Treatment of Recurrent Non-Paroxysmal Atrial Fibrillation Using Focal Impulse and Rotor Mapping (FIRM)-Guided Rotor Ablation: Early Recurrence and Long-Term Outcomes Stefan Georg Spitzer, MD1,2, László Károlyi, MD1, Carola Rämmler, Dipl.-Ing.1, Frank Scharfe, MD1, Thomas Weinmann, MD1, Mirko Zieschank, Dipl.-Ing. (BA)1, Anke Langbein, MD1 1
Praxisklinik Herz und Gefäße Dresden, Akademische Lehrpraxisklinik der TU Dresden, Dresden,
2
Brandenburg University of Technology Cottbus-Senftenberg, Institute of Medical Technology, Germany.
[email protected]
Short title: FIRM ablation outcomes for recurrent non-paroxysmal AF Corresponding author: Stefan G. Spitzer, MD, FESC, FHRS Praxisklinik Herz und Gefäße Forststraße 3 01099 Dresden | Germany
This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/jce.13110.
This article is protected by copyright. All rights reserved.
Tel: +49 (351) 8064 – 115 Fax: +49 (351) 8064 – 110 E-Mail: [email protected]
Dr. Spitzer reported honoraria relevant to this topic and travel support, but did not specify the company. Other authors: No disclosures.
ABSTRACT
INTRODUCTION A patient-tailored ablation approach focused on the elimination of both pulmonary vein triggers as well as substrate drivers may result in favourable outcomes with recurrent persistent AF patients.
OBJECTIVE We evaluated the long-term outcomes of rotor ablation combined with conventional pulmonary vein isolation (PVI) in patients with recurrent non-paroxysmal AF.
METHODS
2
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58 consecutive patients underwent FIRM-guided rotor ablation followed by conventional PVI for the treatment of recurrent non-paroxysmal AF. A software algorithm was used to display rotational activity at rotor sites by creating propagation maps from unipolar electrograms recorded using a 64electrode basket catheter. These rotor sites were targeted for ablation, followed by conventional PVI.
RESULTS All patients had non-paroxysmal AF (83% longstanding persistent) and a previously failed conventional ablation procedure. Stable rotors were identified in all patients (mean of 3.0 ± 1.6 per patient), with 55.2% having right atrial rotors and 96.9% left atrial rotors, respectively. Complications occurred in 5.2% of patients, none related to the FIRM procedure. The median follow-up was 12 months. At 6 and 12 months of follow-up, 73.2% and 76.9% of patients remained free from AF/AT, respectively. Excluding 2 patients who underwent a successful redo ablation procedure/electrical cardioversion, at 12 months of follow-up, 69.2% were free from any AF/AT and 73.1% were free from AF after a single FIRM-guided ablation procedure.
CONCLUSION A high degree of success was observed in this cohort of primarily long-standing persistent AF patients treated for recurrent AF with FIRM-guided rotor ablation. Prospective randomized controlled trials are needed.
3
This article is protected by copyright. All rights reserved.
KEYWORDS: Atrial fibrillation, catheter ablation, rotor, spiral wave, FIRM
INTRODUCTION Over the past decade, catheter ablation has evolved to become a routine procedure for patients with atrial fibrillation who are refractory to medical therapy. Although pulmonary vein isolation (PVI) is widely accepted as the treatment of choice for patients with paroxysmal atrial fibrillation1-4, there has been no broad consensus regarding the most effective ablation strategy for non-paroxysmal AF, in part due to the lack of consensus regarding the mechanism(s) underlying its maintenance. It has been suggested that the importance of atrial substrate increases as the duration and severity of AF increases, but this has been challenged by the findings reported in the STAR-AF 2 trial, which reported a lack of incremental long-term benefit associated with additional substrate ablation5, thereby raising questions about the importance of substrate versus focal trigger isolation. Moreover, 4
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there remains a lack of consensus around the ideal procedural endpoint for ablation of nonparoxysmal AF in that some investigators have reported a relationship between procedural termination of AF and improved clinical outcomes6-9, while others have reported evidence demonstrating that procedural AF termination is not a predictive endpoint10,11. Furthermore, these issues are compounded in patients with longstanding persistent AF who are refractory to catheter ablation, where such non-responders progressively reach a point of no return coined “domestification of AF”12.
