Adenosine-guided pulmonary vein isolation for the treatment of paroxysmal atrial fibrillation: an international, multicentre, randomised superiority trial

Pulmonary Vein Stenosis After Atrial Fibrillation Ablation: Insights From the ADVICE Trial

BACKGROUND

Pulmonary vein (PV) stenosis is a complication of atrial fibrillation (AF) ablation. The incidence of PV stenosis after routine post-ablation imaging remains unclear and is limited to single-centre studies. Our objective was to determine the incidence and predictors of PV stenosis following circumferential radiofrequency ablation in the multicentre Adenosine Following Pulmonary Vein Isolation to Target Dormant Conduction Elimination (ADVICE) trial.

METHODS

Patients with symptomatic AF underwent circumferential radiofrequency ablation in one of 13 trial centres. Computed tomographic (CTA) or magnetic resonance (MRA) angiography was performed before ablation and 90 days after ablation. Two blinded reviewers measured PV diameters and areas. PVs with stenosis were classified as severe (> 70%), moderate (50%-70%), or mild (< 50%). Predictors of PV stenosis were identified by means of multivariable logistic regression.

RESULTS

A total of 197 patients (median age 59.5 years, 29.4% women) were included in this substudy. PV stenosis was identified in 41 patients (20.8%) and 47 (8.2%) of 573 ablated PVs. PV stenosis was classified as mild in 42 PVs (7.3%) and moderate in 5 PVs (0.9%). No PVs had severe stenosis. Both cross-sectional area and diameter yielded similar classifications for severity of PV stenosis. Diabetes was associated with a statistically significant increased risk of PV stenosis (OR 4.91, 95% CI 1.45-16.66).

CONCLUSIONS

In the first systematic multicentre evaluation of post-ablation PV stenosis, no patient acquired severe PV stenosis. Although the results are encouraging for the safety of AF ablation, 20.8% of patients had mild or moderate PV stenosis, in which the long-term effects are unknown.

Localization of Residual Conduction Gaps After Wide Antral Circumferential Ablation of Pulmonary Veins

Ablation of atrial fibrillation (AF) is the cornerstone therapy for patients with symptomatic AF resistant to anti-arrhythmic drugs or as first-line therapy, and is based on permanent pulmonary vein (PV) isolation. The presence of a conduction gap in a wide antral circumferential ablation lesion around PVs is often sufficient to transform an initially successful ablation into a procedural failure, thus necessitating a redo intervention. The strategy during a redo procedure is based on the detection and ablation of the reconnection gap. Finding gaps is often simple, but also sometimes challenging, because gaps may be difficult to detect, resulting in unnecessary radiofrequency delivery. The present review aimed to describe the various techniques published thus far to detect residual reconnections along the encircling ablation lines around PVs, to help electrophysiologists to detect and ablate reconnection gaps.

Pulmonary Vein Isolation With Single Pulse Irreversible Electroporation

Background:

Irreversible electroporation (IRE) is a promising new nonthermal ablation technology for pulmonary vein (PV) isolation in patients with atrial fibrillation. Experimental data suggest that IRE ablation produces large enough lesions without the risk of PV stenosis, artery, nerve, or esophageal damage. This study aimed to investigate the feasibility and safety of single pulse IRE PV isolation in patients with atrial fibrillation.

Methods:

Ten patients with symptomatic paroxysmal or persistent atrial fibrillation underwent single pulse IRE PV isolation under general anesthesia. Three-dimensional reconstruction and electroanatomical voltage mapping (EnSite Precision, Abbott) of left atrium and PVs were performed using a conventional circular mapping catheter. PV isolation was performed by delivering nonarcing, nonbarotraumatic 6 ms, 200 J direct current IRE applications via a custom nondeflectable 14-polar circular IRE ablation catheter with a variable hoop diameter (16–27 mm). A deflectable sheath (Agilis, Abbott) was used to maneuver the ablation catheter. A minimum of 2 IRE applications with slightly different catheter positions were delivered per vein to achieve circular tissue contact, even if PV potentials were abolished after the first application. Bidirectional PV isolation was confirmed with the circular mapping catheter and a post ablation voltage map. After a 30-minute waiting period, adenosine testing (30 mg) was used to reveal dormant PV conduction.

Results:

All 40 PVs could be successfully isolated with a mean of 2.4±0.4 IRE applications per PV. Mean delivered peak voltage and peak current were 2154±59 V and 33.9±1.6 A, respectively. No PV reconnections occurred during the waiting period and adenosine testing. No periprocedural complications were observed.

Conclusions:

In the 10 patients of this first-in-human study, acute bidirectional electrical PV isolation could be achieved safely by single pulse IRE ablation.

Chamber-specific transcriptional responses in atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia, yet the molecular signature of the vulnerable atrial substrate is not well understood. Here, we delineated a distinct transcriptional signature in right versus left atrial cardiomyocytes (CMs) at baseline and identified chamber-specific gene expression changes in patients with a history of AF in the setting of end-stage heart failure (AF+HF) that are not present in heart failure alone (HF). We observed that human left atrial (LA) CMs exhibited Notch pathway activation and increased ploidy in AF+HF but not in HF alone. Transient activation of Notch signaling within adult CMs in a murine genetic model is sufficient to increase ploidy in both atrial chambers. Notch activation within LA CMs generated a transcriptomic fingerprint resembling AF, with dysregulation of transcription factor and ion channel genes, including Pitx2, Tbx5, Kcnh2, Kcnq1, and Kcnip2. Notch activation also produced distinct cellular electrophysiologic responses in LA versus right atrial CMs, prolonging the action potential duration (APD) without altering the upstroke velocity in the left atrium and reducing the maximal upstroke velocity without altering the APD in the right atrium. Our results support a shared human/murine model of increased Notch pathway activity predisposing to AF.

Distinct transcriptional changes occur in human left versus right atrial cardiomyocytes in atrial fibrillation, including Notch pathway activation, which alters electric properties and ploidy in murine models.

Efficacy of isoproterenol in the evaluation of dormant conduction and arrhythmogenic foci identification in atrial fibrillation ablation

Background

Catheter ablation for atrial fibrillation (AF) is an established therapy. However, postoperative recurrence is a serious issue caused by the reconduction of the isolated pulmonary veins (PV) and the onset of non-PV foci. The objectives of this study were to elucidate dormant conduction, confirm PV arrhythmia substrate, induce non-PV foci after PV isolation, and assess the acute efficacy of high dose isoproterenol (ISP) when administered in addition to adenosine.

Methods

The study consisted of 100 patients with drug-refractory AF (paroxysmal and persistent) who underwent ablation therapy (either radio-frequency or cryoballoon ablation) as the first-line of therapy at our hospital. All patients first underwent PV isolation (PVI) and were administered adenosine followed by ISP (6 μg × 5 min). The effects were observed, and the therapeutic strategy was evaluated.

Results

Persistent dormant conduction due to ISP administration was observed in 13 patients. In over half of the patients, arrhythmia substrates were identified in the PV. Ten patients presented with persistent PV firing. The ablation of non-PV foci was additionally performed in 23 patients.

Conclusions

We found that dormant conduction, as a result of ISP administration, is persistent and ISP is useful when performing an ablation. In addition, ISP administration is useful for the identification of PV arrhythmia substrates and induction of non-PV foci. However, the effectiveness of ISP may be partially due to the complementary effect of adenosine, and, therefore, a combination of the two drugs seems preferable.

