title: Cryoballoon ablation of pulmonary veins for paroxysmal atrial fibrillation: first results of the North American Arctic Front (STOP AF) pivotal trial. Acute and Long-Term Outcomes of Catheter Ablation of Atrial Fibrillation Using the Second-Generation Cryoballoon versus Open-Irrigated Radiofrequency: A Multicenter Experience. Long-term outcomes after cryoballoon pulmonary vein isolation: results from a prospective study in 605 patients. Comparison of lesion formation between contact force-guided and non-guided circumferential pulmonary vein isolation: a prospective, randomized study. Cryoballoon Versus Open Irrigated Radiofrequency Ablation in Patients With Paroxysmal Atrial Fibrillation Cryoballoon versus radiofrequency catheter ablation for paroxysmal atrial fibrillation. Early Recurrence After Pulmonary Vein Isolation of Paroxysmal Atrial Fibrillation With Different Ablation Technologies - Prospective Comparison of Radiofrequency vs. Second-Generation Cryoballoon Ablation. Point-by-Point Radiofrequency Ablation Versus the Cryoballoon or a Novel Combined Approach: A Randomized Trial Comparing 3 Methods of Pulmonary Vein Isolation for Paroxysmal Atrial Fibrillation (The Cryo Versus RF Trial). Randomized, Controlled Trial of the Safety and Effectiveness of a Contact Force–Sensing Irrigated Catheter for Ablation of Paroxysmal Atrial Fibrillation: Results of the TactiCath Contact Force Ablation Catheter Study for Atrial Fibrillation (TOCCASTAR) Study Contact-force guided radiofrequency vs. second-generation balloon cryotherapy for pulmonary vein isolation in patients with paroxysmal atrial fibrillation-a prospective evaluation. The COR trial: a randomized study with continuous rhythm monitoring to compare the efficacy of cryoenergy and radiofrequency for pulmonary vein isolation. Histopathology of cryoballoon ablation-induced phrenic nerve injury. Cryoballoon or Radiofrequency Ablation for Paroxysmal Atrial Fibrillation. Phrenic nerve paralysis during cryoballoon ablation for atrial fibrillation: a comparison between the first- and second-generation balloon. Circumferential pulmonary vein isolation with the cryoballoon technique results from a prospective 3-center study.
abstract: OBJECTIVES This study sought to assess the safety and effectiveness of a novel cryoballoon ablation technology design ed to achieve single-delivery pulmonary vein ( PV ) isolation . BACKGROUND St and ard radiofrequency ablation is effective in eliminating atrial fibrillation ( AF ) but requires multiple lesion delivery at the risk of significant complications . METHODS Patients with documented symptomatic paroxysmal AF and previously failed therapy with ≥ 1 membrane active antiarrhythmic drug underwent 2:1 r and omization to either cryoballoon ablation ( n = 163 ) or drug therapy ( n = 82 ) . A 90-day blanking period allowed for optimization of antiarrhythmic drug therapy and reablation if necessary . Effectiveness of the cryoablation procedure versus drug therapy was determined at 12 months . RESULTS Patients had highly symptomatic AF ( 78 % paroxysmal , 22 % early persistent ) and experienced failure of at least one antiarrhythmic drug . Cryoablation produced acute isolation of three or more PVs in 98.2 % and all four PVs in 97.6 % of patients . PVs isolation was achieved with the balloon catheter alone in 83 % . At 12 months , treatment success was 69.9 % ( 114 of 163 ) of cryoblation patients compared with 7.3 % of antiarrhythmic drug patients ( absolute difference , 62.6 % [ p < 0.001 ] ) . Sixty-five ( 79 % ) drug-treated patients crossed over to cryoablation during 12 months of study follow-up due to recurrent , symptomatic AF , constituting drug treatment failure . There were 7 of the result ing 228 cryoablated patients ( 3.1 % ) with a > 75 % reduction in PV area during 12 months of follow-up . Twenty-nine of 259 procedures ( 11.2 % ) were associated with phrenic nerve palsy as determined by radiographic screening ; 25 of these had resolved by 12 months . Cryoablation patients had significantly improved symptoms at 12 months . CONCLUSIONS The STOP AF trial demonstrated that cryoballoon ablation is a safe and effective alternative to antiarrhythmic medication for the treatment of patients with symptomatic paroxysmal AF , for whom