Dual energy for pulmonary vein isolation using dual-energy focal ablation technology integrated with a three-dimensional mapping system: SmartfIRE 3-month results.

AIMS: Contact force (CF)-sensing radiofrequency (RF) catheters with an ablation index have shown reproducible outcomes for the treatment of atrial fibrillation (AF) in large multicentre studies. A dual-energy (DE) focal CF catheter to deliver RF and unipolar/biphasic pulsed field ablation (PFA), integrated with a three-dimensional (3D) mapping system, can provide operators with additional flexibility. The SmartfIRE study assessed the safety and efficacy of this novel technology for the treatment of drug-refractory, symptomatic paroxysmal AF. Results at 3 months post-ablation are presented here. METHODS AND RESULTS: Pulmonary vein isolation (PVI) was performed using a DE focal, irrigated CF-sensing catheter with the recommendation of PFA at posterior/inferior and RF ablation at the anterior/ridge/carina segments. Irrespective of energy, a tag size of 3 mm; an inter-tag distance ≤6 mm; a target index of 550 for anterior, roof, ridge, and carina; and a target index of 400 for posterior and inferior were recommended. Cavotricuspid isthmus ablation was permitted in patients with documented typical atrial flutter. The primary effectiveness endpoint was acute procedural success. The primary safety endpoint was the rate of primary adverse events (PAEs) within 7 days of the procedure. A prespecified patient subset underwent oesophageal endoscopy (EE; 72 h post-procedure), neurological assessment (NA; pre-procedure and discharge), and cardiac computed tomography (CT)/magnetic resonance angiogram (MRA) imaging (pre-procedure and 3 months post-procedure) for additional safety evaluation, and a mandatory remapping procedure (Day 75 ± 15) for PVI durability assessment. Of 149 patients enrolled between February and June 2023, 140 had the study catheter inserted (safety analysis set) and 137 had ablation energy delivered (per-protocol analysis set). The median (Q1/Q3) total procedure and fluoroscopy times were 108.0 (91.0/126.0) and 4.2 (2.3/7.7) min (n = 137). The acute procedural success rate was 100%. First-pass isolation was achieved in 89.1% of patients and 96.8% of veins. Cavotricuspid isthmus ablations were successfully performed in 12 patients [pulsed field (PF) only: 6, RF only: 5, and RF/PF: 1]. The PAE rate was 4.4% [6/137 patients; 2 pulmonary vein (PV) stenoses, 2 cardiac tamponades/perforations, 1 stroke, and 1 pericarditis]. No coronary artery spasm was reported. No oesophageal lesion was seen in the EE subset (0/31, 0%). In the NA subset (n = 30), microemboli lesions were identified in 2 patients (2/30, 6.7%), both of which were resolved at follow-up; only 1 was symptomatic (silent cerebral lesion, 3.3%). In the CT/MRA subset (n = 30), severe PV narrowing (of >70%) was detected in 2 patients (2/30, 6.7%; vein level 2/128, 1.6%), of whom 1 underwent dilatation and stenting and 1 was asymptomatic; both were associated with high index values and a small inter-tag distance. In the PV durability subset (n = 30), 100/115 treated PVs (87%) were durably isolated and 18/30 patients (60.0%) had all PVs durably isolated. CONCLUSION: A DE focal CF catheter with 3D mapping integration showed a 100% acute success rate with an acceptable safety profile in the treatment of paroxysmal AF. Prespecified 3-month remapping showed notable PVI durability. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT05752487.

Pulsed field ablation using focal contact force-sensing catheters for treatment of atrial fibrillation: acute and 90-day invasive remapping results.

AIMS: Pulsed field ablation (PFA) has emerged as a promising alternative to thermal ablation for treatment of atrial fibrillation (AF). We report performance and safety using the CENTAURI™ System (Galvanize Therapeutics) with three commercial, focal ablation catheters. METHODS AND RESULTS: ECLIPSE AF (NCT04523545) was a prospective, single-arm, multi-centre study evaluating safety and acute and chronic pulmonary vein isolation (PVI) durability using the CENTAURI System in conjunction with the TactiCath SE, StablePoint, and ThermoCool ST ablation catheters. Patients with paroxysmal or persistent AF were treated at two centres. Patients were analysed in five cohorts based upon ablation settings, catheter, and mapping system. Pulsed field ablation was performed in 82 patients (74% male, 42 paroxysmal AF). Pulmonary vein isolation was achieved in 100% of pulmonary veins (322/322) with first-pass isolation in 92.2% (297/322). There were four serious adverse events of interest (three vascular access complications and one lacunar stroke). Eighty patients (98%) underwent invasive remapping. Pulsed field ablation development Cohorts 1 and 2 showed a per-patient isolation rate of 38% and 26% and a per-PV isolation rate of 47% and 53%, respectively. Optimized PFA Cohorts 3-5 showed a per-patient isolation rate of 60%, 73%, and 81% and a per-PV isolation rate of 84%, 90%, and 92%, respectively. CONCLUSION: ECLIPSE AF demonstrated that optimized PFA using the CENTAURI System with three commercial, contact force-sensing, solid-tip focal ablation catheters resulted in transmural lesion formation and high proportion of durable PVI with a favourable safety profile, thus providing a viable treatment option for AF that integrates with contemporary focal ablation workflows.

