RADAR

Wide-area antral pulmonary vein and posterior wall isolation by way of segmental nonocclusive applications using a novel radiofrequency ablation balloon

Background— The characteristics of atrial electrograms associated with atrial fibrillation (AF) termination are controversial. We investigated the electrogram characteristics that indicate procedural AF termination during continuous complex fractionated electrogram ablation. Methods and Results— Fifty-two consecutive patients with persistent AF (47 men; aged 54±9 years), who underwent electrogram-based catheter ablation in the left atrium and coronary sinus after pulmonary vein isolation, were enrolled. The intracardiac bipolar atrial electrogram recordings were characterized by (1) fractionation interval (FI) analysis (>6 seconds), (2) kurtosis (shape of the FI histogram), and (3) skewness (asymmetry of the FI histogram). Sites showing complex, fractionated electrograms (mean FI ≤60 ms) were targeted, and AF was terminated in 20 patients (38%) after the pulmonary vein isolation. The conventional complex fractionated electrogram sites (mean ≤120 ms) in patients with AF termination exhibited higher median kurtosis (2.69 [interquartile range, 2.03–3.46] versus 2.35 [interquartile range, 1.79–2.48]; P =0.024) and higher complex fractionated electrogram-mean interval (102.7±19.8 versus 87.7±15.0; P =0.008) than patients without AF termination. Furthermore, AF termination sites had higher median kurtosis than targeted sites without AF termination (5.13 [interquartile range, 3.51–6.47] versus 4.18 [interquartile range, 2.91–5.34]; P <0.01) in patients with procedural termination. In addition, patients with AF termination had a higher sinus rhythm maintenance rate after a single procedure than patients without AF termination (log-rank test, P =0.007). Conclusions— A kurtosis analysis using the FI histogram may be a useful tool in identifying the critical substrate for persistent AF and potential responders to catheter ablation.

See Article by Calvo et al There is an urgent need to define the mechanisms that sustain atrial fibrillation (AF), as ablation at anatomic and empirical targets has not improved outcomes over pulmonary vein isolation alone.1–4 Rotational drivers are promising mechanistic targets which are highly topical, yet for which data continue to accumulate. Scientifically, rotational drivers maintain AF using the gold standard of optical mapping,5 across most species including human atria. Clinically, several studies of rotor ablation show promising results,6 although divergent data7 have to be reconciled. Because AF mechanisms may vary with mapping technique, novel mapping studies in this space are welcome. In this issue of Circulation: Arrhythmia and Electrophysiology , Calvo et al8 studied patients with long-standing persistent AF using a novel technique (CartoFinder) and identified sites of rotational activity. These sites fluctuated yet remained spatially stable over time and, when ablated, the impact on local and remote tissue was consistent with elimination of mechanistic drivers. The authors found stable sites of rotational activity (defined as >3 cycles, observed mean 9.2±2.2) in both …

Background/IntroductionThe TAILORED-AF trial (NCT04702451) was the first randomized, superiority trial demonstrating that artificial intelligence (AI)-guided ablation of persistent atrial fibrillation (AF) patients targeting spatiotemporal dispersion in addition to pulmonary vein isolation (PVI) is superior to PVI alone after one year of follow-up.PurposeThis TAILORED-AF sub-analysis aims to characterize spatiotemporal dispersion regions in relation to atrial regions where AF terminated during an AI-guided tailored ablation procedure.MethodsSpatiotemporal dispersion maps were built during index ablation procedures with an artificial intelligence-guided spatiotemporal dispersion software. Dispersion atrial extent was defined as the ratio of dispersion surface area in a chamber over its total chamber surface area quantified with an in-house algorithm. The algorithm estimates pixel surface area values from 2D snapshots collected from 3D navigation maps. After (i) conversion of antero-posterior and postero-anterior 2D view snapshots into grayscale-transformed images, (ii) the background was removed and the atria were segmented. Then, (iii) tags were detected, segmented and (iv) connected to remnant regions. Finally, spatiotemporal dispersion region locations and extent were superimposed with tags corresponding to AF termination locations in patients in whom AF was terminated. This corresponded to a location where AF terminated by ablation into sinus rhythm/atrial tachycardia or where the AF cycle length increased by a minimum of 20ms.ResultsThe Tailored arm population included 187 persistent and long-standing persistent AF patients. The dispersion extent was higher in the left atrium (LA) compared to the right atrium (RA) (14.7% [8.1%-24.5%] vs 0.6% [0.0%-2.5%], p<0.0001). All patients (100%) had dispersion in the LA, whereas dispersion was only detected in the RA in 79% of the patients. The most frequent regions in LA exhibiting dispersion were the LA posterior wall with 20% [8%-31%] extent, LA anterior wall with 15% [8%-25%] extent and the LA roof with 10% [4%-19%] extent.The acute AF termination rate was 66%. All AF termination locations (100%) were found within dispersion regions: 25% in the lower quartile dispersion extent, 26% in the medium quartile and 49% in the higher quartile. In 81% of the patients, AF termination occurred in the LA, from which 20% located in the PV region and 80% outside the PV region. AF terminated in the RA in 19% of the patients (Figure).Conclusion(s)While pursuing an AI-guided ablation of persistent atrial fibrillation, spatiotemporal dispersion and AF termination predominantly occurs in the left atrium. Still, 19% of termination is observed after ablation in minimally extended regions of the RA. These findings highlight the importance of mapping and ablating in the RA when conducting a spatiotemporal dispersion-based ablation.

