Posterior LA Research Articles

Impact of additional pulsed field ablation in unsuccessful radiofrequency linear lesions -acute and chronic data

Abstract Background Performing linear ablation such as roof line, inferior line in the posterior part of LA and posterior mitral isthmus (MI) line in addition to PVI is one of the strategies for treating persistent atrial fibrillation. However, remnant conduction or reconnection in the lines is linked with atrial arrhythmia recurrence, either AF or AT. Radiofrequency ablation (RFA) is often unsuccessful achieving durable linear ablation. It is not yet well known whether using pulsed field ablation (PFA) would be superior in achieving complete linear lesions. Purpose We sought to evaluate the benefit of using PFA in unsuccessful RF ablation linear lesions. Methods We studied 17 patients that underwent redo procedures due to atrial arrhythmia recurrence. All of them underwent PFA (using a pentaspline PFA catheter) ablation lines due to previous unsuccessful RF ablation, either due to remnant conduction in the line or to reconnection of the line. Lines of block were evaluated based on activation mapping and differential pacing maneuvers close to the lines. Results We conducted 16 dome-posterior lines and 6 posterolateral mitral isthmus lines using PFA after unsuccessful RF ablation linear lesions. PFA was performed after several unsuccessful procedure, 1.3±0.4 for the roof line, 1.3±0.5 for the postero-inferior line and 1.7±0.9 for the MI line. In 4 out of 6 pts with MI isthmus ablation using PFA ethanol injection within vein of Marshall (Et-VOM) was conducted in a previous procedure and in 4 out of 6 patients with MI isthmus RF ablation within coronary sinus (CS) was performed in a previous procedure. Specifically, for the dome-posterior line, 2 patients underwent PFA deliveries only at the gap region in the posterior LA and in other 14 cases, PFA deliveries were performed at 3.2±0.8 sites of the posterior wall between LPV and RPV. We used a total of 15.5±4.6 PFA deliveries to complete the dome-posterior line. Dome-posterior line bidirectional block based on activation mapping and differential pacing maneuvers was achieved in all cases (16/16, 100%) after PFA. For the MI line, we performed a total of 11.8±2.3 application deliveries at 2.5±0.5 sites in the MI region. Posterior MI line bidirectional block based on activation mapping and differential pacing maneuvers was achieved in 5 out of 6 patients (83.3%). In one case additional Et-VOM was needed to achieve MI block. There was no AT/AF recurrence in all these 17 patients. Conclusion PFA treatment seems promising to back-up RF failed linear lesions. But we cannot exclude that it is in fact the combination of the 2 energies that was successful in those resistant cases.

Intraprocedural and outcome findings in repeat left atrial procedures after pulsed field ablation for pulmonary vein isolation in paroxysmal and persistent atrial fibrillation

Abstract Background Pulsed Field Ablation (PFA) has emerged as a promising novel technique for pulmonary vein isolation (PVI) in the setting of atrial fibrillation. First outcome data revealed comparable success rates to radiofrequency and cryoablation. However, data on lesion dimensions and reconnection of PV after PFA potentially causing recurrence of AF is sparse. We, therefore report on pivotal reconnection sites and ablation extend after PFA-PVI. Methods All patients after PFA-PVI for paroxysmal or persistent AF at our center between September 2021 and October 2023 were included in this retrospective analysis. Baseline characteristics, procedural and outcome data were obtained. Furthermore, in all redo procedures of these patients lesion dimensions and the occurrence and location of PV gaps were evaluated. Results A total of 123 patients with atrial fibrillation underwent successful PFA-PVI during index procedure. The study cohort comprised [n= 52; 42%] paroxysmal and [n= 71; 58%] persistent atrial fibrillation cases. After a median follow-up of 123 (IQR 93-150) days recurrence of atrial arrhythmia (all AF) occurred in 9 [14. 5%] patients. Of these, 6 [9.6%] patients underwent a redo procedure due to recurrence of atrial fibrillation (3 PAF and 3 persAF [50%]; p=1). All left atrial maps and 24 PVs were analyzed. All 6 [100%] patients exhibited electrical reconnection of one or more pulmonary vein. Analysis of redo procedures revealed that the dimensions of PFA-induced lesions varied among patients: The right inferior pulmonary vein (RIPV) showed reconnection in all redo-patients (100%). Also frequent reconnection was observed for the RSPV (3 pts [50%]) and LIPV (2 pts [33%]). The gap size was 66±40% of the circumference in the reconnected RPVs and 61±31% in the reconnected LPVs. A roof-line lesion set was performed in 4 out of 6 pts (67%) due to the initially antral PV lesions affecting the posterior wall and LA roof potentially creating an isthmus for roof-dependent atrial tachycardia (AT). Conclusion Outcome data for PFA-PVI are comparable to other energy sources used for PVI. However, reconnection of PV also occurs after PFA-PVI. This retrospective analysis of redo procedures after initially successful PVI identified the RIPV as pivotal for reconnection. Furthermore, map analysis revealed that reconnection gaps extend to up to 2/3 of the initial circumferential PV ablation area. Furthermore, PFA seems to create new critical isthmuses potentially causing AT. No difference in reconnection was seen comparing PAF and persAF.