Pulmonary vein isolation by visually guided laser balloon ablation: single-center 5-year follow-up results.

BACKGROUND: Visually guided laser balloon (VGLB) ablation is a balloon-based treatment for atrial fibrillation (AF) that uses a titratable laser energy source to perform pulmonary vein isolation (PVI), allowing for real-time visualization of target tissue and ablation lesions through an endoscopic camera. Few long-term data on this technique are currently available. This report presents acute efficacy, procedural data, complication rates, and long-term AF-free survival up to 5 years post-ablation. METHODS: In this single-center, retrospective, observational report, 152 patients (72.4% male, mean age 60.6 ± 9.7 years, 62.5% paroxysmal AF, 598 pulmonary veins in total) treated with the first-generation VGLB system between 2014 and 2016 were included for analysis. AF ablation consisted of PVI only. RESULTS: Acute PVI was achieved in 98.2% of veins, with first-pass isolation in 92.5%. Procedure duration of 129 min [IQR 113-150], fluoroscopy time of 15 min [IQR 11-20], and dose area product of 5016 mGy·cm2 [IQR 3603-8711] were recorded. During a median follow-up of 51 months [IQR 45-57], 74.3% of patients remained free of AF (78.8% for paroxysmal and 65.3% for persistent AF, p = 0.108). Freedom of AF at 1, 2, 3, and 4 years follow-up was 88.2%, 82.2%, 78.9%, and 74.8%, respectively. PV reconnections were identified in only 46.9% of redo procedures. The median number of PV reconnections during redo procedures was 0 [IQR 0-2]. Anti-arrhythmic drug use was significantly reduced after ablation (p < 0.001). The most commonly reported complications were minor vascular complications (4.6%) and transient phrenic nerve paralysis (3.3%). CONCLUSIONS: First-generation VGLB ablation demonstrated high acute isolation rates, reasonable procedure times and low complication rates. Long-term freedom from AF was 78.8% for paroxysmal AF and 65.3% for persistent AF, performing PVI only.

Damage to the left descending coronary artery due to radiofrequency ablation in the right ventricular outflow tract: Clinical case series and anatomical considerations.

The purpose of this paper was to highlight the importance of the anatomy of the right ventricular outflow tract (RVOT) and the proximity of the mid segment of the left anterior descending coronary artery (LAD) to the RVOT in the setting of ablation of ventricular arrhythmias in the RVOT. During the period from 2014 till 2017, five patients with injury to the LAD during ablation within RVOT were identified in three centers, in Belgium, Germany and Israel. The clinical characteristics, procedural data and follow up data, where available, are reported. The literature review over coronary artery damage during radiofrequency ablation procedures is provided and the anatomy of the RVOT and the neighboring vascular structures is discussed. We present five patients who underwent radiofrequency ablation of ventricular arrhythmias mapped to the inferior and anterior part of the RVOT, at the insertion of the right ventricular wall to the septum, whereby ablation resulted in occlusion in four and severe stenosis in one, of the mid segment of the LAD coronary artery. All patients underwent percutaneous coronary intervention and stenting, four of them immediately during the same procedure and one 3 days later because of lack of signs and symptoms of acute coronary occlusion. In conclusion, the mid segment of the LAD at the level of the second septal perforator/second diagonal branch runs in very close proximity to the endocardial aspect of the lower part of the RVOT and care should be taken during ablation of ventricular arrhythmias in this region. Additional imaging such as intracardiac echocardiography and coronary angiography may be helpful in avoiding complications.

Prospective Randomized Evaluation of High Power During CLOSE-Guided Pulmonary Vein Isolation: The POWER-AF Study.

