Cryoablation of atrial fibrillation in "very severe" obese patients (BMI ≥ 40): Indications, feasibility, procedural safety and efficacy, and clinical outcome (the ICE-Obese Extreme).

BACKGROUND: Management of atrial fibrillation (AF) in very severe obese patients is challenging. Cryoballoon ablation (CBA) represents an effective rhythm control strategy. However, data in this patient group were limited. METHODS: Highly symptomatic AF patients with body mass index (BMI) ≥ 40 kg/m2 who had failed antiarrhythmic drug therapy and electrocardioversion and failure to achieve targeted body-weight-reduction underwent CBA. RESULTS: Data of 72 very severe obese AF patients (Group A) and 129 AF patients with normal BMI (Group B, BMI < 25 kg/m2) were consecutively collected. Group A had significantly younger age (60.6 ± 10.4 vs. 69.2 ± 11.2 years), higher BMI (44.3 ± 4.3 vs. 22.5 ± 1.6 kg/m2). Procedural pulmonary vein isolation (PVI) was successful in all patients (2 touch-up ablation in Group A). Compared to Group B, Group A had similar procedural (61.3 ± 22.6 vs. 57.5 ± 19 min), similar fluoroscopy time (10.1 ± 5.5 vs. 9.2 ± 4.8 min) but significantly higher radiation dose (2852 ± 2095 vs. 884 ± 732 µGym2). We observed similar rates of real-time-isolation (78.6% vs. 78.5%), single-shot-isolation (86.5% vs. 88.8%), but significantly longer time-to-sustained-isolation (53.5 ± 33 vs. 43.2 ± 25 s). There was significantly higher rate of puncture-site-complication (6.9% vs. 1.6%) in Group A. One-year clinical success in paroxysmal AF was (Group A: 69.4% vs. Group B: 80.2%; p < .001), in persistent AF was (Group A: 58.1% vs. Group B: 62.8%; p = .889). In Re-Do procedures Group A had a numerically lower PVI durability (75.0% vs. 83.6%, p = .089). CONCLUSION: For very severe obese AF patients, CBA appears feasible, leads to relatively good clinical outcome.

Pulsed Field Versus Cryoballoon Pulmonary Vein Isolation for Atrial Fibrillation: Efficacy, Safety, and Long-Term Follow-Up in a 400-Patient Cohort.

BACKGROUND: The cryoballoon (CB) represents the gold standard single-shot device for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). Single-shot pulsed field PVI ablation (nonthermal, cardiac tissue selective) has recently entered the arena. We sought to compare procedural data and long-term outcome of both techniques. METHODS: Consecutive AF patients who underwent pulsed field ablation (PFA) and CB-based PVI were enrolled. CB PVI was performed using the second-generation 28-mm CB; PFA was performed using a 31/35-mm pentaspline catheter. Success was defined as freedom from atrial tachyarrhythmia after a 3-month blanking period. RESULTS: Four hundred patients were included (56.5% men; 60.8% paroxysmal AF; age 70 [interquartile range, 59-77] years), 200 in each group (CB and PFA), and baseline characteristics did not differ. Acute PVI was achieved in 100% of PFA and in 98% (196/200) of CB patients (P=0.123; 4 touch-up ablations). Median procedure time was significantly shorter in PFA (34.5 [29-40] minutes) versus CB (50 [45-60] minutes; P<0.001), fluoroscopy time was similar. Overall procedural complications were 6.5% in CB and 3.0% in PFA (P=0.1), driven by a higher rate of phrenic nerve palsies using CB. The 1-year success rates in paroxysmal AF (CB, 83.1%; PFA, 80.3%; P=0.724) and persistent AF (CB, 71%; PFA, 66.8%; P=0.629) were similar for both techniques. CONCLUSIONS: PFA compared with CB PVI shows a similar procedural efficacy but is associated with shorter procedure time and no phrenic nerve palsies. Importantly, 12-month clinical success rates are favorable but not different between both groups.

Impact of body mass index on cryoablation of atrial fibrillation: Patient characteristics, procedural data, and long-term outcomes.