Further intervention for these patients, such as repeat ablation and cardioversion, are associated with a decline in long-term clinical success to the point where rhythm control is no longer possible13. It is conceivable that such a non-responder to conventional ablation is in fact able to sustain normal sinus rhythm, but simply requires a “better” procedure -- a procedure that more effectively targets the patient-specific mechanisms that maintain and perpetuate that patient’s arrhythmia.
In an effort to gain an understanding of the underlying mechanisms that drive AF, optical mapping has been utilized to evaluate the structural substrate at a cellular level. Studies in animal models revealed the presence of reentrant circuits/rotors, with evidence suggesting that these rotors are the mechanism responsible for sustaining AF14,15. However, until recently, there was no evidence directly verifying this mechanism in humans. The presence of rotors in human AF, as revealed by optical mapping, was recently reported, demonstrating that AF was driven by spatially and temporally stable rotational drivers anchored on micro-anatomic tracks, and the targeted ablation of those drivers/rotors was able to terminate the AF16. This suggests that a patient-tailored approach
5
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focused on the elimination of these rotors may be the “better” procedure for patients with recurrent non-paroxysmal AF who are refractory to other interventions.
Although previously published clinical outcomes of rotor ablation, performed in combination with conventional PVI, of non-paroxysmal AF have been mostly favorable, outcomes of rotor ablation for a large group of patients with recurrent persistent AF are lacking. In this study we endeavored to evaluate late success of targeted rotor ablation combined with traditional repeat PVI in patients with recurrent persistent and longstanding persistent AF.
METHODS Patient Population This study consisted of 58 consecutive patients referred for catheter ablation of recurrent longstanding persistent and persistent atrial fibrillation between June 2014 and October 2015. In this IRB-approved study, patients underwent FIRM-guided rotor ablation followed by PVI. Detailed patient characteristics are provided in Table 1.
Procedural Details All anti-arrhythmic medications were discontinued >3 half-lives prior to ablation, except for amiodarone, which was discontinued at least 30 days prior to the procedure. In all patients, we mapped spontaneous AF (47 patients), or induced AF (11 patients) by rapid atrial pacing (e.g., cycle lengths [CL]: 500, 450, 400, 350, 300 milliseconds, then in 10 milliseconds steps to AF). 6
This article is protected by copyright. All rights reserved.
Intraprocedural inducing of AF was necessary in patients that underwent cardioversion prior to procedure, therefore presenting in sinus rhythm despite classified as persistent AF patients before. As illustrated in Figure 1, a direct-contact 64-electrode basket catheter (FIRMap, Abbott, Menlo Park, CA) was placed successively in each atrium to record unipolar electrograms. The size of basket catheter was selected according to the LA-diameter (transseptal puncture site to LA-ridge) measured by transesophageal echocardiography (TEE) and/or computerized tomography (CT). In all cases, basket coverage was confirmed by fluoroscopy, electrogram detection and visualization in the 3D mapping system (NavX, figure 2). Electrograms were filtered at 0.05–500 Hz and exported for analysis by the RhythmView software (Abbott, Menlo Park, CA). The RhythmView FIRM mapping software utilizes previously described computational approaches to generate activation trails for identifying AF rotors within the atria17,18,19. AF propagation maps from contact recordings were projected onto 2D grids referenced to atrial anatomy on electroanatomic shells, which were created using NavX (St. Jude Medical, Minneapolis, Minnesota). Radiofrequency (RF) ablation was performed using an irrigated 3.5mm catheter (ThermoCool, Biosense Webster, Diamond Bar, California) or an irrigated 4mm catheter (Therapy Cool Flex, St. Jude Medical, Minneapolis, Minnesota) by applying lesions for about 300s around the identified rotor core. RF energy was delivered at 30 W with a target temperature of 45°C, and depending on the localization of ablation energy was reduced to 25 W (e.g., posterior wall of the left atrium). Rotors were targeted for ablation based on rotational activity as identified by the RAP feature with a repetitive, spatially stable rotational pattern from the default 4-second time segment, unless judged to be a false positive upon visual inspection of the operator. If rotational activity at a different location was noted in a different time segment, as identified by RAP with a repetitive, spatially stable rotational pattern, those locations were similarly targeted for ablation. Rotor
7
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mapping was repeated to confirm rotor elimination, and if necessary, additional RF ablation was performed at the rotor location.