BACKGROUND: CLOSE-guided atrial fibrillation (AF) ablation is based on contiguous (intertag distance ≤6 mm), optimized (Ablation Index >550 anteriorly and >400 posteriorly) point-by-point radiofrequency lesions. The optimal radiofrequency power remains unknown. METHODS: The POWER-AF study is a prospective, randomized controlled monocentric study including patients with paroxysmal AF, planned for first CLOSE-guided pulmonary vein isolation using a contact force radiofrequency catheter (Thermocool SmartTouch, Biosense Webster, Inc, Irvine, CA). A total of 100 patients were randomized into 2 groups (1:1). The control group received AF ablation using the standard CLOSE protocol (35 W), whereas in the experimental group, pulmonary vein isolation was performed using high power (45 W). Endoscopic evaluation was performed in patients with intraesophageal temperature rise >38.5 °C. RESULTS: The resulting sample size was 96 (48+48) patients. In the high power group, shorter procedure time (80 versus 102 minutes, P<0.001), shorter total radiofrequency application time (16 versus 26 minutes, P<0.001), and radiofrequency time per application (26 versus 37 s anteriorly, P<0.001 and 13 versus 17 s posteriorly, P<0.001) were observed. Endoscopic evaluation (performed in 19/48 versus 25/48 patients respectively, P=0.31) showed an ulcerative perforation in a high power group patient (treated by endoscopic stenting and normalization after ≈4 months) and a superficial ulcerative lesion in a control group patient (conservative treatment). Both occurred following excessive Ablation Index applications (up to 460 and 480, respectively) with excessive contact force (30 g on average, with peaks up to 50 g). Six-months AF recurrence was not significantly different (10% in high power versus 8% in control, P=0.74). CONCLUSIONS: This randomized controlled study shows that a 45 W radiofrequency power CLOSE protocol in patients with paroxysmal AF significantly increases the global procedural efficiency with similar midterm efficacy. However, our study showed a narrower safety margin and a limited increased efficiency at the posterior wall using high power. This advocates against the use of high power in the region neighboring the esophagus.

Evaluation of higher power delivery during RF pulmonary vein isolation using optimized and contiguous lesions.

AIMS: "CLOSE"-guided pulmonary vein isolation (PVI) is based on contiguous (≤6 mm) and optimized radiofrequency (RF) ablation lesions (ablation index [AI] ≥ 400 posteriorly and ≥ 550 anteriorly]. However, the optimal RF power to reach the desired AI is unknown. Therefore we evaluated the efficiency of an ablation strategy using higher power (40 W) during a first "CLOSE"-guided PVI. METHODS: Eighty consecutive patients undergoing "CLOSE"-guided PVI for symptomatic paroxysmal atrial fibrillation were ablated with 40 W (group A). Results were compared with 105 consecutive patients enrolled in the "CLOSE to CURE"-study and were ablated using the same protocol with 35 W (group B). RESULTS: In group A, ablation was associated with shorter ablation procedure time (91 vs 111 minutes; P < .001), shorter fluoroscopy time (5 vs 11 minutes; P < .001), shorter PVI time (48 vs 64 minutes; P < .001), shorter RF time (20 vs 28 minutes; P < .001), lower RF time per application (22 vs 29 seconds; P < .001), less RF applications (52 vs 58; P < .001), and less catheter dislocations (1 vs 2; P = .002). The impedance drop (12 vs 13 Ω; P = .192), first-pass isolation rate (99% vs 93%; P = .141) and acute reconnection rate (6% vs 4%; P > .733) were similar in both groups (groups A and B, respectively). No complications occurred. In group A, a gastroscopy-performed in five patients with esophageal temperature rise more than 42°C-did not reveal any esophageal lesion. Postprocedural recurrence of atrial tachyarrhythmia at 1 year was not significantly different between both groups. CONCLUSIONS: Using the "CLOSE"-protocol, increased power increases the efficiency of PVI without compromising patients' safety.

Long-term impact of catheter ablation on arrhythmia burden in low-risk patients with paroxysmal atrial fibrillation: The CLOSE to CURE study.

