Reverse structural left atrial remodeling and atrial tachycardia in patients with repeat ablation for atrial fibrillation.

BACKGROUND: Catheter ablation has been evolved to a cornerstone in the therapy of atrial fibrillation (AF); however, atrial tachycardias (AT) after AF ablation are still an important issue. Besides the electrical recurrence of atrial tachyarrhythmia after ablation, left atrial (LA) remodeling has received attention as a consequence of AF. OBJECTIVE: The aim of this study is to evaluate predictors for AT recurrence and LA remodeling in patients with repeat AF ablation procedures. METHODS AND RESULTS: One hundred thirteen patients who underwent repeat AF ablation with 3D electro-anatomical mapping system were evaluated. Mean age was 63.1 ± 9.3 years, and 2.3 ± 0.5 ablation procedures were performed during a time period of 22 [IQR 7;48] months. Reverse structural LA remodeling (LA volume decreased more than 15%) was observed in 25 (22.1%) patients. LA volume index (LAVI) during first procedure was the only predictor for positive reverse structural LA remodeling (hazard ratio (HR): 1.03, 95% CI: 1.00-1.07, p = .036) in multivariate analysis. Fifty-nine (52.2%) patients experienced only AF and 54 (47.8%) patients AT after first procedure. Female gender (HR: 5.21, 95% CI: 1.66-18.08, p = .006), LAVI (HR: 1.06, 95% CI: 1.02-1.11, p = .008) and LA scar percentage (HR: 1.08, 95% CI: 1.02-1.17, p = .019) were independent significant predictors for AT recurrence in multivariate analysis. CONCLUSIONS: Reverse structural LA remodeling occurred in a quarter of patients with repeat ablation procedures for AF. Only larger LAVI during first procedure predicted reverse structural LA remodeling. Half of the patients experienced AT between first and last ablation procedure. Female gender, larger LAVI and larger scar area were significant predictors for AT after catheter ablation for AF.

A novel wide-band dielectric imaging system to guide radiofrequency ablation for pulmonary vein isolation.

INTRODUCTION: Recently, the wide-band dielectric mapping system Kodex-EPD was introduced. This study reports the first clinical experience using a novel system to guide pulmonary vein isolation (PVI) with radiofrequency (RF) ablation. METHODS AND RESULTS: The study included 20 consecutive patients undergoing de-novo PVI for symptomatic paroxysmal or persistent atrial fibrillation guided by Kodex-EPD. The primary efficacy endpoint was successful PVI. Secondary endpoints included procedural parameters and complications. In all 20 patients (mean age 68 ± 8 years, 12 male patients, paroxysmal fibrillation in 14/20 [70%] patients), PVI was successfully completed. One patient underwent additional cavo-tricuspid isthmus ablation for concomitant typical atrial flutter and one patient required additional ablation of a focal atrial tachycardia. A conventional three-dimensional image of the left atrium as well as the innovative endocardial panoramic view were used to guide catheter manipulation and ablation. Median procedure time was 115 [1st; 3rd quartile 93,75; 140] min and median total fluoroscopy time was 9.9 [9.7; 11.2] min, of which a median of 0.8 [0.6; 0.9] min was required to create left atrial maps. Complete left atrial imaging using Kodex-EPD was achieved within a median of 7.1 [5.7; 8.3] min. Median RF ablation time was 45.1 [34.6; 58.7] min. No major complications were observed. CONCLUSION: RF ablation PVI guided by Kodex-EPD seems safe and feasible. The system provides effective three-dimensional guidance for PVI.

Impact of obesity on acute complications of catheter ablation for cardiac arrhythmia.

