Catheter ablation of atrial fibrillation: Radiofrequency catheter ablation for redo procedures after cryoablation

Three-dimensional transesophageal echocardiographic evaluation of pulmonary vein anatomy prior to cryoablation: validation with cardiac CT scan

BACKGROUND

Anatomical characteristics of the left atrium and the pulmonary veins (PVs) may be relevant to the success rate of cryoballoon (CB)-ablation for atrial fibrillation (AF). Cardiac computed tomography (CCT) is considered as the gold standard for preablation imaging. Recently, three-dimensional transesophageal echocardiography (3DTOE) has been proposed for preprocedural assessment of cardiac structures relevant to CB-ablation. The accuracy of 3DTOE has not been validated by other imaging modalities.

OBJECTIVE

We prospectively evaluated the feasibility and the accuracy of 3DTOE imaging for the assessment of left atrial and PV structures prior to pulmonary vein isolation (PVI). In addition, CCT was used to validate the measurements obtained with 3DTOE.

METHODS

PV anatomy of 67 patients (59.7% men, mean age 58.5 ± 10.5 years) was assessed using both 3DTOE and CCT scan prior to PVI with the Arctic Front CB. The following parameters were measured bilaterally: PV ostium area (OA), the major and minor axis diameters of the ostium (a > b) and the width of the carina between the superior and the inferior PVs. In addition, the width of the left lateral ridge (LLR) between the left atrial appendage and the left superior PV. Evaluation of inter-technique agreement was based on linear regression with Pearson correlation coefficient (PCC) and Bland-Altman analysis of biases and limits of agreement.

RESULTS

Moderate positive correlation (PCC 0.5-0.7) was demonstrated between the two imaging methods for the right superior PV's OA and both axis diameters, the width of the LLR and left superior PV (LSPV) minor axis diameter (b) with limits of agreement ˂50% and no significant biases. Low positive or negligible correlation (PCC < 0.5) was found for both inferior PV parameters.

CONCLUSIONS

Detailed assessment of the right superior PV parameters, LLR and LSPV b is feasible with 3DTOE prior to AF ablation. This 3DTOE measurements demonstrated a clinically acceptable inter-technique agreement with those obtained with CCT.

Insurance lesions: Does a second lesion make a difference?

INTRODUCTION

In radiofrequency ablation procedures for cardiac arrhythmia, the efficacy of creating repeated lesions at the same location ("insurance lesions") remains poorly studied. We assessed the effect of type of tissue, power, and time on the resulting lesion geometry during such multiple ablation procedures.

METHODS

A custom ex vivo ablation model was used to assess lesion formation. An ablation catheter was oriented perpendicular to the tissue and used to create lesions that varied by type of tissue (atrial or ventricular free wall), power (30 or 50 W), and time (30, 40, or 50 s for standard ablations and 5, 10, or 15 s for high-power, short-duration [HPSD] ablations). Lesion dimensions were recorded and then analyzed. Radiofrequency ablations were performed on 57 atrial tissue samples (28 HPSD, 29 standard) and 28 ventricular tissue samples (all standard).

RESULTS

With ablation parameters held constant, performing multiple ablations significantly increased lesion depth in ventricular tissue when ablations were performed at 30 W for 50 s. No other set of ablation parameters was shown to affect the width or depth of the resulting lesions in either tissue type.

CONCLUSION

Multiple ablations created with the same power and time, delivered within 30 s of each other at the same exact location, offer no meaningful benefit in lesion depth or width over single ablations, with the exception of ventricular ablation at 30 W for 50 s. Given the risks associated with excessive ablation, our results suggest that this practice should be re-evaluated by clinical electrophysiologists.

The Long-Term Results of Three Catheter Ablation Methods in Patients With Paroxysmal Atrial Fibrillation: A 4-Year Follow-Up Study

