Group L) and additional RA ablation (Group R) (P = 0.177). Mean AF CL >180.50 ms predicted AF termination by PVI (Group P) with 79% sensitivity and 84% specificity while mean AF CL >165.25 ms predicted AF termination by left-side ablation (Group P + Group L) with 67% sensitivity and 75% specificity. After a mean follow-up of 15 ± 7 months, freedom from arrhythmia recurrence was significantly higher in left-side ablation (Group P + Group L) than additional RA ablation (Group R) (P = 0.024). CONCLUSION: Baseline mean AF CL may identify the subset of patients in whom persistent AF can be terminated by different extent of substrate ablation, which may in turn predict the chance of recurrence. However, baseline RA to LA AF CL gradient cannot predict the need for additional RA ablation.

Catheter ablation of atrial fibrillation in patients with chronic lung disease.

BACKGROUND: Chronic lung disease (CLD) is one of the important underlying diseases of atrial fibrillation (AF). The outcomes after radiofrequency catheter ablation of AF in patients with CLD have not yet been reported. We investigated the electroanatomic alterations in pulmonary veins (PVs) in CLD patients with AF and assessed their effect on the outcomes of radiofrequency catheter ablation of AF. METHOD AND RESULTS: We assessed 15 patients who had CLD and underwent radiofrequency catheter ablation of AF. CLD included chronic obstructive pulmonary disease, a tuberculosis-destroyed lung, and interstitial lung disease. For controls, we selected 60 sex-, age-, and procedure era-matched non-CLD patients who received radiofrequency catheter ablation for AF (4 controls for each CLD patient). Eight patients had chronic obstructive pulmonary disease, 6 had a tuberculosis-destroyed lung, and 1 had interstitial lung disease. PV morphology in the affected lung was altered significantly, ie, obliteration, pulling of the PVs toward the destroyed lung, or compensatory bulging of the PV antrum. These alterations were related to arrhythmogenicity in 6 (40%) of 15 patients with CLD. Non-PV foci were more common in the CLD group (4/15, 26.7%) than in the control group (3/60, 5.0%; P=0.025). All non-PV foci were located in the right atrium. The AF recurrence rate in the CLD group (26.7%, 4/15) was similar to that in the control group (18.3%, 11/60; P=0.45). CONCLUSIONS: Significant alteration of PV anatomy was related to arrhythmogenicity, and non-PV foci from the right atrium were commonly observed in the CLD group. Radiofrequency catheter ablation can be performed safely for AF in CLD patients with a comparable success rate to that in patients with normal lungs.