INTRODUCTION: The prevalence of obesity is increasing. However, data on the periprocedural complication rate of catheter ablation for arrhythmia in patients stratified by body mass index (BMI) are scarce. METHODS: This study included 1000 consecutive patients (age 62.0 ± 14.4 years) undergoing catheter ablation for cardiac arrhythmia. The primary study endpoint was any periprocedural major complication (cardiac tamponade, pseudoaneurysm, arteriovenous fistula, transient ischemic attack, stroke, valve damage, myocardial infarction, or death). RESULTS: The mean BMI was 27.6 ± 5.1 kg/m2 and the majority of patients were overweight (BMI 25.0-29.9 kg/m2 , 43.4%). A BMI of 30.0-34.9 kg/m2 (Class I obesity) was present in 177 (17.7%) of patients, a BMI of 35.0-39.9 kg/m2 (Class II obesity) in 67 (6.7%), and a BMI ≥ 40 kg/m2 (Class III obesity) in 16 (1.6%). There were 31 major complications (3.1%) and one fatality (0.1%) due to terminal heart failure in a patient undergoing palliative ventricular tachycardia ablation. There was no significant impact of the BMI on the rate of major complications (p = .495). Compared to normal weight patients, odds ratios for complications in overweight patients, as well as Class I, II, and III obesity were 1.1 (95% confidence interval (CI): 0.8, 1.7), 1.3 (CI: 0.6, 2.6), 1.4 (CI: 0.5, 4.1), and 1.6 (CI: 0.4, 6.3), respectively. Radiation exposure and procedure duration were significantly increased in obese patients (p < .001 and p = .001, respectively). CONCLUSION: In this study, obesity did not have a significant impact on the incidence of periprocedural complications after CA for cardiac arrhythmia.

Impact of a time-to-effect-guided ablation protocol in cryoballoon ablation on the durability of pulmonary vein isolation.

BACKGROUND: Cryoballoon (CB)-based pulmonary vein isolation (PVI) has proven to be as effective as radiofrequency-based ablation. Different ablation protocols took the individual time-to-isolation (TTI) into account aiming at shorter but equally or even more effective freeze cycles. The current study sought to assess the impact of the TTI on PVI durability in patients undergoing a repeat procedure for recurrence of atrial tachyarrhythmia (ATA). METHODS AND RESULTS: In 205 patients with ATA recurrence after previous CB-based PVI, a total of 806 pulmonary veins (PVs) were identified. A total of 126 out of 806 PVs (16%) were previously treated with a TTI-guided ablation (Protocol #1; TTI + 120 s), in 92/806 (11%) PVs TTI was only monitored (m) but fixed freeze cycles were applied (Protocol #2; mTTI) and in 588/806 (73%) a fixed freeze cycle was applied without mTTI. There was no difference in the PV-reconduction rate between the groups (p = .23). The right inferior pulmonary vein (RIPV) showed overall significantly higher reconduction rates compared to the other PVs (RIPV-left inferior PV p < .003, -left superior PV p < .001, -right superior PV p < .013). Twenty-one patients (10%) were demonstrated to have only electrical reconduction of the RIPV, while all other PVs were still electrically isolated. CONCLUSIONS: The TTI-based CB ablation protocol did not show significant differences regarding PV-reconduction rates compared to the other ablation protocols.

Acute and long-term success of left atrial anterior line and mitral isthmus line ablation in patients after mitral valve surgery.

BACKGROUND: Perimitral flutter and atrial fibrillation may occur in patients with prior surgical mitral valve (MV) repair or replacement and can be challenging for percutaneous catheter ablation. This study sought to determine the feasibility, acute success and durability of catheter ablation of atrial fibrillation or atrial tachycardia by way of a mitral isthmus line (MIL) or an anterior line (AL). METHODS: A total of 81 patients (49 males, mean age 62±11 years) with prior MV replacement (n = 30) or reconstruction (n = 51) underwent creation of a MIL (34) and/or an AL (72). RESULTS: Acute bidirectional block of the MIL was successfully achieved in 24/34 cases and of the AL in 64/72 patients. Patients of the control group without prior MV surgery were matched 1:1 with the valve group. In the AL control subgroup, acute bidirectional block was achieved in 65/72 patients. Acute blockage in the MIL control subgroup could be achieved in 31/34 patients. The MIL valve subgroup showed the worst results in terms of durability, whereas a similar trend emerged in the control group and the AL valve subgroup (probability of failure in MIL valve subgroup 2.224 vs. MIL control subgroup 0.605 [Hazard Ratio (HR) = 0.27, 95% confidence interval (CI), 0.11-0.65), P = .004]; probability of failure in AL valve subgroup 0.844 vs. AL control subgroup 1.03 [HR = 1.22 (95% CI, 0.66-2.26), P = .523]). CONCLUSIONS: Percutaneous creation of MIL and AL is feasible and safe in patients with prior MV replacement/repair and associated with moderate acute and long-term success rates to achieve bidirectional block.

