Narrow QRS ectopy with concealed connections from a para-Hisian origin to the proximal left fascicles.

INTRODUCTION: Catheter ablation of ectopy originating from the vicinity of the His bundle can be challenging. METHODS AND RESULTS: We report a case of a 33-year-old man with narrow QRS ectopy with preferential conduction from a para-Hisian origin to the proximal left fascicles, which was successfully eliminated by radiofrequency ablation in the right coronary cusp, guided by ultrahigh-resolution mapping of the His bundle, bundle branch, and fascicular electrograms. CONCLUSION: Some narrow QRS ectopy may originate from the vicinity of the conduction system, instead of the "true" conduction system, and have concealed connections from its origin to the conduction system.

The optimal slow pathway ablation site in atrioventricular nodal reentrant tachycardia cases with an inferiorly located His bundle.

INTRODUCTION: The optimal slow pathway (SP) ablation site in cases with an inferiorly located His bundle (HIS) remains unclear. METHODS AND RESULTS: In 45 patients with atrioventricular nodal reentrant tachycardia, the relationship between the HIS location and successful SP ablation site was assessed in electroanatomical maps. We assessed the location of the SP ablation site relative to the bottom of the coronary sinus ostium in the superior-to-inferior (SPSI), anterior-to-posterior (SPAP), and right-to-left (SPRL) directions. The HIS location was assessed in the same manner. The HIS location in the superior-to-inferior direction (HISSI), SPSI, SPAP, and SPRL were 17.7 ± 6.4, 1.7 ± 6.4, 13.6 ± 12.3, and -1.0 ± 13.0 mm, respectively. The HISSI was positively correlated with SPSI (R2 = 0.62; P < .01) and SPAP (R2 = 0.22; P < .01), whereas it was not correlated with SPRL (R2 = 0.01; P = .65). The distance between the HIS and SP ablation site was 17.7 ± 6.4 mm and was not affected by the location of HIS. The ratio of the amplitudes of atrial and ventricular potential recorded at the SP ablation site did not differ between the high HIS group (HISSI ≥ 13 mm) and low HIS group (HISSI < 13 mm) (0.10 ± 0.06 vs. 0.10 ± 0.06; P = .38). CONCLUSION: In cases with an inferiorly located HIS, SP ablation should be performed at a lower and more posterior site than in typical cases.

Ethanol infusion therapy for peri-mitral atrial tachycardia through the Marshall bundle with electrical irrelevance of left atrial appendage and mitral isthmus.

A 62-year-old man with a history of catheter ablation for atrial fibrillation and atrial tachycardia (AT) received a line of block of the mitral isthmus (MI) and electrical isolation of the left atrial appendage (LAA). Upon entrainment pacing, AT recurred and was diagnosed as peri-mitral AT (PMAT) with electrical irrelevance of MI, LAA, and left pulmonary vein, having a critical isthmus identified as Marshall bundle (MB). MB was then infused with ethanol, leading to the successful treatment of the PMAT.

Intra-septal radiofrequency ablation within the transseptal puncture hole targeting an interatrial connection during a bi-atrial tachycardia.

A 74-year-old man after multiple mitral valve surgeries underwent catheter ablation of a bi-atrial tachycardia (BiAT). Ultra-high resolution activation mapping exhibited a reentrant circuit propagating around the inferior to anterior mitral annulus and right atrial (RA) septum with two interatrial connections. At the transeptal puncture site, continuous fractionated electrograms were recorded during the BiAT, and entrainment pacing revealed a post-pacing interval similar to the tachycardia cycle length, which suggested that the interatrial conduction from the RA to the left atrium (LA) was located just at the transseptal puncture site. A radiofrequency application inside the transseptal puncture hole could successfully eliminate the BiAT. The ablation target for BiATs propagating around the mitral annulus and RA septum is generally the anatomical mitral isthmus (MI). Since the present case had multiple incisions on both the RA and LA septum due to mitral valve surgeries, there was the possibility of the occurrence of a BiAT including the RA and LA septum after performing an MI linear ablation. Therefore, the preferable ablation target for the BiAT in the present case appeared to be the interatrial connection. Ultra-high resolution detailed mapping not only on the atrial endocardium but also in the transseptal puncture hole may be useful for identifying a critical interatrial connection of BiAT circuits.