at least one antiarrhythmic drug has failed , with risks within accepted st and ards for ablation therapy . ( A Clinical Study of the A rct ic Front Cryoablation Balloon for the Treatment of Paroxysmal Atrial Fibrillation [ Stop AF ] ; NCT00523978 ) INTRODUCTION There are limited comparative data on catheter ablation of atrial fibrillation ( CAAF ) using the second-generation cryoballoon ( CB-2 ) versus point-by-point radiofrequency ( RF ) . This study examines the acute/long-term CAAF outcomes using these 2 strategies . METHODS AND RESULTS In this multicenter , retrospective , nonr and omized analysis , procedural and clinical outcomes of 1,196 patients ( 76 % with paroxysmal AF ) undergoing CAAF using CB-2 ( n = 773 ) and open-irrigated , non-force sensing RF ( n = 423 ) were evaluated . Pulmonary vein isolation was achieved in 98 % with CB-2 and 99 % with RF ( P = 0.168 ) . CB-2 was associated with shorter ablation time ( 40 ± 14 min vs. 66 ± 26 min ; P < 0.001 ) and procedure time ( 145 ± 49 minutes vs. 188 ± 42 minutes ; P < 0.001 ) , but greater fluoroscopic utilization ( 29 ± 13 minutes vs. 23 ± 14 minutes ; P < 0.001 ) . While transient ( 7.6 % vs. 0 % ; P < 0.001 ) and persistent ( 1.2 % vs. 0 % ; P = 0.026 ) phrenic nerve palsy occurred exclusively with CB-2 , other adverse event rates were similar between CB-2 ( 1.6 % ) and RF ( 2.6 % ) ; P = 0.207 . However , freedom from AF/atrial flutter/tachycardia at 12 months following a single procedure without antiarrhythmic therapy was greater with CB-2 ( 76.6 % ) versus RF ( 60.4 % ) ; P < 0.001 . While this difference was evident in patients with paroxysmal AF ( P < 0.001 ) , it did not reach significance in those with persistent AF ( P = 0.089 ) . Additionally , CB-2 was associated with reduced long-term need for antiarrhythmic therapy ( 16.7 % vs. 22.0 % ; P = 0.024 ) and repeat ablations ( 14.6 % vs. 24.1 % ; P < 0.001 ) . CONCLUSION In this multicenter , retrospective , nonr and omized study , CAAF using CB-2 coupled with RF as occasionally required was associated with greater freedom from atrial arrhythmias at 12 months following a single procedure without antiarrhythmic therapy when compared to open-irrigated , non-force sensing RF , alone OBJECTIVES The purpose of this study was to investigate long-term outcomes of freedom from atrial fibrillation ( AF ) after pulmonary vein ( PV ) isolation using cryoballoon ablation with balloon-size selection based on individual PV diameters . BACKGROUND Data are lacking on long-term outcomes from cryoablation and on the most effective balloon size . METHODS This was a prospect i ve observational study involving 605 consecutively enrolled patients with symptomatic paroxysmal AF ( n = 579 ) or persistent AF .  Cryoballoon size was based on magnetic resonance imaging and /or conventional angiograms . Patients were followed up every 3 months during the first year after discharge and every 6 months in the second year . After 24 months , follow-up was on an outpatient basis with documented AF episodes recorded . RESULTS The PV isolation was achieved without touch-up in 91.1 % of patients , using the smaller balloon in 26.7 % , the larger balloon in 25.6 % , and both balloons in 47.7 % of patients . Follow-up data for > 12 months ( median 30 months ; interquartile range 18 to 48 months ) were available for 451 patients , 278 ( 61.6 % ) of whom were free of AF recurrence with no need for repeat procedures after the 3-month blanking period . Rates of freedom from AF after 1 , 2 , and 3 repeat procedures ( using cryoballoon or radiofrequency ablation with similar success rates ) were 74.9 % , 76.2 % , and 76.9 % , respectively . Use of the smaller balloons or both balloons produced the highest rates of long-term freedom from AF . Phrenic nerve palsy occurred in 12 patients ( 2 % ) , resolving within 3 to 9 months . CONCLUSIONS Rates of long-term freedom from AF after cryoballoon ablation are similar to those reported for radiofrequency ablation . A choice between balloons may improve outcomes BACKGROUND Contact force ( CF ) monitoring could be useful in accomplishing circumferential pulmonary vein ( PV ) isolation ( CPVI ) for atrial fibrillation ( AF ) . OBJECTIVE The purpose of this study was to compare procedure parameters and outcomes between CF-guided and non-guided CPVI . METHODS Thirty-eight consecutive AF patients ( mean age 60 ± 11 years , 28 paroxysmal AF ) undergoing CPVI were r and omized to non-CF-guided ( n = 19 ) and CF-guided ( n = 19 ) groups .  