The Cryoballoon vs Irrigated Radiofrequency Catheter Ablation (CIRCA-DOSE) Study Results in Context

The Cryoballoon vs Irrigated Radiofrequency Catheter Ablation: Double Short vs Standard Exposure Duration (CIRCA-DOSE) study was a multicentre, randomised, single-blinded trial that compared contact-force radiofrequency ablation and two different regimens of cryoballoon ablation. All patients received an implantable cardiac monitor for the purpose of continuous rhythm monitoring, with all arrhythmia events undergoing independent adjudication by a committee blinded to treatment allocation. The study demonstrated there were no significant differences between contact-force radiofrequency ablation and cryoballoon ablation with respect to recurrence of any atrial tachyarrhythmia, symptomatic atrial tachyarrhythmia, asymptomatic AF, symptomatic AF or AF burden. While the results of the CIRCA-DOSE study are reviewed here, this article focuses on considerations around the design of the study and places the observed outcomes in context.

Adenosine usage during AF ablation in Europe and selected long-term findings from the ESC-EHRA EORP Atrial Fibrillation Ablation Long-Term registry

Background

Adenosine can be used to reveal dormant pulmonary vein (PV) conduction after PV isolation (PVI). This study presents a subanalysis of real-world 1-year follow-up data from the ESC-EHRA EORP Atrial Fibrillation (AF) Ablation Long-Term registry to analyze the usage of adenosine during PVI treatment in terms of rhythm outcome and safety.

Methods

The registry consists of 104 participating centers in 27 countries within the European Society of Cardiology. The registry data was split into an adenosine group (AG) and no-adenosine group (NAG). Procedure characteristics and patient outcome were compared.

Results

Adenosine was administered in 10.8% of the 3591 PVI patients included in the registry. Spain, the Netherlands, and Italy included the majority of adenosine cases (48.8%). Adenosine was applied more often in combination with open irrigation radiofrequency (RF) energy (74.7%) and less often in combination with nonirrigated RF energy (1.6%). After 1 year, a higher percentage of the AG was free from AF compared with the NAG (68.9% vs 59.1%, p < 0.001). Adenosine was associated with better rhythm outcome in RF ablation procedures, but not in cryo-ablation procedures (freedom from AF: RF: AG: 70.9%, NAG: 58.1%, p < 0.001, cryo: AG: 63.9%, NAG: 63.8%, p = 0.991).

Conclusions

The use of adenosine was associated with a better rhythm outcome after 1 year follow-up and seems more useful in patients treated with RF energy compared with patients treated with cryo energy. Given the improved rhythm outcome at 1-year follow-up, it seems reasonable to encourage the use of adenosine during RF AF ablation.

Confirmation of Pulmonary Vein Isolation with High-Density Mapping: Comparison to Traditional Workflows

Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. Yet tools and techniques used for confirmation of PVI vary greatly, and it is unclear whether the use of any particular combination of tools and techniques provides greater sensitivity for identifying gaps periprocedurally. It has been suggested the use of a high-density mapping catheter, which enables simultaneous recording of adjacent bipolar EGMs in two directions, may provide improved sensitivity for gap identification. Anonymized, acute procedural data was prospectively collected in AF ablation cases utilizing various workflows for confirmation of PVI. Post-hoc analysis was performed to evaluate the incidence of gaps detected by different diagnostic catheter technologies, including a high-density mapping catheter and circular mapping catheters (CMCs), and common techniques such as pacing the ablation lines. A total of 139 cases were included across three subgroup analyses: 99 cases were included in an indirect comparison of three mapping catheter technologies, revealing gaps in 36.7%, 38.9%, and 81.8% of cases utilizing a 10-pole CMC, 20-pole CMC, and a high-density mapping catheter, respectively; a direct comparison of diagnostic catheter technologies in 18 cryoballoon ablation cases revealed residual gaps in 22.2% of patients identified by high-density mapping which were missed previously with the use of a 3.3F CMC; in 22 cases utilizing a technique of pacing the ablation lines, high-density mapping identified residual gaps in 68.2% of patients. This proof of concept analysis demonstrated that the use of a high-density catheter which records orthogonal bipoles simultaneously, appears to improve acute detection of gaps in PVI lines relative to other commonly utilized techniques and technologies. The long-term impact of ablating these concealed gaps remains unclear. Further study, including direct comparison of diagnostic catheter technologies in a randomized setting with long-term followup, is warranted.

Use of a multi-electrode radiofrequency balloon catheter to achieve pulmonary vein isolation in patients with paroxysmal atrial fibrillation: 12-Month outcomes of the RADIANCE study

BACKGROUND

The RADIANCE first-in-man study evaluated acute (3-month) safety and design concept in terms of utility of a new multi-electrode radiofrequency (RF) balloon catheter (HELIOSTAR, Biosense Webster) to achieve pulmonary vein isolation (PVI). After study conclusion, a subset of patients was followed up to 12 months.

METHODS

Patients with drug refractory paroxysmal atrial fibrillation were enrolled. Neurological assessment, cardiac and cerebral magnetic resonance imagings were performed pre and post procedure. Ablation was delivered at 15 Watts to each PV for 60 seconds (electrodes adjacent to the posterior wall limited to 20 seconds). Adenosine or isoproterenol was administered to confirm PVI. Esophageal endoscopy was performed 48 hours post procedure. Patients were clinically followed up for 12 months.

RESULTS

Thirty-nine patients underwent catheter ablation from four centers. Mean age was 60.7 ± 10.0 years with 23 (57.5%) being male. Confirmation of PVI was performed in all PVs treated (152/152). Confirmation of isolation after one delivery was performed solely on 137 of 152 PVs of which 79.6% (109/137) achieved isolation with a single delivery of RF energy. Acute PV reconnection was seen in 4.6% (7/150) of PVs. Freedom from documented atrial arrhythmia at 12 months in those followed up was 86.4% (32/37). A total of 75.7% (28/37) of patients were free from atrial arrhythmia and off antiarrhythmic medications.

CONCLUSION

The HELIOSTAR RF balloon catheter allows for rapid and safe PVI with majority of PVs only requiring one application.

General anesthesia or conscious sedation in paroxysmal atrial fibrillation catheter ablation

BACKGROUND

Catheter ablation of paroxysmal atrial fibrillation (AF) can be performed under general anesthesia or conscious sedation. The influence of type of anesthesiology care on procedural characteristics and ablation outcome in patients in whom intracardiac echocardiography (ICE) and elimination of adenosine-mediated dormant conduction (DC) is used is not entirely known.

METHODS

150 patients with paroxysmal AF were randomized to point-by-point radiofrequency catheter isolation of pulmonary veins (PVI) under general anesthesia (n=77) or conscious sedation (n=73). Adenosine-mediated dormant conduction was eliminated in all patients. Antiarrhythmic medication was discontinued after PVI. During twelve months of follow-up, all patients underwent four times 7-day ECG monitorings.

RESULTS

There was no difference between groups in AF recurrence (28.6% vs. 31.5%, P=0.695). Patients in conscious sedation had longer procedure times (160 ± 32.1 vs. 132 ± 31.5 min, P<0.001), longer RF energy application times (40 ± 15 vs. 29 ± 11 min, P<0.001) and longer fluoroscopy times (6.2 min ± 5.3 vs. 4.3 min ± 2.2, P<0.001) with similar complication rates.