If AF persisted after complete rotor elimination, cardioversion was undertaken to restore sinus rhythm. Then conventional ablation was performed for all patients. In case of PV-reconnection conventional ablation protocol consisted of wide-area circumferential PV re-isolation with isolation (entrance and exit block) verified using a circular mapping catheter (Inquiry Optima, St. Jude Medical, Minneapolis, Minnesota). Finally, additional ablation of relevant atrial tachycardias was performed.
Long-Term Clinical Follow-Up Follow-up for arrhythmia recurrence followed HRS/ EHRA/ECAS guidelines1. Clinic visits occurred at 1, 3, 6 and 12 months. ECG was performed at each office visit and arrhythmia recurrence was also detected by 7-day ambulatory monitors to coincide with clinic visits as well as at the time of reported symptoms. Recurrence was defined as any office ECG demonstrating AF or AT, or any episode of AF or AT >30 seconds on ambulatory monitors.
Endpoints The primary study effectiveness endpoint for late success was defined as freedom from arrhythmia at 12 months after ablation. Secondary endpoints include freedom from arrhythmia at 6 months after ablation, early recurrence of AF/AT (ERAF) at 90 days after the ablation procedure, and the 8
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incidence of adverse events related to the ablation procedure. With this endpoint of “late success”, neither freedom from arrhythmia while being treated with a previously ineffective antiarrhythmic drug at the same/lower dose, nor a spontaneously self-terminating recurrence without intervention (electrical cardioversion or ablation) are considered to be treatment failures.
Statistical Analysis Frequencies and proportions were used to describe categorical variables while means and standard deviations were used to describe continuous variables. The Student’s t-test was used to compare continuous variables between 2 groups. Paired continuous variables were compared using linear regression and the paired t-test. The chi-square test was applied to contingency tables for categorical variables. A P value of < 0.05 was considered statistically significant.
RESULTS Patient Characteristics During the study period, 58 FIRM-guided rotor ablation procedures for non-paroxysmal AF were performed. The mean patient age was 62.2 9.4, and the majority of patients were male (72%). All patients had non-paroxysmal AF, 83% (48/58) of which were longstanding persistent. All patients had a previously failed conventional ablation (a mean of 1.4 0.6 per patient), and mean CHA2DS2VASc score was 2.1 ± 1.5. Patient characteristics are further detailed in Table 1.
Acute Procedural Results 9
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Procedural details are summarized in Table 2. The size of basket catheter was selected based on LA diameter, the most common sizes of which were 50mm (45%) and 60mm (52%); the 70mm basket was used in 2 patients (3%). Basket coverage in the right atrium was typically adequate, as indicated by uniform spline spacing with dynamic deformation visualized under fluoroscopy. In the left atrium, incomplete basket coverage and/or spline spread and bunching were often noted. To accommodate for incomplete basket coverage, a segmental mapping and ablation approach was undertaken, whereby areas were successively mapped with manipulation to ensure good basket contact in each area in turn to ensure adequate atrial coverage, then ablated (figure 2).
Stable AF rotors were identified in all patients, with a mean number of 3.0 ± 1.6 per patient. Right atrial rotors were present in 55.2% (32/58) of patients (0.8 ± 0.9 rotors per patient), and left atrial rotors were present in 96.9% (56/58) of patients (2.2 ± 1.3 rotors per patient). Atrial rotor locations are detailed in Table 3 and illustrated in Figure 3.