CPVI was performed with the ThermoCool SmartTouch catheter in both groups . The end-point was bidirectional block between the left atrium ( LA ) and PV . In the CF group , CF was kept between 10 and 20 g during CPVI , whereas in the non-CF group , all CF information was blanked . Radiofrequency energy at 30 W in the anterior and 25 W in the posterior LA wall was applied for 20 - 25 seconds at each point . RESULTS CPVI was successfully accomplished without any major complications in both groups . Mean CF in the non-CF and CF groups were 5.9 ± 4.5 g and 11.1 ± 4.3 g , respectively , for left-side CPVI , and 9.8 ± 6.6 g and 12.1 ± 4.8 g , respectively , for right-side CPVI ( both P < .001 ) . The procedure and fluoroscopy times  for CPVI in the non-CF and CF groups were 96 ± 39 minutes and 59 ± 16 minutes , respectively ( P < .001 ) , and 22 ± 63 seconds and 9 ± 20 seconds ( P = NS ) , respectively . Total number of residual conduction gaps was 6.3 ± 3.0 in the non-CF group and 2.8 ± 1.9 in the CF group ( P < .001 ) . During 6-month follow-up , 84.2 % of patients in the non-CF group and 94.7 % in the CF group were free from any atrial tachyarrhythmias ( P = .34 ) . CONCLUSION CF-guided CPVI  is effective in reducing procedure time and additional touch-up ablation and may improve long-term outcome Background — There is a lack of data on the comparative efficacy and procedural safety of open irrigated radiofrequency ( RF ) and cryoballoon catheter ( CB ) ablation for pulmonary vein isolation in patients with paroxysmal atrial fibrillation . Methods and Results — In a prospect i ve , noninferiority study , 315 patients were r and omly assigned to RF ( n=159 ) or CB ( n=156 ) ablation . The primary end point was freedom from atrial arrhythmia with absence of persistent complications . Patients were largely comparable between groups with more vascular disease in the RF group ( 8.2 % versus 2.6 % for CB ; P=0.028 ) . The primary end point at 12 months was achieved by 70.7 % with RF and 73.6 % with CB ( multiple procedure success ) , including 31 redo procedures in each group ( 19.5 % of RF versus 19.9 % of CB ; P=0.933 ) . For the intention-to-treat population , noninferiority of CB was revealed for the predefined inferiority margin ( risk difference , 0.029 ; 95 % confidence interval , −0.074 to 0.132 ; P<0.001 ) . Rates at 6 months were 63.1 % and 64.1 % for the RF and CB groups ( single procedure success ) , and noninferiority was confirmed ( risk difference , 0.010 ; 95 % confidence interval , −0.097 to 0.116 ; P=0.002 ) . Periprocedural complications for the index procedure were more frequent in the CB group ( 5.0 % RF , 12.2 % CB ; P=0.022 ) with a significant difference in phrenic nerve palsies ( 0 % RF , 5.8 % CB ; P=0.002 ) . Conclusion — This large , prospect i ve , r and omized , controlled study demonstrates noninferiority of CB ablation versus RF ablation for treating patients with paroxysmal atrial fibrillation . Clinical Trial Registration — URL : http://www . clinical trials.gov . Unique identifier : NCT00774566 BACKGROUND Catheter ablation is an established treatment for atrial fibrillation ( AF ) .  Cryoballoon ablation ( CBA ) has emerged as an alternative to radiofrequency ablation ( RFA ) . However , there are few data comparing these modalities for treatment of paroxysmal AF ( pAF ) in the U.S. POPULATION The purpose of this study was to compare procedural times , safety , and efficacy of CBA against RFA . METHODS A single-center prospect i ve cohort study evaluated patients who underwent catheter ablation for pAF using CBA or RFA between January 1 , 2010 and October 31 , 2013 . Patients with prior ablation and those without rhythm follow-up for at least 3 months were excluded . The primary end point was freedom from AF , atrial flutter , and atrial tachycardia ( FFAF ) > 30 seconds after a 3-month blanking period without requirement for antiarrhythmic drugs . We also compared rates of successful pulmonary vein isolation ( PVI ) , fluoroscopy and procedure times , and major