Intra-carina reentrant atrial tachycardia after pulmonary vein isolation of atrial fibrillation.

A 77-year-old man underwent catheter ablation of an atrial tachycardia (AT) after a pulmonary vein (PV) isolation of atrial fibrillation. The AT appeared to be a figure-of-eight reentrant AT by high-resolution mapping: one reentrant circuit rotated clockwise within the right PV (RPV) carina and the other rotated counterclockwise via two conduction gaps along the previous RPV isolation line. However, entrainment pacing from the carina and conduction gaps suggested that the AT was an intra-carina localized reentrant AT with a passive loop around the anterior RPV isolation line via those gaps. A radiofrequency application at the RPV carina terminated the AT.

Ambulatory electrocardiographic markers predict serious cardiac events in patients with chronic kidney disease: The Japanese Noninvasive Electrocardiographic Risk Stratification of Sudden Cardiac Death in Chronic Kidney Disease (JANIES-CKD) study.

BACKGROUND: Noninvasive electrocardiographic markers (NIEMs) are promising arrhythmic risk stratification tools for assessing the risk of sudden cardiac death. However, little is known about their utility in patients with chronic kidney disease (CKD) and organic heart disease. This study aimed to determine whether NIEMs can predict cardiac events in patients with CKD and structural heart disease (CKD-SHD). METHODS: We prospectively analyzed 183 CKD-SHD patients (median age, 69 years [interquartile range, 61-77 years]) who underwent 24-h ambulatory electrocardiographic monitoring and assessed the worst values for ambulatory-based late potentials (w-LPs), heart rate turbulence, and nonsustained ventricular tachycardia (NSVT). The primary endpoint was the occurrence of documented lethal ventricular tachyarrhythmias (ventricular fibrillation or sustained ventricular tachycardia) or cardiac death. The secondary endpoint was admission for cardiovascular causes. RESULTS: Thirteen patients reached the primary endpoint during a follow-up period of 24 ± 11 months. Cox univariate regression analysis showed that existence of w-LPs (hazard ratio [HR] = 6.04, 95% confidence interval [CI]: 1.4-22.3, p = .007) and NSVT [HR = 8.72, 95% CI: 2.8-26.5: p < .001] was significantly associated with the primary endpoint. Kaplan-Meier analysis demonstrated that the combination of w-LPs and NSVT resulted in a lower event-free survival rate than did other NIEMs (p < .0001). No NIEM was useful in predicting the secondary endpoint, although the left ventricular mass index was correlated with the secondary endpoint. CONCLUSION: The combination of w-LPs and NSVT was a significant risk factor for lethal ventricular tachyarrhythmias and cardiac death in CKD-SHD patients.

Antiphospholipid Syndrome Diagnosed as a Result of the Occurrence of an Ischemic Stroke After a Successful Catheter Ablation of Atrial Fibrillation and Continuous Direct Oral Anticoagulants.

We report a case of an ischemic stroke after a successful catheter ablation of atrial fibrillation (AF) and continuous oral anticoagulation therapy with direct oral anticoagulants (DOACs), which was the trigger for diagnosing antiphospholipid syndrome (APS). A 68-year-old woman underwent catheter ablation of persistent AF and continued oral anticoagulation with edoxaban at a dose of 30 mg once daily after the ablation procedure. An asymptomatic intracerebral hemorrhage was detected by brain computed tomography and magnetic resonance imaging one month post-ablation. Oral anticoagulation with dabigatran at 110 mg twice daily was continued thereafter due to a high stroke risk profile of a CHA2D2-VASc score of 3. Eight months after the procedure, the patient had multiple acute cerebral infarctions despite no apparent recurrence of atrial tachyarrhythmias and continuation of the DOAC. A blood examination revealed the presence of anti-cardiolipin-beta2-glycoproteion complex antibodies and lupus anticoagulants, and the patient was diagnosed with primary APS. The DOAC was changed to warfarin. The patient has remained free from any ischemic or hemorrhagic cerebral events for 11 months after the oral anticoagulants were changed. The ischemic stroke in the present case appeared to be associated with APS rather than AF. A diagnosis of APS may be extremely crucial in AF patients who have new-onset ischemic strokes under continuous administration of DOACs, because vitamin K antagonists are more effective for the prevention of APS-related ischemic strokes than DOACs.