INTRODUCTION: Ablation of atrial fibrillation in the context of obesity can be challenging. We sought to evaluate the role of cryoballoon pulmonary vein isolation (CB-PVI) in obese patients with symptomatic atrial fibrillation (AF). METHODS: Patients with a BMI ≥ 25 kg/m2 and symptomatic AF who underwent CB-PVI were retrospectively enrolled. Three groups were defined (G1: BMI of 25-29 kg/m2 ; G2: BMI of 30-34 kg/m2 ; G3: BMI ≥ 35 kg/m2 ). RESULTS: 600 patients were included (59% male; 66 ± 11 years old); 337, 149, and 114 were assigned to G1, G2, and G3, respectively. Acute procedural success was recorded in 99.7% of patients. Procedural and fluoroscopy time were comparable but the radiation dose was significantly higher in G3. Procedural complications were 3% in G1, 5.4% in G2, and 8.8% in G3 (p = .01). The overall freedom from AF after 1-year was 77%. G3 had a significantly worse 1-year success rate compared to G1 and G2 (G3: 66.5% vs. G1: 78.4%; p = .015 and vs. G2: 82.5%; p = .008) with reduced 1-year success in paroxysmal AF (G1: 84.0%; G2: 86.3%; and G3: 69.6%) but not in persistent AF (G1: 68.7%; G2: 77.4%; and G3: 62.1%). G3 showed similar success rates irrespective of AF form (PAF: 69.6% vs. persAF 62.1%; p = .501). CONCLUSION: Cryoballoon ablation in obese patients can be effective with an acceptable safety profile, 77% of patients were in stable SR at 1 year. Severe obese patients (BMI ≥ 35) showed reduced procedural safety and 1-year success rate. In association with life style modification, CB ablation may represent a strategy to enhance rhythm control in the context of obesity.

Incidence and characteristics of phrenic nerve palsy following pulmonary vein isolation with the second-generation as compared with the first-generation cryoballoon in 360 consecutive patients.

AIMS: The second-generation cryoballoon (CB2) with increased surface cooling has recently become available. The aim was to investigate the incidence and characteristics of phrenic nerve palsy (PNP) during pulmonary vein isolation (PVI) using the CB2 as compared with the first-generation balloon (CB1). METHODS AND RESULTS: A total of 360 consecutive patients with atrial fibrillation underwent PVI with the CB1 (106 patients) or the CB2 (254 patients). Right PN function was monitored by continuous stimulation and palpation during septal PV ablation. Persistent PNP (present at discharge) occurred in 2.8 and 1.9% (P = 0.63) of patients, transient PNP (full recovery before discharge) in 5.9 and 3.8% (P = 0.41) of patients in the CB2 and CB1 group, respectively. Phrenic nerve palsy during ablation at the right inferior PV was observed in 0% (CB1) and 4.3% (CB2, P = 0.03) of patients. Using the CB2, a trend of reduced incidence of persistent PNP over quartiles of consecutive patients was observed [4.8% (Q1) vs. 0% (Q4); P = 0.077]. At the culprit PV, PNP occurred after 3.5 ± 2.1 (CB1) and 1.1 ± 0.4 applications (CB2; P = 0.036). Complete recovery of PN function occurred after 29 ± 11 (CB1) and 259 ± 137 days (CB2; P = 0.004). CONCLUSIONS: The rate of transient/persistent PNP associated with the use of the CB2 was 5.9 and 2.8%, respectively. Time to restitution of PN function was longer using the CB2.

High rate of durable pulmonary vein isolation after second-generation cryoballoon ablation: analysis of repeat procedures.

AIMS: Pulmonary vein isolation (PVI) using the first-generation cryoballoon (CB1) was characterized by a high rate of recovered pulmonary vein (PV) conduction along with a typical conduction gap pattern in patients with recurrent atrial tachyarrhythmia (ATa). Second generation (CB2) enables more uniform freezing. However, the rate of chronic PVI and PV conduction gap pattern is unknown. METHODS AND RESULTS: All patients with ATa recurrence undergoing a second procedure after CB2 or (historical) CB1 PVI (28 mm) were enrolled. In all patients, a left atrial three-dimensional electronatomic reconstruction was performed. The rates of chronic PVI and localization of PV conduction gaps were determined and compared between CB1 and CB2. Antral PV re-isolation was performed using irrigated-tip radiofrequency current energy ablation. Of 206 patients (CB2), 18 patients underwent the repeat procedure after 192 (75:245) days. In 6 of 18 (33%) patients, all PVs were electrically isolated whereas in the remaining 12 patients (66%) at least one PV demonstrated PV reconduction. Of 71 PVs [1 left common PV (LCPV)], 55 PVs (77%) were chronically isolated. The right superior PV (RSPV) was characterized by the lowest rate of chronic PVI (RSPV: 56%, LSPV: 76%, RIPV: 83%, LIPV: 94%, LCPV: 100%). Compared with CB1, CB2 ablation resulted in a significantly higher rate of chronic PVI (CB2: 77% vs. CB1: 32%; P < 0.0001) with the greatest improvement along both inferior PVs. CONCLUSION: Second-generation cryoballoon atrial fibrillation ablation is associated with a high rate of durable PVI in patients with ATa recurrence. The RSPV represents the PV with the greatest risk for left atrium-pulmonary vein reconnection.