complication rates . RESULTS A total of 201 patients were included ( CBA = 101 , RFA = 100 ) . The rate of successful PVI was 99.3 % in CBA versus 97.4 % in RFA ( P = 0.08 ) . Procedure times were shorter with CBA ( 192.9 ± 44.0 minutes vs 283.7 ± 78.0 minutes , P < 0.001 ) as well as total fluoroscopy times ( 46.0 ± 22.4 minutes vs 73.0 ± 30.1 minutes , P < 0.001 ) . Overall complication rates were equivalent ; however , fewer cardiac perforations occurred with CBA ( 0 % vs 4 % , P = 0.042 ) . The 1-year FFAF rates were 60.3 % for CBA and 61.1 % for RFA ( log rank P = 0.93 ) . CONCLUSION CBA was associated with equivalent 1-year FFAF rate as RFA for pAF . Procedure and fluoroscopy times were shorter for CBA and fewer cardiac perforations occurred BACKGROUND Inflammation plays a prominent role in the etiology of the early recurrence of  atrial fibrillation ( ERAF ) . We prospect ively compared the proportion of ERAF and time-course patterns of biomarkers between radiofrequency ( RF ) and cryoballoon ( CB ) ablation . METHODS AND RESULTS We enrolled 82 consecutive paroxysmal AF patients undergoing pulmonary vein ( PV ) isolation , performed with either a 28-mm 2nd-generation CB and 3-min freeze technique or point-by-point RF ablation .  Each group had 41 patients . In the RF group , all PVs were successfully isolated with 28.9 ± 6.5 min of RF delivery . In the CB group , a mean of 5.3 ± 1.4 applications/patient was delivered . The proportion of ERAF was similar between the groups . The time-course patterns significantly differed between the groups for high-sensitivity C-reactive protein ( hs-CRP ) value ( P=0.006 ) and myocardial injury markers ( P<0.0001 ) . Greater myocardial injury was observed in the CB than in the RF group ( P<0.0001 ) , whereas the peak hs-CRP value was comparable between the groups . The 2-day post-procedure hs-CRP value was the sole factor correlating with ERAF as identified by the multivariable analysis ( hazard ratio 1.697 ; 95 % confidence interval , 1.005 - 2.865 ; P=0.048 ) in the RF , but not the CB group . CONCLUSIONS The proportion of ERAF was comparable after RF and 2nd-generation CB ablation . Despite CB ablation exhibiting greater myocardial injury than RF ablation , the inflammatory responses were comparable between the groups . The inflammatory response extent predicted ERAF post-RF ablation but not post-CB ablation INTRODUCTION Catheter ablation of paroxysmal AF using the Cryoballoon ( CRYO ) has yielded similar success rates to conventional wide encirclement using radiofrequency catheter ablation ( RFCA ) , but r and omized data are lacking . Pilot data suggested a high success rate with a combined approach ( COMBINED ) using wide encirclement with RFCA followed by 2 CRYO applications to each vein . We compared these 3 strategies in a r and omized controlled trial . METHODS AND RESULTS Patients undergoing first time paroxysmal AF ablation were r and omized to RFCA , CRYO , or COMBINED . Patients were followed up at 3 , 6 , and 12 months with 7 days of ambulatory ECG monitoring . Success was defined as freedom from arrhythmia without antiarrhythmic drugs after a single procedure . A total of 237 patients were r and omized . Success at 1 year was achieved in 47 % in the RFCA group , 67 % in the CRYO group , and 76 % in the COMBINED group ( P < 0.001 for RFCA vs. CRYO , P<0.001 for RFCA vs. COMBINED , and P = 0.220 for CRYO vs. COMBINED ) . Procedure time was 211 ( IQR 174 - 256 ) minutes for RFCA compared to 167 ( 136 - 202 ) minutes for CRYO and 278 ( 243 - 327 ) minutes for COMBINED ( P < 0.001 for RFCA vs. COMBINED , RFCA vs. CRYO , and CRYO vs. COMBINED groups ) . CONCLUSIONS Pulmonary vein isolation for paroxysmal AF is faster with CRYO and results in a higher single procedure success rate than conventional point by point RFCA . The COMBINED approach was not superior to CRYO alone Background — Contact force ( CF ) is a major determinant of lesion size and transmurality and has the potential to improve efficacy of atrial fibrillation ablation . This study sought to evaluate the safety and effectiveness of a novel irrigated radiofrequency ablation catheter that measures real-time CF in the treatment of patients with paroxysmal atrial fibrillation . Methods and Results — A total of 