Abstract 15606: Effectiveness and Safety of the Dual Epicardial & Endocardial Procedure (DEEP) Approach for Treatment of Subjects With Persistent or Long Standing Persistent Atrial Fibrillation (PersAF/LSPAF) With Radiofrequency Ablation

Background: A collaborative approach between Electrophysiologists (EP) and Cardiothoracic Surgeons (CTS) to effectively target pulmonary veins (PVs) and substrate beyond PVs may improve outcomes for persistent and longstanding persistent AF (PersAF/LSPerAF). Hypothesis: A minimally invasive hybrid approach of bilateral thoracoscopic epicardial ablation and left atrial appendage exclusion (LAAE) with endocardial mapping/ablation (Hybrid approach) is safe and effective to treat advanced AF patients who have failed medical therapy. Aim: DEEP (NCT02393885) aims to establish safety and effectiveness of a Bipolar Radiofrequency (RF) System in a Hybrid approach to treat PersAF/LSPerAF. Methods: DEEP is a prospective, international, single arm trial at 17 sites. Key eligibility: adults with drug refractory PersAF/LSPerAF, left atrial diameter (LAD) ≤5.5cm, failed class I/III AAD, and ≤2 previous failed endocardial catheter ablations (CA). Epicardial surgical ablation included PV isolation, roof and floor lines (posterior LA box), left superior PV to LAA lesion, ganglionic plexi and Ligament of Marshall ablation and LAAE. CA followed 91-121 D post epicardial procedure. After 90 D blanking and 90 D AAD optimization periods, 24-hr rhythm monitoring and ECG were performed 6 and 12 M post CA with symptom driven monitoring between. Primary effectiveness was defined as freedom from atrial arrhythmia (>30 sec) absent new/increased dose of previously failed AAD through 12 M. Safety was device/procedure-related SAEs within 30 D of epicardial ablation and 7 D of CA in all who received anesthesia. Results: Ninety patients were enrolled in 2015-2020, 83.3% PersAF, 16.7% LSPerAF, mean age 63.4±7.74 yrs, 83.3% male, mean BMI 29.9, CHAD2DS2-VASc median 2.0 (1.0, 3.0), 48% failed CA, median AF duration 3.8 yrs, mean LAD 4.5cm. Primary effectiveness 70.6% (60/85; 95% CI 60.9%, 80.3%, p=0.0232) and freedom from AF through 12 M 78.8% (p=0.0002). The adverse event rate was 6.7% (6/90); equal in epi- and endocardial cohort. Both primary endpoints met prespecified success criteria. Conclusion: A collaborative approach between EP and CTS to Hybrid ablation is effective for PersAF/LSerPAF when benefit-risk is deemed favorable, given limited alternative treatments.

Optimized workflow for pulmonary vein isolation using 90-W radiofrequency applications: a comparative study.

Ninety-watt applications are more sensitive to catheter instability and produce lesions that are shallower and smaller in diameter than 50-W applications. These characteristics were considered for the development of a combined (90-50 W) pulmonary vein isolation (PVI) strategy which was prospectively compared to a 50 W-only ablation index (AI)-guided PVI strategy. One hundred fifty consecutive paroxysmal AF patients underwent PVI under general anesthesia using CARTO. In the first 75 patients, PVI was performed with a combined (90-50 W) strategy using the QDOT-MICRO catheter in a temperature-controlled mode. This strategy consisted of 90 W-4s applications on the posterior LA wall (at sites of catheter stability and expectedly thin atrial tissue) with an interlesion distance (ILD) ≤ 4mm and 50-W applications elsewhere (at sites of catheter instability or expectedly thick atrial tissue) with ILD < 6mm. In the subsequent 75 patients, PVI was performed with a 50 W-only AI-guided strategy using the SmartTouch-SF catheter in a power-controlled mode. Both groups of patients had similar clinical characteristics and LA dimensions (123.1 ± 24.9ml vs 119 ± 26.8ml, P = 0.33). Total procedural times (61 [56-70] vs 65 [60-75] min, P = 0.12), first-pass PVI (82.6 vs 80%, P = 0.81), acute PV reconnection (0 vs 6.6%, P = 0.05), and 1-year SR maintenance (93.3 vs 90.6%, P = 0.57) rates were also similar in both groups of patients. There were no complications in the combined (90-50 W) group while only 2 groin hematomas were reported in the 50 W group. In paroxysmal AF patients, a combined (90-50 W) strategy for PVI did not improve safety, efficiency, or effectiveness compared to a 50 W-only AI-guided strategy.

Machine learning approach based on echocardiographic data to improve prediction of cardiovascular events in hypertrophic cardiomyopathy

Structural changes and myocardial fibrosis quantification by cardiac imaging have become increasingly important to predict cardiovascular events in hypertrophic cardiomyopathy patients. In this setting, it is likely that a supervised approach, using machine learning, may improve their risk assessment. We retrospectively included patients with confirmed HCM (n = 265, 52 ± 17 years) through clinical and echocardiographic. A supervised machine learning prognosis algorithm, based on echocardiographic data, was obtained to predict cardiovascular (CV) outcomes, and subsequently investigated for their association with myocardial fibrosis (n = 185) assessed by CMR imaging. At follow-up at 57 months, 13 (4.9%) of patients died and 114 (43%) had been hospitalized for CV events. Patient with CV events had higher indexed LV mass, worse diastolic dysfunction, and more severe LV obstruction. HCM-patients with myocardial fibrosis have more severe LV hypertrophy (OR: 3.1; P = 0.003) and longitudinal myocardial deformation (OR: 0.8; P = 0.008). Prognosis algorithm established using machine learning identified left atrium area (> 24 cm2), mechanical dispersion (> 49 ms), posterior wall thickness (> 1.8 cm), and TAPSE (27 mm) as the four most relevant variables to correctly predict cardiovascular events. Our findings suggest that a simple algorithm based on four key variables (posterior wall thickness, mechanical dispersion, LA area and TAPSE) may help risk stratification and decision-making in patients with HCM. Using new treatments to target these parameters might improve outcomes in HCM-patients (Fig. 1).