BACKGROUND: Few studies evaluated the impact of catheter ablation (CA) on atrial tachyarrhythmia (ATA) burden in paroxysmal atrial fibrillation (AF). OBJECTIVE: In the prospective, patient-controlled CLOSE to CURE study, we determined the longer-term impact of optimized CA on ATA burden by using an insertable cardiac monitor (ICM). METHODS: A total of 105 patients with paroxysmal AF were implanted with an ICM 65 (interquartile range [IQR] 61-78) days before CA. CA consisted of contact force-guided pulmonary vein isolation targeting an intertag distance of ≤6 mm and a region-specific ablation index. The primary end point was reduction in ICM-detected ATA burden; secondary end points were single-procedure freedom from ATA, quality of life, and adverse events. RESULTS: The mean age was 62 ± 8 years; the median CHA2DS2-VASc score was 1 (IQR 1-2); and the median left atrial diameter was 43 (IQR 39-43) mm. After pulmonary vein isolation (1.13 ± 0.39 procedures per patient), median ATA burden decreased from 2.68% (IQR 0.09%-15.02%) at baseline to 0% (IQR 0%-0%) during the first year and to 0% (IQR 0%-0%) during the second year (reduction in ATA burden 100% [IQR 100%-100%]; P < .001). Single-procedure freedom from any ATA was 87% at 1 year and 78% at 2 years. Quality of life improved significantly across all scores. Adverse events occurred in 5 patients (4.8%). CONCLUSION: CA has become an effective procedure in paroxysmal AF, with a major impact on ICM-detected ATA burden. Whereas conventional survival analysis suggests a progressive decline in efficacy, we observed that burden reduction is maintained at longer follow-up. These data imply that ATA burden is a more optimal end point for assessing ablation efficacy.

Identification of repetitive atrial activation patterns in persistent atrial fibrillation by direct contact high-density electrogram mapping.

INTRODUCTION: Recent studies have characterized drivers in persistent atrial fibrillation using automated algorithm detection with panoramic endocardial mapping by means of basket catheters. We aimed to identify repetitive atrial activation patterns (RAAPs) during ongoing atrial fibrillation (AF) based upon automated annotation of unipolar electrograms (EGMs) recorded with a high-density regional endocardial contact mapping catheter. METHODS: In 14 persistent AF patients, high-resolution EGMs were recorded for 30 seconds at sequential PentaRay (Biosense Inc) positions covering the entire biatrial surface. All recordings were reviewed off-line with dedicated software allowing automated annotation of the local activation time of the unipolar fibrillatory EGMs (CARTOFINDER; Biosense Inc). RAAPs were defined as a consistent activation pattern (for ≥3 consecutive beats) of either focal activity with centrifugal spread (RAAPfocal ) or rotational activity across the PentaRay splines spanning the AF cycle length (RAAProtational ). RESULTS: A total of 498 PentaRay recordings were analyzed (35.6 ± 7.6 per patient). The number of PentaRay recordings displaying RAAP was 9.8 ± 3.1 per patient (range = 3-15), of which 2.4 ± 2.4 RAAProtational (range = 0-7), and 7.4 ± 4.4 RAAPfocal (range = 1-13). 77% of RAAPs portrayed focal firing. The median number of repetitions per 30 second recording was 11 (range = 3-225) per recording. RAAPs were observed both in the right atrium (RA) (35%) and left atrium (LA) (65%), with the majority being near the left PVs/appendage (35% of all RAAPs) and the superior vena cava/right appendage (23% of all RAAPs). CONCLUSION: High-resolution, sequential endocardial EGM-based mapping allows identification of RAAPs in persistent AF. In our series, focal firing was the most frequently observed pattern.

Pulmonary Vein Reconnection No Longer Occurs in the Majority of Patients After a Single Pulmonary Vein Isolation Procedure.

OBJECTIVES: This study sought to determine the prevalence of patients with 4 isolated veins at repeat ablation after "CLOSE" -guided pulmonary vein isolation (PVI), a strategy based on delivery of contiguous and optimized radiofrequency lesions. BACKGROUND: The likelihood of finding 4 isolated veins at a repeat ablation for atrial fibrillation (AF) recurrence after a first PVI is low. METHODS: Patients undergoing repeat ablation for AF recurrence after first CLOSE-guided PVI were included. At repeat: 1) the status of the PV was evaluated; and 2) high-density voltage mapping was performed. In case of pulmonary vein reconnection (PVR), veins were reisolated. In patients with 4 isolated veins, empirical trigger or substrate ablation was performed. RESULTS: Of 326 patients undergoing CLOSE-guided PVI for paroxysmal AF, 45 patients underwent repeat ablation for AF recurrence (11 ± 7 months after first PVI). In 28 patients, all veins were still isolated (62%). They showed similar clinical characteristics and similar time from first PVI to AF recurrence (8 ± 7 vs. 6 ± 6 months, respectively, p = 0.453) compared with patients with PVR. In contrast, they were characterized by a higher incidence of low voltage (57% vs. 17%, p = 0.033). Patients with 4 isolated veins, compared with patients treated for PVR, showed a lower 12-month freedom from AF after repeat ablation (61% vs. 88%, p = 0.045). CONCLUSIONS: After CLOSE-guided ablation, PVR is no longer the rule in patients with AF recurrence. Patients with AF recurrence and 4 isolated veins present with a similar clinical profile and time to recurrence as patients with PVR.