CONCLUSION

Conscious sedation is not inferior to general anesthesia in regard to arrhythmia recurrence or complication rates of catheter ablation of paroxysmal atrial fibrillation. However, it is associated with longer procedure times, longer time of radiofrequency energy application and longer fluoroscopy times.

Intraprocedural endpoints to predict durable pulmonary vein isolation: a randomized trial of four post-ablation techniques

AIMS

The optimal procedural endpoint to achieve permanent pulmonary vein isolation (PVI) during ablation of atrial fibrillation (AF) remains unknown. We aimed to compare the impact of prolonged waiting periods and adenosine triphosphate (ATP) testing after PVI on long-term freedom from AF.

METHODS AND RESULTS

In total, 538 patients (median age 61 years, 62% male) undergoing first-time radiofrequency ablation for paroxysmal AF were randomized into four groups: Group 1 [PVI (no testing), n = 121], Group 2 (PVI + 30min waiting phase, n = 151), Group 3 (PVI+ATP, n = 131), and Group 4 (PVI + 30min+ATP, n = 135). The primary endpoint was freedom from AF. Repeat mapping to assess for late pulmonary vein (PV) reconnection was performed in patients who remained AF-free for >3 years (n = 46) and in those who had repeat ablation for AF recurrence (n = 82). During initial procedure, acute PV reconnection was observed in 33%, 26%, and 42% of patients in Groups 2, 3, and 4, respectively. At 36 months, no significant differences in freedom from AF recurrence were observed among all four groups (55%, 61%, 50%, and 62% for Groups 1, 2, 3, and 4, respectively; P = 0.258). Late PV reconnection was commonly observed, with a similar incidence between patients with and without AF recurrence (74% vs. 83%; P = 0.224).

CONCLUSION

Although PVI remains the cornerstone for AF ablation, intraprocedural techniques to assess for PV reconnection did not improve long-term success. Patients without AF recurrence after 3 years exhibited similarly high rates of PV reconnection as those that underwent repeat ablation for AF recurrence. The therapeutic mechanisms of AF ablation may not be solely predicated upon durable PVI.

The low acute effectiveness of a high-power short duration radiofrequency current application technique in pulmonary vein isolation for atrial fibrillation

BACKGROUND

Application of high power radiofrequency (RF) energy for a short duration (HPSD) to isolate pulmonary vein (PV) is an emerging technique. But power and duration settings are very different across different centers. Moreover, despite encouraging preclinical and clinical data, studies measuring acute effectiveness of various HPSD settings are limited.

METHODS

Twenty-five consecutive patients with symptomatic atrial fibrillation (AF) were treated with pulmonary vein isolation (PVI) using HPSD. PVI was performed with a contact force catheter (Thermocool SF Smart-Touch) and Carto 3 System. The following parameters were used: energy output 50 W, target temperature 43°C, irrigation 15 mL/min, targeted contact force of > 10 g. RF energy was applied for 6-10 s. Required minimal interlesion distance was 4 mm. Twenty minutes after each successful PVI adenosine provocation test (APT) was performed by administrating 18 mg adenosine to unmask dormant PV conduction.

RESULTS

All PVs (100 PVs) were successfully isolated. RF lesions needed per patient were 131 ± 41, the average duration for each RF application was 8.1 ± 1.7 s. Procedure time was 138 ± 21 min and average of total RF energy duration was 16.3 ± 5.2 min and average amount of RF energy was 48209 ± 12808 W. APT application time after PVI was 31.1 ± 8.3 min for the left sided PVs and 22.2 ± 4.6 min (p = 0.005) for the right sided PVs. APT was transiently positive in 18 PVs (18%) in 8 (32%) patients.

CONCLUSIONS

Pulmonary vein isolation with high power for 6-10 s is feasible and shortens the procedure and ablation duration. However, acute effectiveness of the HPSD seems to be lower than expected. Further studies combining other ablation parameters are needed to improve this promising technique.

Remote Therapy to Improve Outcomes in Lung Transplant Recipients: Design of the INSPIRE-III Randomized Clinical Trial

BACKGROUND

Impaired functional capacity and emotional distress are associated with lower quality of life (QoL) and worse clinical outcomes in post lung transplant patients. Strategies to increase physical activity and reduce distress are needed.

METHODS

The Investigational Study of Psychological Interventions in Recipients of Lung Transplant-III study is a single site, parallel group randomized clinical trial in which 150 lung transplant recipients will be randomly assigned to 3 months of telephone-delivered coping skills training combined with aerobic exercise (CSTEX) or to a Standard of Care plus Education control group. The primary endpoints are a global measure of distress and distance walked on the 6-Minute Walk Test. Secondary outcomes include measures of transplant-specific QoL, frailty, health behaviors, and chronic lung allograft dysfunction-free survival.

RESULTS

Participants will be evaluated at baseline, at the conclusion of 3 months of weekly treatment, at 1-year follow-up, and followed annually thereafter for clinical events for up to 4 years (median = 2 y). We also will determine whether functional capacity, distress, and health behaviors (eg, physical activity, medication adherence, and volume of air forcefully exhaled in 1 second (FEV1), mediate the effects of the CSTEX intervention on clinical outcomes.

CONCLUSIONS

Should the CSTEX intervention result in better outcomes compared with the standard of care plus post-transplant education, the remotely delivered CSTEX intervention can be made available to all lung transplant recipients as a way of enhancing their QoL and improving clinical outcomes.

High Predictive Value of Adenosine Provocation in Predicting Atrial Fibrillation Recurrence After Pulmonary Vein Isolation With Visually Guided Laser Balloon Compared With Radiofrequency Ablation

BACKGROUND

We recently demonstrated that the acute reconnection rate detected with adenosine provocation test (APT) was significantly lower after pulmonary vein isolation (PVI) with visually guided laser balloon ablation (VGLB) than with RF ablation (RF). We evaluated the recurrence rate of atrial arrhythmias at 12 months after VGLB vs. RF and the significance of APT results for the outcome.

METHODS AND RESULTS

Fifty patients with paroxysmal AF were randomized to either RF or VGLB ablation in a 1 : 1 fashion. After PVI each PV underwent an APT. All patients underwent a 3-day Holter and clinical follow-up every 3 months. Significantly less PVs reconnected during APT in the VGLB-arm (10 PV (10.8%) vs. 29 PV (30.9%); P=0.001). Significantly less patients had a recurrence of atrial arrhythmia in the VGLB-arm (3 vs. 9; P=0.047). In the VGLB-arm no recurrence was seen in those patients with a negative APT (negative predictive value (NPV)=100%). Only 3 of the 8 patients with a positive APT in the VGLB-arm had a recurrence (positive PV (PPV)=37%). Recurrences in the RF-arm were seen in 3 patients with positive APT as well as in 6 patients with negative APT (PPV=18% and NPV=33%).

CONCLUSIONS

There was significantly less recurrence of atrial arrhythmias at 12 months after PVI with VGLB. A negative APT after PVI with VGBL predicted freedom from AF with a very high NPV meaning that the high acute efficiency of the VGLB persisted long term.