PO-04-134 STAR MAPPING METHOD TO IDENTIFY ENDO-EPICARDIAL DISSOCIATION AND DRIVING SITES IN PERSISTENT ATRIAL FIBRILLATION

Recurrence rates following ablation for persistent AF (psAF) remain high with the underlying mechanisms complex and poorly understood. Asynchronous activation of the endocardial and epicardial surfaces during AF, defined as endo-epicardial dissociation (EED) may be a driver for AF. We aim to investigate whether using the novel vector mapping approach, Stochastic Trajectory Analysis of Ranked (STAR) signals, endo- epicardial dissociation and early sites of activation (ESA) can be identified. Six (6) patients underwent endo-epicardial AF ablation utilizing the pericardial percutaneous CO2 insufflation technique. Two AdvisorTM HD Grid mapping catheters were placed in corresponding endocardial and epicardial positions in the left atrium. During AF, 30 second segments were recorded at the base of the left atrial appendage, anterior, inferior, left lateral and posterior LA wall. Fifteen (15) corresponding endo-epicardial segments were analysed using STAR maps and assessed for ESA and variation in direction of activation wavefront between the endocardium and epicardium. Activation wavefront direction was defined as dissociated if there was >40-degree difference between activation direction of simultaneous endo-epicardial wavefronts on STAR mapping. For each 30 second recording if there was more than 1 dominant wavefront direction, the 2 most common were used and an average taken. The overall mean difference in angulation of wavefront between the endocardium and epicardium was 71 ± 55 degrees. Nine (9) of 15 STAR maps (53%) showed activation angulation difference of >40 degrees between the endocardial and epicardial wavefront activation. Of these 9, 3 were on the posterior wall, 3 were at the base of the appendage, 2 were on the left lateral wall and 1 was on the anterior wall. ESA was identified in 6 STAR mapped endo and epicardial segments of AF, with 4 of these 6 (67%) ESAs in the epicardium. STAR mapping identifies activation wavefront discrepancy showing EED in multiple sites of the atrium with the majority of ESAs in the epicardial atrial surface.

AB-453068-3 ESOPHAGEAL TEMPERATURE AND ESOPHAGEAL DAMAGE IN HIGH POWER SHORT DURATION ABLATION SETTINGS

Radiofrequency ablation (RFA) of atrial fibrillation (AF) using high-power short-duration (HPSD) ablation settings (50W, 10s or up to 90W, 4s) are increasingly common, seeking to maximize resistive rather than conductive heating to limit the risk of esophageal damage. The real-time luminal esophageal temperature (LET) response and the risk of esophageal damage of HPSD are not fully established. To investigate the LET and esophageal risk of HPSD RFA on the posterior LA wall. We ablated the deep inferior pulmonary vein (IPV) in close proximity to the esophagus in 14 pigs, using either Termocool SmartTouch Catheter (HPSD 50W/10s, n=7), or QDOT Catheter (HPSD 90W/4s, n=7). LET was monitored with a 12-sensor CIRCA probe. RFA was delivered in the IPV in apposition with the esophagus as verified on 3D maps. We collected LET, ablation parameters; endoscopy, macro- and microscopic examination of the esophagus. In 3 pigs in each group, survival was prolonged 1 month for chronic characterization of esophageal lesions. Total energy delivered (90W/4s vs. 50W/10s) was higher in QDOT group (60.8±18.8W vs. 48.9±0.1W, p<0.005), as was the peak temperature at ablation catheter tip (51.2±3.1°C vs. 25.3±2.8°C, p<0.005). Peak LET was lower in the 90W/4s group than in the 50W/10s group, (38.7±1.5°C vs. 40.5±3.1°C, p<0.005). Temperatures >40°C were reached in 14/90 90W/4s ablations vs 43/94 in 50W/10s ablations (p<0.001). Acute esophageal lesions were found in all pigs. In the 90W/4s group, acute lesions involved affecting outer muscularis layer in 4/4 and up to submucosa in 1/4. However, no chronic lesions were identified in 3/3. In the 50W/10s group: 4/4 acute lesions involved entire muscularis layer into the submucosa, and reaching the mucosa in 2. Chronic lesions were found in only 1 on pig in the 50W/10s group – complete muscularis layer replacement with scar (with submucosal inflammation). All lesions occurred after high LETs. (Figure) HPSD 50W/10s can create high LET and significant acute and chronic esophageal damage. QDOT catheter at 90W/4s leads to lower peak LETs, can lead to acute lesions but no chronic esophageal damage. LET can be used to monitor risk of esophageal damage in both HPSD protocols.

