Acute Atrial Fibrillation Termination Research Articles

Optoelectronic control of cardiac rhythm: Toward shock-free ambulatory cardioversion of atrial fibrillation.

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia, progressive in nature, and known to have a negative impact on mortality, morbidity, and quality of life. Patients requiring acute termination of AF to restore sinus rhythm are subjected to electrical cardioversion, which requires sedation and therefore hospitalization due to pain resulting from the electrical shocks. However, considering the progressive nature of AF and its detrimental effects, there is a clear need for acute out-of-hospital (i.e., ambulatory) cardioversion of AF. In the search for shock-free cardioversion methods to realize such ambulatory therapy, a method referred to as optogenetics has been put forward. Optogenetics enables optical control over the electrical activity of cardiomyocytes by targeted expression of light-activated ion channels or pumps and may therefore serve as a means for cardioversion. First proof-of-principle for such light-induced cardioversion came from in vitro studies, proving optogenetic AF termination to be very effective. Later, these results were confirmed in various rodent models of AF using different transgenes, illumination methods, and protocols, whereas computational studies in the human heart provided additional translational insight. Based on these results and fueled by recent advances in molecular biology, gene therapy, and optoelectronic engineering, a basis is now being formed to explore clinical translations of optoelectronic control of cardiac rhythm. In this review, we discuss the current literature regarding optogenetic cardioversion of AF to restore normal rhythm in a shock-free manner. Moreover, key translational steps will be discussed, both from a biological and technological point of view, to outline a path toward realizing acute shock-free ambulatory termination of AF.

Individualized ablation strategy to treat persistent atrial fibrillation: Core-to-boundary approach guided by charge-density mapping

Noncontact charge-density mapping allows rapid real-time global mapping of atrial fibrillation (AF), offering the opportunity for a personalized ablation strategy. The purpose of this study was to compare the 2-year outcome of an individualized strategy consisting of pulmonary vein isolation (PVI) plus core-to-boundary ablation (targeting the conduction pattern core with an extension to the nearest nonconducting boundary) guided by charge-density mapping, with an empirical PVI plus posterior wall electrical isolation (PWI) strategy. Forty patients (age 62 ± 12 years; 29 male) with persistent AF (10 ± 5 months) prospectively underwent charge-density mapping-guided PVI, followed by core-to-boundary stepwise ablation until termination of AF or depletion of identified cores. Freedom from AF/atrial tachycardia (AT) at 24 months was compared with a propensity score-matched control group of 80 patients with empirical PVI + PWI guided by conventional contact mapping. Acute AF termination occurred in 8 of 40 patients after charge-density mapping-guided PVI alone and in 21 of the remaining 32 patients after core-to-boundary ablation in the study cohort, compared with 8 of 80 (10%) in the control cohort (P<.001). On average, 2.2 ± 0.6 cores were ablated post-PVI before acute AF termination. At 24 months, freedom from AF/AT after a single procedure was 68% in the study group vs 46% in the control group (P = .043). An individualized ablation strategy consisting of PVI plus core-to-boundary ablation guided by noncontact charge-density mapping is a feasible and effective strategy for treating persistent AF, with a favorable 24-month outcome.

Spectral characterization and impact of stepwise ablation protocol including LAA electrical isolation on persistent AF

To study how left atrial appendage electrical isolation (LAAEI) impacts atrial dominant frequency (DF) in patients with long-standing persistent atrial fibrillation (LSPAF). LAAEI is associated with a high probability of freedom from atrial fibrillation (AF) and spectral analysis may identify high-frequency sources. How LAAEI impacts the AF dynamics and the subgroup of LSPAF patients in whom LAAEI would be most beneficial, is unclear. Twenty patients with LSPAF were included in the study. Fast Fourier transforms (FFT) were performed on atrial electrograms recorded from 13 sites in the LA and RA. The highest peak frequency was defined as DF. There was no significant difference in DF between atrial sites except for at the superior vena cava which had the lowest DF at baseline. Stepwise ablation consisting of circumferential pulmonary vein isolation and a linear ablation set of mitral isthmus and roof significantly reduced the DF within the coronary sinus (CS) (5.93 ± 0.98Hz vs. 5.09 ± 0.72Hz, p < .05) and the LA posterior wall (LApos) (6.26 ± 0.92Hz vs. 5.43 ± 0.98Hz, p < .01). LAAEI preferentially further decreased the DF at the LApos (p < .01), but not at the CS. In cases where there was<13.6% reduction in the DF of the LApos following the stepwise ablation, the addition of LAAEI was associated with an increased restoration of sinus rhythm (55%, p < .05). LAAEI in addition to stepwise ablation results in further reduction of the DF in the LApos, which is associated with acute termination of AF and favorable ablation outcome.