<i>Circulation: Arrhythmia and Electrophysiology</i> Editors’ Picks

Funding Acknowledgements Type of funding sources: None. Background CARTOFINDER allows for a simultaneous and automated detection of repetitive focal and rotational activations during electroanatomical mapping using a multi-electrode catheter in patients with atrial fibrillation (AF). Aim This study aimed to validate the CARTOFINDER algorithm for the detection of potential drivers for AF under routine clinical conditions and to access the effects of PVI and additional substrate modification on regions of interests (ROI) from CARTOFINDER mapping. Methods Forty-four consecutive patients underwent AF ablation for persistent AF using a 3D-mapping system with the novel integrated CARTOFINDER module. All patients presented with persistent AF and mapping was performed using a multi-electrode catheter. The ablation workflow was divided into the following steps: 1. 3D reconstruction of the right (RA) and left atrium (LA). 2. Identification of the individual ROIs separated for focal and rotational activity in the RA and LA. 3. Ablation index guided pulmonary vein isolation (PVI). 4. Repeat mapping for ROIs in the RA and LA. 5. Direct current electrical cardioversion. 6. Confirmation of persistent PVI and bipolar ultra-high density mapping of the RA and LA followed by substrate modification if there was evidence for local bipolar low-voltage in the LA. Results Acute PVI was achieved in all patients (100%). In 28% of these patients additional LA substrate modification was performed. AF termination was observed in 4 patients. Mean procedure duration was 137 ± 30 min, mapping time for ROIs in the RA was 8 ± 5 min and 11 ± 5 for the LA, respectively. A mean number of 149 ± 82 ROIs were revealed from CARTOFINDER. In the LA, focal activity was predominantly observed inside the LA appendage (LAA) and in close relationship to the pulmonary vein ostia. The majority of rotational activities was found along the mitral valve annulus. In the RA, the majority of ROIs was found at the septum and in close relationship to the RA appendage. During re-mapping for ROIs after AF ablation we observed the elimination of ROIs close to the linear ablation set for PVI. In addition, rotational activity could not be re-identified at repeat mapping. Conclusions ROIs could be discriminated and visualized utilizing CARTOFINDER in all patients. These ROIs might potentially be an additional and individual ablation target beyond PVI in patients with persistent AF.

Non-inducibility of AF post electrophysiologically based PV isolation predicts freedom from AF

Marshall bundle elimination, Pulmonary vein isolation, and Line completion for ANatomical ablation of persistent atrial fibrillation (Marshall-PLAN): Prospective, single-center study

Prevalence of Silent Cerebral Ischemia in Paroxysmal and Persistent Atrial Fibrillation and Correlation With Cognitive Function

PO-02-065 CATHETER ABLATION WITH TERMINATION OF PERSISTENT ATRIAL FIBRILLATION USING SPATIOTEMPORAL DISPERSION

Objective To analyze the relationship of long-pause after atrial fibrillation termination and sinus nodal recovery time(SNRT)and impact of pulmonary vein isolation on it in order to disclose the potential mechanism of long-pause after atrial fibrillation and to discussthe optional therapy for this kind of long-pause.Methods Eleven patientswith syncope or presyncope because of long-pause after paroxysmal atrial fibrillation termination were involved in this study.Segmental pulmonary veins isolation wag performed.SNRT160 and SNRT600 were measured by ahial stimulation at S1S1 160 heats/min and 600 beats/min for one minute before and after pulmonary vein isolation.Results All pulmonary vein isolation was achieved in 11 patients.Seven patients were free of atrial fibrillation and syncope or presyneope during mean(13±7)months'follow-up.Permanent pacemaker wag implanted in 2 patients because of syncope or presyncope resulting from long-panse demonstrated by electrogram.The other 2 patients with recurrence of atrial fibrillation were still in follow-up without any antiarrhythmic drugs because of long-pause.The long-pause was(3464±918)ms before ablation.SNRT160 was(1655±378)ma and(1491±284)ma before and after ablation.SNRT600 was(1682±419)ms and(1518±218)ms before and after ablation.There was no significant difference of SNRT before and after pulmonary vein isolation.No significant relalionship between long-pause and SNRT was observed.Conclusions Eradication of paroxysmal atrial fibrillation by pulmonary vein isolation is effective treatment for long-pause resulting from atrial fibrillation termination.Sinus nodal malfunction may be not contribute to the long-pause resulting from paroxysmal atrial fibrillation. Key words: Atrial fibrillation; Pulmonary veins

Managing atrial fibrillation in the CRT patient: Controversy or consensus?