PO-01-138 NON-INVASIVE 3-D MAPPING (ECGI) OF MACRO-REENTRANT ATRIAL ARRHYTHMIAS

Peri-valvular atrial arrhythmias are the most common macro-reentrant mechanism seen in both de-novo and repeat atrial fibrillation (AF) ablations. Standard 12-lead ECG’s poorly predict tachycardia mechanisms especially post AF ablation. Identifying the mechanism of tachycardia non-invasively could help in procedural planning, expedite the invasive procedure, and identify critical areas sustaining persistent AF in patients with concomitant AF. The objective was to determine if ECGi could identify the mechanism of atrial flutters in patients with or without prior AF ablations. 30 patients (11 de-novo, 19 prior ablation) underwent non-invasive propagation and phase mapping (CardioInsight, Medtronic, Inc) and intracardiac bi-atrial high-density activation mapping (HD Grid and Precision, Abbott Medical). An 8-segment model (RA lateral, RA anterior, CTI, Septum, LA anterior, LA lateral, CS, LA posterior) was used for directionality in the propagation maps, and a 9-segment model for phase map analysis was used for presence and localization of ‘rotational hinge points’ which can occur with wavefronts moving in different directions within close proximity. The precise tachycardia mechanism (counterclockwise (CCW) or clockwise (CW) and cavo-tricuspid isthmus (CTI) or mitral isthmus (MI) dependent) was determined by intracardiac activation maps, entrainment, and confirmed with termination by ablation. Directionality in a region was deemed concordant if non-invasive and intracardiac maps matched or was declared discordant/indeterminate. A total of 31 macro-reentrants maps were analyzed: 16 CCW-CTI; 7 CW-CTI; 4 CCW-MI; 4 CW-MI. Regional directional concordance percentages shown in theTable. A total of 30/31 phase maps identified at least one region as a 'rotational hinge point', with 26/31 maps showing paired 'hinge points'. Location of rotations are shown in the Figure. ECGi can be used in macro-reentant atrial arrhythmias to determine directionality of activation with best concordance on the lateral walls of both atria. In our study, 97% of peri-valvular atrial flutters had at least one 'rotational hinge point' with 84% showing them paired representing macro-reentant circuit. Posterior LA wall rotational area was present in all peri-mitral flutters. Additionally, paired 'hinge points' with lateral atrial wall directionality were the best determinants of the macro-reentant mechanism.Tabled 1Directional ConcordanceRA LatRA AntCTISeptumLA AntLA LatCSLA PostCCW-CTI88%69%88%44%44%--50%--CW-CTI71%43%71%43%43%--29%--CCW-MI100%50%--75%75%100%100%50%CW-MI100%60%--40%40%80%80%20% Open table in a new tab

Arrhythmogenic epicardial LA-PV connection at the peri-oesophageal posterior LA is safely and effectively blocked by ethanol infusion to the vein of Marshall.

Arrhythmogenic epicardial LA-PV connection at the peri-oesophageal posterior LA is safely and effectively blocked by ethanol infusion to the vein of Marshall.

Very High-Power Short-Duration (HPSD) Ablation for Pulmonary Vein Isolation: Short and Long-Term Outcome Data.

Background: Circumferential pulmonary vein isolation (PVI) using radiofrequency ablation (RFA) is a standard of care intervention for patients with symptomatic atrial fibrillation (AF). During follow-up, a substantial number of patients need a redo procedure due to reconnections on the basis of insufficient non-transmural ablation lesions. High-power short-duration ablation (HPSD) is expected to create efficient lesions while causing fewer complications than in conventional RFA settings. The aim of this study was to compare one-year outcome data of very HPSD (90 Watt, 4 s) to a strategy using 50 Watt HPSD ablation guided by the CLOSE protocol using the Ablation Index (AI), an arbitrary unit composed of power, contact force and ablation time. Methods: We retrospectively analyzed short and long-term (median follow-up 23.2 ± 9.9 months) outcome data from 52 patients that were scheduled for first-do-symptomatic PVI. A very HPSD ablation protocol with 90 Watt and a 4 s duration cut-off was compared to an HPSD CLOSE approach (50 Watts; AI 550 at the anterior LA wall; AI 400 at the posterior LA wall, the roof and the floor) in terms of freedom from AF recurrence in a long-term electrocardiogram (ECG) over a five days surveillance period. To gain an impression of the subjective sense of wellbeing, the Atrial Fibrillation Effects on QualiTy-of-Life (AFEQT) score was recorded. Results: Overall freedom from AF was found in 81% (90 W 4 s) vs. 87.5% (50 W), (p = 0.52). There were 3 AF recurrences during the blanking period (90 W 4 s) vs. 1 (50 W). Within each population, one patient was scheduled for a redo-PVI-procedure. The AFEQT score was in favor of the 90 Watt 4 s approach (86.1 vs. 77.5; p = 0.37). Conclusion: Within our relatively small studied population, we found hints that in addition to shortening ablation times and radiation exposure without significantly increasing the rate of relevant intraprocedural complications, very high power short-duration ablation (90 W 4 s) provides comparable efficacy rates after one year.