Unmasking Adenosine: The Purinergic Signalling Molecule Critical to Arrhythmia Pathophysiology and Management

Adenosine was identified in 1929 and immediately recognised as having a potential role in therapy for arrhythmia because of its negative chronotropic and dromotropic effects. Adenosine entered mainstream use in the 1980s as a highly effective agent for the termination of supraventricular tachycardia (SVT) involving the atrioventricular node, as well as for its ability to unmask the underlying rhythm in other SVTs. Adenosine has subsequently been found to have applications in interventional electrophysiology. While considered a safe agent because of its short half-life, adenosine may provoke arrhythmias in the form of AF, bradyarrhythmia and ventricular tachyarrhythmia. Adenosine is also associated with bronchospasm, although this may reflect irritant-induced dyspnoea rather than true obstruction. Adenosine is linked to numerous pathologies relevant to arrhythmia predisposition, including heart failure, obesity, ischaemia and the ageing process itself. This article examines 90 years of experience with adenosine in the light of new European Society of Cardiology guidelines for the management of SVT.

Prevalence and clinical impact of spontaneous and adenosine-induced pulmonary vein reconduction in the Contact-Force vs. Cryoballoon Atrial Fibrillation Ablation (CIRCA-DOSE) study

BACKGROUND

Use of intraprocedural observation and pharmacologic challenges have been proposed as means to differentiate permanent pulmonary vein (PV)-left atrial conduction block from inadequate ablation lesions.

OBJECTIVE

The purpose of this study was to determine the prevalence and clinical impact of spontaneous and adenosine-provoked reconnection using contemporary atrial fibrillation (AF) ablation technologies.

METHODS

The CIRCA-DOSE (Cryoballoon vs. Irrigated Radiofrequency Catheter Ablation: Double Short vs. Standard Exposure Duration) study enrolled 346 patients with paroxysmal AF and randomized them to contact force-guided radiofrequency ablation (CF-RF) or cryoballoon ablation. Patients underwent provocative testing with adenosine after a 20-minute observation period. All patients received an implantable cardiac monitor for arrhythmia monitoring.

RESULTS

Spontaneous reconnection was observed in 5.4% of PVs (71/1318) during the 20-minute postprocedure observation period, and dormant conduction was elicited in 5.7% of PVs (75/1318). Both spontaneous reconnection and dormant conduction were more common after CF-RF compared to cryoballoon ablation (P = .03 and P <.0001, respectively). Acute PV reconnection (spontaneous or adenosine-provoked) was associated with a significantly higher incidence of recurrent atrial tachyarrhythmia in the cryoballoon group (hazard ratio [HR] 2.39; 95% confidence interval [CI] 1.44-3.96; P = .0007) but not in the CF-RF group (HR 1.47; 95% CI 0.84-2.58; P = .16). In the absence of acute reconnection, the freedom from recurrent arrhythmia did not differ between groups (HR 0.95; 95% CI 0.6057-1.495; P = .83).

CONCLUSION

Patients without spontaneous or adenosine-provoked reconnection had better outcomes compared to those with acute PV reconnection, suggesting that efforts should be directed toward ensuring an ideal ablation lesion at the first attempt in order to achieve durable PV isolation.

Precise Drug Sequential Therapy Can Improve the Cardioversion Rate of Atrial Fibrillation with Valvular Disease after Radiofrequency Ablation

OBJECTIVE

Based on pathogenesis of atrial fibrillation (AF), investigate the effects of precision drugs continuous therapy on AF cardioversion rate after radiofrequency catheter ablation.

METHODS

We included 1334 patients who underwent mitral valve replacement with bipolar radiofrequency ablation due to mitral valve disease with AF during June 2011 to July 2017. The data of clinical and related laboratory examinations at discharge and follow-up were recorded. All patients were treated with or without angiotensin-converting enzyme inhibitor (ACEI) and angiotensin II-receptor blocker (ARB) drugs according to their conditions and doctor's willingness. The heart rhythm was evaluated after treatment and follow-up of 6 months.

RESULTS

All 1162 cases were followed up, including 825 cases in mitral stenosis (MS) group, 337 cases in mitral regurgitation (MR) group. In MS group, left atrial diameter(LAD) and left ventricular diameter(LVD) of the patients taking ACEI and ARB were significantly lower (P < 0.05), and they can increase AF cardioversion rate from 79.1% of the control group to 83.7% and 82.8%, respectively (P = 0.03 and 0.04). In MR group, the patients with ACEI compared with control group, there were no significant differences in LAD, LVD, right atrial diameter (RAD), right ventricular diameter (RVD), left ventricular ejection fraction(LVEF), and left ventricular fractional shortening(LVFS) (P > 0.05); but ARB group, LAD, LVD decreased significantly (P < 0.05). And ACEI can increase AF cardioversion rate from 76.1% in the control group to 77.2% (P = 0.62), ARB to 81.6% (P = 0.02).

CONCLUSION

It does improve AF cardioversion rate after radiofrequency catheter ablation that the precise anti-structural remodeling drugs continuous therapy was adopted based on the pathogenesis of AF.

Safety and outcome of very high-power short-duration ablation using 70 W for pulmonary vein isolation in patients with paroxysmal atrial fibrillation

Aims

Pulmonary vein isolation (PVI) using radiofrequency ablation (RFA) in patients with paroxysmal atrial fibrillation (PAF) is effective but hampered by pulmonary vein reconnection due to insufficient ablation lesions. High-power delivery over a short period of time (HPSD) in RFA is stated to create more efficient lesions. The aim of this study was to compare intraprocedural safety and outcome of HPSD ablation to conventional power settings in patients undergoing PVI for PAF.

Methods and results

We included 197 patients with PAF that were scheduled for PVI. An ablation protocol with 70 W and a duration cut-off of 7 s at the anterior left atrium (LA) and 5 s at the posterior LA (HPSD group; n = 97) was compared to a conventional power protocol with 30–40 W for 20–40 s (standard group; n = 100) in terms of periprocedural complications and a 1-year outcome. The HPSD group showed significantly less arrhythmia recurrence during 1-year follow-up with 83.1% of patients free from atrial fibrillation compared to 65.1% in the standard group (P &lt; 0.013). No pericardial tamponade, periprocedural thromboembolic complications, or atrio-oesophageal fistula occurred in either group. Mean radiofrequency time (12.4 ± 3.4 min vs. 35.6 ± 12.1 min) and procedural time (89.5 ± 23.9 min vs. 111.15 ± 27.9 min) were significantly shorter in the HPSD group compared to the standard group (both P &lt; 0.001).

Conclusion

High-power short-duration ablation demonstrated a comparable safety profile to conventional ablation. High-power short-duration ablation using 70 W for 5–7 s leads to significantly less arrhythmia recurrences after 1 year. Radiofrequency and procedural time were significantly shortened.

Pulmonary vein antral isolation causes depolarization of vein sleeves: Implications for the assessment of isolation

PURPOSE

Pulmonary vein isolation (PVI) for atrial fibrillation has been shown to result in inexcitability of a large fraction of pulmonary veins (PVs), but the mechanism is unknown. We investigated the mechanism of PV inexcitability by assessing the effects of PVI on the electrophysiology of PV sleeves.

METHODS

Patients undergoing first-time radiofrequency PVI were studied. Capture threshold, effective refractory period (ERP), and excitability were measured in PVs and the left atrial appendage (LAA) before and after ablation. Adenosine was used to assess both transient reconnection and transient venous re-excitability.