Stroke and left atrial thrombi after cryoballoon ablation of atrial fibrillation: incidence and predictors. Results from a long-term follow-up.

Stroke after catheter ablation (CA) of atrial fibrillation (AF) is a potential complication with long term consequences. Aim of this study was to determine incidence and potential predictors of stroke and left atrial appendage (LAA) thrombi after AF ablation with cryo-energy. Two hundred nine consecutive patients with symptomatic drug refractory AF (65% male; 61 ± 11 yo, 69% paroxysmal AF, mean CHA2DS2-VASc score 2 ± 1.4) were enrolled between October 2012 until December 2015. Long term follow-up was performed with outpatient clinic visits at 6-month intervals. Incidence of stroke after CA was 1.4% (3/209 pts) at long term follow-up. Two out of 3 pts experienced stroke during the first 3 month after CA and one after 36 months. At long term follow-up LAA thrombi were found in two patients (1%) that were on therapeutic oral anticoagulation. Recurrence of AF was found in 4 out of 5 pts with stroke or LAA thrombi. Patients with stroke or LAA thrombi did not differed from those without in term of age, gender, CV risk factors, LA size and AF type. They differed only for EHRA score (2.4 vs 1.3, p = 0.01) before CA. At multivariate analysis after correction for age, gender, LA size, LVEF and AF type, only EHRA score (ß 1.92, 95% C.I. 1.3-35 p = 0.02), was an independent predictor of stroke/LAA thrombi. Incidence of stroke after cryoablation is low, with a relative higher prevalence during the first 3 months after CA. Prospective, multicenter long-term registries are needed for a better stroke risk stratification.

Quantification of Left Atrial Fibrosis in Patients After Pulmonary Vein Isolation Using the Second-Generation Cryoballoon.

Left atrial (LA) fibrosis is associated with a poor outcome after atrial fibrillation (AF) ablation. This study examined the extent of low-voltage areas in patients with recurrence of atrial tachyarrhythmia (ATA) after CB-based pulmonary vein isolation (PVI).Sixty patients (mean age 67 ± 10 years, n = 32 female; n = 34 paroxysmal AF) who received radiofrequency redo-procedure due to recurrence of ATA within 6 months after CB-based PVI were included. A point-by point 3D-map was performed, and low-voltage sites were delineated based on bipolar voltage < 0.5 mV. The extent of fibrosis was categorized as stage A (0-10% of the LA wall), stage B (10-30%), stage C (30-50%), and stage D (> 50%).The median area of LA low-voltage sites was 28.9 (9; 50.3) cm2, corresponding to 17.4 (6; 30.6) % of the LA wall surface. 17/60 (28.3%) patients were categorized as fibrosis stage A, 21/60 (35%) as stage B, 18/60 (30%) as stage C, and 4/60 (6.7%) as stage D. Patient age and LA diameter were associated with more pronounced LA fibrosis; the extent of LA fibrosis was significantly higher in patients with LA tachycardia (LAT) during redo-procedures (P < 0.01), and ablation of linear lesions was more often performed (P < 0.01).In patients after CB2-based PVI, expanded LA tissue fibrosis was associated with the occurrence of LAT and more extensive LA ablation during redo-procedures.

Radiofrequency or cryoballoon ablation for index pulmonary vein isolation: What is the impact on long-term clinical outcomes after repeat ablation?