Comparison of ostial versus very wide antral circumferential pulmonary vein isolation using pulsed field ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background Pulmonary vein isolation (PVI) is the gold standard for first-time atrial fibrillation (AF) ablation procedures. Wide antral circumferential ablation (WACA) in comparison to ostial PVI has been attributed to an improved rhythm outcome after AF ablation. Pulsed field ablation (PFA) is a novel energy source with promising safety and efficacy advantages over existing ablation methods due to its unique myocardial tissue specificity. Feasibility of PFA for very WACA has not been investigated so far. Objective To evaluate procedural characteristics and lesion formation during wide antral circumferential PVI in comparison to ostial PVI using a PFA system. Methods Thirty-seven consecutive AF patients underwent first-time PFA under deep sedation. Patients eighter received ostial (ostial group; N = 15: 66 % paroxysmal AF; age: 69 years; 66 % male) or very wide antral (vWACA group; N = 22: 59 % paroxysmal AF; age: 62 years; 73 % male) PFA. Pre and post ablation LA voltage maps were acquired using a 20-pole spiral catheter together with a 3-dimensional electroanatomic mapping system (voltage cutoff ≤0.5 mV). On post ablation maps, lesion size by encircling the ablated area was measured. In all patients, 8 pulse trains (2kV/2.5 sec, bipolar, biphasic, 4x basket/flower configuration each) were delivered to each pulmonary vein (PV). In the vWACA-group, extra pulse trains in flower configuration were added to each PV in a wide antral position continuous intraluminal esophageal temperatures (TESO) were monitored with an S-shaped esophageal temperature probe. Results A median of 8 [IQR 8;8] and 10 [IQR 10;11] pulse trains per PV for ostial and vWACA PVI were applied. vWACA PFA resulted in significant larger lesion formation (47.3 cm2 [IQR 39.1; 52.0]) in comparison to ostial PFA (35.5 cm2 [IQR 30.3; 38.1], p=0.013) with consecutive posterior LA wall isolation in 19/22 (86 %) patients (Figure 1). In the vWACA group, median TESO increased by 0.7 °C (TESOmax 36.5 °C [IQR 36.0;36.9]). However, the vWACA approach was not associated with a significant increase in procedure time, sedation dosage or exposure to radiation. Conclusion Very wide antral circumferential PFA of the PVs is feasible and was associated with significant larger lesion formation in comparison to conventional ostial PFA. Concomitant posterior LA wall isolation occurred in the majority of patient and did not result in a clinically significant increase of intraluminal esophageal temperatures, procedure time, sedation and radiation dosage.

PC-578-03 RIGHT ATRIAL ATYPICAL FLUTTER WITH 2:1 INTRA-ATRIAL BLOCK MIMICKING LEFT ATRIAL FOCAL AND LOCALISED REENTRANT TACHYCARDIA

Atrial-level blocks are known confounders for diagnosis of SVTs and commonly occur after previous linear ablation lesions. 1. To demonstrate importance of recognition of atrial-level block in SVT diagnosis and treatment. 2. To review underlying assumptions in using entrainment to localize SVT origins. 3. To discuss the importance of thorough biatrial mapping in determination of unclear SVT mechanisms. N/A A 74y M with a history of bioprosthetic MV replacement, atypical RA flutter ablation (2018), and permanent pacemaker (2020) for sick sinus syndrome presented with fatigue and 76% AF/AT burden. For index RA ablation, both an intercaval line using bridging scar near the atriotomy site anterior to the appendage and a cavotricuspid isthmus line were made. Tachycardia was induced via burst pacing. Initial entrainment from CS suggested a L-sided tachycardia. A Pentaray map of the tachycardia showed LA anteroseptal reentry with entrainment at the site giving a PPI-TCL < 30ms. PVI and anteroseptal line were performed which changed cycle length but not CS activation. LA re-mapping demonstrated focal breakout near RIPV; ablation lengthened cycle length to 290ms without rhythm cessation. After PVI confirmation, mapping of the RA showed 2:1 intra-atrial conduction in the lateral RA with 1:1 conduction in the septal RA (fig A). Mapping 1:1 areas of RA conduction showed a gap in previous IVC line with intact CTI block with the majority of the cycle length at the posteroseptal floor (fig B), immediately opposite the site of initial LA anteroseptal reentry (fig C). During ablation of IVC line gap, progressive lengthening of the TCL was noted followed by termination of rhythm without inducibility (fig D). Response to entrainment assumes 1:1 conduction through the entire circuit, and contributed to the appearance of a left sided tachycardia upon initial CS entrainment. The finding of a LA RIPV tachycardia upon remapping the LA after PVI is consistent with a separate focal tachycardia but could represent epicardial connections from the CS to the posterior LA.

Abstract 9548: De Novo Atypical Atrial Flutters: Locations, Mechanisms, and Long Term Outcomes Post Ablation

Introduction: Atypical atrial flutter (aAFL) has been described in the absence of prior atrial interventions, but prognosis for these patients after catheter ablation is poorly defined. This study was designed to define characteristics and ablation outcomes in patients with de novo aAFL. Methods: Patients with non-CTI flutter, without prior ablation or cardiac surgery, were identified from an institutional database. Clinical, mapping, ablation, and follow up data were compared to an equally sized group of randomly selected patients with typical flutter (tAFL). Results: The 35 patients with aAFL had 45 mapped non-CTI flutters. aAFL patients had similar age, gender, cardiovascular comorbidities, and LA size compared to tAFL, except aAFL patients had higher LVEF (54 ± 12 vs 46 ± 19%, p=0.04). Cycle length of aAFL was longer (268 [IQR 231, 310] vs 230 [220, 250] msec, p=0.0006). aAFL localized to the RA in 16, LA in 28, and biatrial in 1. Mechanisms were macroreentry in 23 (8 RA, 15 LA) and localized reentry in 22 (8 RA, 14 LA). Areas of scar predominated in the lateral/posterior RA (N=9), anterior LA (N=14), and posterior LA (N=6). Most common LA circuits were perimitral reentry (N=8) and roof dependent (N=8), including dual loop reentry. Localized reentry occurred most commonly in the anterior LA (N=7) or involved the pulmonary veins (N=4). Ablation was acutely successful for 41/45 aAFLs (91%) and for all tAFL. After median follow-up of 33 [6.6, 55] mo, atrial arrhythmias recurred in 23/34 aAFL patients (68%) and 24/35 tAFL patients (69%); those with aAFL had earlier recurrences (1.9 [0.43, 11] vs 19 [2.3, 36] mo, p=0.01). First recurrences after aAFL ablation were more likely to be AFL rather than AF (83% vs 17%) whereas tAFL patients were more likely to recur with AF (24% AFL vs 76% AF, p&lt;0.0001). Conclusions: Patients with de novo aAFL tend to have spontaneous scar, commonly in the lateral/posterior RA and anterior LA, consistent with an atrial myopathy. Ablation can be accomplished with high acute success, but recurrent atrial arrhythmias are common, most re-presenting with atrial tachycardias. Future studies should clarify if a substrate-based approach or adjunctive antiarrhythmic drugs would result in better long term outcomes.

