Expert Review of Medical Devices
ISSN: 1743-4440 (Print) 1745-2422 (Online) Journal homepage: http://www.tandfonline.com/loi/ierd20
A critical evaluation of second-generation AF ablation technologies: cryoballoons and contact forces Jason Andrade, Marc Dubuc & Laurent Macle To cite this article: Jason Andrade, Marc Dubuc & Laurent Macle (2016): A critical evaluation of second-generation AF ablation technologies: cryoballoons and contact forces, Expert Review of Medical Devices, DOI: 10.1586/17434440.2016.1153970 To link to this article: http://dx.doi.org/10.1586/17434440.2016.1153970
Accepted author version posted online: 15 Feb 2016.
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Date: 18 February 2016, At: 01:24
Publisher: Taylor & Francis Journal: Expert Review of Medical Devices DOI: 10.1586/17434440.2016.1153970 A critical evaluation of second-generation AF ablation technologies: cryoballoons and contact forces Authors: Jason Andrade, Marc Dubuc and Laurent Macle Downloaded by [117.253.106.82] at 01:24 18 February 2016
Corresponding author: Jason Andrade [email protected] Institut De Cardiologie de Montreal Ringgold standard institution Montreal, Quebec H1T 1C8 Canada Abstract Despite considerable success, pulmonary isolation procedures have limitations. Considerable effort has been directed towards developing technologies to achieve safer and more durable pulmonary vein isolation. The two biggest advances in the last few years have centered on the development of dedicated “single-shot” pulmonary vein isolation tools, the most mature of which is the Arctic Front cryoballoon (Medtronic, Minneapolis, MN). Similarly, recognizing that electrodetissue contact is important determinant of lesion durability point-by-point radiofrequency ablation catheters have evolved to integrate an accurate real-time quantitative assessment of catheter contact force. This editorial discusses recent evidence regarding these technologies. Keywords atrial fibrillation, ablation, cryoballoon, contact force, pulmonary vein isolation
1
Downloaded by [117.253.106.82] at 01:24 18 February 2016
For many highly symptomatic patients with atrial fibrillation catheter ablation offers an efficacious means to maintaining sinus rhythm.1, 2 Over the past 15 years large-scale observational studies and randomized controlled trials have demonstrated that the success rate of catheter ablation in maintaining sinus rhythm is universally superior to that of drug therapy, thus moving it from an “experimental therapy” to the standard of care for the maintenance of sinus rhythm. 3-11 In addition, catheter ablation has been shown to be superior to AADs for the improvement of symptoms, exercise capacity, and quality of life.5, 12-14
The early percutaneous catheter ablation procedures were designed to compartmentalize the left atrium (LA) into smaller regions incapable of sustaining the critical number of circulating wavelets, functionally replicating the lines of a surgical Cox maze procedure. While AF maintenance by randomly propagating wavelets may occur in some cases, the identification of sites of AF initiation and/or perpetuation within the pulmonary veins (PV) led to the development of percutaneous procedures designed to electrically isolate the PV (PVI) from the vulnerable LA substrate. The contemporary AF ablation procedure, as recommended by major heart rhythm societies, involves the creation of wide circumferential ablative lesions within the LA myocardium outside of the tubular veins with a goal of electrical PVI, effectively targeting not only the initiating triggers of AF (the PVs) but also the mass of electrically active LA tissue capable of sustaining the fibrillatory wavelets responsible for perpetuating AF. However, despite considerable success PVI has limitations. Recurrence due to a failure to effectuate a lasting transmural lesion is not infrequent.3-11 As such, considerable effort has been directed towards developing technologies to achieve safer and more durable PV isolation. The two biggest advances in the last few years have centered on: 1) the development of dedicated “single-shot” PVI tools, the most mature of which is the Arctic Front cryoballoon (Medtronic, Minneapolis, MN), and 2) the integration of an accurate real-time quantitative assessment of catheter contact force into focal point-by-point RF ablation catheters. Cryoballoon Ablation
The cryoballoon system consists of a steerable 10.5-Fr catheter with distally mounted polyurethane and polyester balloons specifically designed to facilitate PVI. Cryorefrigerant is delivered to the distal aspect of the inner balloon from an external CryoConsole® via an ultrafine injection tube where it is pressurized through a restriction tube before undergoing a liquid-to-gas phase change as it enters the distal aspect of the inner balloon. The cryorefrigerant then absorbs heat from the tissue before returning to the console through a central lumen maintained under vacuum. In a recent observational meta-analysis, we reported that cryoballoon ablation resulted in a high procedural success rate (>98% of patients achieving complete PVI) and a 1-year freedom from recurrent AF (1 year single procedure success of 60% off AAD; 73% if a 3-month blanking period was included).15 A subsequent
2
comparative meta-analysis reported similar freedom from recurrent AF at a mean follow-up of 16.5 months vs. standard (“first-generation”) RF ablation (66.9% vs 65.1%; RR 1.01; 95% CI: 0.94 to 1.07, P = 0.87).