Abstract 16884: Evaluating the Effectiveness of Atrial Fibrillation Ablation Guided by Spatiotemporal Electrogram Dispersion

Introduction: Catheter ablation of atrial fibrillation (AF) guided by spatiotemporal dispersion (SD) of electrograms has been proposed as an ablation strategy to treat patients with persistent AF. However, external validation of this technique is lacking. Here we report a single center experience using ablation by SD. Hypothesis: Targeting regions with SD is associated with a high rate of termination and favorable freedom from AF among patients with persistent AF. Methods: Patients with persistent AF who underwent SD from November 2018 to January 2020 were included in this study. All patients underwent pulmonary vein isolation (PVI) in addition to targeting areas of SD. Lesions on areas of electrogram dispersion were anchored to the PVI or to mitral or posterior wall lines where appropriate. EKG, Holter, event monitors or device interrogations were obtained at 3 and 6 months to assess for arrhythmia recurrence. Results: 44 patients met the inclusion criteria and were included in the study. The patients had a mean age of 69±8 years and were 68 % male. The prevalence of comorbidities was as follows: hypertension (89%), diabetes (21%), OSA (37%) and CAD (26%). Average CHADSVASC score was 2.9±1.4, LVEF was 53±11% and left atrium (LA) diameter was 5.2±1 cm. The recurrence rate of AF at 6 months was 14% whereas the recurrence of atrial tachycardia was 20%. Acute AF termination was observed in 73% of the patients. Termination to sinus occurred in 38% of the patients and the remaining terminated to atrial tachycardia which was subsequently ablated to sinus. The mean procedure duration was 240±90 minutes. Univariate analysis showed recurrence was associated with LA diameter (r=.52; p&lt;.001). No recurrences were observed among patients with a LA diameter &lt; 5 cm. Termination rates were higher among patients with LA diameter &lt; 5 cm when compared to LA diameter ≥ 5 cm. However, it did not reach statistical significance (80% vs. 60%; p=.21). Conclusions: The target of electrograms with SD during AF ablation added to PVI was associated with a high termination rate and a good freedom from AF recurrence at 6 months. The ideal candidate for this procedure may be those with LA diameter &lt; 5 cm among persistent AF. The long-term efficacy of this technique merits further studies in larger populations.

Abstract 16313: Islands of Organized 1:1 Conduction Within Atrial Fibrillation as Potential Targets for Ablation

Introduction: Organized regions in atrial fibrillation (AF) substrate are well known, but how they are defined and if they can be used to improve ablation are unclear. We hypothesized that large islands of 1:1 electrogram (EGM) propagation (i.e. ‘atrial tachycardias’) within AF may serve as effective ablation targets. Methods: We recruited 40 persistent AF patients at ablation (age 54.5 ± 5.1 years). Group 1 had acute AF termination during ablation (n=20) and Group 2 did not (n=20). Basket catheters (64 poles) were placed in both atria and unipolar EGMs were analyzed to identify islands from vector contours (Wavefront Field, WFF, fig A, left) and if electrograms have 1:1 activation on classical analysis (fig A, right). Results: Organized islands of 1:1 EGM within AF were identified by vector analysis of panoramic maps, in 100% of Group 1 and 75% of Group 2 patients (p&lt;0.01). Sites lay outside PVs in both Group 1 (70%) and Group 2 (95%). Organized 1:1 island sites controlled larger areas prior to termination in Group 1 than prior to cardioversion in Group 2 (44.1 ±11.1% vs. 16.6 ± 6.9% mapped atrium, p&lt;0.0001, fig B). In Group 1, sites of AF termination had larger organized islands than competing sites (22.4 ± 7.0%; P &lt; 0.01). Conclusions: We demonstrate organized of 1:1 electrograms in AF, akin to ‘atrial tachycardia’. Islands were larger in patients with AF termination, and at their ultimate termination sites than at random sites or patients without AF termination. Future studies should identify mechanisms for organized islands.