Catheter ablation of the left and right atrial appendages without isolation in persistent atrial fibrillation

Electrical isolation of the left atrial appendage (LAA) improves outcomes of patients with persistent atrial fibrillation (AF) but may increase the risk of thromboembolism. The purpose of this study was to describe a method to map and ablate appendage drivers without complete electrical isolation. One hundred thirteen patients underwent an ablation procedure for persistent AF. The procedure was performed during AF and consisted of pulmonary vein and posterior LA isolation as well as ablation of the LAA. The right atrium (RA) was targeted in patients with a right-to-left gradient in cycle length (CL). The end point of appendage ablation was CL slowing or AF termination but not complete isolation. Among the 113 patients (mean age 64.6 ± 8.6 years; ejection fraction 54% ± 13%; LA diameter 46 ± 6.5 mm), radiofrequency ablation terminated AF in 51 patients (45%). RA ablation was performed in 41 patients (36%) at the index or repeat procedure. The mean AF CL in the RA appendage (RAA) was shorter than that in the LAA (160 ± 32 ms vs 186 ± 29 ms; P < .01) in thesepatients. The most frequent target in the RA was the RAA (CLs approaching 50-60 ms). Discontinuing radiofrequency ablation upon AF termination or conduction slowing prevented LAA isolation. After a mean follow-up of 24 ± 15 months, 89 patients (78%) remained arrhythmia-free without antiarrhythmic medications. An ablation strategy guided by the AF CL addresses LAA drivers without complete electrical isolation and also helps identify the RAA as a source of persistent AF.

Standardised computed tomographic assessment of left atrial morphology and tissue thickness in humans.

AimsLeft atrial (LA) remodelling is a common feature of many cardiovascular pathologies and is a sensitive marker of adverse cardiovascular outcomes. The aim of this study was to establish normal ranges for LA parameters derived from coronary computed tomographic angiography (CCTA) imaging using a standardised image processing pipeline to establish normal ranges in a previously described cohort.MethodsCCTA imaging from 193 subjects recruited to the Budapest GLOBAL twin study was analysed. Indexed LA cavity volume (LACVi), LA surface area (LASAi), wall thickness and LA tissue volume (LATVi) were calculated. Wall thickness maps were combined into an atlas. Indexed LA parameters were compared with clinical variables to identify early markers of pathological remodelling.ResultsLACVi is similar between sexes (31 ml/m2 v 30 ml/m2) and increased in hypertension (33 ml/m2 v 29 ml/m2, p = 0.009). LASAi is greater in females than males (47.8 ml/m2 v 45.8 ml/m2 male, p = 0.031). Median LAWT was 1.45 mm. LAWT was lowest at the inferior portion of the posterior LA wall (1.14 mm) and greatest in the septum (median = 2.0 mm) (p < 0.001). Conditions known to predispose to the development of AF were not associated with differences in tissue thickness.ConclusionsThe reported LACVi, LASAi, LATVi and tissue thickness derived from CCTA may serve as reference values for this age group and clinical characteristics for future studies. Increased LASAi in females in the absence of differences in LACVi or LATVi may indicate differential LA shape changes between the sexes. AF predisposing conditions, other than sex, were not associated with detectable changes in LAWT.Clinical trial registration:http://www.ClinicalTrials.gov/NCT01738828.

Assessing the atrial substrate: electrograms from the coronary sinus can predict left atrial fibrosis

Abstract Background Left atrial fibrosis plays a key role regarding the success rate of pulmonary vein isolation for atrial fibrillation. It can be analyzed using LGE-MRI or invasive LA electroanatomical mapping. Assessing LA substrate prior to performing LA ablation procedures might help in optimizing the ablation approach. Method We analysed highdensity-electroanatomical maps of the left atrium derived by Carto 3 from 282 consecutive atrial fibrillation patients scheduled for RF pulmonary vein isolation (PVI). Maps were divided into 5 different anatomical areas and fibrosis was defined as local voltage &amp;lt;0.5mV. The extent of fibrosis was analyzed and compared with signal recordings from different positions of a diagnostic catheter positioned in the coronary sinus (CS) using Pearson correlation analysis. Results PVI was carried out in 282 patients (male 72%, mean age 63±10.8 years). A minimum of 1000 evenly distributed local electrograms were recorded in every patient. Significant LA fibrosis (&amp;gt;5%) was present in 54% of the patients with the maximum incidence of 100% at the anterior and 80% at the posterior wall. Signal amplituds in the proximal CS position significantly correlated with presence of LA fibrosis in the posterior LA (R 0.84, p&amp;lt;0.001), LA roof (R 0.65; p&amp;lt;0.001), left lateral (R 0.54; p&amp;lt;0.001), septal (R 0.47; p&amp;lt;0.001), and even LA anterior wall (R 0.56; p&amp;lt;0.001). Comparable results were found when using distal CS signals or a signal averaged over all individual CS signals. When used as a diagnostic tool, a CS amplitude &amp;lt;1.9mV could predict fibrosis at the posterior left atrial wall with a specificity of 97% and a sensitivity of 67% (PLR 24, AUC 0.91, 95% CI 0.87 - 0.95; p&amp;lt;0.001). A cut-off value of 1.9mV could be used to identify patients with only minimal LA fibrosis (&amp;lt;5%) with specificity of 88% and a sensitivity of 50% (PLR 4.2, AUC 0.81, 95% CI 0.71–0.89; p&amp;lt;0.001. Conclusion Voltage signals in the CS are significantly associated with presence of fibrosis in all left atrial areas. Moreover, CS voltage signals can be used to identify presence of significant left atrial extrapulmonary vein fibrosis and could help guiding left atrial ablation procedures and choice of ablation technique. Funding Acknowledgement Type of funding source: None

Early Follow-up After Colorectal Surgery Reduces Postdischarge Emergency Department Visits.