Downloaded by [117.253.106.82] at 01:24 18 February 2016
Since the publication of these analyses the cryoballoon has undergone a significant iterative evolution. In the first generation catheter, 6.2 L/min of vapor was sprayed to the distal face of the balloon through 4 jets positioned 90° from one another, slightly distal to the cryoballoon equator. The second-generation (Arctic Front Advance) catheter refined the design by increasing, and repositioning the jets more distally resulting in an increased uniformity of cooling around the entirety of the distal surface of the cryoballoon.
Recent studies have examined the short and long-term success with the secondgeneration cryoballoon. Studies of planned re-mapping procedures have demonstrated that the durability of PVI at three months post index ablation procedure has improved from 67% of PVs (23% of patients with all 4 PVs isolated) with standard RF, to 88% of PVs (67% of patients with all 4 PVs isolated) with the first generation cryoballoon, to 91% of PVs (79% of patients with all 4 PVs isolated).16-21 Clinically this has translated into a one-year freedom from recurrent AF of 82% with the second generation cryoballoon (11 studies; 1725 patients), which was significantly improved compared to the first generation cryoballoon in a separate comparative meta-analysis (OR of arrhythmia recurrence 0.34 [0.26-0.45] when compared to first-generation cryoballoon; 10 studies, 2310 patients).22 While there was no significant difference in access site complication or pericardial effusion, significantly more phrenic nerve palsies (transient and persistent) were observed with the first generation cryoballoon. Contact Force
The most commonly used point-by-point RF contact force sensing catheter systems are TactiCath (St. Jude Medical, St Paul, USA) and SmartTouch (Biosense Webster, Diamond Bar, CA). TactiCath estimates axial and lateral contact force by examining the wavelength of the light emitted from fiberoptic tubes embedded within an open irrigated-tip ablation catheter. Forces applied at the tip of the catheter result in micro-deformation of optical fibers, changing in the wavelength of the light proportional to the force applied (with a sensitivity of 1g). SmartTouch uses electromagnetic location technology to detect movement between a precision spring (mounted within the tip of a 3.5mm externally irrigated RF ablation catheter) and three location sensor coils are also mounted within the shaft of the catheter. These movements are sampled every 50 msec and calibrated to produce a contact force reading (in grams) that is averaged over 1 second. Recent data suggests that incorporating real-time contact force assessment into the ablation procedure results in a reduction in procedure time, ablation time and total energy delivery, with a comparable safety profile to that observed with standard irrigated RF.18, 23 However, the two largest multicenter trials evaluating this technology demonstrated a one-year success of 68% (TactiCath, TOCCASTAR24) and
3
74% (SmartTouch, SMART-AF25). In the case of the former the success was no different from that observed with standard non-contact force RF ablation. Interestingly, post-hoc analyses of these studies have suggested that the outcomes were improved when the procedure was performed with adequate CF parameters (84% one-year freedom from AF in the 47% of patients in whom ablation was in the target range ≥80% of the time in SMART-AF, and 76% one-year freedom from AF in the 57% of patients in whom ≥90% of the lesions were >10g in TOCCASTAR). No differences in the incidence of complications have been reported between patients undergoing ablation with the contact force vs. non-contact force sensing RF ablation catheters in randomized (TOCCASTAR) or non-randomised studies.24, 26, 27 Downloaded by [117.253.106.82] at 01:24 18 February 2016
Conclusion
Second generation AF ablation technologies have resulted in improved clinical outcomes, while achieving a reduction in procedure time. Financial and competing interests disclosure J. Andrade is an advisor to and has received grants from Medtronic. M. Dubuc has received grants from Medtronic. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.