RESULTS

We assessed 248 veins among 67 patients. Mean PV ERP (249.7 ± 54.0 ms) and capture threshold (1.4 ± 1.6 mA) increased to 300.5 ± 67.1 and 5.7 ± 5.6 mA, respectively (P < .0001 for both) in the 26.9% PVs that remained excitable, but no change was noted in either measure in the LAA. In 16.3% of the 73.1% inexcitable veins, transient PV re-excitability (as opposed to reconnection) was seen with adenosine administration.

CONCLUSIONS

Antral PVI causes inexcitability in a majority of the PVs, which can transiently be restored in some with adenosine. Among PVs that remain excitable, ERP and capture threshold increase significantly. These data imply resting membrane potential depolarization of the of PV myocardial sleeves. As PV inexcitability hampers the assessment of entrance and exit block, demonstrating transient PV re-excitability during adenosine administration helps ensure true isolation.

Unified mechanism of local drivers in a percolation model of atrial fibrillation

The mechanisms of atrial fibrillation (AF) are poorly understood, resulting in disappointing success rates of ablative treatment. Different mechanisms defined largely by different atrial activation patterns have been proposed and, arguably, this dispute has slowed the progress of AF research. Recent clinical evidence suggests a unifying mechanism of local drivers based on sustained reentrant circuits in the complex atrial architecture. Here, we present a percolation inspired computational model showing spontaneous emergence of AF that strongly supports, and gives a theoretical explanation for, the clinically observed diversity of activation. We show that the difference in surface activation patterns is a direct consequence of the thickness of the discrete network of heart muscle cells through which electrical signals percolate to reach the imaged surface. The model naturally follows the clinical spectrum of AF spanning sinus rhythm, paroxysmal AF, and persistent AF as the decoupling of myocardial cells results in the lattice approaching the percolation threshold. This allows the model to make the prediction that, for paroxysmal AF, reentrant circuits emerge near the endocardium, but in persistent AF they emerge deeper in the bulk of the atrial wall. If experimentally verified, this may go towards explaining the lowering ablation success rate as AF becomes more persistent.

[Catheter ablation of atrial fibrillation : Status quo]

Catheter ablation of atrial fibrillation (AF) is a standard part of treatment with respect to rhythm control. In this article, the authors provide a review of the state-of-the-art knowledge of AF catheter ablation including current indications, possible energy forms, procedural methods and endpoints as well as follow-up and further anticoagulation.

Cryoballoon or Radiofrequency Ablation for Atrial Fibrillation Assessed by Continuous Monitoring: A Randomized Clinical Trial

BACKGROUND

Advanced generation ablation technologies have been developed to achieve more effective pulmonary vein isolation (PVI) and minimize arrhythmia recurrence after atrial fibrillation (AF) ablation.

METHODS

We randomly assigned 346 patients with drug-refractory paroxysmal AF to contact force-guided radiofrequency ablation (CF-RF; n=115), 4-minute cryoballoon ablation (Cryo-4; n=115), or 2-minute cryoballoon ablation (Cryo-2; n=116). Follow-up was 12 months. The primary outcome was time to first documented recurrence of symptomatic or asymptomatic atrial tachyarrhythmia (AF, atrial flutter, or atrial tachycardia) between days 91 and 365 after ablation or a repeat ablation procedure at any time. Secondary end points included freedom from symptomatic arrhythmia and AF burden. All patients received an implantable loop recorder.

RESULTS

One-year freedom from atrial tachyarrhythmia defined by continuous rhythm monitoring was 53.9%, 52.2%, and 51.7% with CF-RF, Cryo-4, and Cryo-2, respectively (P=0.87). One-year freedom from symptomatic atrial tachyarrhythmia defined by continuous rhythm monitoring was 79.1%, 78.2%, and 73.3% with CF-RF, Cryo-4, and Cryo-2, respectively (P=0.26). Compared with the monitoring period before ablation, AF burden was reduced by a median of 99.3% (interquartile range, 67.8%-100.0%) with CF-RF, 99.9% (interquartile range, 65.3%-100.0%) with Cryo-4, and 98.4% (interquartile range, 56.2%-100.0%) with Cryo-2 (P=0.36). Serious adverse events occurred in 3 patients (2.6%) in the CF-RF group, 6 patients (5.3%) in the Cryo-4 group, and 7 patients (6.0%) in the Cryo-2 group, with no significant difference between groups (P=0.24). The CF-RF group had a significantly longer procedure duration but significantly shorter fluoroscopy exposure (P<0.001 vs cryoballoon groups).

CONCLUSIONS

In this multicenter, randomized, single-blinded trial, CF-RF and 2 different regimens of cryoballoon ablation resulted in no difference in 1-year efficacy, which was 53% by time to first recurrence but >98% burden reduction as assessed by continuous cardiac rhythm monitoring.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT01913522.

Evaluation of a simple technique aiming at optimizing point-by-point isolation of the left pulmonary veins: a randomized study

Aims

We sought to evaluate the efficacy and the safety of a simple technique for stabilizing the ablation catheter during anterior pulmonary vein (PV) encirclement in patients ablated for paroxysmal atrial fibrillation. This consisted of bending the ablation catheter in the left atrium, creating a loop that was cautiously advanced together with the long sheath at the ostium and then within the left superior PV. The curve was then progressively released to reach a stable contact with the anterior part of the left PVs.

Methods and results

Eighty consecutive patients (age 64 ± 11 years, left atrial diameter 43 ± 8 mm) undergoing ‘CLOSE’-guided PV isolation were prospectively randomized into two groups depending on whether the loop technique was used or not. When using the loop technique, the encirclement of the left PVs was shorter [20 min (interquartile range, IQR 17–24) vs. 26 min (IQR 18–33), P < 0.01] with a high rate of first pass isolation [(100%) vs. (97%), P = 0.9] and adenosine proof isolation [(93%) vs. (95%), P = 0.67]. Most specifically, at the anterior part of the left PVs, there were less dislocations [0 (IQR 0–0) vs. 1 (IQR 0–4), P < 0.001], radiofrequency duration was shorter (272 ± 85 s vs. 378 ± 122 s, P < 0.001), force-time integral was higher [524 gs (IQR 427–687) vs. 398 gs (IQR 354–451), P < 0.001], average contact force was higher [20 g (IQR 13–27) vs. 11g (IQR 9–16), P < 0.001], and impedance drop was higher [12 Ω (IQR 9–19) vs. 10 Ω (IQR 7–14), P < 0.001].

Conclusion

This study describes a simple technique to facilitate catheter stability at the anterior part of the left PVs, resulting in more efficient left PV encirclement without compromising safety.

Pace capture and adenosine triphosphate provocation are complementary rather than mutually exclusive methods to ensure durable pulmonary vein isolation

INTRODUCTION

Adenosine triphosphate (ATP)-provoked dormant conduction (DC) and pacing for unexcitability are used to identify conduction gaps along the ablation lines after circumferential pulmonary vein isolation (CPVI). We aim to determine whether ATP provocation and pacing are interchangeable as endpoints for ablation of paroxysmal atrial fibrillation (PAF).