Thirty-day readmissions, emergency department visits, and observation stays are common after colorectal surgery (9%-25%, 8%-12%, and 3%-5%), yet it is unknown to what extent planned postdischarge care can decrease the frequency of emergency department visits. This study's aim was to determine whether early follow-up with the surgical team reduces 30-day emergency department visits. This retrospective cohort study used a central data repository of clinical and administrative data for 2013 through 2018. This study was conducted in a large statewide health care system (10 affiliated hospitals, >300 practices). All adult patients undergoing colorectal surgery were included unless they had a length of stay <1 day or died during the index hospitalization. Early (<10 days after discharge) versus late (≥10 days) follow-up at the outpatient surgery clinic, or no outpatient surgery clinic follow-up, was assessed. The primary outcome measured was the time to 30-day postdischarge emergency department visit. Our cohort included 3442 patients undergoing colorectal surgery; 38% of patients had an early clinic visit. Overall, 11% had an emergency department encounter between 11 and 30 days after discharge. Those with early follow-up had decreased emergency department encounters (adjusted HR 0.13; 95% CI, 0.08-0.22). An early clinic visit within 10 days, compared to 14 days, prevented an additional 142 emergency department encounters. Nationwide, this could potentially prevent 8433 unplanned visits each year with an estimated cost savings of $49 million annually. We used retrospective data and were unable to assess for health care utilization outside our health system. Early follow-up within 10 days of adult colorectal surgery is associated with decreased subsequent emergency department encounters. See Video Abstract at http://links.lww.com/DCR/B330. EL SEGUIMIENTO TEMPRANO DESPUÉS DE LA CIRUGÍA COLORRECTAL REDUCE LAS VISITAS AL SERVICIO DE URGENCIAS POSTERIOR AL ALTA: Los readmisión a los treinta días, las visitas al servicio de urgencias y las estancias de observación son comunes después de la cirugía colorrectal, 9-25%, 8-12% y 3-5%, respectivamente. Sin embargo, se desconoce en qué medida la atención planificada posterior al alta puede disminuir la frecuencia de las visitas al servicio de urgencias.Determinar si el seguimiento temprano con el equipo quirúrgico reduce las visitas a 30 días al servicio de urgencias.Este estudio de cohorte retrospectivo utilizó un depósito central de datos clínicos y administrativos para 2013-2018.Gran sistema de salud estatal (10 hospitales afiliados,> 300 consultorios).Se incluyeron todos los pacientes adultos de cirugía colorrectal a menos que tuvieran una estadía <1 día o murieran durante el índice de hospitalización.Temprano (<10 días después del alta) versus tardío (≥10 días) o sin seguimiento en la clínica de cirugía ambulatoria.Tiempo para la visita al servicio de urgencias a 30 días después del alta.Nuestra cohorte incluyó 3.442 pacientes de cirugía colorrectal; El 38% de los pacientes tuvieron una visita temprana a clínica. En total, el 11% tuvo un encuentro con el servicio de urgencias entre 11 y 30 días después de ser dado de alta. Aquellos con seguimiento temprano disminuyeron las visitas al servicio de urgencias (HR 0,13; IC del 95%: 0,08 a 0,22). Además, una visita temprana a la clínica en un plazo de 10 días, en comparación con 14 días, evitó 142 encuentros adicionales en el servicio de urgencias. A nivel nacional, esto podría prevenir 8.433 visitas no planificadas cada año con un ahorro estimado de $ 49 millones anuales.Utilizamos datos retrospectivos y no pudimos evaluar la utilización de la atención médica fuera de nuestro sistema de salud.El seguimiento temprano dentro de los 10 días de la cirugía colorrectal en adultos se asocia con una disminución de los encuentros posteriores en el servicio de urgencias. Consulte Video Resumen en http://links.lww.com/DCR/B330. (Traducción-Dr. Gonzalo Hagerman).

Hot balloon versus cryoballoon ablation for persistent atrial fibrillation: Lesion area, efficacy, and safety.

The clinical efficacy and safety of hot balloon ablation (HBA) for the treatment of persistent AF (PerAF) remain unclear. We aimed to evaluate the clinical efficacy and safety of HBA versus cryoballoon ablation (CBA) as a treatment for PerAF. Of 195 consecutive patients who underwent initial catheter ablation for PerAF (AF lasting for longer than7 days but shorter than 12 months), 158 propensity score-matched (79 HBA and 79 CBA) patients were included in our retrospective study. All patients who underwent HBA received applications of energy to the upper posterior LA wall with a larger balloon in addition to single shots to each pulmonary vein (PV) ostium, whereas those who underwent CBA received simple single-shot applications. The electrically isolated surface area (ISA), including the PV antrum and part of the posterior LA wall, was assessed by high-resolution mapping. The success of the PV isolation with balloon shots alone did not differ between HBA and CBA (81% vs. 85%; p = .52). The ISA was generally wide in both groups and significantly larger in the HBA group than in the CBA group (61 ± 16% vs. 51 ± 12%; p < .001). The incidence of procedure-related complications did not differ significantly (HBA 4% vs. CBA 1%; p = .62) nor did the arrhythmia recurrence rate (HBA 11% vs. CBA 18% at 18 months; p = .26). Despite the difference in protocols, HBA and CBA performed for PerAF appear comparable in terms of wide antral lesion creation, clinical efficacy, and safety. Further prospective studies, based on a unified methodology, are needed.