All identified rotors were successfully eliminated, as confirmed by repeat rotor mapping after ablation. The mean ablation area per rotor was 3.4 ± 1.9 cm2, and the mean ablation time to terminate each rotor was 352 seconds (5.9 minutes). Peri-procedural termination of AF was observed in 8.6% (5/58) of patients and AF cycle length prolongation of greater than 10% was observed in 33% (19/58) of patients. We did not observe any regular atrial tachycardia during the procedures; therefore, application of additional left atrial lines was not necessary. Ablation of cavotricuspid isthmus was performed in 1 patient because of documented typical right atrial flutter prior to ablation procedure. Pulmonary veins were re-isolated in all patients, with a total of 48 reconnections occurring in the RIPV, 42 in the RSPV, 39 in the LIPV, 38 in the LSPV, and 5 in the 10
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LcoPV. Complications occurred in 5.2% of patients (3/58), which included 2 pseudoaneurysms requiring surgical treatment and 1 pericardial effusion during PVI requiring puncture. Complications did not appear to be related to the basket catheter.
Long-Term Clinical Outcomes Follow-up data after the 90-day blanking period was available for 52 patients, with a median followup of 12 months (IQR = 6-16 Months). Early recurrence of AF/AT at 3 months was noted for 32.7% (17/52) of patients. At 6 and at 12 months of follow-up, 73.2% (30/41) and 76.9% (20/26) of patients remained free from any AF/AT, respectively. At 12 months of follow-up, 80.8% (21/26) of patients remained free from AF. The 12-month freedom from AF/AT includes 5 patients who spontaneously converted from persistent AF to normal sinus rhythm without intervention, 1 patient who underwent a successful electrical cardioversion 6-months prior, and 1 patient who underwent a successful re-ablation procedure. Excluding the 1 patient who underwent a successful re-ablation procedure and the 1 patient who underwent the successful electrical cardioversion, at 12 months of follow-up, 69.2% (18/26) of patients were free from any AF/AT and 73.1% (19/26) of patients were free from AF after a single FIRM ablation procedure, with 2 patients remaining on previously ineffective antiarrhythmic medication. In the 5 patients with spontaneous conversion to sinus rhythm we found a trend towards shorter AF duration (2.61.3 versus 4.10.6 years) and higher number of LA rotors (3.22.0 versus 2.21.3) compared to the whole patient population.
11
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There was no statistically significant difference in outcomes whether on or off antiarrhythmic drugs (p
Praxisklinik Herz und Gefäße Dresden, Akademische Lehrpraxisklinik der TU Dresden, Dresden,
2
Brandenburg University of Technology Cottbus-Senftenberg, Institute of Medical Technology, Germany.
[email protected]
Short title: FIRM ablation outcomes for recurrent non-paroxysmal AF Corresponding author: Stefan G. Spitzer, MD, FESC, FHRS Praxisklinik Herz und Gefäße Forststraße 3 01099 Dresden | Germany
This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/jce.13110.
This article is protected by copyright. All rights reserved.
Tel: +49 (351) 8064 – 115 Fax: +49 (351) 8064 – 110 E-Mail: [email protected]
Dr. Spitzer reported honoraria relevant to this topic and travel support, but did not specify the company. Other authors: No disclosures.
ABSTRACT
INTRODUCTION A patient-tailored ablation approach focused on the elimination of both pulmonary vein triggers as well as substrate drivers may result in favourable outcomes with recurrent persistent AF patients.
OBJECTIVE We evaluated the long-term outcomes of rotor ablation combined with conventional pulmonary vein isolation (PVI) in patients with recurrent non-paroxysmal AF.
METHODS
2
This article is protected by copyright. All rights reserved.
58 consecutive patients underwent FIRM-guided rotor ablation followed by conventional PVI for the treatment of recurrent non-paroxysmal AF. A software algorithm was used to display rotational activity at rotor sites by creating propagation maps from unipolar electrograms recorded using a 64electrode basket catheter. These rotor sites were targeted for ablation, followed by conventional PVI.