Aims: Catheter ablation of paroxysmal atrial fibrillation (PAF) has been shown to be effective and safe. However, recurrence of PAF varies between 10 and 30% for radiofrequency ablation. There have been no reports comparing long-term recurrence rates following radiofrequency ablation, cryoablation, and three-dimensional guided cryoablation plus radiofrequency ablation. The aim of this study was to observe the long-term recurrence rate of PAF when treated by these three catheter ablation methods, and to explore clinical factors that can potentially predict PAF recurrence following catheter ablation. Methods: There were 238 patients involved in this study, including 106 radiofrequency (RF) ablation cases (RF group), 66 cryoablation cases (Freeze group), and 66 cases treated by three-dimensional guided cryoablation combined with radiofrequency ablation (Freeze-plus-RF group). All patients underwent standardized follow-up. The recurrence rate of atrial fibrillation (AF) in the three groups was calculated. Predictive factors for the recurrence of AF were also investigated. Results: At 48 months (the median follow-up period), the sinus rhythm maintenance rate was 77.4% in the RF group, 72.7% in the Freeze group, and 81.8% in the Freeze-plus-RF group. The maintenance rate of sinus rhythm was highest in the Freeze-plus-RF group, but differences among the three groups were not statistically significant. Further analysis found that the preoperative left atrial appendage emptying velocity (LAAEV) (recurrence vs. no recurrence, 56.58 ± 18.37 vs. 65.59 ± 18.83, respectively, p = 0.003), left atrial (LA) anteroposterior dimension (recurrence vs. no recurrence, 36.56 ± 4.65 vs. 35.00 ± 4.37, respectively; p = 0.028), and LA vertical dimension (recurrence vs. no recurrence, 56.31 ± 6.96 vs. 53.72 ± 6.52, respectively; p = 0.035) were related to postoperative recurrence. Multiple Cox regression analysis showed that only LAAEV was predictive of postoperative recurrence of PAF (hazard ratio: 0.979; 95% confidence interval: 0.961-0.997). Conclusion: Our study found that there was no statistically significant difference in long-term recurrence rates among the RF, Freeze, and Freeze-plus-RF groups. Preoperative LAAEV is an independent predictor of postoperative recurrence of PAF.

Cryoballoon or radiofrequency ablation? Alternating technique for repeat procedures in patients with atrial fibrillation

BACKGROUND

Which technique is better for repeat ablation in patients with atrial fibrillation (AF) remains unclear. The aim of the study was to compare long-term efficacy of repeat ablation using the alternative technique for the first redo ablation procedure: (a) cryoballoon (CB) re-ablation after a failed index pulmonary vein isolation (PVI) with radiofrequency (RF) ablation, RF-then-CB group or (b) RF repeat ablation following a failed CB ablation, CB-then-RF group.

METHODS

Within the 1STOP Italian Project, consecutive patients undergoing repeat ablation with a different technique from the index procedure were included.

RESULTS

We studied 474 patients, 349 in RF-then-CB and 125 in CB-then-RF group. Less women (21% vs 30%; P = .041), more persistent AF (33% vs 22%; P = .015), longer duration of AF (60 vs 31 months; P < .001), and more hypertension (50% vs 36%; P = .007) were observed in the RF-then-CB cohort as compared with the CB-then-RF group. The number of reconnected PVs was 3.7 ± 0.7 and 1.4 + 1.3 in RF-then-CB and CB-then-RF group, respectively (P < .001). During the follow-up, significantly less AF recurrence occurred in the CB-then-RF group (22% vs 8%, HR = 0.46; 95% CI: 0.24-0.92; P = .025). Cohort designation was the only independent predictor of AF recurrence.

CONCLUSION

Alternation of energy source for repeat ablation was safe and effective, regardless the energy used first. However, patients initially treated with CB PVI undergoing repeat ablation with RF current had less AF recurrence at long-term follow-up as compared with those originally treated by RF ablation receiving a CB repeat ablation.

Second-generation cryoballoon ablation for recurrent atrial fibrillation after an index procedure with radiofrequency versus cryo: Different pulmonary vein reconnection patterns but similar long-term outcome-Results of a multicenter analysis

INTRODUCTION

Repeated procedures are often needed for long-term success of atrial fibrillation ablation. There are scarce data regarding cryoballoon use for such procedure.

METHODS AND RESULTS

We analyzed acute effect and long-term follow-up of second-generation cryoballoon ablation, performed as a repeat procedure after an index radiofrequency vs cryoballoon ablation. Sixty-one patients from three centers were included. In 36 cases radiofrequency (RF-I) and in 25 cryoballoon ablation (CB-I) was the index procedure. During redo procedure, pulmonary vein reconnection was less frequent in CB-I vs RF-I (51.5% vs 66.9%; P = 0.017). After cryoballoon, left inferior (P =  0.027) and right superior (P = 0.06) pulmonary veins were less likely to exhibit reconnection. Moreover, patients after initial RF ablation frequently presented multiple-vein reconnection (P = 0.018), while patients after cryoablation more often had only one vein reconnected (P = 0.008). During reablation procedures, all 149 reconnected veins in both groups were isolated, with no differences in procedural parameters, except for procedure time, shorter in CB-I group (65.5 vs 71.1 minutes; P = 0.04). Transient phrenic nerve palsy was the only complication in both groups (5.6% and 8.0%; ns). After mean follow-up of 15 ± 9 months, 70.3% of patients were free from atrial fibrillation (AF), with no differences between the groups (P = 0.71). In multivariate Cox-regression analysis, the persistent form of arrhythmia (P = 0.009) and relapse in the blanking period (P = 0.0004) were the only independent predictors of AF recurrence.