Purpose of ReviewAtrial fibrillation (AF), the most common sustained arrhythmia, is associated with high rates of morbidity and mortality. Maintenance of stable sinus rhythm (SR) is the intended treatment target in symptomatic patients, and catheter ablation aimed at isolating the pulmonary veins provides the most effective treatment option, supported by encouraging clinical outcome data. A variety of energy sources and devices have been developed and evaluated. In this review, we summarize the current state of the art of catheter ablation of AF and describe future perspectives.Recent FindingsCatheter ablation is a well-established treatment option for patients with symptomatic AF and is more successful at maintaining SR than antiarrhythmic drugs. Antral pulmonary vein isolation (PVI) as a stand-alone ablation strategy results in beneficial clinical outcomes and is therefore recommended as first-line strategy for both paroxysmal and persistent AF. While radiofrequency-based PVI in conjunction with a three-dimensional mapping system was for many years considered to be the “gold standard”, the cryoballoon has emerged as the most commonly used alternative AF ablation tool, especially in patients with paroxysmal AF. Patients with persistent or long-standing persistent AF and with arrhythmia recurrence after previous PVI may benefit from additional ablation strategies, such as substrate modification of various forms or left atrial appendage isolation. New technologies and techniques, such as identification of the AF sources and magnetic resonance imaging-guided substrate modification, are on the way to further improve the success rates of catheter ablation for selected patients and might help to further reduce arrhythmia recurrence.ConclusionsPulmonary vein isolation is the treatment of choice for symptomatic patients with paroxysmal and persistent drug-refractory AF. The reconnection of previously isolated pulmonary veins remains the major cause of AF recurrence. Novel ablation tools, such as balloon technologies or alternative energy sources, might help to overcome this limitation. Patients with non-paroxysmal AF and with AF recurrence might benefit from alternative ablation strategies. However, further studies are warranted to further improve our knowledge of the underlying mechanisms of AF and to obtain long-term clinical outcomes on new ablation techniques.

In this issue of the Circulation: Arrhythmia and Electrophysiology , Kurotobi et al1 determined the number of arrhythmogenic foci in atria provocable with isoproterenol infusion in patients with paroxysmal, persistent, and permanent atrial fibrillation (AF). The results show that persistent AF has more foci than paroxysmal AF. However, when AF persists for >12 months, the number of foci were reduced. The authors suggest that the increased number of foci probably is involved in the development of persistent AF. However, because this association is not observed for AF that persists for >12 months, the importance of these foci in AF maintenance remains unclear. Article see p 39 In ambulatory canine models, simultaneous sympathovagal discharges (rather than isolated sympathetic activation) are typical triggers of paroxysmal atrial tachycardia (AT) and AF.2,3⇓ These observations are explained by the late phase-3 early afterdepolarization (EAD), which depends on the coexistence of increased amplitude and duration of intracellular calcium (Cai) transient and the shortened action potential duration (APD).4,5⇓ Vagal stimulation shortens APD and therefore is needed to promote the late phase-3 EAD. In the Kurotobi study, however, arrhythmogenic foci were induced by isoproterenol alone, without the need of vagal stimulation or the use of parasympathomimetic agents. These results are different from that obtained in canine studies. The first possible explanation is that the pulmonary veins (PVs) naturally have shorter APDs with elevated (less negative) membrane potentials.6,7⇓ Rapid activation may further shorten the APD in the PVs.8 These changes are independent of the vagal tone. Jais et al9 reported the effective refractory periods of the PVs were shorter …

Objective. The purpose of this prospective, randomized, single-center, uncontrolled, open study was to assess the efficiency of surgical treatment of the most common worldwide disease of the cardiovascular system – coronary heart disease (CHD) in combination with atrial fibrillation (AF). Methods. Different techniques of AF ablation in patients with coronary artery disease during coronary bypass surgery were analyzed. 98 patients with longstanding persistent AF were randomized into three groups: PVI+CABG (n = 31) group underwent isolation of the pulmonary veins, the CABG+MM group (n = 37) received a modified mini-MAZE procedure (isolation of pulmonary veins in combination with left isthmus ablation and formation of an ablation line on the roof of the left atrium) and CABG with anatomical ablation of ganglionated plexi zones was performed for the CABG+GP group patients (n = 30). <br />Results. It was found out that in patients with coronary artery disease and longstanding persistent AF, only radiofrequency fragmentation of the left atrium performed during CABG surgery can yield satisfactory results in the long term, with efficiency running up to 48.65%. Predictors of AF return in the patients with longstanding persistent AF are: the size of the left atrium exceeding 6.5 cm (OR 1.18, CI 1.01–1.75; p = 0.043) and a long (over 10 years) AF history (OR 1.07, CI 0.23–5.03; p = 0.038). <br />Conclusion. Ganglionated plexi ablation performed simultaneously with CABG in patients with long standing persistent AF has a low efficiency in the long term (33.3%) and cannot be an independent method of treatment of this form of AF.