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Introduction: Strategies beyond pulmonary vein isolation (PVI) in persistent atrial fibrillation (persAF) are debated. A novel mapping tool provides algorithmic detection of ablation targets based on electrogram (EGM) properties specific to stable localized rotational activations. Methods: The mapping tool was used on 31 patients (20 de novo). The algorithm was used to optimize PVI line placement and guide additional ablations. Targets were detected by calculating local cycle length (L‐CL) and local spread of activation within that L‐CL (Duty Cycle; DC) for EGMs with consistent morphology and activation. At least two left atrial (LA) maps (pre‐PVI and post‐PVI) were acquired in atrial fibrillation (AF) in all patients (except those with AF termination during PVI). Extra‐pulmonary vein (PV) targets were compared between the two LA maps in each patient. Follow‐up included Holter monitoring every 3 months. Results: Patients had a median of 3 extra‐PV drivers/targets. The majority (81%) were localized in the same areas between the two LA maps. All patients had progressive AF organization demonstrated by global activation slowing: histogram peak L‐CL increased from 162 to 171 ms (post‐PVI; p =.0003) than to 175 ms (posttarget ablation; p =.04). Moreover, L‐CL dispersion was reduced by ablation; in 50% their values tended to cluster around two dominant cycles. In de novo patients AF terminated to sinus rhythm or atrial tachycardia (AT) within 48 h postprocedure in 88% of cases, and at 18 months mean follow‐up recurrence occurred in only five (25%) patients (three persAF, two AT). There were no complications. Conclusion: The algorithmic detection of EGMs consistent with localized reentry during sequential mapping of persAF provided reproducible targets for ablation. This allowed personalized PVI and limited, highly‐selective, extra‐PV ablation. Results of this initial experience included progressive organization of AF with ablation and a low recurrence rate after a single procedure. [ABSTRACT FROM AUTHOR]

No study has assessed the durability of pulmonary vein isolation (PVI) with radiofrequency (RF) and cryoballoon (CB) in patients with persistent atrial fibrillation. These data are especially lacking for those with significantly diseased left atria (LA). The goals of this study were to assess PVI durability in patients with significant LA disease and to compare reconnection rates between RF and CB. Forty-four patients (mean age 63 years; 34 (77%) male; median time since atrial fibrillation diagnosis 22.5 months; median indexed LA volume 36 mL/m2) were randomized 1:1 to RF or CB PVI. A redo procedure using ultra-high-density electroanatomic mapping was mandated at 2 months, where PV reconnections were identified and reisolated. Thirty-eight patients underwent both procedures (CB n = 17; RF n = 21). Index RF procedures were longer (median 158 minutes vs 97 minutes; P <.001) but required less fluoroscopy (9.5 minutes vs 23 minutes; P <.001). At the index RF procedure, a median of 47% of LA myocardium had voltage < 0.5 mV, suggesting that half of the mapped LA comprised scar. PV reconnection was observed in 73 of 152 PVs (48.0%) and was more frequent with CB (58.8%) than with RF (39.3%) (P =.022). Reconnection of at least 1 PV was detected in >75% of patients. Significantly more ablation was required during the redo procedure to reisolate PVs in the CB arm (median 10.8 minutes vs 1.2 minutes; P <.001). PVI durability may be poor in those with significant LA scarring and dilatation, even with modern thermal ablation technologies. RF resulted in significantly better PVI durability than did CB in this complex population. [ABSTRACT FROM AUTHOR]

Background: Ultra-high-density mapping systems allow more precise measurement of the heart chambers at corresponding conduction velocities (CVs) and voltage amplitudes (VAs). Our aim for this study was to define and compare a basic value set for unipolar CV and VA in all four heart chambers and their separate walls in healthy, juvenile porcine hearts using ultra-high-density mapping. Methods: We used the Rhythmia Mapping System to create electroanatomical maps of four pig hearts in sinus rhythm. CVs and VAs were calculated for chambers and wall segments with overlapping circular areas (radius of 5 mm). Results: We analysed 21 maps with a resolution of 1.4 points/mm2. CVs were highest in the left atrium (LA), followed by the left ventricle (LV), right ventricle (RV), and right atrium (RA). As for VA, LV was highest, followed by RV, LA, and RA. The left chambers had a higher overall CV and VA than the right. Within the chambers, CV varied more in the right than in the left chambers, and VA varied in the ventricles but not in the atria. There was a slightly positive correlation between CVs and VAs at velocity values of <1.5 m/s. Conclusions: In healthy porcine hearts, the left chambers showed higher VAs and CVs than the right. CV differs mainly within the right chambers and VA differs only within the ventricles. A slightly positive linear correlation was found between slow CVs and low VAs. [ABSTRACT FROM AUTHOR]

Abstract New tools of mapping systems may allow to detect residual conduction around the atriotomy and could eliminate the subjectivity of the human eye, analyzing thousands of electrograms in a matter of seconds and providing a clear and fast identification.