300 patients with symptomatic , drug-refractory , paroxysmal atrial fibrillation were enrolled in a prospect i ve , multicenter , r and omized , controlled trial and r and omized to radiofrequency ablation with either a novel CF-sensing catheter or a non-CF catheter ( control ) . The primary effectiveness end point consisted of acute electrical isolation of all pulmonary veins and freedom from recurrent symptomatic atrial arrhythmia off all antiarrhythmic drugs at 12 months . The primary safety end point included device-related serious adverse events . End points were powered to show noninferiority . All pulmonary veins were isolated in both groups . Effectiveness was achieved in 67.8 % and 69.4 % of subjects in the CF and control arms , respectively ( absolute difference , −1.6 % ; lower limit of 1-sided 95 % confidence interval , −10.7 % ; P=0.0073 for noninferiority ) . When the CF arm was stratified into optimal CF ( ≥90 % ablations with ≥10 g ) and nonoptimal CF groups , effectiveness was achieved in 75.9 % versus 58.1 % , respectively ( P=0.018 ) . The primary safety end point occurred in 1.97 % and 1.40 % of CF patients and control subjects , respectively ( absolute difference , 0.57 % ; upper limit of 1-sided 95 % confidence interval , 3.61 % ; P=0.0004 for noninferiority ) . Conclusions — The CF ablation catheter met the primary safety and effectiveness end points . Additionally , optimal CF was associated with improved effectiveness . Clinical Trial Registration — http://www . clinical trials.gov . Unique identifier : NCT01278953 AIMS In the setting of paroxysmal atrial fibrillation ( AF ) , there are no available data comparing the mid-term outcome of patients undergoing pulmonary vein isolation ( PVI ) catheter ablation using contact-force (CF)-guided radiofrequency ( RF ) vs. second-generation balloon cryotherapy . METHODS AND RESULTS Prospect i ve single-centre evaluation , carried out from March 2011 to February 2013 , comparing CF radiofrequency ( Thermocool ( ® ) SmartTouch ™ , Biosense Webster , Inc. ) ( CF group ) with cryoballoon ablation ( A rct ic Front Advance ™ 28 mm cryoballoon , Medtronic , Inc. ) ( CB group ) , in regards to procedural safety and efficacy , as well as recurrence at 12 months . Overall , 150 consecutive patients were enrolled ( 75 in each group ) . The characteristics of patients of both the groups were similar ( 61.2 ± 9.9 years , women 25.3 % , mean AF duration 4.1 ± 4.0 years , mean CHA2DS2-VASc score 1.4 ± 1.3 , mean HAS-BLED 1.4 ± 0.6 ) . Duration of the procedure was significantly lower in the CF group ( 110.7 ± 32.5 vs. 134.5 ± 48.3 min , P = 0.001 ) , with a lower duration of fluoroscopy ( 21.5 ± 8.5 vs. 25.3 ± 9.9 min , P = 0.017 ) and X-ray exposure ( 4748 ± 2411 cGy cm² vs. 7734 ± 5361 cGy cm² , P = 0.001 ) . In contrast , no significant difference was found regarding significant procedural complication ( 2.7 vs. 1.3 % in CF and CB groups , respectively ; P = 0.56 ) , and PVI was eventually achieved in all cases . At 12 months , AF recurrence occurred in 11 patients ( 14.7 % ) in the CB group and in 9 patients ( 12.0 % ) in the CF group ( HR = 1.20 95 % CI 0.50 - 2.90 ; log rank P = 0.682 ) . CONCLUSIONS Our preliminary findings suggest that CF-guided radiofrequency and cryotherapy present very similar performances in the setting of paroxysmal AF catheter ablation BACKGROUND Results from r and omized trials design ed to compare cryoenergy with radiofrequency for pulmonary vein ( PV ) isolation are lacking . OBJECTIVE To compare the efficacy of a simplified strategy for PV cryoablation ( group C ) vs PV isolation with open-irrigated radiofrequency catheters ( group R ) . METHODS Fifty patients with paroxysmal atrial fibrillation ( AF ) and 4 independent PVs received a Reveal XT implantable cardiac monitor and were r and omized to group C or group R. In group C , PV ablation was done with a single A rct ic Front balloon ( 23 or 28 mm ) per patient and two 300-second applications per PV . No further applications were delivered to close residual conduction gaps . In group R , bidirectional PV conduction block was pursued with Lasso and Navistar ThermoCool catheters and the CARTO system . The primary end point was the proportion of patients remaining free from AF recurrences ≥2 minutes without taking antiarrhythmic drugs 12 months after ablation . RESULTS The primary end point was met by 12 ( 48 % ) patients in group C and 25 ( 68 % ) patients in group R ( odds ratio 0.43 ; P = .05 ) . This difference disappeared after adjustment for acute procedural outcome . In patients for whom all 4 PVs were blocked at the end of the procedure , there was no difference between group C and group R in the primary end point ( 67 % vs 68 % ; P = .94 ) . CONCLUSIONS The efficacy of the simplified strategy for PV cryoablation tested in this study is inferior to PV isolation using open-irrigated radiofrequency catheters with electrophysiological and electroanatomical guidance . Complete PV conduction block is critical to the success of AF ablation INTRODUCTION Hemi-diaphragmatic paralysis is the most common complication associated with cryoballoon ablation for atrial fibrillation , yet the histopathology of phrenic nerve injury has not been well described . METHODS AND RESULTS A pre clinical r and omized study was conducted to characterize the histopathology of phrenic nerve injury induced by cryoballoon ablation and assess the potential for electromyographic ( EMG ) monitoring to limit phrenic nerve damage . Thirty-two dogs underwent cryoballoon ablation of the right superior pulmonary vein with the objective of inducing phrenic nerve injury . Animals were r and omized 1:1 to st and ard monitoring ( i.e. , interruption of ablation upon reduction in diaphragmatic motion ) versus EMG guidance ( i.e. , cessation of ablation upon a 30 % reduction in the diaphragmatic compound motor action potential [ CMAP ] amplitude ) . The acute procedural endpoint was achieved in all dogs . Phrenic nerve injury was characterized by Wallerian degeneration , with subperineural injury to large myelinated axons and evidence of axonal regeneration . The degree of phrenic nerve injury paralleled the reduction in CMAP amplitude ( P = 0.007 ) . Animals r and omized to EMG guidance had a lower incidence of acute hemi-diaphragmatic paralysis ( 50 % vs 100 % ; P = 0.001 ) , persistent paralysis at 30 days ( 21 % vs 75 % ; multivariate odds ratio 0.12 , 95 % confidence interval [ 0.02 , 0.69 ] , P = 0.017 ) , and a lesser severity of histologic injury ( P = 0.001 ) . Mature pulmonary vein ablation lesion characteristics , including circumferentiality and transmurality , were similar in both groups . CONCLUSION Phrenic nerve injury induced by cryoballoon ablation is axonal in nature and characterized by Wallerian degeneration , with potential for recovery . An EMG-guided approach is superior to st and ard monitoring in limiting phrenic nerve damage BACKGROUND Current guidelines recommend pulmonary-vein isolation by means of catheter ablation as treatment for drug-refractory paroxysmal atrial fibrillation .  Radiofrequency ablation is the most common method , and cryoballoon ablation is the second most frequently used technology . METHODS We conducted a multicenter , r and omized trial to determine whether cryoballoon ablation was noninferior to radiofrequency ablation in symptomatic patients with drug-refractory paroxysmal atrial fibrillation . The primary efficacy end point in a time-to-event analysis was the first documented clinical failure ( recurrence of atrial fibrillation , occurrence of atrial flutter or atrial tachycardia , use of antiarrhythmic drugs , or repeat ablation ) following a 90-day period after the index ablation . The noninferiority margin was prespecified as a hazard ratio of 1.43 . The primary safety end point was a composite of death , cerebrovascular events , or serious treatment-related adverse events . RESULTS A total of 762 patients underwent r and omization ( 378 assigned to cryoballoon ablation and 384 assigned to radiofrequency ablation ) . The mean duration of follow-up was 1.5 years . The primary efficacy end point occurred in 138 patients in the cryoballoon group and in 143 in the radiofrequency group ( 1-year Kaplan-Meier event rate estimates , 34.6 % and 35.9 % , respectively ; hazard ratio , 0.96 ; 95 % confidence interval [ CI ] , 0.76 to 1.22 ; P<0.001 for noninferiority ) . The primary safety end point occurred in 40 patients in the cryoballoon group and in 51 patients in the radiofrequency group ( 