Improved 1-year clinical success rate of pulmonary vein isolation with the second-generation cryoballoon in patients with paroxysmal atrial fibrillation.

BACKGROUND: The second-generation cryoballoon (CB2) has recently been introduced featuring improved surface cooling. Increased procedural efficacy of pulmonary vein isolation (PVI) when compared to the first-generation balloon (CB1) has been reported. The aim of the study was to investigate the clinical outcome of cryoballoon PVI after 1 year using the CB2 as compared to the CB1. METHODS AND RESULTS: A total of 105 consecutive patients with paroxysmal atrial fibrillation (AF) were studied. Cryoballoon PVI (28 mm) was performed in 50 patients using the CB1, and in 55 patients using the CB2. Patients were scheduled for 72-hour Holter ECG recording at 3, 6, 9, and 12 months and every 6 months thereafter. The study endpoint was defined as recurrent AF or atrial tachycardia >30 seconds documented after a blanking period of 90 days after the procedure. Complete PVI was achieved in 49/50 (98%) and 55/55 (100%) patients in the CB1 and CB2 group, respectively. After a mean follow-up of 416 ± 75 days, 21 (CB1 group) and 10 (CB2 group) patients reached the study endpoint. Kaplan-Meier estimates of arrhythmia-free survival after a single procedure without AAD therapy after 1 year were 63.9% versus 83.6% (P = 0.008) in the CB1 and CB2 group, respectively. Persistent phrenic nerve palsy with delayed healing occurred in 2 (CB1 group) and 3 (CB2 group) patients. CONCLUSION: Clinical outcome of PVI using the CB2 was significantly improved when compared to the CB1.

Improved lesion formation using the novel 28 mm cryoballoon in atrial fibrillation ablation: analysis of biomarker release.

AIMS: Recently, a novel second-generation (G2) cryoballoon (CB) was introduced. Comparative analysis of lesion formation in terms of myocardial biomarker release [first-generation CB (G1) vs. G2] has not been studied. To compare myocardial biomarker release using the 28 mm G1 vs. G2 CB. METHODS AND RESULTS: In patients (patients) treated with the simplified single big CB (SBCB) strategy for pulmonary vein isolation (PVI), myocardial biomarkers [troponin T (TnT), creatine kinase, lactic dehydrogenase (LDH)] were measured at 12, 24, and 48 h after PVI. Two groups were defined: Group 1 (G1; freezing time: 300 s), Group 2 (G2; freezing time: 240 s). Mean biomarker peak values were compared. To correct for between-group differences in cumulative freezing time, an index calculated as peak biomarker release divided by cumulative freezing time was calculated. Sixty-six CB PVI procedures (G1: 33 patients, G2: 33 patients) were analysed. Pulmonary vein isolation was achieved in all the patients using the simplified SBCB technique only. Mean freezing time (51 ± 10 vs. 33 ± 6 min, P < 0.01) was significantly shorter in G2. All biomarker levels tended to be higher in G2 vs. G1. The indexed biomarkers values were significantly higher in G2: TnT: 18.8 ± 8.5 vs. 32.3 ± 13.6 pg/L/min (P < 0.01); creatinephosphokinase: 6.7 ± 2.7 vs. 11.7 ± 3.9 U/L/min (P < 0.01); LDH: 5.2 ± 1.0 vs. 9.1 ± 2.7 U/L/min (P < 0.01). On a 6-month follow-up (180 days), G2 revealed a significantly higher success rate (20/33 vs. 28/33; P = 0.027). CONCLUSION: Pulmonary vein isolation using the G2 CB increased the myocardial biomarker release index and is linked to a significantly improved 6 months success rate.

Comparison of balloon catheter ablation technologies for pulmonary vein isolation: the laser versus cryo study.