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New tools of mapping systems may allow to detect residual conduction around the atriotomy and could eliminate the subjectivity of the human eye, analyzing thousands of electrograms in a matter of seconds and providing a clear and fast identification. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study was to investigate electrophysiological findings in patients with arrhythmia recurrence undergoing a repeat ablation procedure using ultra–high‐density (UHDx) mapping following an index procedure using either contact–force (CF)‐guided radiofrequency current (RFC) pulmonary vein isolation (PVI) or second‐generation cryoballoon (CB) PVI for treatment of atrial fibrillation (AF). Methods and Results: Fifty consecutive patients with recurrence of AF and/or atrial tachycardia (AT) following index CF‐RFC PVI (n = 21) or CB PVI (n = 29) were included. A 64‐pole mini‐basket mapping catheter in combination with an UHDx‐mapping system‐guided ablation was used. RFC was applied using a catheter tip with three incorporated mini‐electrodes. PV reconnection rates were higher after CF‐RFC PVI (CF‐RFC: 2.5 ± 1.3 PVs vs CB: 1.4 ± 0.9 PVs; P =.0025) and left PVs were more frequently reconnected (CF‐RFC: 64% PVs vs CB: 35% PVs; P =.0077). Fractionated signals along the antral index ablation line (FS) were found in 30% of CB‐PVI patients (CF‐RFC: 9.5% vs CB:30%; P =.098) targeted for ablation. In five cases, FS were a critical part of maintaining consecutive AT. The main AT mechanism found during reablation (n = 45 ATs) was macroreentry (80% [36/45], CF‐RFC: 78.9% vs CB: 80.8%; P = 1.0) with a variety of circuits throughout both atria. Conclusion: UHDx mapping is sensitive in detecting conduction gaps along the index ablation line. Left PVs are more frequently reconnected after initial CF‐RFC PVI. FS are a common finding after CB PVI and can maintain certain forms of ATs. ATs after index PVI are mostly macroreentries with a broad spectrum of entities. [ABSTRACT FROM AUTHOR]

Background: Whether unidirectional conduction block (UB) can be observed after creation of a radiofrequency (RF) line is still debated. Previous studies reported a prevalence of 9 to 33% of UB, but the assessment was performed using a point-by-point recording across the line. Ultra-high-density (UHD) system may bring some new insights on the exact prevalence of UB. Purpose: A prospective study was conducted to assess the prevalence of UB and bidirectional block (BB) using UHD system after RF line creation. Methods: Patients referred for atrial RF ablation procedure were included in this multicenter prospective study. UHD maps were performed by pacing both sides of the created line. Results: A total of 80 maps were created in 40 patients (67 ± 12 years, 70% male) by pacing (mean cycle length 600 ± 57 ms) from both sides of the cavotricuspid isthmus line. After a 47 ± 17 min waiting time after the last RF application, UHD maps (mean number of 4842 ± 5010 electrograms, acquired during 6 ± 5 min) showed that BB was unambiguously confirmed on all of them. UB was not observed in any map. After a mean follow-up of 12 ± 4 months, 6 (14%) patients experienced an arrhythmia recurrence. Conclusion: After creation of an RF line, no case of UB was observed using UHD mapping, suggesting that the presence of a conduction block along a RF line is always associated with a block in the opposite direction. [ABSTRACT FROM AUTHOR]

Premature atrial complexes (PACs) are a common finding in patients with structural heart disease, as well as in healthy subjects. In addition to the clinical spectrum ranging from asymptomatic patients to irritating palpitations, PACs are suggested to be associated with an increased risk of atrial fibrillation and stroke. Medical treatment leads to a significant reduction in PACs with clear symptom relief in a large proportion of patients, but is limited in cases of PACs that are refractory to antiarrhythmic drug (AAD) treatment. Furthermore, proarrhythmic effects of AAD or the patient's refusal of AAD treatment due to side effects need to be considered. Ablation of PACs is a good alternative to medical therapy with a comparable safety profile and at least comparable efficacy. In recent years, ultra-high-density (UHD) mapping with multiple improvements for successful ablation has been evolving. Before the introduction of UHD mapping, ablation strategies included activation mapping with single-tip catheters or conventional mapping aiming for the earliest activation of the PAC locally, with the earliest activation suspected to be the origin of the PAC and targeted by radiofrequency (RF) ablation. Using UHD mapping, a three-dimensional local activation map of the atrium can be acquired, identifying the point of earliest activation within the high-resolution map. PAC ablation has therefore developed into a true alternative for the treatment of symptomatic PACs.

An 18-year-old male who had a past medical history of an intracardiac total cavopulmonary connection (TCPC) operation was referred to our hospital for radiofrequency catheter ablation (RFCA) of supraventricular tachycardia (SVT). Two types of SVTs were induced, and 3-dimensional (3D) maps were created using an ultra-high-density 3-dimensional mapping system (Rhythmia). The earliest atrial activation site (EAAS) of SVT1 was at the superior part of the conduit, and the EAAS of SVT2 was at the inferior part of the single atrium (SA). The SVTs were terminated by energy deliveries to the EAAS from the conduit in SVT1 and from inside the single atrium in SVT2. Detailed maps of the SVTs were important to understand the mechanisms of the SVTs. The Rhythmia system was useful for the detailed mapping of complex arrhythmias. The use of Rhythmia in patients after a TCPC is difficult, because puncturing the TCPC conduit and proceeding and manipulating the Orion catheter via a narrow puncture hole are difficult. We were the first to succeed in ablating two atrial tachycardias (ATs) originating from the inside and outside of the conduit after a TCPC operation by using an ultra-high-density 3-dimensional mapping system.