METHODS AND RESULTS

A total of 107 patients with PAF were randomly divided into two groups after completion of CPVI. In group I (A-P group, n = 53), ATP was administered first. If DC was uncovered, additional ablation was performed until ATP tests were negative. Bipolar pacing along the ablation line was performed subsequently. In group II (P-A group, n = 54), the same protocol was used, but the pacing and the ATP tests were performed in the opposite sequence. The 12-month ablation outcomes of all patients were compared with those of a historical control group of 107 patients with PAF in whom only ATP test was performed. Regardless of which test was performed first, the other modality still identified conduction gaps. In group I, pacing maneuvers identified gaps in 49% (n = 26) of patients who had negative ATP tests. In group II, ATP tests uncovered DC in 18.5% (n = 10) of patients in whom pacing identified no gaps. After 12 months, a higher proportion of patients (91.6%) were free from atrial tachyarrhythmias compared with the historical control group (81.3%; P = 0.031).

CONCLUSION

Pacing along the ablation lines and ATP provocation are complementary tests for evaluating the durability of CPVI and can lead to better long-term outcomes when used in combination.

Atrial fibrillation inducibility after pulmonary vein isolation under general anaesthesia

AIMS

Atrial fibrillation (AF) inducibility with rapid atrial pacing following AF ablation is associated with higher risk of AF recurrence. The predictive value of AF inducibility in paroxysmal AF patients after pulmonary vein isolation (PVI), done under general anaesthesia (GA), remains questionable since GA might alter AF inducibility and/or sustainability.

METHODS

Consecutive patients (n = 120) with paroxysmal AF without prior catheter ablation (CA) were enlisted in the study. All patients were ablated under GA. We have used a point-by-point CA and elimination of dormant conduction after adenosine in all patients. A predefined stimulation protocol was used to induce arrhythmias after PVI. Regular supraventricular tachycardias were mapped and ablated. Patients were divided into 3 subgroups - noninducible, inducible AF with spontaneous termination in five minutes, inducible AF without spontaneous termination. During 12 months of follow-up, all patients were examined four-times with 7-day ECG recordings.

RESULTS

There was no statistical difference between the three subgroups in a rate of arrhythmia recurrence (11.1 vs. 27.5 vs. 27.3%, P=0.387), despite a clear trend to a better success rate in the non-inducible group. The subgroups did not differ in left atrial (LA) diameter (41.0±6, 43.0±7, 42.0±5 mm, P=0.962) or in any other baseline parameter.

CONCLUSION

AF inducibility as well as presence or absence of its early spontaneous termination after PVI done under general anaesthesia in paroxysmal AF patients were not useful as predictors of procedural failure.

Long-term outcome of paroxysmal atrial fibrillation catheter ablation with and without pulmonary vein dormant conduction after adenosine challenge

OBJECTIVES

The prognostic significance of adenosine-mediated pulmonary vein (PV) dormant conduction is unclear. We prospectively followed patients with adenosine-mediated PV reconduction with a subsequent repeated ablation until there was no reconduction inducible with patients without reconduction after PV isolation.

METHOD AND RESULTS

Consecutive patients (n=179) with paroxysmal atrial fibrillation (AF) without prior catheter ablation (CA) were enlisted in the study. We used a point-by-point CA and general anesthesia in all patients. Twenty minutes after PV isolation we administered adenosine in a dose sufficient to produce an atrioventricular block. If a dormant conduction was present (n=54) we performed additional ablation until there was no adenosine mediated reconduction inducible. During 36 months of follow-up, all patients were examined for eight 7-day ECG recordings. There was no difference in arrhythmia recurrence rate between patients with and without dormant conduction (29.6 vs. 24.8% at 12 months, P=0.500; 31.5 vs. 30.4% at 36 months, P=1.000), for any echocardiographic parameter or any parameter of the ablation procedure.

CONCLUSION

The patients with dormant conduction after adenosine during catheter ablation of paroxysmal atrial fibrillation with complete elimination of the dormant conduction by additional extensive ablation have the same outcome in the long term as patients without a dormant conduction.

Clinical Implications of Unmasking Dormant Conduction After Circumferential Pulmonary Vein Isolation in Atrial Fibrillation Using Adenosine: A Systematic Review and Meta-Analysis

Purpose: Circumferential pulmonary vein isolation (CPVI) is a routine ablation strategy of atrial fibrillation (AF). The adenosine test can be used to unmask dormant conduction (DC) of pulmonary veins after CPVI, thereby demonstrating possible pulmonary vein re-connection and the need for further ablation. However, whether adenosine test could help improve the long term successful rate of CPVI is still controversial. This systemic review and meta-analysis was to determine the clinical utility of the adenosine test. Methods: PubMed, EMBASE, Web of Science and Cochrane Library database were searched through July 2016 to identify relevant studies using the keywords "dormant pulmonary vein conduction," "adenosine test," "circumferential pulmonary vein isolation," and "atrial fibrillation." A random-effects model was used to compare pooled outcomes and tested for heterogeneity. Results: A total of 17 studies including 5,169 participants were included in the final meta-analysis. Two groups of comparisons were classified: (1) Long-term successful rate in those AF patients underwent CPVI with and without adenosine test [Group A (+) and Group A (-)]; (2) Long-term successful rate in those patients who had adenosine test with and without dormant conduction [Group DC (+) and Group DC (-)]. The overall meta-analysis showed that no significant difference can be observed between Group A (+) and Group A (-) (RR 1.08; 95% CI 0.97-1.19; P = 0.16; I2 = 66%) and between Group DC (+) and Group DC (-) (RR 1.01; 95% CI 0.91-1.12; P = 0.88; I2 = 60%). Conclusion: Pooled meta-analysis suggested adenosine test may not improve long-term successful rate in AF patients underwent CPVI. Furthermore, AF recurrence may not be decreased by eliminating DC provoked by adenosine, even though adenosine test was applied after CPVI.

The modified ablation index: a novel determinant of acute pulmonary vein reconnections after pulmonary vein isolation

BACKGROUND

Although pulmonary vein isolation (PVI) guided by the ablation index (AI) has been well-developed, acute PV reconnections (PVRs) still occur. This study aimed to compare the prognostic performance of the modified AI and its optimal cut-off value for the prediction of acute PVRs to ensure durable PVI.

METHODS

Three-dimensional left atrium (LA) voltage maps created before an extensive encircling PVI in 64 patients with atrial fibrillation (AF) (45 men, 62 ± 10 years) were examined for an association between electrogram voltage amplitude recorded from the PV-LA junction and acute post-PVI PVRs (spontaneous PVRs and/or ATP-provoked dormant PV conduction).

RESULTS

Acute PVRs were observed in 22 patients (34%) and 33 (3%) of the 1012 PV segments. Acute PVRs were significantly associated with segments with higher bipolar voltage zones (3.23 ± 1.17 vs. 1.97 ± 1.20 mV, P < 0.0001), lower mean AI values (449 [428-450] vs. 460 [437-486], P = 0.05), and radiofrequency lesion gaps ≥ 6 mm (48 vs. 32%, P = 0.04), but not with contact force, force-time integral, or power. We created the modified AI calculated as AI/LA bipolar voltage, and found it to be significantly lower in areas with acute PVRs than in those without (152 [109-185] vs. 256 [176-413] AU/mV, P < 0.0001). Univariate analysis showed the prognostic performance of the modified AI, with an area under the curve of 0.801 (0.775-0.825), to be the highest of all the significant parameters.

CONCLUSIONS

Low values of the novel modified AI on the PV-encircling ablation line were strongly associated with acute PVRs.