Endoscopic evaluation of the esophagus after catheter ablation of atrial fibrillation using contiguous and optimized radiofrequency applications.

BACKGROUND: The incidence of endoscopically detected esophageal lesions after pulmonary vein isolation (PVI) is as high as 18%. Intraesophageal temperature rise (ITR) during ablation is a predictor of esophageal injury. OBJECTIVE: The purpose of this study was to describe an ablation strategy aiming to enclose the pulmonary veins with contiguous, stable, and optimized radiofrequency applications (referred to as CLOSE-PVI). We evaluated esophageal and periesophageal injury with endoscopy in patients revealing ITR during CLOSE-PVI. METHODS: Eighty-five patients with ITR during CLOSE-PVI underwent endoscopy of the esophagus (with ultrasound in 38 patients). PVI consisted of contact force (CF)-guided encircling of the veins using 35-W applications, respecting strict criteria of intertag distance (≤6 mm) and ablation index (AI; 550 arbitrary unit [au] anterior wall, 400 au posterior wall, 300 au if ITR >38.5°C). RESULTS: Endoscopy was performed 9 ± 4 days after PVI. At the posterior wall, median power was 35 W [interquartile range (IQR) 35-35], application time 18 ± 5 seconds, CF 13 ± 6g, and AI 403 ± 38 au. A median of 5 applications [IQR 4-7] per patient over a length of 21.8 ± 6.8 mm resulted in ITR >38.5°C (median 39.9°C, IQR 39.2°C-41.2°C, range 38.6°C-50.0°C). For these applications, median power was 35 W [IQR 30-35], application time 14 ± 3 seconds, CF 12 ± 5g, and AI 351 ± 38 au. The incidence of esophageal erythema/erosion on endoscopy was 1 of 85 (1.2%) and of ulceration was 0 of 85 (0%). The incidence of mediastinal or esophageal injury on ultrasound was 0 of 38 (0%). CONCLUSION: The occurrence of esophageal or periesophageal injury after CLOSE-PVI is markedly low (1.2%). Absence of esophageal ulceration in patients with ITR suggests that this strategy of delivering contiguous, relatively high-power, and short-duration radiofrequency applications at the posterior wall is safe.

Evaluation of a Strategy Aiming to Enclose the Pulmonary Veins With Contiguous and Optimized Radiofrequency Lesions in Paroxysmal Atrial Fibrillation: A Pilot Study.

OBJECTIVES: This study sought to evaluate the safety and the acute and 1 year outcomes of an ablation protocol aiming to enclose the PV with a contiguous and optimized RF circle by targeting region-specific criteria for lesion depth assessed by ablation index and interlesion distance. BACKGROUND: Reconnections after pulmonary vein (PV) isolation are explained by insufficient lesion depth and/or discontiguity of radiofrequency (RF) lesions. METHODS: A total of 130 consecutive patients with paroxysmal atrial fibrillation (AF) underwent PV encircling using a contact force-sensing catheter. RF was delivered targeting interlesion distance ≤6 mm and ablation index ≥400 at posterior wall and ≥550 at anterior wall. Recurrence was defined as any AF, atrial tachycardia (AT), or atrial flutter (AFL) (AF/AT/AFL >30 s) on Holter electrocardiographs at 3, 6, and 12 months. RESULTS: Procedure and RF time per circle were 155 ± 28 min and 17 ± 5 min, respectively. Incidence of first-pass and adenosine-proof isolation were 98% and 98%, respectively. One short-lived transient ischemic attack was observed. At 12 months, single-procedure freedom from AF/AT/AFL was 91.3% in those 104 patients off antiarrhythmic drug therapy and 96.2% in those 26 patients on antiarrhythmic drug therapy. Single-procedure freedom from both AF/AT/AFL and antiarrhythmic drug therapy was 73.1%. CONCLUSIONS: This study suggests that an ablation protocol respecting strict criteria for lesion depth and contiguity results in acute durable PV isolation followed by a high single-procedure arrhythmia-free survival at 1 year. A prospective, multicenter trial is ongoing.

Improving procedural and one-year outcome after contact force-guided pulmonary vein isolation: the role of interlesion distance, ablation index, and contact force variability in the 'CLOSE'-protocol.