4
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References: 1. Karch MR, Zrenner B, Deisenhofer I, Schreieck J, Ndrepepa G, Dong J, Lamprecht K, Barthel P, Luciani E, Schomig A and Schmitt C. Freedom from atrial tachyarrhythmias after catheter ablation of atrial fibrillation: a randomized comparison between 2 current ablation strategies. Circulation. 2005;111:2875-80. 2. Oral H, Knight BP, Tada H, Ozaydin M, Chugh A, Hassan S, Scharf C, Lai SW, Greenstein R, Pelosi F, Jr., Strickberger SA and Morady F. Pulmonary vein isolation for paroxysmal and persistent atrial fibrillation. Circulation. 2002;105:1077-81. 3. Pappone C, Vicedomini G, Augello G, Manguso F, Saviano M, Baldi M, Petretta A, Giannelli L, Calovic Z, Guluta V, Tavazzi L and Santinelli V. Radiofrequency catheter ablation and antiarrhythmic drug therapy: a prospective, randomized, 4year follow-up trial: the APAF study. Circ Arrhythm Electrophysiol. 2011;4:808-14. 4. Wazni OM, Marrouche NF, Martin DO, Verma A, Bhargava M, Saliba W, Bash D, Schweikert R, Brachmann J, Gunther J, Gutleben K, Pisano E, Potenza D, Fanelli R, Raviele A, Themistoclakis S, Rossillo A, Bonso A and Natale A. Radiofrequency ablation vs antiarrhythmic drugs as first-line treatment of symptomatic atrial fibrillation: a randomized trial. JAMA. 2005;293:2634-40. 5. Jais P, Cauchemez B, Macle L, Daoud E, Khairy P, Subbiah R, Hocini M, Extramiana F, Sacher F, Bordachar P, Klein G, Weerasooriya R, Clementy J and Haissaguerre M. Catheter ablation versus antiarrhythmic drugs for atrial fibrillation: the A4 study. Circulation. 2008;118:2498-505. 6. Oral H, Pappone C, Chugh A, Good E, Bogun F, Pelosi F, Jr., Bates ER, Lehmann MH, Vicedomini G, Augello G, Agricola E, Sala S, Santinelli V and Morady F. Circumferential pulmonary-vein ablation for chronic atrial fibrillation. N Engl J Med. 2006;354:934-41. 7. Packer DL, Irwin JM, Champagne J, Guerra PG, Dubuc M, Wheelan KR, Kowal RC, Reddy VY, Lehmann J, Holcomb RG and Ruskin J. Cryoballoon ablation of pulmonary veins for paroxysmal atrial fibrillation: first results of the North American Arctic Front STOP-AF pivotal trial. J Am Coll Cardiol. 2010;55:E3015-3016. 8. Krittayaphong R, Raungrattanaamporn O, Bhuripanyo K, Sriratanasathavorn C, Pooranawattanakul S, Punlee K and Kangkagate C. A randomized clinical trial of the efficacy of radiofrequency catheter ablation and amiodarone in the treatment of symptomatic atrial fibrillation. Journal of the Medical Association of Thailand = Chotmaihet thangphaet. 2003;86 Suppl 1:S8-16. 9. Noheria A, Kumar A, Wylie JV, Jr. and Josephson ME. Catheter ablation vs antiarrhythmic drug therapy for atrial fibrillation: a systematic review. Arch Intern Med. 2008;168:581-6. 10. Stabile G, Bertaglia E, Senatore G, De Simone A, Zoppo F, Donnici G, Turco P, Pascotto P, Fazzari M and Vitale DF. Catheter ablation treatment in patients with drug-refractory atrial fibrillation: a prospective, multi-centre, randomized, controlled study (Catheter Ablation For The Cure Of Atrial Fibrillation Study). Eur Heart J. 2006;27:216-21. 11. Wilber DJ, Pappone C, Neuzil P, De Paola A, Marchlinski F, Natale A, Macle L, Daoud EG, Calkins H, Hall B, Reddy V, Augello G, Reynolds MR, Vinekar C, Liu CY, Berry SM and Berry DA. Comparison of antiarrhythmic drug therapy and 5
