Conversion of atrial fibrillation to sinus rhythm during cryoballoon ablation: A favorable and not unusual phenomenon during second-generation cryoballoon pulmonary vein isolation.

BACKGROUND: The prevalence and the clinical impact of conversion of atrial fibrillation (AF) to sinus rhythm (SR) during cryoballoon ablation (CB-A) are unknown. OBJECTIVE: The purpose of this study was to evaluate the prevalence of restoration of SR during CB-A and the clinical impact of this phenomenon. METHODS: Between January 2012 and September 2018, all patients who experienced conversion of AF to SR during CB-A were included. This group was subsequently matched for gender, age, type of AF, diagnosis-to-ablation time, and left atrial size with patients who underwent CB-A and did not experienced conversion of AF to SR. After discharge, patients were scheduled for follow-up visits at 1, 3, 6, and 12 months and 24 hours Holter recordings were obtained at each follow-up visit. All documented AF episodes of >30 seconds were considered as recurrence. A 3 month post-procedural blanking period (BP) was applied. RESULTS: A total of 1559 patients underwent pulmonary veins isolation by CB-A between January 2012 and September 2018; among them, 58 patients (3.7%) experienced restoration of SR during CB-A. In total, 53 patients (41 males [77.3%], mean age 61.4 ± 13.3 years) were included in the case group. During CB-A, restoration of SR occurred more frequently during right-side PVs applications (right inferior pulmonary vein 39.6%, right superior pulmonary vein 30.2%). If considering a BP, at 2 year follow-up, freedom from recurrences was 86.5% in the case group and 68.0% in the control group (P = .036). CONCLUSION: Conversion of AF to SR is a favorable and relatively frequent phenomenon during cryoballoon pulmonary vein isolation ablation.

Pulmonary veins anatomical determinants of cooling kinetics during second-generation cryoballoon ablation.

AIM: The aim of the study was to investigate the role of anatomical characteristics of the pulmonary veins (PVs) determining cooling kinetics during second-generation cryoballoon ablation (CbA). METHODS AND RESULTS: we enrolled all consecutive patients who underwent CbA for symptomatic atrial fibrillation in our center from January 2019 to March 2019. All patients had complete computed tomography scans of the heart before the ablation. Anatomical characteristics were tested for prediction of a nadir temperature (NT) ≤ -48°C. Significant differences were noted among PV max diameter (20.8 ± 2.8 vs 18.5 ± 2.5 mm; P < .001); PV minimum diameter (15.2 ± 3.0 vs 13.0 ± 3.1 mm; P < .001); PV area (268.1 ± 71.9 vs 206.2 ± 58.7 mm2 ; P < .001); PV ovality (1.4 ± 0.3 vs 1.5 ± 0.3; P = .005); and PV trunk length (27.4 ± 7.4 vs 21.3 ± 6.5 mm; P < .001). A scoring system was created by assigning one point each ranging from 0 (best anatomical combination) to 5. In the group with a score of 0, 94.0% of the CbA could reach a NT ≤ -48°C whereas with a score of 5, only 29.0% (P < .001). Left superior pulmonary vein with short trunk length and acute angle of PV branch was significantly associated with warmer NT (11.8% satisfactory CbA; P = .003). Regarding right inferior pulmonary vein, trunk length (P = .004), maximum diameter (P = .044), and transverse angle (P = .008) were independently associated with good NT. CONCLUSION: Anatomical PV features are associated with cooling kinetics and an anatomical score could predict lower NT during second-generation CbA. Specific characteristics were identified for inferior PV. Although heart imaging is not mandatory prior CbA, it can be a useful tool to predict cooling kinetics.

Mid-term outcome following second-generation cryoballoon ablation for atrial fibrillation in heart failure patients: effectiveness of single 3-min freeze cryoablation performed in a cohort of patients with reduced left ventricular systolic function.

PURPOSE: Currently, information on the mid-term outcome of cryoballoon ablation (CB-A) for drug-resistant atrial fibrillation in patients with reduced left ventricular systolic function is limited. METHODS: Thirty-eight consecutive patients with paroxysmal or persistent atrial fibrillation (84.2% male), with median left ventricular ejection fraction of 37.3% were included in our study. All patients underwent the procedure with the 28-mm cryoballoon advance. RESULTS: There were no mayor complications related to the CB-A procedure. Median follow-up was 26.5 ±â€Š13.7 months. The freedom from atrial fibrillation after a blanking period of 3 months was 42.9% in our cohort of patients. During the follow-up period, 13 patients underwent at least a new electrophysiological procedure. After a single procedure, the univariate predictors of clinical recurrence after the blanking period were age and persistent atrial fibrillation. CONCLUSION: Second-generation CB-A of atrial fibrillation seems feasible and safe in patients with heart failure with reduced ejection fraction and heart failure with mid-range ejection fraction, in terms of complications rate and number of applications per vein. All pulmonary veins could be isolated with the 28-mm cryoballoon advance only.

Anatomical extent of pulmonary vein isolation after cryoballoon ablation for atrial fibrillation: comparison between the 23 and 28 mm balloons.

BACKGROUND: Pulmonary vein isolation seems to occur in the distal part of the ostium leaving the atrium largely unablated when using the 23 mm cryoballoon catheter ablation for atrial fibrillation. We hypothesize that ablating with the larger 28 mm cryoballoon would target a wider portion of the left atrial cavity. AIM: To compare the anatomical extent of pulmonary vein isolation using electroanatomical mapping when performing atrial fibrillation ablation with a 23 mm or a 28 mm cryoballoon. METHODS: Eight consecutive patients selected for circumferential pulmonary vein cryoballoon isolation for highly symptomatic paroxysmal atrial fibrillation were randomly assigned to ablation with the 23 or 28 mm balloon. After ablation, electroanatomical mapping was performed to compare the anatomical extent of pulmonary vein isolation between the two balloon dimensions. RESULTS: Extent of pulmonary vein isolation significantly differed when the lesions with either balloon dimensions were compared. Pulmonary vein isolation only occurred in the tubular part of the ostium when performed with the 23 mm balloon. Conversely, the lesion created with the 28 mm balloon included a larger portion of the left atrium. In fact, when using the smaller balloon (23 mm) the mean documented extent of electrical isolation was 20.7 ± 2.8% of the maps' surface, whereas it was 40.2 ± 3.9% when performing ablation with the bigger balloon (28 mm). The difference in calculated area of electrical isolation between group A and B was statistically significant (P < 0.05). CONCLUSION: Pulmonary vein isolation occurs significantly more proximally in the atrium when performing atrial fibrillation ablation with a 28 mm cryoballoon when compared with a 23 mm balloon.

Extreme bradycardia during pulmonary vein isolation: keep on ablating in that region?

Increasing evidence supports the theory that the cardiac autonomic nervous system plays a pivotal role in triggering and maintaining atrial fibrillation. We describe a case of extreme bradycardia during catheter ablation of atrial fibrillation in a 67-year-old man. Interestingly, despite numerous radiofrequency applications, we could not abolish the vagal reflex. Our case underlines the need to look for more specific and reproducible end points when performing this procedure.