AIMS: The current study sought to assess the impact of the utilized energy source during index ablation on long-term clinical outcomes after repeat ablation of atrial fibrillation (AF). Index ablation procedures were either performed using radiofrequency current (RFC) (RFC group) or cryoballoon (CB) ablation (CB group). Repeat ablation was performed by the use of RFC. METHODS: A total of 195 patients (138 RFC group; 57 CB group) with paroxysmal AF were included. All patients had a recurrence of AF following the index ablation procedure. Freedom from AF was estimated with the Kaplan-Meier method. RESULTS: After a 3 years follow-up, the estimated arrhythmia-free survival did not differ between the two groups (RFC group 48% vs CB group 47%, P = .78). During index ablation, procedure times were significantly shorter in the CB group (95 [80, 140] vs 140 [115, 164] minutes, P ≤ .001), whereas fluoroscopy times (16 [11; 22] vs 19 [14; 25] minutes, P = .003), the dose area product (1862 [1203; 2922] vs 3148 [1756; 5888] cGycm2 , P ≤ .001) and the amount of contrast dye (92 ± 32 vs 123 ± 33 mL, P ≤ .001) were significantly lower in the RFC group. During repeat ablation, procedure times were significantly shorter in patients being initially treated with RFC (115 [85; 145] vs 125 [105; 150] minutes, P = .007). There was a trend towards a higher pulmonary vein reconnection rate in the RFC group without meeting statistical significance (P = .074). CONCLUSIONS: In patients with repeat ablation of AF, index RFC or CB ablation are equally effective in terms of freedom from AF. Although CB ablation results in shorter index procedures times, durations of repeat ablation are significantly longer.

Reconduction After Second-Generation Cryoballoon-Based Pulmonary Vein Isolation　- Impact of Different Ablation Strategies.

BACKGROUND: The second-generation cryoballoon (CB2) has demonstrated high procedural efficacy and convincing clinical success rates for pulmonary vein isolation (PVI). Nevertheless, data on the impact of different ablations protocols on durability are limited. The aim was to comparing the durability of PVI following 3 different ablation strategies in patients with recurrence of atrial fibrillation or atrial tachycardia undergoing repeat procedures.Methods and Results:In 192 patients, a total of 751 PVs were identified. All PVs were successfully isolated during index PVI. Thirty-one out of 192 (16%) patients were treated with a bonus-freeze protocol (group 1), 67/192 (35%) patients with a no bonus-freeze protocol (group 2), and 94/192 (49%) patients with a time-to-effect-guided protocol (group 3). Persistent PVI was documented in 419/751 (55.8%) PVs, and in 41/192 (21%) patients, all PVs were persistently isolated. The total rate of PV reconnection was not significantly different between the groups (P=0.134) and the comparison of individual PVs revealed no differences (P-values for RSPV: 0.424, RIPV: 0.541, LSPV: 0.788, LIPV: 0.346, LCPV: 0.865). The procedure times were significantly reduced by omitting the bonus-freeze and applying individualized application times (group 1: 123.4±31.5 min, group 2: 112.9±39.8 min, group 3: 86.67±28.4 min, P<0.001). CONCLUSIONS: Comparing 3 common ablation protocols, no differences for durable PVI were detected. Procedure times were significantly reduced by omitting the bonus-freeze cycle and by applying individualized application times.

The clip and the tip: Lessons learned from ablation of atrial fibrillation in patients postpercutaneous mitral valve repair.

BACKGROUND: Atrial fibrillation (AF) and higher grade mitral valve regurgitation are often associated. For both, there are interventional therapeutic options such as pulmonary vein isolation (PVI) and percutaneous mitral valve repair (PMVR) using MitraClip. OBJECTIVE: This study investigated the feasibility, safety and clinical outcome of AF ablation in patients with prior PMVR. METHODS: This study included patients with symptomatic AF who underwent PVI after prior PMVR at a tertiary care center (14 consecutive patients, group I). A propensity-score matched group of 42 patients (1:3 matching, group II) without prior valve repair acted as controls. RESULTS: Acute PVI was achieved in all patients. No difference was found regarding median procedure time (group I: 125.0 [Q1: 120.0; Q3: 176.3] vs group II: 135.0 [120.0; 177.5] minutes; P = 0.87) and median fluoroscopy duration (group I: 17.2 [12.9; 25.9] vs group II: 18.6 [12.3; 25.9] minutes; P = 0.95). In group I, one patient suffered a postprocedural transient ischemic attack. No further major complications occurred (P = 0.25). No periprocedural interference with the MitraClip was noted. The Kaplan-Meier estimate 18-month overall arrhythmia-free survival after the index procedure including a 3-month blanking period was 64.8% (95% confidence interval [CI] 42.1-99.8%) for the study group and 68.3% (95% CI, 54.6-85.6%) for the control group P = 0.35). A higher percentage of left atrial tachycardias was observed in the study group (67% vs 12% of patients with any arrhythmia recurrence; P = 0.01). CONCLUSION: Catheter ablation of AF in patients with prior PMVR is feasible and safe and results in satisfying clinical outcome.