INTRODUCTION: Balloon catheters have been developed to facilitate pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (PAF). We sought to compare the safety and efficacy of the cryoballoon (CB) and the laserballoon (LB) in a pilot study. METHODS AND RESULTS: One hundred and forty patients with drug-refractory PAF were prospectively allocated in a 1:1 fashion to undergo a PVI procedure with the 28 mm CB or the LB and were followed for 12 months using 3-day Holter ECG recording. The primary efficacy endpoint was a documented AF recurrence ≥ 30 seconds between 90 and 365 days after the index ablation. In total, 269 of 270 PVs (99.6%) and 270 of 273 PVs (98.9%) were acutely isolated in the CB and LB group, respectively. Mean procedural time was 136 ± 30 minutes for the CB group and 144 ± 33 minutes for the LB group (P = 0.13). Mean fluoroscopy time was longer in the CB group (21 ± 9 minutes vs 15 ± 6 minutes; P < 0.001). During 12 months follow-up, 37% of patients in the CB group and 27% in the LB group experienced an AF recurrence (P = 0.18). Phrenic nerve palsies occurred in 5.7% (CB) and 4.2% (LB) of patients, respectively. CONCLUSION: Balloon catheters are a viable option to safely perform a PVI procedure in patients with drug-refractory PAF. Ninety-nine percent of PVs may be acutely isolated with a single balloon catheter. The AF free survival rate after a single ablation procedure was not statistically different between groups.

Endoscopic ablation systems.

Pulmonary vein (PV) isolation for ablation of atrial fibrillation is a well-accepted therapy option for high symptomatic patients refractory to antiarrhythmic drugs. Radiofrequency point-by-point ablation is the gold-standard technique; however, in the last two decades, many new technologies have been developed. The endoscopic ablation system makes direct PV ostium visualization possible, despite the large anatomy variation thanks to its compliant balloon. The laser generator delivers precise lesions that in the first clinical studies seem to be durable, with a safety and efficacy profile similar to the other PV isolation techniques. If these early results are confirmed by larger clinical studies, the endoscopic ablation system will offer a new paradigm in ablation of cardiac arrhythmias by directly visualizing the target substrate.

Improved procedural efficacy of pulmonary vein isolation using the novel second-generation cryoballoon.

INTRODUCTION: The cryoballoon technology has the potential to isolate a pulmonary vein (PV) with a single energy application. However, using the first-generation cryoballoon (CB-1G) repeated freezing or additional focal ablation is often necessary. The novel second-generation cryoballoon (CB-2G) features a widened zone of optimal cooling comprising the whole frontal hemisphere. The aim of this study was to investigate the impact of the novel design on procedural efficacy of cryoballoon PV isolation (CB-PVI). METHODS AND RESULTS: Single transseptal CB-PVI using an endoluminal spiral mapping catheter was performed in 60 consecutive patients (CB-1G, 28 mm, 300 seconds application time: 30 patients; CB-2G, 28 mm, 240 seconds application time: 30 patients). When compared to the CB-1G, using the CB-2G increased single-shot PVI rate from 51% to 84% (P < 0.001) and decreased procedure duration (128 ± 27 vs 98 ± 30 minutes; P < 0.001), and fluoroscopy exposure time (19.5 ± 7.4 vs 13.4 ± 5.3 min; P = 0.001). Effective CB-2G PVI could be performed with increased real-time PVI visualization rate (49% vs 76%; P < 0.001). Time to PVI (T(PVI)) was shorter in the CB-2G group (79 ± 60 vs. 52 ± 36 seconds; P = 0.049). Procedure-related complications occurred in 2 patients in the CB-1G group and 1 patient in the CB-2G group. CONCLUSIONS: The CB-2G significantly improved procedural efficacy compared to the CB-1G and provided reliable T(PVI) measurement. T(PVI) may be used to adjust application time and number individually in future studies. Final conclusions regarding the safety profile of the CB-2G requires additional research.

Luminal esophageal temperature predicts esophageal lesions after second-generation cryoballoon pulmonary vein isolation.