Fractionated Mapping-Guided Ablation Strategy in Patients with Long-Standing Persistent Atrial Fibrillation: a Case Series

Although pulmonary vein isolation (PVI) remains the cornerstone of ablation for paroxysmal atrial fibrillation (AF), optimal ablation strategy for long-standing persistent AF (LSPAF) remains unclear. This article presents two patients with LSPAF in whom acute AF termination was achieved during ablation by using fractionated-guided extended PVI, posterior wall isolation, and mitral isthmus.

Initial experience with fractionation mapping-guided ablation strategy in patients with long-standing persistent atrial fibrillation.

We aimed to define the role of extended pulmonary vein isolation (PVI), posterior wall isolation, and mitral isthmus lines to eliminate electrograms exhibiting fractionation pattern during stepwise ablation on acute atrial fibrillation (AF) termination rate in patients with long-standing persistent AF (LSPAF). Twelve patients with LSPAF underwent ablation during AF. Using the fractionation mapping tool of the Ensite™ (Abbott Medical, Chicago, USA) system, sites exhibiting discrete atrial complexes and consistent activation sequence were mapped. The areas with a fractionation score above 4 were accepted as potential drivers for AF. During stepwise ablation consisting of circumferential PVI, roof and floor lines for posterior wall isolation, and mitral isthmus lines, ablation lines were extended toward potential AF drivers on the fractionation map as much as possible until sinus was achieved by ablation. Fractionation-guided ablation caused acute AF termination in 8 of 12 patients. In 6 of 12 cases, AF returned to sinus rhythm during the extended ablation. In 2 patients, AF shifted to sinus after cavotricuspid isthmus ablation. Sinus was achieved by cardioversion in 3 of cases. Procedural failure was seen in one case with significant scar tissue. During a mean follow-up of 31.5 ± 11months, overall arrhythmia-free survival was 92% with 2 procedures. This pilot study demonstrates that fractionation mapping-guided ablation may provide an adjunctive benefit in terms of acute AF termination in patients with LSPAF. These results should be confirmed by larger, randomized, comparison studies between linear ablation and extended ablation without elimination of electrograms (EGMs) with fractionation.

Specific Electrogram Characteristics Identify the Extra-Pulmonary Vein Arrhythmogenic Sources of\xa0Persistent Atrial Fibrillation \u2013 Characterization of the Arrhythmogenic Electrogram Patterns During Atrial Fibrillation and Sinus Rhythm

Identification of atrial sites that perpetuate atrial fibrillation (AF), and ablation thereof terminates AF, is challenging. We hypothesized that specific electrogram (EGM) characteristics identify AF-termination sites (AFTS). Twenty-one patients in whom low-voltage-guided ablation after pulmonary vein isolation terminated clinical persistent AF were included. Patients were included if short RF-delivery for <8sec at a given atrial site was associated with acute termination of clinical persistent AF. EGM-characteristics at 21 AFTS, 105 targeted sites without termination and 105 non-targeted control sites were analyzed. Alteration of EGM-characteristics by local fibrosis was evaluated in a three-dimensional high resolution (100 µm)-computational AF model. AFTS demonstrated lower EGM-voltage, higher EGM-cycle-length-coverage, shorter AF-cycle-length and higher pattern consistency than control sites (0.49 ± 0.39 mV vs. 0.83 ± 0.76 mV, p < 0.0001; 79 ± 16% vs. 59 ± 22%, p = 0.0022; 173 ± 49 ms vs. 198 ± 34 ms, p = 0.047; 80% vs. 30%, p < 0.01). Among targeted sites, AFTS had higher EGM-cycle-length coverage, shorter local AF-cycle-length and higher pattern consistency than targeted sites without AF-termination (79 ± 16% vs. 63 ± 23%, p = 0.02; 173 ± 49 ms vs. 210 ± 44 ms, p = 0.002; 80% vs. 40%, p = 0.01). Low voltage (0.52 ± 0.3 mV) fractionated EGMs (79 ± 24 ms) with delayed components in sinus rhythm (‘atrial late potentials’, respectively ‘ALP’) were observed at 71% of AFTS. EGMs recorded from fibrotic areas in computational models demonstrated comparable EGM-characteristics both in simulated AF and sinus rhythm. AFTS may therefore be identified by locally consistent, fractionated low-voltage EGMs with high cycle-length-coverage and rapid activity in AF, with low-voltage, fractionated EGMs with delayed components/ ‘atrial late potentials’ (ALP) persisting in sinus rhythm.