Predictors of freedom from atrial arrhythmia recurrence after cryoballoon ablation for persistent atrial fibrillation: A multicenter study.

AIMS: We sought to assess (1) clinical outcomes of second-generation cryoballoon (CB) ablation for persistent atrial fibrillation (AF), and (2) the association of baseline and procedural covariates with atrial arrhythmia recurrence (AAR) after ablation. METHODS: A total of 135 patients (63 ± 11 years, 96 men [71%]) with persistent AF underwent CB ablation at three experienced electrophysiology centers. Freedom from AAR was estimated with the Kaplan-Meier method. A Cox proportional-hazards model was used to estimate the effects of baseline and procedural covariates on the likelihood of AAR. RESULTS: Freedom from AAR at 6, 12, and 18 months was estimated at 91% (95% confidence interval [CI] 86%-96%), 75% (95% CI, 67%-83%), and 53% (95% CI, 43%-65%), respectively. The presence of an implantable cardiac device (Hazard ratio [HR] 3.09; 95% CI, 1.37-7.00; P = .007), a left atrial (LA) diameter > 50 mm (HR 1.69; 95% CI, 1.02-2.79; P = .043), and absence of antiarrhythmic drug (AAD) therapy before the ablation procedure (HR 3.12; 95% CI, 1.72-5.64; P < .001) were associated with AAR. A trend toward an increased risk of AAR was revealed for women (HR 1.73; 95% CI, 0.96-3.11; P = .069). CONCLUSIONS: CB ablation for persistent AF resulted in freedom from AAR about that reported for RF ablation. The presence of an implantable cardiac device, LA size, and absence of AAD therapy at baseline were associated with the risk of AAR.

Management of arrhythmia recurrence in patients with pulmonary vein stenosis following atrial fibrillation ablation.

AIMS: Arrhythmia recurrence is a common clinical problem in patients with pulmonary vein stenosis (PVS) following catheter ablation of atrial fibrillation. The study sought to analyse the management of arrhythmia recurrence in patients with PVS. METHODS AND RESULTS: Retrospective analysis was performed on 29 patients with high-degree PVS. Follow-up contained clinical visits, Holter-electrocardiogram recordings and invasive pulmonary vein (PV) angiography and electrophysiological studies. Arrhythmia recurrence was observed in 18 patients (62%) after PVS formation. Fifteen of 18 patients (83.3%) with and 1 of 11 patients (9.1%) without arrhythmia recurrence had electrical PV reconnection (P = 0.0003). In 14 of 16 patients repeat pulmonary vein isolation (PVI) was conducted (radiofrequency ablation in 12 and cryoballoon ablation in 2 cases). Repeat PVI was successful in all PVs in nine patients and incomplete in five patients (failed attempt in two patients with stent implantation, no attempt in three patients with stenotic PVs). Freedom from arrhythmia recurrence was estimated at 56.3% [95% confidence interval (CI) 36.4-72.0%] after 24 months. At the end of the follow-up, complete PVI was documented in 19 of 23 patients (82.6%) with stable sinus rhythm and in 2 of 6 patients with arrhythmia recurrence (33.3%) (P = 0.0335). The Kaplan-Meier estimate of recurrence-free survival of restenosis after interventional PVS treatment was similar in patients without and with repeat ablation [75.6% (95% CI 57.0-94.3%) and 67.0% (95% CI 43.2-90.7%) after 500 days, P = 0.77]. CONCLUSIONS: Pulmonary vein reconnection is the major driver of arrhythmia recurrence in PVS patients. Repeat PVI is feasible and does not lead to progression of PVS or restenosis if the procedure is carefully performed.

Efficacy and Safety of Cryoballoon Ablation in Patients With Heart Failure and Reduced Left Ventricular Ejection Fraction　- A Multicenter Study.