Adenosine as a Marker and Mediator of Cardiovascular Homeostasis: A Translational Perspective

Adenosine, a purine nucleoside, is produced broadly and implicated in the homeostasis of many cells and tissues. It signals predominantly via 4 purinergic adenosine receptors (ADORs) - ADORA1, ADORA2A, ADORA2B and ADOosine signaling, both through design as specific ADOR agonists and antagonists and as offtarget effects of existing anti-platelet medications. Despite this, adenosine has yet to be firmly established as either a therapeutic or a prognostic tool in clinical medicine to date. Herein, we provide a bench-to-bedside review of adenosine biology, highlighting the key considerations for further translational development of this proRA3 in addition to non-ADOR mediated effects. Through these signaling mechanisms, adenosine exerts effects on numerous cell types crucial to maintaining vascular homeostasis, especially following vascular injury. Both in vitro and in vivo models have provided considerable insights into adenosine signaling and identified targets for therapeutic intervention. Numerous pharmacologic agents have been developed that modulate adenmising molecule.

Less Pulmonary Vein Reconnection at Redo Procedures Following Radiofrequency Point-by-Point Antral Pulmonary Vein Isolation With the Use of Contemporary Catheter Ablation Technologies

OBJECTIVES

This study investigated whether real-world use of contemporary technologies changed pulmonary vein (PV) reconnection and redo pulmonary vein isolation (PVI) procedure frequencies.

BACKGROUND

Previous studies consistently reported that following PVI recurrence of PV conduction is observed in >80% of patients.

METHODS

Consecutive patients undergoing 529 first and/or redo radiofrequency point-by-point PVI between January 2013 and December 2016 were included.

RESULTS

Between 2013 and 2016, redo PVI rate in atrial fibrillation significantly decreased (p < 0.001); in ≤12 months, first redo PVI rate decreased from 19% to 4%. The percentage of patients having PV reconnection at second PVI significantly decreased from 90% to 29% (p = 0.001). One PVI was performed in 393 and >1 in 79 patients. Female sex was associated with >1 PVI (hazard ratio [HR]: 1.86; 95% confidence interval [CI]: 1.10 to 3.13; p = 0.02). Sixty patients underwent first and second PVI in the study period. Female sex (HR: 2.79; 95% CI: 1.67 to 4.64; p < 0.001) and left atrial diameter (HR: 1.05; 95% CI: 1.01 to 1.08; p = 0.01) were associated with more and use of automatic ablation annotation algorithm during first PVI with fewer (HR: 0.54; 95% CI: 0.32 to 0.92; p = 0.02) redo PVI procedures. In 31 of 60 patients, ≥1 PV was reconnected at second PVI. The need for "touch-up" applications at the first PVI was the only predictor of PV reconnection.

CONCLUSIONS

Redo rate in atrial fibrillation and PV reconnection at redo PVI significantly decreased in recent years. Male sex, left atrial diameter, and use of automatic ablation annotation algorithm at first PVI were associated with fewer redo procedures. First-pass isolation was associated with lower PV reconnection rate at second procedure. Female sex was associated with more redo procedures but not higher PV reconnection frequencies.

Repeat ablation for paroxysmal atrial fibrillation - Does adenosine play a role in predicting pulmonary vein reconnection patterns?

BACKGROUND

Pulmonary vein (PV) reconduction after PV isolation (PVI) unmasked by adenosine is associated with a higher risk for paroxysmal atrial fibrillation (PAF) recurrence. It is unknown if the reconnected PVs after adenosine testing and immediate re-ablation can predict reconnection and reconnection patterns of PVs at repeat procedures. We assessed reconnection of PVs with and without dormant-conduction (DC) during the first and the repeat procedure.

METHODS

We included 67 patients undergoing PVI for PAF and a second procedure for PAF recurrence. DC during adenosine administration at first procedure was seen in 31 patients (46%). 264 PVs were tested with adenosine; DC was found in 48 PVs (18%) and re-ablated during first procedure. During the second procedure, all PVs where checked for reconnection.

RESULTS

Fifty-eight patients (87%) showed PV reconnection during the second procedure. Reconnection was found in 152/264 PVs (58%). Of 216 PVs without reconnection during adenosine testing at the first ablation, 116 PVs (53.7%) showed reconnection at the repeat procedure. Overall, 14.9% of patients showed the same PV reconnection pattern in the first and second procedure, expected statistical probability of encountering the same reconnection pattern was only 6.6%(p = 0.012).

CONCLUSIONS

In repeat procedures PVs showed significantly more often the same reconnection pattern as during first procedure than statistically expected. More than 50% of initial isolated PVs without reconnection during adenosine testing showed a reconnection during repeat ablation. Techniques to detect susceptibility for PV re-connection like prolonged waiting-period should be applied. Elimination of DC should be expanded from segmental to circumferential re-isolation or vaster RF application.

No association between dormant conduction sites and pulmonary vein reconnection sites in late atrial fibrillation recurrence after catheter ablation

OBJECTIVE

Despite use of provocation testing to unmask dormant left atrium (LA)-PV conduction after index pulmonary vein isolation (PVI) for atrial fibrillation (AF), AF recurrence still occurs, with PV reconnection as the main cause. In an effort to answer the question whether freedom from AF recurrence can be achieved by ablation that targets sites of dormant conduction, we compared sites of dormant conduction against sites of PV reconnection identified at the time of repeat ablation for AF recurrence.

MATERIALS AND METHODS

The study group comprised 46 patients (30 men/16 women, aged 58.7±10.3 years) with AF (paroxysmal: n=37, persistent: n=9) who underwent repeat ablation for AF recurrence 12.3 (7.4-29.7) months after the index ablation procedure. Ipsilateral PVs were divided into 8 segments each (736 total segments), and the relation between dormant conduction sites and PV reconnection sites was determined per segment.

RESULTS

Dormant LA-PV conduction was unmasked and ablated in 22 (47.8%) of the 46 patients at sites within 43 (5.8%) of the 736 PV segments. Late PV reconnection was found within 122 (17%) of the 736 PV segments at the time of re-ablation for AF recurrence. Only 22 (18%) of these 122 PV segments corresponded to dormant conduction sites identified during the index procedure.

CONCLUSION

Although additional ablation to eliminate dormant PV conduction unmasked during the index ablation procedure is performed, the majority of PVs that show reconduction at the time of treatment for clinical AF recurrence are PVs that have not shown dormant conduction.

Influence of balloon temperature and time to pulmonary vein isolation on acute pulmonary vein reconnection and clinical outcomes after cryoballoon ablation of atrial fibrillation

BACKGROUND

Limited data exist on indicators of durable pulmonary vein isolation (PVI) undergoing cryoballoon ablation (CBA) for atrial fibrillation (AF). We investigated whether balloon temperature and time to PVI can be used to predict early PV reconduction (EPVR), including residual PV conduction and adenosine triphosphate-induced dormant conduction and the relation between touch-up ablation of EPVR sites and mid-term recurrence of AF.

METHODS

We obtained procedural and outcome data from the records of 130 consecutive patients who underwent CBA and followed up for 13.4 months.