RESULTS All patients had non-paroxysmal AF (83% longstanding persistent) and a previously failed conventional ablation procedure. Stable rotors were identified in all patients (mean of 3.0 ± 1.6 per patient), with 55.2% having right atrial rotors and 96.9% left atrial rotors, respectively. Complications occurred in 5.2% of patients, none related to the FIRM procedure. The median follow-up was 12 months. At 6 and 12 months of follow-up, 73.2% and 76.9% of patients remained free from AF/AT, respectively. Excluding 2 patients who underwent a successful redo ablation procedure/electrical cardioversion, at 12 months of follow-up, 69.2% were free from any AF/AT and 73.1% were free from AF after a single FIRM-guided ablation procedure.
CONCLUSION A high degree of success was observed in this cohort of primarily long-standing persistent AF patients treated for recurrent AF with FIRM-guided rotor ablation. Prospective randomized controlled trials are needed.
3
This article is protected by copyright. All rights reserved.
KEYWORDS: Atrial fibrillation, catheter ablation, rotor, spiral wave, FIRM
INTRODUCTION Over the past decade, catheter ablation has evolved to become a routine procedure for patients with atrial fibrillation who are refractory to medical therapy. Although pulmonary vein isolation (PVI) is widely accepted as the treatment of choice for patients with paroxysmal atrial fibrillation1-4, there has been no broad consensus regarding the most effective ablation strategy for non-paroxysmal AF, in part due to the lack of consensus regarding the mechanism(s) underlying its maintenance. It has been suggested that the importance of atrial substrate increases as the duration and severity of AF increases, but this has been challenged by the findings reported in the STAR-AF 2 trial, which reported a lack of incremental long-term benefit associated with additional substrate ablation5, thereby raising questions about the importance of substrate versus focal trigger isolation. Moreover, 4
This article is protected by copyright. All rights reserved.
there remains a lack of consensus around the ideal procedural endpoint for ablation of nonparoxysmal AF in that some investigators have reported a relationship between procedural termination of AF and improved clinical outcomes6-9, while others have reported evidence demonstrating that procedural AF termination is not a predictive endpoint10,11. Furthermore, these issues are compounded in patients with longstanding persistent AF who are refractory to catheter ablation, where such non-responders progressively reach a point of no return coined “domestification of AF”12.
Further intervention for these patients, such as repeat ablation and cardioversion, are associated with a decline in long-term clinical success to the point where rhythm control is no longer possible13. It is conceivable that such a non-responder to conventional ablation is in fact able to sustain normal sinus rhythm, but simply requires a “better” procedure -- a procedure that more effectively targets the patient-specific mechanisms that maintain and perpetuate that patient’s arrhythmia.
In an effort to gain an understanding of the underlying mechanisms that drive AF, optical mapping has been utilized to evaluate the structural substrate at a cellular level. Studies in animal models revealed the presence of reentrant circuits/rotors, with evidence suggesting that these rotors are the mechanism responsible for sustaining AF14,15. However, until recently, there was no evidence directly verifying this mechanism in humans. The presence of rotors in human AF, as revealed by optical mapping, was recently reported, demonstrating that AF was driven by spatially and temporally stable rotational drivers anchored on micro-anatomic tracks, and the targeted ablation of those drivers/rotors was able to terminate the AF16. This suggests that a patient-tailored approach
5
This article is protected by copyright. All rights reserved.
focused on the elimination of these rotors may be the “better” procedure for patients with recurrent non-paroxysmal AF who are refractory to other interventions.
Although previously published clinical outcomes of rotor ablation, performed in combination with conventional PVI, of non-paroxysmal AF have been mostly favorable, outcomes of rotor ablation for a large group of patients with recurrent persistent AF are lacking. In this study we endeavored to evaluate late success of targeted rotor ablation combined with traditional repeat PVI in patients with recurrent persistent and longstanding persistent AF.
METHODS Patient Population This study consisted of 58 consecutive patients referred for catheter ablation of recurrent longstanding persistent and persistent atrial fibrillation between June 2014 and October 2015. In this IRB-approved study, patients underwent FIRM-guided rotor ablation followed by PVI. Detailed patient characteristics are provided in Table 1.
Procedural Details All anti-arrhythmic medications were discontinued >3 half-lives prior to ablation, except for amiodarone, which was discontinued at least 30 days prior to the procedure. In all patients, we mapped spontaneous AF (47 patients), or induced AF (11 patients) by rapid atrial pacing (e.g., cycle lengths [CL]: 500, 450, 400, 350, 300 milliseconds, then in 10 milliseconds steps to AF). 6
This article is protected by copyright. All rights reserved.