Bilateral Cardiac Sympathetic Denervation for Treatment-Resistant Ventricular Arrhythmias in Heart Failure Patients with a Reduced Ejection Fraction.

The sympathetic nervous system plays an important role in life-threatening ventricular arrhythmias (VAs). Bilateral cardiac sympathetic denervation (BCSD) is performed for refractory VAs. We sought to assess our institutional experience with BCSD in managing treatment-resistant monomorphic ventricular tachycardia (MMVT) in heart failure patients with a reduced ejection fraction (HFrEF).Four patients with HFrEF (EF 30.0 ± 8.2%, New York Heart Association [NYHA] class IV 1) underwent BCSD for MMVT (VT storm 3, repetitive VT requiring implantable cardioverter defibrillator [ICD] therapy 1) refractory to antiarrhythmic drugs, catheter ablation and ICD therapy. BCSD was effective for suppressing VT in 3 patients for whom deep sedation was effective for suppressing VT. One patient remained alive after 14 months of follow-up without episodes of VT. One patient died of acute myocardial infarction before discharge and 1 patient died from unknown cause at 3 days post-discharge. In contrast, BCSD was completely ineffective for suppressing VT in a patient with NYHA class IV for whom deep sedation and stellate ganglion block were ineffective. This patient died on the 10th post-CSD day, despite left ventricular assist device implantation. In all cases, BCSD was successfully performed without procedure-related complications.Despite the limited number of cases, our results showed that BCSD in patients with HFrEF suppressed refractory MMVT in acute-phase except for a patient with NYHA class IV; however, the prognoses were not good. BCSD may be a treatment option at an earlier stage of NYHA and a bridge to orthotopic heart transplantation, even if BCSD is effective for suppressing VAs.

A confluent non-enhanced dark core on serial late gadolinium enhancement imaging after a moderator band-ventricular tachycardia ablation.

A 77-year-old man underwent radiofrequency catheter ablation of incessant ventricular arrhythmias (VAs) originating from the right ventricular (RV) moderator band (MB). Activation mapping during the VAs exhibited a centrifugal pattern with the earliest activation site (EAS) on the RV septum. A local impedance (LI)-guided radiofrequency application targeting the EAS with a maximum power output of 50W successfully eliminated the VAs and resulted in an LI drop of up to 35 Ω. Late gadolinium enhancement magnetic resonance imaging (LGE-MRI) on the day after the ablation procedure demonstrated a confluent non-enhanced dark core on the RV septal portion of the MB. On the LGE-MRI two months after the procedure, the dark core region became contracted and instead the peripheral region surrounding the dark core exhibited a bright enhancement. The size of the dark core and peripheral enhanced regions on the LGE-MRI remained almost unchanged two months to two years after the procedure. He had no VA recurrences during a two-year follow-up period. Previous LGE-MRI studies reported that an ablated area within healthy ventricular myocardium exhibits a bright homogenous enhancement during the post-ablation chronic phase, while that within ventricular scar tissue exhibits a confluent non-enhanced dark core. This case suggested the presence of a dark core with a peripheral enhancement corresponding to the ablated area within the healthy myocardium of the RV-MB. LGE-MRI may be useful for accurately detecting RF ablation lesions on the RV-MB and visualizing the serial changes in the LGE-MRI characteristics from the post-ablation acute to chronic phases.

Prevalence, characteristics, and predictors of endocardial and nonendocardial conduction gaps during local impedance-guided extensive pulmonary vein isolation of atrial fibrillation with high-resolution mapping.