CONCLUSIONS

The use of second-generation cryoballoon is associated with less frequent pulmonary vein reconnection compared with RF ablation. Cryoballoon is safe and effective for repeated AF ablation, regardless of the technique used for the initial procedure.

Second-generation cryoballoon ablation for recurrent atrial fibrillation after an index cryoballoon procedure: a staged strategy with variable balloon size

PURPOSE

Currently, information on the optimal approach of redo procedures for paroxysmal atrial fibrillation (PAF) is limited. Radiofrequency ablation is the preferred technique, with reported success rates of 50-70% at 1-2 years, whereas only few reports exist on redo cryoballoon (CB) ablations. We describe outcomes on a systematic approach of repeat procedures with a second-generation cryoballoon (CB-2) after a successful index CB ablation.

METHODS

Cohort study of 40 consecutive patients with recurrent PAF (55% male), median CHA2DS2-VASc score 1 (IQR 0-3). Per protocol, a staged variable balloon size strategy was followed with a different balloon size during the redo as compared to the index procedure. Minimal follow-up was 12 months (median 17 months [IQR 14-39]).

RESULTS

Overall, 120 pulmonary veins (PVs) (75%) showed chronic isolation: 64% (41/64) for first-generation cryoballoon (CB-1) and 82% (79/96) for CB-2 index procedures, respectively (p = 0.01). The overall mean number of reconnected PVs per patient was 1.0 (40/40): 1.4 for CB-1 and 0.7 for CB-2 index procedures (p = 0.008). Phrenic nerve palsies (n = 7) resolved before the end of the procedure. At 1 year, 70% of patients were free of recurrent AF. In multivariate analysis, the only independent predictor of recurrence was the number of prior cardioversions.

CONCLUSIONS

A systematic approach of repeat procedures with a CB-2 using a different balloon size than during the index CB ablation is safe, with acceptable 1-year outcomes. Future comparative studies on the optimal redo technique and approach are warranted to further improve rhythm control in AF.

Radiofrequency catheter ablation for redo procedures after pulmonary vein isolation with the cryoballoon technique : Long-term outcome

BACKGROUND

Catheter ablation has become the first line of therapy in patients with symptomatic, recurrent, drug-refractory atrial fibrillation (AF). Cryoablation has been shown to be a safe and effective technique for pulmonary vein (PV) isolation. However, the arrhythmia recurrence rate is high after cryoablation procedures. Radiofrequency catheter ablation has been shown to be an effective strategy for redo procedures in these patients and to provide a favourable outcome during midterm follow-up. The aim of this study was to analyse whether the strategy also provides favourable results during long-term follow-up (5 years).

METHODS

In this study 30 patients (paroxysmal AF: 22 patients, persistent AF: 8 patients) underwent a redo procedure after initially successful circumferential PV isolation with the cryoballoon technique (Arctic Front Balloon, Medtronic). The redo ablation procedures were performed using a segmental approach or a circumferential ablation strategy (CARTO; Biosense Webster, Diamond Bar, CA, USA) depending on the intraprocedural findings.

RESULTS

During the repeat procedure, a mean number of 2.9 reconnected PV (SD ± 1.0) were detected. In 20 patients, a segmental approach was sufficient to eliminate the residual PV conduction because only a few PV fibres were recovered (1-3 reconnected PV; group A). In the remaining 10 patients, a circumferential ablation strategy was used because of a complete recovery of the pulmonary vein - left atrial (PV-LA) conduction (group B). All reconnected PV were isolated successfully again. A third or fourth ablation procedure had to be performed in 4 (3 and 1, respectively) patients (13.3%). At 5‑year follow-up, 66.7% of all patients were free from an arrhythmia recurrence (20 out of 30). There were no major complications during long-term follow-up.

CONCLUSION

In patients with an initial circumferential PV isolation using the cryoballoon technique, a repeat ablation procedure can be safely and effectively performed using radiofrequency catheter ablation providing good long-term follow-up results.