Downloaded by [117.253.106.82] at 01:24 18 February 2016
radiofrequency catheter ablation in patients with paroxysmal atrial fibrillation: a randomized controlled trial. JAMA. 2010;303:333-40. 12. Bunch TJ, Crandall BG, Weiss JP, May HT, Bair TL, Osborn JS, Anderson JL, Muhlestein JB, Horne BD, Lappe DL and Day JD. Patients treated with catheter ablation for atrial fibrillation have long-term rates of death, stroke, and dementia similar to patients without atrial fibrillation. J Cardiovasc Electrophysiol. 2011;22:839-45. 13. Piccini JP, Lopes RD, Kong MH, Hasselblad V, Jackson K and Al-Khatib SM. Pulmonary vein isolation for the maintenance of sinus rhythm in patients with atrial fibrillation: a meta-analysis of randomized, controlled trials. Circ Arrhythm Electrophysiol. 2009;2:626-33. 14. Wokhlu A, Monahan KH, Hodge DO, Asirvatham SJ, Friedman PA, Munger TM, Bradley DJ, Bluhm CM, Haroldson JM and Packer DL. Long-term quality of life after ablation of atrial fibrillation the impact of recurrence, symptom relief, and placebo effect. J Am Coll Cardiol. 2010;55:2308-16. 15. Andrade JG, Khairy P, Guerra PG, Deyell MW, Rivard L, Macle L, Thibault B, Talajic M, Roy D and Dubuc M. Efficacy and safety of cryoballoon ablation for atrial fibrillation: A systematic review of published studies. Heart Rhythm. 2011;8:144451. 16. Kuck KH, Hoffmann BA, Ernst S, Wegscheider K, Treszl A, Metzner A, Eckardt L, Lewalter T, Breithardt G, Willems S and Gap AFAI. Impact of Complete Versus Incomplete Circumferential Lines Around the Pulmonary Veins During Catheter Ablation of Paroxysmal Atrial Fibrillation: Results From the Gap-Atrial FibrillationGerman Atrial Fibrillation Competence Network 1 Trial. Circ Arrhythm Electrophysiol. 2016;9:e003337. 17. Willems S, Steven D, Servatius H, Hoffmann BA, Drewitz I, Mullerleile K, Aydin MA, Wegscheider K, Salukhe TV, Meinertz T and Rostock T. Persistence of pulmonary vein isolation after robotic remote-navigated ablation for atrial fibrillation and its relation to clinical outcome. J Cardiovasc Electrophysiol. 2010;21:1079-84. 18. Neuzil P, Reddy VY, Kautzner J, Petru J, Wichterle D, Shah D, Lambert H, Yulzari A, Wissner E and Kuck KH. Electrical reconnection after pulmonary vein isolation is contingent on contact force during initial treatment: results from the EFFICAS I study. Circ Arrhythm Electrophysiol. 2013;6:327-33. 19. Kautzner J, Neuzil P, Lambert H, Peichl P, Petru J, Cihak R, Skoda J, Wichterle D, Wissner E, Yulzari A and Kuck KH. EFFICAS II: optimization of catheter contact force improves outcome of pulmonary vein isolation for paroxysmal atrial fibrillation. Europace. 2015;17:1229-35. 20. Reddy VY, Sediva L, Petru J, Skoda J, Chovanec M, Chitovova Z, Di Stefano P, Rubin E, Dukkipati S and Neuzil P. Durability of Pulmonary Vein Isolation with Cryoballoon Ablation: Results from the Sustained PV Isolation with Arctic Front Advance (SUPIR) Study. J Cardiovasc Electrophysiol. 2015;26:493-500. 21. Ahmed H, Neuzil P, Skoda J, D'Avila A, Donaldson DM, Laragy MC and Reddy VY. The permanency of pulmonary vein isolation using a balloon cryoablation catheter. J Cardiovasc Electrophysiol. 2010;21:731-7. 6