Aims: We have recently shown that a contact force (CF)-guided ablation protocol respecting region-specific criteria of lesion contiguity and lesion depth ('CLOSE' protocol) is associated with high incidence of acute durable pulmonary vein (PV) isolation (PVI) and a high single-procedure arrhythmia-free survival at 1 year. In the present study, we compared efficiency, safety, and efficacy of 'CLOSE'-guided PVI to conventional CF-guided PVI (CONV-CF). Methods and results: Fifty consecutive paroxysmal atrial fibrillation (AF) patients underwent PV encircling using a CF-sensing catheter targeting an interlesion distance (ILD) ≤6 mm and ablation index (AI) ≥400 and ≥550 at posterior and anterior wall ('CLOSE' group). Results were compared to the last 50 patients undergoing 'CONV-CF'. All patients underwent adenosine testing after PVI. Arrhythmia recurrence was defined as any atrial tachyarrhythmia (ATA) >30 s on Holter at 3, 6, and 12 months. Clinical characteristics did not differ. Contact force variability was comparable in between both groups (proportion of applications with intermittent contact 2% in 'CLOSE' vs. 1% in CONV-CF, P = 0.67). In the 'CLOSE' group, procedure time and radiofrequency (RF) time per circle were shorter (respectively 149 ± 33 min vs. 192 ± 42 min, P < 0.0001 and 18 ± 4 min vs 28 ± 7.5 min, P < 0.0001) and incidence of adenosine-proof isolation was higher (97% vs. 82%, P < 0.001). No complications were observed in the 'CLOSE' group, one tamponade in the 'CONV-CF' group. At 12 months, single-procedure freedom from ATA was 94% in 'CLOSE' vs. 80% in 'CONV-CF' group (P < 0.05). In both groups, the majority of reconnections at repeat were associated with either ILD > 6 mm and/or AI < 400/550 (100% vs. 83%, P = 0.99). Conclusion: 'CLOSE'-guided PVI improves procedural and 1 year outcome in CF-guided PVI while shortening procedure time. Improvement cannot be explained by differences in CF variability and is most likely due to the strict application of criteria for contiguity and ablation index. A randomized controlled trial is needed to exclude the possible contribution of a learning curve.

PulmOnary vein isolation With vs. without continued antiarrhythmic Drug trEatment in subjects with Recurrent Atrial Fibrillation (POWDER AF): results from a multicentre randomized trial.

Aims: Catheter ablation is indicated in patients with symptomatic paroxysmal atrial fibrillation (AF) resistant to antiarrhythmic drug therapy (ADT). We investigated whether continued use of previously ineffective ADT beyond the post-ablation blanking period reduces recurrence of atrial tachyarrhythmia within the 1st year after ablation. Methods and results: This was a multicentre, randomized controlled study in patients undergoing contact force-guided pulmonary vein isolation (PVI) for paroxysmal AF in whom previously ineffective ADT was continued during a blanking period of 3 months. If free of AF at the end of the blanking period, patients were randomly assigned in the ratio of 1:1 to continue ADT (ADT ON group, n = 77) or discontinue ADT (ADT OFF group, n = 76). Patients were followed up until 1 year after PVI, with clinical visits, Holter monitoring, and quality-of-life (QOL) questionnaires at 6 and 12 months post-procedure. Analysis of the primary endpoint (any documented atrial tachyarrhythmia lasting >30 s) was performed according to the modified intention-to-treat principle. Secondary endpoints included repeat ablation, unscheduled visits, and QOL score. Baseline clinical characteristics and initial ablation procedure characteristics were comparable between both groups. Three patients were lost to follow-up in each arm. The primary endpoint was observed in 2 of 74 (2.7%) patients in the ADT ON group vs. 16 of 73 (21.9%) patients in the ADT OFF group (P < 0.001). The ADT ON group had a lower rate of repeat ablation [1.4% vs. 19.2%, hazard ratio (HR) = 0.053; 95% confidence interval (CI) 0.007-0.399; P < 0.01) and less unscheduled arrhythmia-related health care visits (2.7% vs. 20.5%, HR = 0.055, 95% CI 0.007-0.410; P < 0.01). Quality-of-life scores were similar in both groups. Conclusion: In patients free of AF at the end of 3 months of post-ablation blanking period, continued use of previously ineffective ADT significantly reduces the recurrence of atrial tachyarrhythmia in the 1st year after PVI.

Clinical assessment and comparison of annotation algorithms in high-density mapping of regular atrial tachycardias.