P978Core to block: a new ablation strategy for treating persistent atrial fibrillation

Abstract Background Ablation strategy targeting the core of atrial fibrillation (AF) rotors alone can lead to both stabilisation and destabilisation of rotational activity. Non-contact dipole density mapping system is designed to rapidly identify dynamic regional atrial activation patterns of interest (API) during AF. Purpose To assess the feasibility of an ablation strategy consisted of pulmonary vein isolation + targeting the core of APIs followed by linear ablation to the nearest non-conducting boundary to treat persistent AF. Methods The ablation strategy includes: 1. Antral pulmonary vein electrical isolation (APVI); 2. APIs (focal, localised rotational and localised irregular activation; Figure1) detection by dipole density mapping; 3. API core ablation followed by linear ablation to the nearest non-conduction barrier (APVI/mitral valve); 4. repeat step 2 and 3 in LA (RA, if necessary) until sinus rhythm is achieved. Results Consecutive 40 persistent AF patients (mean 62±12 years, 29 males, AF duration 10±4 months, LA diameter 42±9 mm) were included from 2 centres. An average of 2.0±0.7 APIs per patient were targeted post-APVI. Acute AF termination by ablation was achieved in 27/40 (68%) patients. The mean ablation time of APVI and “Core to block” was 33±12 mins and 31±22 mins, respectively. No major complication occurred. During a mean follow-up of 12±5 months, 32/40 patients (80%) maintained sinus rhythm. Conclusion APVI + “Core to block” guided by the dipole density mapping is feasible for treating persistent AF. A larger randomised study is needed to test the effectiveness of this ablation strategy. Acknowledgement/Funding None

The use of non-invasive mapping in persistent AF to predict acute procedural outcome

BackgroundECG imaging (ECGI) with phase mapping has been used to identify rotational activity non-invasively that can be targeted during atrial fibrillation (AF) ablation. Acute termination of AF using this method has shown improved clinical outcomes. In this study we sought to evaluate whether patterns of rotational density are associated with acute procedural outcomes when using a step-wise ablation strategy. Methods50 patients with persistent or long-standing persistent AF underwent non-invasive 3D mapping with CardioInsight™ prior to AF ablation. Composite maps of rotational activity were created and prioritized based on the density of rotations on a biatrial model. Stepwise ablation of pulmonary vein isolation (PVI) ± rotations ± linear lesions was done with AF termination as the procedural endpoint. ResultsAcute termination of AF was achieved in 34 patients (68%). Median number of rotations in the left atrium (LA), interatrial septum and right atrium (RA) were 22.2 (9.4 to 29.3), 12.0 (4.3 to 13.4), 25.0 (14.5 to 31.3), respectively. In patients with acute AF termination, a higher number of rotations in the LA was observed, 20.3 (10.0 to 37.1) compared to 10.6 (7.7 to 17.2) in the RA (p = 0.02). Additionally, high density of rotations in the posterior inferior right atrium (segment 2B on the biatrial model) was observed in patients without acute AF termination (p = 0.02). ConclusionAcute termination of persistent and long-standing persistent AF using rotational ablation guided by ECGI phase mapping can be achieved in a high percentage of both index and re-do cases. The distribution and pattern of these rotations may be associated with procedural outcomes and could potentially be used to stratify patients.

Outcomes following persistent atrial fibrillation ablation using localized sources identified with Ripple map.

BackgroundAblation of persistent atrial fibrillation (AF) remains challenging. Identification and ablation of localized AF drivers may offer the possibility for improved outcomes. Ripple map is a novel software algorithm that may allow improved localization of possible AF drivers through the whole chamber graphical display of continuously recorded bipolar electrograms. The objective of this study was to determine whether regions of high‐frequency Ripple activation (HFRA) observed on Ripple map provide useful ablation targets in patients with persistent AF.Methods and ResultsConsecutive patients underwent the first‐time ablation of persistent AF (n = 162) using a standard stepwise (n = 105) or a Ripple map guided approach (n = 57). Ripple map guided patients underwent pulmonary vein antral isolation followed by ablation of HFRA sites. Acute termination of AF was observed in 91.2% of the Ripple‐guided patients vs 52.4% in the stepwise approach, P < .0001. Following a single ablation procedure, after 18 months 98.2% of Ripple map guided patients were free of AF, compared with 81.4% of standard stepwise ablation (P = .005). Freedom from atrial tachycardia (54.4% Ripple map vs 52.4% standard, P = .9) or any atrial arrhythmia (52.6% Ripple map vs 39.0% standard, P = .10) did not differ between the two strategies. In a subset analysis (n = 30 of 56), Ripple map regions corresponded to sites with spatiotemporal dispersion in all atrial locations. No differences were observed in the rate of procedural complications.ConclusionsAblation of HFRA sites identified with Ripple map resulted in a higher rate of acute termination and improved freedom from AF compared to a standard stepwise approach.