BACKGROUND: Second-generation cryoballoon (CB2)-based pulmonary vein isolation (PVI) has demonstrated encouraging results in the treatment of atrial fibrillation (AF). This study sought to assess data on the safety, efficacy and clinical success of CB2-based PVI in patients with heart failure (HF) and reduced ejection fraction (HFrEF).Methods and Results:CB2-based PVI was performed in 551 consecutive patients in 3 highly experienced EP centers. Patients with HF and LVEF ≤40% were included (HFrEF group, n=50/551, 9.1%). Data were compared with propensity score-matched patients without HF and preserved left ventricular EF (LVEF) (n=50, control group). The median LVEF was HFrEF: 37% (35, 40) and control: 55% (55, 55), P<0.0001. Major periprocedural complications were registered in 4/50 (8%, HFrEF group) and 3/50 (6%, control group), P=0.695. The 12-month freedom from AF recurrence was 73.1% (95% confidence interval (CI): 61-88, HFrEF group) and 72.6% (95% CI: 61-87, control group), P=0.25. NYHA class decreased from 2.4±0.8 (baseline) to 1.7±0.8 at 12-month follow-up (P<0.0001). LVEF improved from a median of 37% (35, 40) prior to ablation to a median of 55% (40, 55), P<0.0001. CONCLUSIONS: CB2-based PVI in patients with HFrEF appeared to be safe, was associated with comparable periprocedural complications and showed promising clinical success rates equal to those for patients with preserved LVEF. NYHA class and LVEF significantly improved at 12-month follow-up.

Higher contact force, energy setting, and impedance rise during radiofrequency ablation predicts charring: New insights from contact force-guided in vivo ablation.

INTRODUCTION: Higher contact force (CF) theoretically increases the risk of blood charring, diminishing lesion formation. We aimed to investigate the relationship between CF, impedance change, and char formation during pulmonary vein isolation (PVI). METHODS: CF was assessed during PVI in 65 patients. Radiofrequency ablation (RFA) with power-controlled mode was applied in the point-by-point manner. The RFA were divided into five groups: group A (CF < 10 g), group B (10 g ≤ CF < 20 g), group C (20 g ≤ CF < 30 g), group D (30 g ≤ CF < 40 g), and group E (CF ≥ 40 g). Gradual impedance rise (gIR) was defined as >5 Ω increase during each 10-second period of RFA. Catheter tip was assessed for charring during, and at the end of each procedure. RESULTS: In total, 2,064 applications were analyzed. During 0-10 seconds, impedance was significantly decreased in groups with higher CF (P < 0.05). During 10-20 seconds, an impedance decrease was not significantly different among the five groups. During 20-30 seconds, mean impedance increased in group E. A gIR was noted at least once during RFA in 63 patients (97%). The incidence of gIR during RFA after 20 seconds was significantly higher in groups D and E (77/504 [15.3%] vs. 90/1560 [5.8%], P < 0.001). Charring occurred in 8 of 65 (12%) patients. A gIR after 20 seconds was significantly associated with a higher incidence of macroscopic charring (6/20 [30%] vs. 2/45 [4%], P < 0.01). CONCLUSIONS: gIR was noted with higher applied CFs after 20 seconds of RFA. This impedance rise may be avoided by keeping the applied CF under 26.9 g with negative predictive value of 95%. Our data suggested that gIR may be related to the incidence of charring.

Significant reduction of radiation exposure in cryoballoon-based pulmonary vein isolation.

Aims: Procedure times and left atrial dwell times of cryoballoon (CB)-based ablation strategies for atrial fibrillation (AF) are shorter as compared to radiofrequency ablation, yet fluoroscopy times are longer and result in a higher radiation exposure. The objective of this study is to evaluate a modified fluoroscopy protocol aiming at reduction of radiation exposure in CB ablation. Methods and results: A total of 120 patients with symptomatic AF underwent pulmonary vein isolation (PVI) using the second generation CB and an ablation strategy considering the individual time-to-isolation. The first 60 patients (Group 1) underwent CB-based PVI with conventional fluoroscopy settings. An optimized approach was applied in the following 60 patients (Group 2) by (i) using fluoroscopy instead of filming for verification of pulmonary vein (PV) occlusion after contrast injection, (ii) reducing the frame rate, and (iii) pursuing maximal collimation on the region of interest. A total of 475 PVs were identified and successfully isolated. Median dose area product and fluoroscopy time were significantly shorter in Group 2 as compared to Group 1 [389 (285; 550) cGycm2 vs. 2168 (1355; 3490) cGycm2 (P < 0.0001) and 10 (8; 12) min vs. 14 (11; 19) min (P < 0.0001)]. Additionally, median time-to-isolation of the PVs was significantly shorter in Group 2 [44 (30; 65) s vs. 33 (20; 46) s (P < 0.0001)]. Conclusions: The implementation of an optimized fluoroscopy protocol significantly reduces radiation exposure in CB-based PVI without compromising acute efficacy and safety.