RESULTS

EPVR was identified in 86 (17%) PVs of 61 (47%) patients. Balloon temperatures during 30 seconds (-27 ± 5.7°C vs -31 ± 5.5°C), 60 seconds (-36 ± 5.6°C vs -41 ± 5.4°C), and at the nadir point (-41 ± 7.4°C vs -49 ± 7.0°C) were significantly higher, and the time to PVI was longer (90 ± 50 seconds vs 52 ± 29 seconds) in PVs with EPVR than in those without (P < 0.0001 for all). Among PVs without EPVR, the time to PVI was longer and balloon temperature was lower for the left superior pulmonary vein/ right inferior pulmonary vein (LSPV/RIPV) than for the right superior pulmonary vein/left inferior pulmonary vein (RSPV/LIPV) (time: 60 ± 25/73 ± 37 seconds vs 41 ± 31/45 ± 20 seconds, P < 0.0001) (temp: -39.2 ± 11.3/-39.4 ± 8.3°C vs -33.8 ± 10.6/-33.6 ± 6.8°C, P = 0.0023). AF recurrence rates were equivalent between patients with and without EPVR (13% [8/69] vs 15% [9/61], P = 0.845).

CONCLUSIONS

Cryoballoon temperature and time to PVI appear to be useful in predicting durable PVI, that is, prevention of EPVR, but the balloon temperature and time required for PVI differ between PVs. Although EPVR does not predict AF recurrence, high success rates can be expected when touch-up ablation of EPVR sites is performed.

Efficacy of adjunctive measures used to assist pulmonary vein isolation for atrial fibrillation: a systematic review

PURPOSE OF REVIEW

Pulmonary vein reconnection leading to recurrence of atrial arrhythmias after pulmonary vein isolation (PVI) for atrial fibrillation remains a significant challenge. A number of adjunctive measures during PVI have been used to attempt to reduce pulmonary vein reconnection and recurrence of atrial arrhythmias. We performed a systematic review of the literature and meta-analysis of studies evaluating the efficacy of adjunctive measures used during PVI in reducing recurrent atrial arrhythmias.

RECENT FINDINGS

Our literature search found four interventions that met the prespecified definition of adjunctive measure: adenosine testing post-PVI, contact force-guided PVI, pacing inexcitability of the ablation line during PVI and additional ablation based on the computed tomography thickness of the pulmonary vein-left atrial appendage ridge. Sixteen studies enrolling 3507 patients met all inclusion and exclusion criteria. PVI performed with adjunctive measures was shown to reduce the 1-year recurrence rate of atrial arrhythmias. The point estimate for the combined relative risk of atrial arrhythmia recurrence was 0.56 [95% confidence interval (CI): 0.43-0.73; P value <0.001] in the PVI with adjunctive measures group.

SUMMARY

PVI for atrial fibrillation assisted by adjunctive measures results in clinically significant reduction of recurrent atrial arrhythmias. Additional research is required to assess the relative efficacy of individual or combined adjunctive strategies used during PVI for atrial fibrillation.

Impact of impedance decrease during radiofrequency current application for atrial fibrillation ablation on myocardial lesion and gap formation

BACKGROUND

The clinical impact of a decrease in impedance during radiofrequency catheter ablation (RFCA) has not been fully clarified. The aim of the study was to analyze the impact of impedance decrease and to determine its optimal cutoff value during RFCA.

METHODS

We evaluated 34 consecutive patients (total 3264 lesions, mean age 66 ± 8.7 years, 10 females) who underwent their first ablation for atrial fibrillation (AF). The impedance decrease, average contact force (CF), application time, force-time integral (FTI), product of impedance decrease and application time (PIT), and the product of impedance decrease and FTI (PIFT) were measured for all lesions. Levels of cardiac troponin I (TrpI) were measured for assessment of myocardial injury. The incidence of intraprocedural pulmonary vein-left atrium reconnection or dormant conduction (reconnection) was determined. The relationships between the ablation parameters and the increase in TrpI (ΔTrpI) were evaluated. The predictive value of the parameters for reconnection was assessed using receiver operating characteristic (ROC) curve analysis.

RESULTS

Reconnection was detected in 18 patients. Average FTI and PIT were significantly correlated with ΔTrpI (FTI: r2 = .19, P = .0090, PIT: r2 = .21, P = .0058). PIFT was correlated with ΔTrpI and was the best of the three indexes (PIFT: r2 = .29, P = .0010). In ROC curve analysis, the area under the curve for predicting reconnection was 0.71 and the optimal cutoff value was 5200 for PIFT (sensitivity 78%, specificity 63%).

CONCLUSION

The combination of CF and a decrease in impedance could be important in the evaluation of myocardial lesions and reconnection during RFCA.

High-density mapping and ablation of concealed low-voltage activity within pulmonary vein antra results in improved freedom from atrial fibrillation compared to pulmonary vein isolation alone

BACKGROUND

Despite advancements, the goal of durable pulmonary vein isolation (PVI) in all patients undergoing ablation for atrial fibrillation (AF) remains elusive. New high-density mapping (HDM) allows detection of concealed low-voltage signals (CLVSs) that persist after PVI and may represent vulnerabilities in the lesion set.

OBJECTIVE

The purpose of this study was to determine the incidence of CLVSs after PVI and the effect of CLVS ablation on outcomes.

METHODS

We conducted a case control study comparing 150 patients undergoing HDM-guided PVI and subsequent CLVS mapping and ablation (39 redo, 111 de novo) against 452 historical controls undergoing traditional PVI alone. PVI was similarly performed and confirmed in both groups.

RESULTS

Baseline characteristics were similar, except left atrial size was larger in the HDM-guided group. Acute PVI was achieved in nearly all patients in both groups. In the HDM group, 31 of 150 patients exhibited CLVS after luminal PVI, and all were subsequently eliminated. During mean follow-up of 320 days, after controlling for baseline characteristics, the HDM-guided group exhibited a hazard ratio of 0.19 in freedom from AF (P <.001). De novo patients exhibited a hazard ratio of 0.44 relative to redo patients in the HDM-guided group. Both subgroups exhibited significantly lower event rates compared to controls in log-rank analysis (P <.001).

CONCLUSION

CLVSs are commonly identified with HDM after PVI, likely representing vulnerabilities in antral lesion sets. Ablation of these targets seems to significantly improve freedom from AF compared to PVI alone.

Adenosine Testing After Atrial Fibrillation Ablation: Systematic Review and Meta-Analysis

BACKGROUND

Adenosine can be used to reveal dormant pulmonary vein (PV) conduction after pulmonary vein isolation (PVI) for the treatment of atrial fibrillation (AF). We performed a systematic review and meta-analysis to assess the impact of adenosine administration in patients undergoing PVI for AF.

METHODS

Meta-analysis of 22 studies was performed to assess the rates of freedom from AF in 1) patients with dormant PV conduction versus patients without dormant PV conduction, and 2) patients given routine adenosine post PVI versus patients not given adenosine. Relative-risks (RR) were calculated using random effects modelling.

RESULTS

In 18 studies, 3038 patients received adenosine and freedom from AF in those patients with dormant PV reconnection was significantly lower (62.9%) compared to patients without PV reconnection (67.2%) (RR 0.87; 95% CI: 0.78-0.98). In seven studies with 3049 patients, the freedom from AF was significantly higher in patients who received adenosine (67%) versus those patients who did not receive adenosine (63%) (RR: 1.11; 95% CI: 1.01-1.22).

CONCLUSIONS

The present study showed clear benefits of adenosine testing for freedom from AF recurrence. Adenosine-guided dormant conduction is associated with higher AF recurrence despite further ablation. Future studies should investigate the optimal methodology, including dosage and waiting time between PVI and adenosine administration.