Effect of Acute Termination of Atrial Fibrillation on the Outcome of Ablation of Persistent Atrial Fibrillation

Effect of Acute Termination of Atrial Fibrillation on the Outcome of Ablation of Persistent Atrial Fibrillation

Usefulness of High-Dose Oral Flecainide for Termination of Recent-Onset Atrial Fibrillation in Children

A high dose of oral flecainide has been used for acute termination of atrial fibrillation (AF) and atrial flutter or intra-atrial re-entry tachycardia (AFL-IART) in adults. The use of flecainide for these conditions in children has not been well described. We describe our institutional experience on acute termination of AF or AFL-IART in children with a single high dose of oral flecainide in a hospital setting. All patients who received a single high dose of oral flecainide from 2009 to 2016 who were <21 years of age were included. Patients were treated only if AF or AFL-IART was less than 24 hours of duration. The dose was 300 mg for patients >70 kg, 200 mg for patients 40 to 70 kg, and 5 mg/kg for patients <40 kg. Charts were reviewed to determine demographic information, flecainide dose, termination of arrhythmia, and time to termination. There were 22 patients identified. The median age was 16 years (range 4.6 to 20.3) with a median weight of 75 kg (range 19 to 112). There were 13 patients with AF (11 with a normal heart, 85%) and 9 patients with AFL-IART (1 with a normal heart, 11%) (p <0.05). The median dose of flecainide given was 3.6 mg/kg (range 2.7 to 6.1) or 136 mg/m2 (range 90 to 171). AF in all patients (13/13, 100%) and AFL-IART in 5 of 9 patients (55%) terminated acutely (p <0.05). All patients with normal heart (12/12, 100%) and 6 of the 10 patients (60%) with heart disease have their arrhythmia terminated acutely (p <0.05). The only patients whose tachycardia did not terminate were 4 patients with IART and heart disease. The arrhythmia terminated in a median time of 60 minutes (range 30 to 120). There were no adverse events or proarrhythmia encountered. In conclusion, a single high dose of oral flecainide successfully terminated AF of less than 24 hours' duration in all pediatric patients without side effects. This approach is less effective for AFL-IART in patients with heart disease.

Efficacy and safety of driver-guided catheter ablation for atrial fibrillation: A systematic review and meta-analysis.

Targeting localized drivers (electrical rotors or focal impulses) during catheter ablation for atrial fibrillation (AF) has been proposed as a strategy to improve procedural success. However, the strength and quality of the evidence to support this approach is unclear. Clinical studies reporting efficacy or safety outcomes of driver-guided ablation for AF were identified in Medline, Embase, the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, Pubmed, and conference abstracts from major scientific meetings. Random-effects meta-analysis of efficacy outcomes from controlled studies was performed. Thirty-one reports from 30 studies were included: two randomized controlled trials, five nonrandomized controlled studies, and 23 uncontrolled studies. In controlled studies, driver-guided ablation has been associated with higher rates of acute AF termination (RR 2.08, 95% CI 1.43-3.05; P< 0.001) and increased freedom from AF/atrial tachycardia (AT) at ≥1 year (RR 1.34, 95% CI 1.05-1.70; P=0.02). Similar rates of procedural complications have been reported between ablation strategies. Overall, current data on driver-guided ablation are predominantly from nonrandomized studies with considerable heterogeneity in mapping and ablation strategies used and in clinical outcomes reported. Pooled data on the efficacy of AF driver-guided catheter ablation suggest increased freedom from AF/AT relative to conventional strategies. However, most studies are nonrandomized and of moderate quality. Though promising data exist, there remains no conclusive evidence for the efficacy of AF driver ablation. Robust data from randomized trials are needed.