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22. Pandya B, Sheikh A, Spagnola J, Bekheit S, Lafferty J and Kowalski M. Safety and efficacy of second-generation versus first-generation cryoballoons for treatment of atrial fibrillation: a meta-analysis of current evidence. J Interv Card Electrophysiol. 2015. 23. Reddy VY, Shah D, Kautzner J, Schmidt B, Saoudi N, Herrera C, Jais P, Hindricks G, Peichl P, Yulzari A, Lambert H, Neuzil P, Natale A and Kuck KH. The relationship between contact force and clinical outcome during radiofrequency catheter ablation of atrial fibrillation in the TOCCATA study. Heart Rhythm. 2012;9:1789-95. 24. Reddy VY, Dukkipati SR, Neuzil P, Natale A, Albenque JP, Kautzner J, Shah D, Michaud G, Wharton M, Harari D, Mahapatra S, Lambert H and Mansour M. Randomized, Controlled Trial of the Safety and Effectiveness of a Contact ForceSensing Irrigated Catheter for Ablation of Paroxysmal Atrial Fibrillation: Results of the TactiCath Contact Force Ablation Catheter Study for Atrial Fibrillation (TOCCASTAR) Study. Circulation. 2015;132:907-15. 25. Natale A, Reddy VY, Monir G, Wilber DJ, Lindsay BD, McElderry HT, Kantipudi C, Mansour MC, Melby DP, Packer DL, Nakagawa H, Zhang B, Stagg RB, Boo LM and Marchlinski FE. Paroxysmal AF catheter ablation with a contact force sensing catheter: results of the prospective, multicenter SMART-AF trial. J Am Coll Cardiol. 2014;64:647-56. 26. Andrade JG, Monir G, Pollak SJ, Khairy P, Dubuc M, Roy D, Talajic M, Deyell M, Rivard L, Thibault B, Guerra PG, Nattel S and Macle L. Pulmonary vein isolation using "contact force" ablation: the effect on dormant conduction and long-term freedom from recurrent atrial fibrillation--a prospective study. Heart Rhythm. 2014;11:191924. 27. Marijon E, Fazaa S, Narayanan K, Guy-Moyat B, Bouzeman A, Providencia R, Treguer F, Combes N, Bortone A, Boveda S, Combes S and Albenque JP. Real-time contact force sensing for pulmonary vein isolation in the setting of paroxysmal atrial fibrillation: procedural and 1-year results. J Cardiovasc Electrophysiol. 2014;25:130-
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ISSN: 1743-4440 (Print) 1745-2422 (Online) Journal homepage: http://www.tandfonline.com/loi/ierd20
A critical evaluation of second-generation AF ablation technologies: cryoballoons and contact forces Jason Andrade, Marc Dubuc & Laurent Macle To cite this article: Jason Andrade, Marc Dubuc & Laurent Macle (2016): A critical evaluation of second-generation AF ablation technologies: cryoballoons and contact forces, Expert Review of Medical Devices, DOI: 10.1586/17434440.2016.1153970 To link to this article: http://dx.doi.org/10.1586/17434440.2016.1153970
Accepted author version posted online: 15 Feb 2016.