BACKGROUND: The novel second-generation cryoballoon (CB) facilitates pulmonary vein isolation (PVI) by improved surface cooling. The impact of this redesign on collateral damage is unknown. OBJECTIVE: To investigate the incidence of esophageal lesions after PVI using the second-generation CB and the role of luminal esophageal temperature (LET) measurement as a predictor of lesion formation. METHODS: Thirty-two consecutive patients underwent PVI using the second-generation 28 mm CB. Target application time was 2 × 240 seconds. Ninety-two percent of the PVs were isolated after 1 cryoenergy application. Complete PVI was achieved in all patients. LET with 3 thermocouples was continuously measured during cryoenergy application. Freezing was interrupted only if weakening/loss of phrenic nerve function or low LET (<5 °C) was observed. RESULTS: The lowest measured LET was-12 °C (despite cryoapplication interruption). Postprocedural gastroesophagoscopy was performed after 1-3 days in all patients and showed lesions in 6 of 32 (19%) patients. A minimum LET of≤12 °C predicted esophageal lesions with 100% sensitivity and 92% specificity (area under the receiver-operator characteristic curve 0.97; 95% CI 0.93-1.02; P = .001). Persistent phrenic nerve palsy occurred in 2 (6%) patients during ablation at the right inferior pulmonary vein. Repeat gastroesophagoscopy confirmed healing of lesions after 16 ± 14 days. CONCLUSIONS: Second-generation 28 mm CB PVI is associated with significant esophageal cooling, resulting in lesion formation in 19% of the patients. LET measurement accurately predicts lesion formation and may enhance the safety of the novel device.

Energy titration strategies with the endoscopic ablation system: lessons from the high-dose vs. low-dose laser ablation study.

AIMS: To assess the effects of low-dose (LD) and high-dose (HD) ablation on acute and chronic success in patients with atrial fibrillation (AF). While the concept of visually guided pulmonary vein isolation (PVI) has been established little is known on energy titration using laser ablation. METHODS AND RESULTS: In 60 patients with AF, PVI using the endoscopic ablation system (EAS) was performed in two groups. Visually guided ablation was carried out after obtaining optimal tissue contact with 5.5-8.5 W in the LD group and with >8.5 W in the HD group. Acute PVI after a single visually guided circular lesion set was achieved in 89% (HD) and 69% (LD), respectively, (P = 0.0004). In 70 and 39% of patients all PVs were isolated after a single ablation circle in the HD and LD group, respectively, (P = 0.009). After gap ablation all PVs were isolated with the EAS. More energy was deployed (6483 ± 1834 vs. 5306 ± 2258 Ws; P ≤ 0.0001) with less applications (31.6 ± 8 vs. 35.2 ± 15 applications per PV; P = 0.03) leading to shorter procedure times (128 ± 17 vs. 154 ± 38 min; P = 0.001). During median follow-up of 311 days (261-346) recurrence rate was 17 and 40% in the HD and LD group, respectively. In both groups one phrenic nerve palsy was observed. CONCLUSION: For the first time, it was demonstrated that high ablation power affects acute and chronic outcomes. High-dose laser balloon ablation allows for an acute PVI rate of 89% solely by visually guided circular ablation and is associated with a chronic success rate of 83% after a single procedure.

Single transseptal big Cryoballoon pulmonary vein isolation using an inner lumen mapping catheter.

BACKGROUND: The single big cryoballon technique for pulmonary vein isolation (PVI) has been limited by the need for two transseptal punctures (TP). We therefore investigated feasibility and safety of a simplified approach using a single TP and a novel circumferential mapping catheter (CMC). METHODS: Patients underwent 28-mm cryoballoon PVI using a single TP. The CMC (Achieve(©) Medtronic Inc., Minneapolis, MN, USA) served as (1) guidewire and (2) as a PV mapping tool. Primary endpoint was PVI without switching to a regular guidewire. Secondary endpoints included: (1) PV signal quality during freezing, (2) time to PVI, (3) classification of successful ablation technique, (4) complications, and (5) procedural data. RESULTS: A total of 32 patients (126 PVs) were studied (mean age: 62 ± 11 years, 24 males, left atrium: 40 ± 4 mm). The primary endpoint was achieved in 29/32 patients (91%) and 123/126 PVs (98%) with a procedure and fluoroscopy time of 126 ± 26 minutes and 18.9 ± 7.5 minutes, respectively. Real-time visualization of PVI could be observed in 61/126 (48%) PVs. Time to sustained PVI versus nonsustained PVI was 66 ± 56 seconds versus 129 ± 76 seconds (P < 0.001). One phrenic nerve palsy was observed. After a follow-up of 250 ± 84 days 23/32 patients (72%) remained in sinus rhythm. CONCLUSION: The "simplified single big cryoballoon" PVI strategy appears to be safe and feasible. However, real-time PV recording was achieved in <50% of PVs. Therefore, further catheter refinements are warranted. (PACE 2012; 35:1304-1311).