Combined Cryoballoon and Radiofrequency Ablation Versus Radiofrequency Ablation Alone for Long-Standing Persistent Atrial Fibrillation

BackgroundTo achieve sinus rhythm, ablation of long-standing persistent atrial fibrillation (LSPAF) usually requires substrate modification in addition to pulmonary vein isolation (PVI). In the present article, we aimed to compare clinical and substrate modification effects of 2 distinct PVI strategies during stepwise ablation in patients with LSPAF: (1) Combined approach: cryoballoon (CB) for PVI and radiofrequency (RF) ablation for substrate modification and (2) RF-only approach: RF ablation for both PVI and substrate modification. Materials and MethodsA total of 34 patients were divided into 2 groups: 19 in the combined group and 15 in the RF group. Left atrial (LA) complex fractionated atrial electrogram (CFAE) maps were acquired before and after PVI and compared between groups. The groups were compared for acute atrial fibrillation termination (AFT) rates and long-term arrhythmia-free survival. ResultsA significant reduction on total LA CFAE area was observed with PVI in both groups. In the CB group, when pulmonary veins were excluded, the reduction of LA CFAE area was the most significant on the posterior wall of left atrium and which was greater than in the RF group. Although the ratio of AFT was higher in the CB group (44% versus 33%, respectively), single-procedure arrhythmia-free survival at 1 year was comparable between groups (68% in the CB group versus 66% in the RF group). Times of total procedure, fluoroscopy and post-PVI RF were all shorter in the CB group. ConclusionsCB may cause greater substrate modification on the posterior wall and increase AFT rate during LSPAF ablation.

Ablation as targeted perturbation to rewire communication network of persistent atrial fibrillation.

Persistent atrial fibrillation (AF) can be viewed as disintegrated patterns of information transmission by action potential across the communication network consisting of nodes linked by functional connectivity. To test the hypothesis that ablation of persistent AF is associated with improvement in both local and global connectivity within the communication networks, we analyzed multi-electrode basket catheter electrograms of 22 consecutive patients (63.5 ± 9.7 years, 78% male) during persistent AF before and after the focal impulse and rotor modulation-guided ablation. Eight patients (36%) developed recurrence within 6 months after ablation. We defined communication networks of AF by nodes (cardiac tissue adjacent to each electrode) and edges (mutual information between pairs of nodes). To evaluate patient-specific parameters of communication, thresholds of mutual information were applied to preserve 10% to 30% of the strongest edges. There was no significant difference in network parameters between both atria at baseline. Ablation effectively rewired the communication network of persistent AF to improve the overall connectivity. In addition, successful ablation improved local connectivity by increasing the average clustering coefficient, and also improved global connectivity by decreasing the characteristic path length. As a result, successful ablation improved the efficiency and robustness of the communication network by increasing the small-world index. These changes were not observed in patients with AF recurrence. Furthermore, a significant increase in the small-world index after ablation was associated with synchronization of the rhythm by acute AF termination. In conclusion, successful ablation rewires communication networks during persistent AF, making it more robust, efficient, and easier to synchronize. Quantitative analysis of communication networks provides not only a mechanistic insight that AF may be sustained by spatially localized sources and global connectivity, but also patient-specific metrics that could serve as a valid endpoint for therapeutic interventions.

Impact of acute atrial fibrillation termination and prolongation of atrial fibrillation cycle length on the outcome of ablation of persistent atrial fibrillation: A substudy of the STAR AF II trial

Controversy exists about the impact of acute atrial fibrillation (AF) termination and prolongation of atrial fibrillation cycle length (AFCL) during ablation on long-term procedural outcome. The purpose of this study was to analyze the influence of AF termination and AFCL prolongation on freedom from AF in patients from the STAR AF II (Substrate and Trigger Ablation for Reduction of Atrial Fibrillation Trial-Part II) trial. Acute changes in AFCL and AF termination were collected during the index procedure of the STAR AF II trial and compared to recurrence of AF at 18 months. Recurrence was assessed by ECG, Holter (3, 6, 9, 12, 18 months), and weekly transtelephonic ECG monitoring for 18 months. AF terminated in 8% of the pulmonary vein isolation (PVI) arm, 45% in the PVI+complex electrogram arm, and 22% of the PVI+linear ablation arm (P <.001), but freedom from AF did not differ among the 3 groups (P = .15). Freedom from AF was significantly higher in patients who presented to the laboratory in sinus rhythm (SR) compared to those without AF termination (63% vs 44%, P = .007). Patients with AF termination had an intermediate outcome (53%) that was not significantly different from those in SR (P = .84) or those who did not terminate (P = .08). AF termination was a univariable predictor of success (P = .007), but by multivariable analysis, presence of early SR was the strongest predictor of success (hazard ratio 0.67, P = .004). Prolongation of AFCL was not predictive of 18-month freedom from AF. Acute AF termination and prolongation in AFCL did not consistently predict 18-month freedom from AF. Presence of SR before or early during the ablation was the strongest predictor of better outcome.