Submit your article to this journal
Article views: 5
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ierd20 Download by: [117.253.106.82]
Date: 18 February 2016, At: 01:24
Publisher: Taylor & Francis Journal: Expert Review of Medical Devices DOI: 10.1586/17434440.2016.1153970 A critical evaluation of second-generation AF ablation technologies: cryoballoons and contact forces Authors: Jason Andrade, Marc Dubuc and Laurent Macle Downloaded by [117.253.106.82] at 01:24 18 February 2016
Corresponding author: Jason Andrade [email protected] Institut De Cardiologie de Montreal Ringgold standard institution Montreal, Quebec H1T 1C8 Canada Abstract Despite considerable success, pulmonary isolation procedures have limitations. Considerable effort has been directed towards developing technologies to achieve safer and more durable pulmonary vein isolation. The two biggest advances in the last few years have centered on the development of dedicated “single-shot” pulmonary vein isolation tools, the most mature of which is the Arctic Front cryoballoon (Medtronic, Minneapolis, MN). Similarly, recognizing that electrodetissue contact is important determinant of lesion durability point-by-point radiofrequency ablation catheters have evolved to integrate an accurate real-time quantitative assessment of catheter contact force. This editorial discusses recent evidence regarding these technologies. Keywords atrial fibrillation, ablation, cryoballoon, contact force, pulmonary vein isolation
1
Downloaded by [117.253.106.82] at 01:24 18 February 2016
For many highly symptomatic patients with atrial fibrillation catheter ablation offers an efficacious means to maintaining sinus rhythm.1, 2 Over the past 15 years large-scale observational studies and randomized controlled trials have demonstrated that the success rate of catheter ablation in maintaining sinus rhythm is universally superior to that of drug therapy, thus moving it from an “experimental therapy” to the standard of care for the maintenance of sinus rhythm. 3-11 In addition, catheter ablation has been shown to be superior to AADs for the improvement of symptoms, exercise capacity, and quality of life.5, 12-14
The early percutaneous catheter ablation procedures were designed to compartmentalize the left atrium (LA) into smaller regions incapable of sustaining the critical number of circulating wavelets, functionally replicating the lines of a surgical Cox maze procedure. While AF maintenance by randomly propagating wavelets may occur in some cases, the identification of sites of AF initiation and/or perpetuation within the pulmonary veins (PV) led to the development of percutaneous procedures designed to electrically isolate the PV (PVI) from the vulnerable LA substrate. The contemporary AF ablation procedure, as recommended by major heart rhythm societies, involves the creation of wide circumferential ablative lesions within the LA myocardium outside of the tubular veins with a goal of electrical PVI, effectively targeting not only the initiating triggers of AF (the PVs) but also the mass of electrically active LA tissue capable of sustaining the fibrillatory wavelets responsible for perpetuating AF. However, despite considerable success PVI has limitations. Recurrence due to a failure to effectuate a lasting transmural lesion is not infrequent.3-11 As such, considerable effort has been directed towards developing technologies to achieve safer and more durable PV isolation. The two biggest advances in the last few years have centered on: 1) the development of dedicated “single-shot” PVI tools, the most mature of which is the Arctic Front cryoballoon (Medtronic, Minneapolis, MN), and 2) the integration of an accurate real-time quantitative assessment of catheter contact force into focal point-by-point RF ablation catheters. Cryoballoon Ablation
The cryoballoon system consists of a steerable 10.5-Fr catheter with distally mounted polyurethane and polyester balloons specifically designed to facilitate PVI. Cryorefrigerant is delivered to the distal aspect of the inner balloon from an external CryoConsole® via an ultrafine injection tube where it is pressurized through a restriction tube before undergoing a liquid-to-gas phase change as it enters the distal aspect of the inner balloon. The cryorefrigerant then absorbs heat from the tissue before returning to the console through a central lumen maintained under vacuum. In a recent observational meta-analysis, we reported that cryoballoon ablation resulted in a high procedural success rate (>98% of patients achieving complete PVI) and a 1-year freedom from recurrent AF (1 year single procedure success of 60% off AAD; 73% if a 3-month blanking period was included).15 A subsequent
2
comparative meta-analysis reported similar freedom from recurrent AF at a mean follow-up of 16.5 months vs. standard (“first-generation”) RF ablation (66.9% vs 65.1%; RR 1.01; 95% CI: 0.94 to 1.07, P = 0.87).