55Non-invasive ECG-imaging for identification of atrial arrhythmogenic low voltage substrate in patients with persistent atrial fibrillation

Abstract Background/Introduction Left atrial (LA) fibrosis is associated with increased arrhythmia recurrence rates after pulmonary vein isolation (PVI) and increased stroke risk in patients with atrial fibrillation (AF). So far, detection and quantification of LA fibrosis is only feasible by invasive electrophysiological mapping of low-voltage-substrate (LVS) or delayed enhancement areas in MRI. Purpose The aim of this study was to assess the distribution and extent of atrial fibrosis by non-invasive ECG-Imaging (ECGI) in patients with persistent AF prior to PVI. Methods Thirty-seven consecutive patients (66 ± 9 years, 84% male) presenting for their first PVI were included. Patients with AF were cardioverted into sinus rhythm (SR). One day prior to AF ablation procedure, patients underwent ECGI in SR using the 252-electrode-array (CardioInsight) and a low-X-ray-dose, non-injected cardiac CT-scan to assess the relationship between ECGI-electrodes and cardiac epicardial structures. Prior to PVI, high-density biatrial voltage and activation maps were acquired in SR (CARTO-3). Localization and extent of atrial LVS (relevant fibrosis: LA-LVS: ≥5cm2 at &amp;lt;0.5mV threshold) and biatrial activation times depicted by CARTO were compared with atrial activation/conduction times assessed by non-invasive ECGI. Presence of LA-LVS was classified according to its extent into 3 stages and compared to the inter- and intraatrial conduction delay in ECGI. Results Relevant atrial fibrosis was found in 17/37(46%) patients. Presence of biatrial LVS resulted in a linear increase of the biatrial activation time in CARTO-SR-maps (146 ± 18ms in patients without LVS vs 184 ± 27ms in patients with LVS, p &amp;lt; 0.001) and in non-invasive ECGI (133 ± 11ms vs 170 ± 20ms, p &amp;lt; 0.001). Both the extent of biatrial LVS and invasively measured total activation time correlated well with non-invasive total atrial conduction time (TACT) in ECGI (r = 0.91 and r = 0.82, respectively, figure). Moreover, the extent of LA-LVS showed an excellent correlation to TACT in ECGI (r = 0.89). A combination of inter-atrial (RA-LA) conduction delay and TACT in ECGI allowed to quantify the extent of LA-LVS and to distinguish between three stages of LA-LVS: Stage 1 (minimal LA-LVS: 1 ± 2cm2): ECGI revealed rapid RA&amp;LA activation with short TACT 132 ± 9ms; Stage 2 (moderate LA-LVS: 14 ± 8cm2 involving the anteroseptal LA) was associated with delayed LA activation and prolonged TACT measuring 161 ± 7ms; Stage 3 (extensive LA-LVS involving the anteroseptal and posterior LA: 26 ± 17cm2) was characterized by a significantly delayed LA activation with a TACT of 178 ± 24ms in ECGI. Conclusion Analysis of interatrial conduction delay and total atrial conduction time (TACT) in non-invasive ECGI allows accurate staging of patients with arrhythmogenic atrial LVS who present an increased risk for arrhythmia recurrences and stroke. Abstract Figure.

Perioperative neonatal brain injury is associated with worse school‐age neurodevelopment in children with critical congenital heart disease

To assess the impact of perioperative neonatal brain injury and brain volumes on neurodevelopment throughout school-age children with critical congenital heart disease (CHD). Thirty-four survivors of neonatal cardiac surgery (seven females, 27 males) were included. Neonatal preoperative and postoperative cerebral magnetic resonance imaging was performed and neurodevelopment was assessed at 24months (SD 0.7, n=32, using Bayley Score of Infant and Toddler Development, Child Behavior Checklist) and 6years (mean age 5y 11mo; SD 0.3, n=30, using Movement Assessment Battery for Children, Wechsler Preschool and Primary Scale of Intelligence, Child Behavior Checklist, Teacher Report Form). Brain injury, brain volumes, and cortical measures were related to outcome with adjustment for maternal educational level. Two-year cognitive score and 6-year Full-scale IQ were poorer in children with neonatal white matter injury (n=21, all p<0.05), with higher teacher-reported attention problems (p=0.03). Five of six children with involvement of the posterior limb of the internal capsule showed motor problems (p=0.03). Children with a below-average Fulll-scale IQ (<85, n=9) showed smaller volumes of basal ganglia thalami (-8%, p=0.03) and brain stem (-7%, p=0.03). Our findings provide evidence of unfavourable outcome in school-age children with critical CHD who acquire perioperative neonatal brain injury. This paper extends knowledge about neonatal brain injury and long-term outcome in congenital heart disease. Children with white matter injury show lower IQ and more attention problems at school age. Injury of the posterior limb of the internal capsule increases the risk of motor problems. This study provides evidence for worse outcomes in neonates acquiring brain injury around cardiac surgery.