BACKGROUND: High-density automated mapping of regular atrial tachycardias (ATs) requires accurate assessment of local activation times (LATs). OBJECTIVE: To evaluate high-density mapping of ATs and compare the accuracy of different automated LAT annotation algorithms. METHODS: Fifteen patients underwent AT ablation guided by the automated ConfiDENSEۛ high-density mapping module (Carto 3 v4) allowing manual reannotation (edited maps). For each AT, unedited automated maps were reconstructed offline by three algorithms: maximum unipolar slope (LATSlope ), bipolar peak (LATPeak ), and a new hybrid annotation algorithm (LATHybrid ). Five blinded experts were asked to define the (1) tachycardia mechanism, (2) ablation target, and (3) level of difficulty of these unedited maps. RESULTS: Twenty-one ATs (cycle length 300 ± 46 ms, activation points 955 ± 421) were successfully ablated using LATHybrid guided ablation with manual editing in a small number of points. At 6 months, 14 (93%) of the patients were free of AT recurrences. Unedited LATHybrid maps showed the highest accuracy in defining the tachycardia mechanism (LATHybrid : 49% vs. LATPeak : 27% vs. LATSlope : 28%, P < 0.001) and ablation target (LATHybrid : 65% vs. LATPeak : 39% vs. LATSlope : 31%, P < 0.001). Overall, LATHybrid -annotated maps were graded as "easier to interpret" by the experts (difficulty score 2.3 ± 0.9) versus LATPeak (2.8 ± 1) and LATSlope (3.2 ± 0.8) (P < 0.001). Only 12% of the LATHybrid maps were annotated as uninterpretable compared to 31% of LATSlope and 45% of the LATPeak maps (P < 0.001). CONCLUSION: Automated LATHybrid annotation allows better and easier recognition of the tachycardia mechanism compared to automated LATPeak and LATSlope algorithms, although fully automated mapping still requires further improvements.

Automated verification of pulmonary vein isolation in radiofrequency- and cryoballoon-guided ablation.

BACKGROUND: Verification of pulmonary vein isolation (PVI) can be challenging due to the coexistence of pulmonary vein potentials and far-field potentials. This study aimed to prospectively validate a novel algorithm for automated verification of PVI in radiofrequency (RF)-guided and cryoballoon (CB)-guided ablation strategies. METHODS: A data set of 620 (RF: 516 EGMs and CB: 104 EGMs) bipolar electrograms (EGM), recorded by circular mapping catheter placed at the left atrium-pulmonary vein (PV) junction, were prospectively analyzed by a two-step algorithm. The algorithm differentiates isolated from nonisolated EGMs based on typology and specific parameters of the bipolar EGMs. EGMs were recorded at baseline and after proven isolation in RF- and CB-guided procedures. Additionally, in the RF group, EGMs during encircling of the PVs were analyzed. RESULTS: In the RF and CB group, the algorithm correctly identifies EGMs as isolated or nonisolated with respectively 93% and 96% sensitivity and 86% and 90% specificity. In the RF subgroups of (1) baseline and proven isolated EGMs, (2) EGMs during encircling, and (3) EGMs in redo procedures sensitivity was 96%, 88%, and 100%, respectively, with specificity of 81%, 91%, and 100%. Fourteen out of 14 (100%) reconnected PVs were correctly identified as containing PVPs. Eleven out of 12 (92%) failed freeze attempts were correctly identified as being nonisolated. CONCLUSION: We validated a two-step algorithm for automated PVI verification, applicable both for RF- and CB-guided PVI. The algorithm automatically differentiates isolated from nonisolated PVs with high accuracy and without the need for pacing maneuvers.

Determinants of Acute and Late Pulmonary Vein Reconnection in Contact Force-Guided Pulmonary Vein Isolation: Identifying the Weakest Link in the Ablation Chain.

BACKGROUND: Pulmonary vein reconnection (PVR) still determines recurrences of atrial fibrillation after contact force (CF)-guided pulmonary vein isolation. We studied whether acute PVR (adenosine and waiting time) and late PVR (at repeat) are explained by incomplete transmurality and contiguity within the deployed radiofrequency circle. METHODS AND RESULTS: We analyzed 42 CF-guided ipsilateral pulmonary vein isolation procedures. For each radiofrequency tag within the circle, we collected data reflecting lesion depth (time of application, power, impedance drop [Δ-Imp], CF, force-time integral [FTI], and ablation index [AI]) and contiguity (automated interlesion distance [ILD]). Ablation line contiguity index (ALCI) was developed as a novel automated algorithm combining depth and contiguity into one single criterion. Each circle was subdivided into 10 segments. For each segment, we determined its weakest link by annotating timemin, powermin, Δ-Impmin, CFmin, FTImin, AImin, ILDmax, and ALCImin. Compared with segments without PVR (n=758), PVR segments (n=44) were characterized by lower Δ-Impmin (4.8 versus 7.4 Ω), CFmin (8.5 versus 11.8 g), FTImin (351 versus 473 gs), AImin (367 versus 408 arbitrary unit [au]), and higher ILDmax (6.8 versus 5.5 mm). ALCImin was significantly lower in segments with PVR (74% versus 104%; P<0.001) and was associated with the highest accuracy to predict durable segments (area under the curve=0.73). CONCLUSIONS: In CF-guided pulmonary vein isolation, PVR is explained by lack of both lesion depth and contiguity within the deployed radiofrequency circle. ALCI, a novel measure combing contiguity and depth, is the most accurate predictor for durable segments. By avoiding weak links in the ablation chain, ALCI-guided ablation is expected to improve success rate of point-by-point radiofrequency ablation.