Intraprocedural inducing of AF was necessary in patients that underwent cardioversion prior to procedure, therefore presenting in sinus rhythm despite classified as persistent AF patients before. As illustrated in Figure 1, a direct-contact 64-electrode basket catheter (FIRMap, Abbott, Menlo Park, CA) was placed successively in each atrium to record unipolar electrograms. The size of basket catheter was selected according to the LA-diameter (transseptal puncture site to LA-ridge) measured by transesophageal echocardiography (TEE) and/or computerized tomography (CT). In all cases, basket coverage was confirmed by fluoroscopy, electrogram detection and visualization in the 3D mapping system (NavX, figure 2). Electrograms were filtered at 0.05–500 Hz and exported for analysis by the RhythmView software (Abbott, Menlo Park, CA). The RhythmView FIRM mapping software utilizes previously described computational approaches to generate activation trails for identifying AF rotors within the atria17,18,19. AF propagation maps from contact recordings were projected onto 2D grids referenced to atrial anatomy on electroanatomic shells, which were created using NavX (St. Jude Medical, Minneapolis, Minnesota). Radiofrequency (RF) ablation was performed using an irrigated 3.5mm catheter (ThermoCool, Biosense Webster, Diamond Bar, California) or an irrigated 4mm catheter (Therapy Cool Flex, St. Jude Medical, Minneapolis, Minnesota) by applying lesions for about 300s around the identified rotor core. RF energy was delivered at 30 W with a target temperature of 45°C, and depending on the localization of ablation energy was reduced to 25 W (e.g., posterior wall of the left atrium). Rotors were targeted for ablation based on rotational activity as identified by the RAP feature with a repetitive, spatially stable rotational pattern from the default 4-second time segment, unless judged to be a false positive upon visual inspection of the operator. If rotational activity at a different location was noted in a different time segment, as identified by RAP with a repetitive, spatially stable rotational pattern, those locations were similarly targeted for ablation. Rotor
7
This article is protected by copyright. All rights reserved.
mapping was repeated to confirm rotor elimination, and if necessary, additional RF ablation was performed at the rotor location.
If AF persisted after complete rotor elimination, cardioversion was undertaken to restore sinus rhythm. Then conventional ablation was performed for all patients. In case of PV-reconnection conventional ablation protocol consisted of wide-area circumferential PV re-isolation with isolation (entrance and exit block) verified using a circular mapping catheter (Inquiry Optima, St. Jude Medical, Minneapolis, Minnesota). Finally, additional ablation of relevant atrial tachycardias was performed.
Long-Term Clinical Follow-Up Follow-up for arrhythmia recurrence followed HRS/ EHRA/ECAS guidelines1. Clinic visits occurred at 1, 3, 6 and 12 months. ECG was performed at each office visit and arrhythmia recurrence was also detected by 7-day ambulatory monitors to coincide with clinic visits as well as at the time of reported symptoms. Recurrence was defined as any office ECG demonstrating AF or AT, or any episode of AF or AT >30 seconds on ambulatory monitors.
Endpoints The primary study effectiveness endpoint for late success was defined as freedom from arrhythmia at 12 months after ablation. Secondary endpoints include freedom from arrhythmia at 6 months after ablation, early recurrence of AF/AT (ERAF) at 90 days after the ablation procedure, and the 8
This article is protected by copyright. All rights reserved.
incidence of adverse events related to the ablation procedure. With this endpoint of “late success”, neither freedom from arrhythmia while being treated with a previously ineffective antiarrhythmic drug at the same/lower dose, nor a spontaneously self-terminating recurrence without intervention (electrical cardioversion or ablation) are considered to be treatment failures.
Statistical Analysis Frequencies and proportions were used to describe categorical variables while means and standard deviations were used to describe continuous variables. The Student’s t-test was used to compare continuous variables between 2 groups. Paired continuous variables were compared using linear regression and the paired t-test. The chi-square test was applied to contingency tables for categorical variables. A P value of < 0.05 was considered statistically significant.