1-year Kaplan-Meier event rate estimates , 10.2 % and 12.8 % , respectively ; hazard ratio , 0.78 ; 95 % CI , 0.52 to 1.18 ; P=0.24 ) . CONCLUSIONS In this r and omized trial , cryoballoon ablation was noninferior to radiofrequency ablation with respect to efficacy for the treatment of patients with drug-refractory paroxysmal atrial fibrillation , and there was no significant difference between the two methods with regard to overall safety . ( Funded by Medtronic ; FIRE AND ICE Clinical Trials.gov number , NCT01490814 . ) BACKGROUND Phrenic nerve palsy ( PNP ) is the most frequently observed complication during  cryoballoon ablation ( CB ; A rct ic Front , Medtronic , MN ) occurring in roughly 7%-9 % of the cases . The new second-generation cryoballoon ablation A rct ic Front Advance ( CB-A ) ( A rct ic Front ) has recently been launched in the market . OBJECTIVE To evaluate the incidence of right PNP with the new CB-A in comparison with the first-generation balloon in a series of consecutive patients that underwent pulmonary vein isolation with this modality . METHODS The study was design ed as an observational study with a prospect i ve follow-up . In total , 121 consecutive patients were included : 80 patients with the CB ( group 1 ) and 41 with the CB-A ( group 2 ) . RESULTS Mean procedural times , fluoroscopic times , and time to pulmonary vein isolation documented by real-time recordings were significantly lower in group 2 ( P ≤ .05 ) . The occurrence of PNP was significantly higher in group 2 ( 6.25 % [ 5 of 80 ] in group 1 vs 19.5 % [ 8 of 41 ] in group 2 ; P = .033 ) . At 7 months , PNP persisted in 1 ( 2.5 % ) patient in the CB-A group . CONCLUSIONS Right PNP seems to occur in a significantly larger number of patients with the second-generation CB-A. However , this complication is reversible in nearly all cases on short-term follow-up . More refined phrenic nerve monitoring during right-sided pulmonary vein ablation and less vigorous wedging maneuvers in the pulmonary vein ostia might significantly reduce the occurrence of this complication OBJECTIVES The purpose of this study was to investigate the efficacy safety of the novel cryoballoon device ( A rct ic Front , Cryocath , Quebec , Canada ) . BACKGROUND Antral pulmonary vein ( PV ) ablation with radiofrequency energy is widely used as a strategy for catheter ablation of paroxysmal atrial fibrillation ( PAF ) . A novel double lumen cryoballoon catheter was design ed for circumferential pulmonary vein isolation ( PVI ) with the cryoablation technique . METHODS We consecutively enrolled 346 patients with symptomatic , drug refractory paroxysmal ( n = 293 ) or persistent ( n = 53 ) atrial fibrillation ( AF ) . In all patients , PVI of all targeted PVs was the therapeutic aim . The primary end points of this nonr and omized study were : 1 ) acute isolation rate of targeted PV ; and 2 ) first electrocardiogram-documented recurrence of AF . The secondary end point was occurrence of PV stenosis or atrio-esophageal fistula . RESULTS The 1,360 of 1,403 PVs ( 97 % ) were targeted with balloons or balloons in combination with the use of Freezor Max ( Cryocath ) . We found that ablation with the cryoballoon result ed in maintenance of sinus rhythm in 74 % of patients with PAF and 42 % of patients with persistent AF . No PV narrowing occurred . The most frequent complication was right phrenic nerve palsy observed during cryoballoon ablation at the right superior PV . CONCLUSIONS Pulmonary vein isolation with a new cryoballoon technique is feasible . Sinus rhythm can be maintained in the majority of patients with PAF by circumferential PVI using a cryoballoon ablation system . Cryoablation was less effective in patients with persistent AF than in patients with PAF
target: Conclusions CB-2 tended to be more effective in comparison to NCF catheter and at least non-inferior to CF catheter , with shorter procedure time and similar safety endpoint
background: Purpose Currently , radiofrequency ( RF ) and cryoballoon are the most commonly used ablation technologies for atrial fibrillation ( AF ) .
  We performed a meta- analysis to assess the efficacy and safety of the second-generation cryoballoons ( CB-2 ) compared with RF for paroxysmal atrial fibrillation ( PAF ) ablation .