Contact Force in Atrial Fibrillation: Role of Atrial Rhythm and Ventricular Contractions: Co-Force Atrial Fibrillation Study.

BACKGROUND: In an experimental model, variable and intermittent contact force (CF) resulted in a significant decrease in lesion volume. In humans, variability of CF during pulmonary vein isolation has not been characterized. METHODS AND RESULTS: In 20 consecutive patients undergoing CF-guided circumferential pulmonary vein isolation, 914 radiofrequency applications (530 in sinus rhythm and 384 in atrial fibrillation) were analyzed. The variability of the 60% CF range (CF(60%)) was 17±9.6 g. Hundred seventy-one (19%) applications were delivered with constant, 717 (78%) with variable, and 26 (3%) with intermittent CF. The mean CF and force-time integral were significantly higher during applications with variable than with intermittent or constant CF. There was no significant difference in CF variability, CF(60%) variability, and force-time integral between applications delivered in sinus rhythm and atrial fibrillation. The main reasons for CF variability were systolo-diastolic heart movement (29%) and respiration (27%). In 10 additional patients, during adenosine-induced atrioventricular block, the minimum CF significantly increased at 19 sites (5.3±4.4 versus 13.4±5.9 g; P<0.001) and at 16 sites intermittent or variable CF became constant. At only 1 site systolo-diastolic movement remained the main reason for variable CF. CONCLUSIONS: CF during pulmonary vein isolation remains highly variable despite efforts to optimize contact. CF and CF parameters were similar during sinus rhythm and atrial fibrillation. The main reasons for CF variability are systolo-diastolic heart movement and respiration. The systolo-diastolic peaks and nadirs of CF are because of ventricular contractions at the large majority of pulmonary vein isolation sites.

Cardiac three-dimensional rotational angiography can be performed with low radiation dose while preserving image quality.

AIMS: The effective radiation dose (ED) of three-dimensional rotational angiography (3DRA) is 5-8 mSv, leading to reticence on its use. We evaluated the potential of 3DRA with a reduced number of frames (RNF) and a reduced dose per frame. METHODS AND RESULTS: Three-dimensional rotational angiography was performed in 60 patients (52.5 ± 9.6 years, 16 females) referred for ablation in the right (RA; n = 10) and left atrium (LA; n = 50). In a simulation group (n = 20), the effect of dropping frames from a conventional 248 frames 3DRA LA acquisition was simulated. In a prospective group (n = 40), RNF 3DRA were acquired of LA (n = 30) and RA (n = 10) with 67 frames (0.24 Gy/frame) and 45 frames (0.12 µGy/frame), respectively. Accuracy was evaluated qualitatively and quantitatively. Effective radiation dose was determined by Monte Carlo simulation on every frame. In the simulation group, surface errors increased minimally and non-significantly when reducing frames from 248 to 124, 83, 62, 50, 42, and 31: 0.49 ± 0.51, 0.52 ± 0.46, 0.61 ± 0.49, 0.62 ± 0.47, 0.71 ± 0.48, and 0.81 ± 0.47 mm, respectively (Pearson coefficient 0.20). All 3D LA images were clinically useful, even with only 31 frames. In the prospective group, good or optimal 3D image quality was achieved in 80% of LA and all of RA reconstructions. These accurate models were obtained with ED of 2.6 ± 0.4 mSv for LA and 1.2 ± 0.5 mSv for RA. CONCLUSION: Three-dimensional rotational angiography is possible with a significant reduction in ED (to the level of prospectively gated cardiac computed X-ray tomography) without compromising image quality. Low-dose 3DRA could become the preferred online 3D imaging modality for pulmonary vein isolation and other anatomy-dependent ablations.