Downloaded by [117.253.106.82] at 01:24 18 February 2016
Since the publication of these analyses the cryoballoon has undergone a significant iterative evolution. In the first generation catheter, 6.2 L/min of vapor was sprayed to the distal face of the balloon through 4 jets positioned 90° from one another, slightly distal to the cryoballoon equator. The second-generation (Arctic Front Advance) catheter refined the design by increasing, and repositioning the jets more distally resulting in an increased uniformity of cooling around the entirety of the distal surface of the cryoballoon.
Recent studies have examined the short and long-term success with the secondgeneration cryoballoon. Studies of planned re-mapping procedures have demonstrated that the durability of PVI at three months post index ablation procedure has improved from 67% of PVs (23% of patients with all 4 PVs isolated) with standard RF, to 88% of PVs (67% of patients with all 4 PVs isolated) with the first generation cryoballoon, to 91% of PVs (79% of patients with all 4 PVs isolated).16-21 Clinically this has translated into a one-year freedom from recurrent AF of 82% with the second generation cryoballoon (11 studies; 1725 patients), which was significantly improved compared to the first generation cryoballoon in a separate comparative meta-analysis (OR of arrhythmia recurrence 0.34 [0.26-0.45] when compared to first-generation cryoballoon; 10 studies, 2310 patients).22 While there was no significant difference in access site complication or pericardial effusion, significantly more phrenic nerve palsies (transient and persistent) were observed with the first generation cryoballoon. Contact Force
The most commonly used point-by-point RF contact force sensing catheter systems are TactiCath (St. Jude Medical, St Paul, USA) and SmartTouch (Biosense Webster, Diamond Bar, CA). TactiCath estimates axial and lateral contact force by examining the wavelength of the light emitted from fiberoptic tubes embedded within an open irrigated-tip ablation catheter. Forces applied at the tip of the catheter result in micro-deformation of optical fibers, changing in the wavelength of the light proportional to the force applied (with a sensitivity of 1g). SmartTouch uses electromagnetic location technology to detect movement between a precision spring (mounted within the tip of a 3.5mm externally irrigated RF ablation catheter) and three location sensor coils are also mounted within the shaft of the catheter. These movements are sampled every 50 msec and calibrated to produce a contact force reading (in grams) that is averaged over 1 second. Recent data suggests that incorporating real-time contact force assessment into the ablation procedure results in a reduction in procedure time, ablation time and total energy delivery, with a comparable safety profile to that observed with standard irrigated RF.18, 23 However, the two largest multicenter trials evaluating this technology demonstrated a one-year success of 68% (TactiCath, TOCCASTAR24) and
3
74% (SmartTouch, SMART-AF25). In the case of the former the success was no different from that observed with standard non-contact force RF ablation. Interestingly, post-hoc analyses of these studies have suggested that the outcomes were improved when the procedure was performed with adequate CF parameters (84% one-year freedom from AF in the 47% of patients in whom ablation was in the target range ≥80% of the time in SMART-AF, and 76% one-year freedom from AF in the 57% of patients in whom ≥90% of the lesions were >10g in TOCCASTAR). No differences in the incidence of complications have been reported between patients undergoing ablation with the contact force vs. non-contact force sensing RF ablation catheters in randomized (TOCCASTAR) or non-randomised studies.24, 26, 27 Downloaded by [117.253.106.82] at 01:24 18 February 2016
Conclusion
Second generation AF ablation technologies have resulted in improved clinical outcomes, while achieving a reduction in procedure time. Financial and competing interests disclosure J. Andrade is an advisor to and has received grants from Medtronic. M. Dubuc has received grants from Medtronic. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.