Catheter ablation of atrial fibrillation in very young adults: a 5-year follow-up study.

Aims: Catheter ablation is an established therapy for symptomatic atrial fibrillation (AF). However, outcome data on catheter ablation for AF in young adults is scarce. Methods and results: From 2005-2014, 85 consecutive young adults (mean age 31 ± 4 years; 69% men) with symptomatic paroxysmal AF (PAF, n = 52) and persistent (Pers) AF (n = 33) underwent pulmonary vein isolation (PVI) [±ablation of complex fractionated atrial electrograms/linear lesions in PVI non-responders] at our centre. Follow-up was based on outpatient visits including 24-h Holter-ECG at 3, 6 and, 12 months post ablation, and every 12 months thereafter. Recurrence was defined as any AF/atrial tachycardia episode >30s following a 3-month blanking period. Follow-up was available for 74/85 (87%) patients. After a median follow-up of 4.6 years (Q1: 2.6; Q3: 6.6) and a mean of 1.5 ± 0.6 (median 1, range 1-3) ablation procedures 84% [including 13% on previously ineffective antiarrhythmic drugs (AAD)] of patients were in stable SR. Single-procedural 1-year/5-year arrhythmia-free survival was 66% [95% confidence interval (CI): 56-78%]/44% (95% CI: 33-59%), respectively. Structural heart disease [SHD; hazard ratio (HR) 2.79 (95% CI 1.52-5.12), P = 0.001] and obesity [HR 1.10 (95% CI 1.00-1.21) per unit increase in body mass index >27 kg/m2, P = 0.05] independently predicted AF recurrence. Major complications occurred in 6/122 (4.9%) procedures (PV stenosis in 3, cardiac tamponade in 1, stroke in 1, and arterial-venous fistula in 1). Conclusion: In the majority of very young adults catheter ablation for AF is effective, and associated with an acceptable complication rate. SHD and obesity are predictors for AF recurrence in this population.

Pulmonary vein stenosis or occlusion after catheter ablation of atrial fibrillation: long-term comparison of drug-eluting versus large bare metal stents.

Aims: Pulmonary vein stenosis or occlusion (PVS/O) following catheter ablation of atrial fibrillation is a rare but potentially severe complication. Treatment options include angioplasty with or without stent implantation, but data on outcome and optimal treatment strategy are limited. We report long-term results after catheter-based treatment of patients with symptomatic PVS/O. Methods and results: Retrospective analysis was performed in patients undergoing pulmonary vein (PV) angiography for suspected PVS/O. All patients with PVS/O were treated with balloon angioplasty and implantation of a coronary drug-eluting stent (DES) or a peripheral large-diameter bare metal stent (LD-BMS). A total of 25 high-degree PVS/Os in 19 patients were treated. Nine PVs were treated with angioplasty and DES implantation and 16 with angioplasty and LD-BMS implantation. The ostial PV diameter was not different in the DES and LD-BMS groups (10.2 ± 2.5 mm vs. 11.1 ± 1.9 mm, P = 0.34), but the PV/stent diameter ratio was significantly lower in the former (0.43 ± 0.13 vs. 0.82 ± 0.13, P < 0.0001). Angiographic stent restenosis was observed at a median of 539 (interquartile range 99-774) days in 9 of 23 (39%) treated PVs. The restenosis rate in the LD-BMS group was only one-third of that in the DES group [3/14 (21%) vs. 6/9 (67%), respectively; P = 0.08]. Conclusion: The use of LD-BMS for the treatment of PVS/O was associated with an acceptable long-term outcome. Coronary DES implantation resulted in a high rate of restenosis and should therefore not be performed. Larger trials are needed to confirm our findings.

Antegrade-transseptal approach for left ventricular tachyarrhythmia in patients with previous Mitraclip implantation.