RESULTS Patient Characteristics During the study period, 58 FIRM-guided rotor ablation procedures for non-paroxysmal AF were performed. The mean patient age was 62.2 9.4, and the majority of patients were male (72%). All patients had non-paroxysmal AF, 83% (48/58) of which were longstanding persistent. All patients had a previously failed conventional ablation (a mean of 1.4 0.6 per patient), and mean CHA2DS2VASc score was 2.1 ± 1.5. Patient characteristics are further detailed in Table 1.
Acute Procedural Results 9
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Procedural details are summarized in Table 2. The size of basket catheter was selected based on LA diameter, the most common sizes of which were 50mm (45%) and 60mm (52%); the 70mm basket was used in 2 patients (3%). Basket coverage in the right atrium was typically adequate, as indicated by uniform spline spacing with dynamic deformation visualized under fluoroscopy. In the left atrium, incomplete basket coverage and/or spline spread and bunching were often noted. To accommodate for incomplete basket coverage, a segmental mapping and ablation approach was undertaken, whereby areas were successively mapped with manipulation to ensure good basket contact in each area in turn to ensure adequate atrial coverage, then ablated (figure 2).
Stable AF rotors were identified in all patients, with a mean number of 3.0 ± 1.6 per patient. Right atrial rotors were present in 55.2% (32/58) of patients (0.8 ± 0.9 rotors per patient), and left atrial rotors were present in 96.9% (56/58) of patients (2.2 ± 1.3 rotors per patient). Atrial rotor locations are detailed in Table 3 and illustrated in Figure 3.
All identified rotors were successfully eliminated, as confirmed by repeat rotor mapping after ablation. The mean ablation area per rotor was 3.4 ± 1.9 cm2, and the mean ablation time to terminate each rotor was 352 seconds (5.9 minutes). Peri-procedural termination of AF was observed in 8.6% (5/58) of patients and AF cycle length prolongation of greater than 10% was observed in 33% (19/58) of patients. We did not observe any regular atrial tachycardia during the procedures; therefore, application of additional left atrial lines was not necessary. Ablation of cavotricuspid isthmus was performed in 1 patient because of documented typical right atrial flutter prior to ablation procedure. Pulmonary veins were re-isolated in all patients, with a total of 48 reconnections occurring in the RIPV, 42 in the RSPV, 39 in the LIPV, 38 in the LSPV, and 5 in the 10
This article is protected by copyright. All rights reserved.
LcoPV. Complications occurred in 5.2% of patients (3/58), which included 2 pseudoaneurysms requiring surgical treatment and 1 pericardial effusion during PVI requiring puncture. Complications did not appear to be related to the basket catheter.
Long-Term Clinical Outcomes Follow-up data after the 90-day blanking period was available for 52 patients, with a median followup of 12 months (IQR = 6-16 Months). Early recurrence of AF/AT at 3 months was noted for 32.7% (17/52) of patients. At 6 and at 12 months of follow-up, 73.2% (30/41) and 76.9% (20/26) of patients remained free from any AF/AT, respectively. At 12 months of follow-up, 80.8% (21/26) of patients remained free from AF. The 12-month freedom from AF/AT includes 5 patients who spontaneously converted from persistent AF to normal sinus rhythm without intervention, 1 patient who underwent a successful electrical cardioversion 6-months prior, and 1 patient who underwent a successful re-ablation procedure. Excluding the 1 patient who underwent a successful re-ablation procedure and the 1 patient who underwent the successful electrical cardioversion, at 12 months of follow-up, 69.2% (18/26) of patients were free from any AF/AT and 73.1% (19/26) of patients were free from AF after a single FIRM ablation procedure, with 2 patients remaining on previously ineffective antiarrhythmic medication. In the 5 patients with spontaneous conversion to sinus rhythm we found a trend towards shorter AF duration (2.61.3 versus 4.10.6 years) and higher number of LA rotors (3.22.0 versus 2.21.3) compared to the whole patient population.
11
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There was no statistically significant difference in outcomes whether on or off antiarrhythmic drugs (p