4
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References: 1. Karch MR, Zrenner B, Deisenhofer I, Schreieck J, Ndrepepa G, Dong J, Lamprecht K, Barthel P, Luciani E, Schomig A and Schmitt C. Freedom from atrial tachyarrhythmias after catheter ablation of atrial fibrillation: a randomized comparison between 2 current ablation strategies. Circulation. 2005;111:2875-80. 2. Oral H, Knight BP, Tada H, Ozaydin M, Chugh A, Hassan S, Scharf C, Lai SW, Greenstein R, Pelosi F, Jr., Strickberger SA and Morady F. Pulmonary vein isolation for paroxysmal and persistent atrial fibrillation. Circulation. 2002;105:1077-81. 3. Pappone C, Vicedomini G, Augello G, Manguso F, Saviano M, Baldi M, Petretta A, Giannelli L, Calovic Z, Guluta V, Tavazzi L and Santinelli V. Radiofrequency catheter ablation and antiarrhythmic drug therapy: a prospective, randomized, 4year follow-up trial: the APAF study. Circ Arrhythm Electrophysiol. 2011;4:808-14. 4. Wazni OM, Marrouche NF, Martin DO, Verma A, Bhargava M, Saliba W, Bash D, Schweikert R, Brachmann J, Gunther J, Gutleben K, Pisano E, Potenza D, Fanelli R, Raviele A, Themistoclakis S, Rossillo A, Bonso A and Natale A. Radiofrequency ablation vs antiarrhythmic drugs as first-line treatment of symptomatic atrial fibrillation: a randomized trial. JAMA. 2005;293:2634-40. 5. Jais P, Cauchemez B, Macle L, Daoud E, Khairy P, Subbiah R, Hocini M, Extramiana F, Sacher F, Bordachar P, Klein G, Weerasooriya R, Clementy J and Haissaguerre M. Catheter ablation versus antiarrhythmic drugs for atrial fibrillation: the A4 study. Circulation. 2008;118:2498-505. 6. Oral H, Pappone C, Chugh A, Good E, Bogun F, Pelosi F, Jr., Bates ER, Lehmann MH, Vicedomini G, Augello G, Agricola E, Sala S, Santinelli V and Morady F. Circumferential pulmonary-vein ablation for chronic atrial fibrillation. N Engl J Med. 2006;354:934-41. 7. Packer DL, Irwin JM, Champagne J, Guerra PG, Dubuc M, Wheelan KR, Kowal RC, Reddy VY, Lehmann J, Holcomb RG and Ruskin J. Cryoballoon ablation of pulmonary veins for paroxysmal atrial fibrillation: first results of the North American Arctic Front STOP-AF pivotal trial. J Am Coll Cardiol. 2010;55:E3015-3016. 8. Krittayaphong R, Raungrattanaamporn O, Bhuripanyo K, Sriratanasathavorn C, Pooranawattanakul S, Punlee K and Kangkagate C. A randomized clinical trial of the efficacy of radiofrequency catheter ablation and amiodarone in the treatment of symptomatic atrial fibrillation. Journal of the Medical Association of Thailand = Chotmaihet thangphaet. 2003;86 Suppl 1:S8-16. 9. Noheria A, Kumar A, Wylie JV, Jr. and Josephson ME. Catheter ablation vs antiarrhythmic drug therapy for atrial fibrillation: a systematic review. Arch Intern Med. 2008;168:581-6. 10. Stabile G, Bertaglia E, Senatore G, De Simone A, Zoppo F, Donnici G, Turco P, Pascotto P, Fazzari M and Vitale DF. Catheter ablation treatment in patients with drug-refractory atrial fibrillation: a prospective, multi-centre, randomized, controlled study (Catheter Ablation For The Cure Of Atrial Fibrillation Study). Eur Heart J. 2006;27:216-21. 11. Wilber DJ, Pappone C, Neuzil P, De Paola A, Marchlinski F, Natale A, Macle L, Daoud EG, Calkins H, Hall B, Reddy V, Augello G, Reynolds MR, Vinekar C, Liu CY, Berry SM and Berry DA. Comparison of antiarrhythmic drug therapy and 5
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