Aims: Antegrade-transseptal approach to treat left ventricular tachyarrhythmia (LVT) is useful and widespread. Meanwhile, Mitraclip has been recently introduced as an alternative to mitral valve surgery for severe mitral regurgitation, usually coexisting with ventricular arrhythmias. However, data on the antegrade approach for mapping and ablating LVT in these patients are insufficient. We evaluated the feasibility and clinical impact of the antegrade approach for LVT after Mitraclip implantation. Methods and results: We included five patients (all men; age 72.6 ± 10.5 years) with Mitraclip implantation who underwent catheter ablation for LVT and employed the antegrade approach. Post-ablation mitral valve function was systematically evaluated by transthoracic echocardiography. Six procedures with the antegrade approach were performed on the five patients; three of these patients developed electrical storm. The number of implanted Mitraclip was 1 in two patients, 2 in two patients, and 3 in one patient, for a mean duration of 417 ± 324 days before ablation. After 117-day median follow-up, there was no recurrence of electrical storm, but ventricular tachyarrhythmia recurred and required implantable cardioverter defibrillator therapy in one patient (only sporadic anti-tachycardia pacing); two patients died because of reasons other than ventricular arrhythmia. There was no procedure-related injury on the mitral valve immediately and 3 months after ablation. Conclusions: Antegrade ablation of LVT after Mitraclip implantation may be feasible. Non-arrhythmic death during follow-up suggested the need for comprehensive evaluation before and after ablation.

Is less more? Impact of different ablation protocols on periprocedural complications in second-generation cryoballoon based pulmonary vein isolation.

Aims: Second-generation cryoballoon (CB2) based pulmonary vein isolation (PVI) has emerged as an effective treatment option for symptomatic atrial fibrillation (AF). The current study sought to assess the impact of different ablation protocols on the incidence and characteristics of procedural complications in a large patient cohort. Methods and results: A total of 563 consecutive patients with symptomatic AF who underwent CB2-based ablation between July 2012 and January 2016, were assessed. Three different ablation protocols were applied and characterized by (#1) a bonus-freeze following PVI, (#2) no bonus-freeze after PVI, and (#3) a 'time-to-effect'-guided strategy. Major complications occurred in 30/563 patients (5.3%) with phrenic nerve palsy (PNP) as the most frequent complication occurring in 2.7% of the cases. The overall incidence of complications was significantly lower in patients treated with a 'time-to-effect' guided ablation strategy compared with the other ablation protocols (8.1% [17/211] (protocol #1+#2) vs. 3.7% [13/352] (protocol #3), respectively; P = 0.026). The 'time-to-effect' guided ablation protocol was associated with less applied freeze-cycles and shorter freeze-cycle durations. Additionally, shorter procedure times, radiation exposures and lower volumes of contrast medium needed were assessed for the 'time-to-effect' guided protocol as compared with the other ablation protocols. Conclusion: The overall incidence of complications was 5.3% in our analysis. The most frequent complication was PNP. The use of a time-to-effect guided ablation protocol was associated with a lower incidence of major complications compared with a bonus-freeze and no bonus-freeze protocol.

Does Size Matter? Cryoballoon-Based Pulmonary Vein Isolation Using a Novel 25-mm Circular Mapping Catheter.

BACKGROUND: Real-time recording of pulmonary vein isolation (PVI) using a circular mapping catheter has become a key aspect of cryoballoon (CB) ablation. The aim of this study was to investigate the procedural safety, efficacy and rate of real-time pulmonary vein (PV) recording using a novel circular mapping catheter with a 25-mm loop size for CB-based PVI.Methods and Results:A total of 40 patients with symptomatic atrial fibrillation (AF) underwent PVI using a second-generation CB and a novel 25-mm circular mapping catheter. A total of 159 PV were identified and successfully isolated. Real-time PV recording was achieved in 80% of the PV. In 3 right inferior PV the circular mapping catheter had to be exchanged for a stiff guidewire due to insufficient mechanical support. Therefore, acute PVI using exclusively the circular mapping catheter was achieved in 156/159 PV (98%). Mean procedure and fluoroscopy times were 66±21 min and 15±6 min, respectively. Transient phrenic nerve palsy occurred in 1 patient as the only procedural complication. CONCLUSIONS: The exclusive use of a novel 25-mm circular mapping catheter for CB ablation of AF results in a real-time PV recording rate of 80% and isolation of 98% of targeted PV.