Abstract 13948: High Intraprocedural Atrial Fibrillation Termination Rate by Large Area Rotor Ablation Combined With Pulmonary Vein Isolation

Introduction: There remains contradictory data about the optimal ablation technique and the type of termination of atrial fibrillation (AF) ablation particularly in patient (pt) with persistent AF. The aim of this study was to determine the type of the termination of persistent AF during combined conventional and rotor ablation. Method: This is a single-center, prospective, observational study enrolled thirty-eight pts (24/63% male, mean age 63 years) with AF (mean left atrial size: 46,2 ± 7 mm), who underwent focal impulse and rotor modulation (FIRM) mapping and large area ablation around the core of the identified rotor(s), followed by conventional pulmonary vein isolation(PVI) using contact force catheter aiming 10-20 gr depending on the location. Two distinctive types of the AF termination were defined: sub-acute termination related to rotor elimination, furthermore acute termination due to PVI. Electric cardioversion (ECV) was executed only in the absence of spontaneous conversion to sinus rhythm (SR). Result: In 10(26%) pts acute AF termination after PVI was observed. In further 12 (31%) pts sub-acute termination of the AF could be observed after the identified rotor ablation. The combined technique of conventional and rotor ablation of pts with persistent AF resulted in 57,8% of termination rate. Spontaneous cardioversion could not be reached in 16 (42%) pts however 15 out of them were converted to SR by ECV. Procedural complication occurred in 3 pts presenting with groin hematoma, in one patient left atrial appendage (LAA) thrombus was revealed by transoesophageal echocardiography performed right after the ablation for guiding the planned LAA closure. Conclusion: Large area rotor ablation drag technique combined with contact force sensing technique results in a high termination rate of persistent AF. More studies are warranted to define the clinical significance and long term success rate of rotor ablation in pts with persistent atrial fibrillation.

153-02: Antazoline – new effective antiarrhythmic drug for acute termination of atrial fibrillation. Insights into drug-induced electrocardiographic and haemodynamic effects

153-02: Antazoline – new effective antiarrhythmic drug for acute termination of atrial fibrillation. Insights into drug-induced electrocardiographic and haemodynamic effects

Persistent Atrial Fibrillation FromtheOnset: A Specific Subgroup of Patients With Biatrial Substrate Involvement and Poorer Clinical Outcome.

This study sought to characterize the clinical characteristics, atrial substrate, and prognosis in a subgroup of patients with persistent atrial fibrillation (AF) from the onset (PsAFonset). Patients with AF frequently progress from trigger-driven paroxysmal arrhythmias to substrate-dependent persistent arrhythmias. Patients referred for persistent AF (PsAF) ablation were enrolled from 3 centers. Consecutive patients with PsAFonset (n= 129) were compared with patients with PsAF that progressed from paroxysmal AF (n= 231). In addition, 90 patients (30 patients with PsAFonset and 60 control subjects) were studied with noninvasive mapping to characterize the AF drivers. The degree of fractionation and endocardial voltages were assessed invasively. Patients with PsAFonset were younger (p= 0.047) and more obese (p< 0.001); there were more men (p=0.034), more patients with hypertension (p= 0.044), and these patients had larger left (p< 0.05) and right atria (p< 0.05). Baseline AF cycle length was shorter in the PsAFonset group (p< 0.01); the degree of fractionation was higher (p< 0.001 for both atria), and the endocardial voltage was lower (p< 0.05 for both atria). Patients with PsAFonsethad higher a number of re-entrant driver regions (p< 0.001) and extrapulmonary vein regions that had re-entrant drivers (p< 0.05), whereas control subjects displayed more focal driver regions (p= 0.029). The acute AF termination rate was lower in the PsAFonset group (42% vs. 81%; p< 0.001). During a mean follow-up of 17 ± 11 months fromthelast procedure, patients with PsAFonset had significantly higher AF, atrial tachycardia (AT), and AF/AT recurrence rates (p< 0.01). Patients with PsAFonset represent a distinct subgroup defined by specific demographics, underlying diffuse biatrial substrate disease, and worse clinical outcome. The findings highlight the importance of defining criteria for early detection of atrial substrate disease.