INTRODUCTION: Local impedance (LI) drops during radiofrequency ablation can predict lesion formation. Some conduction gaps during pulmonary vein isolation (PVI) can be associated with nonendocardial connections. This study aimed to investigate the incidence, characteristics, and predictors of endocardial and nonendocardial conduction gaps during an LI-guided PVI. METHODS AND RESULTS: We prospectively enrolled 157 consecutive patients undergoing an initial LI-guided extensive PVI of atrial fibrillation (AF). After the first-pass encirclement, the residual conduction gaps and reconnected gaps were mapped using Rhythmia (Boston Scientific) and a mini-basket catheter. Right and left PV (RPV/LPV) gaps were observed in 22.3% and 18.5% of the patients, respectively: 27 endocardial and 49 nonendocardial gaps. The carina regions were common sites for the gaps (51 carina-related vs. 25 noncarina-related). The carina-related gaps consisted of more nonendocardial gaps than endocardial gaps (RPVs: 90.0% vs. 10.0%, p = .001; LPVs: 76.2% vs. 23.8%, p < .001). A univariate analysis revealed that paroxysmal AF and the left atrial (LA) volume index for RPV endocardial gaps (odds ratio [OR]: 8.640 and 0.946; p = .043 and 0.009), minor right inferior PV diameter for RPV nonendocardial gaps (OR: 1.165; p = .028), and major left inferior PV diameter for LPV endocardial gaps (OR: 1.233; p = .028) were significant predictors. CONCLUSIONS: During the LI-guided PVI, approximately two-thirds of the conduction gaps were nonendocardial. The carina regions had more conduction gaps than noncarina regions, which was due to the presence of nonendocardial connections. Paroxysmal AF, a lower LA volume index, and larger inferior PV diameters may increase the risk of conduction gaps.

Incidence and characteristics of silent cerebral embolisms after radiofrequency-based atrial fibrillation ablation: A propensity score-matched analysis between different mapping catheters and indices for guiding ablation.

INTRODUCTION: The difference in the incidence and characteristics of silent cerebral events (SCEs) after radiofrequency-based atrial fibrillation (AF) ablation between the different mapping catheters and indices used for guiding radiofrequency ablation remains unclear. This study aimed to compare the incidence and characteristics of postablation SCEs between the following two groups: Group C, Ablation Index-guided ablation using two circular mapping catheters with CARTO (Biosense Webster); Group R, local impedance-guided ablation using one mini-basket catheter and one circular mapping with Rhythmia (Boston Scientific). METHODS AND RESULTS: Of 211 consecutive patients who underwent an AF ablation and brain magnetic resonance (MR) imaging after the ablation, 120 patients (each group, n = 60) were selected by propensity score matching. SCEs were detected in 37 patients (30.8%). Group R had a higher incidence of SCEs (51.7% vs. 10.0%; p < .001) and more SCEs per patient (median, 3 vs. 1, p = .028) than Group C. A multivariate analysis demonstrated that nonparoxysmal AF and being Group R were independent positive predictors of SCEs (odds ratios, 6.930 and 15.464; both p < .001). On the follow-up MR imaging, all SCEs in Group C and 87.9% of the SCEs in Group R disappeared (p = .537). CONCLUSIONS: Group R had a significantly higher incidence of SCEs than Group C. Most probably the use of a complexly designed basket mapping catheter is the reason for the difference in the incidence of SCEs but further validation is needed. A nonparoxysmal form of AF may also increase the risk of SCEs during these ablation procedures.

Effect of preventing air intrusion on silent strokes during atrial fibrillation ablation using a mini-basket catheter.

BACKGROUND: Air bubble intrusion through transseptal sheaths during left atrial (LA) catheter ablation can cause cerebral embolisms, especially when using complex-shape catheters. This study aimed to compare the incidence of silent cerebral events (SCEs) after atrial fibrillation (AF) catheter ablation using a mini-basket catheter (IntellaMap Orion; Boston Scientific) between the following groups: group SP, strict prevention of LA air intrusion and group CP, conventional air intrusion prevention. METHODS: We enrolled 123 consecutive AF patients (group SP, n = 61 and group CP, n = 62) who underwent brain magnetic resonance imaging after a local-impedance-guided ablation using one mini-basket catheter and one circular mapping catheter. The preventive strategy in group SP included (a) the insertion of the mini-basket catheter into the transseptal sheaths in a container filled with heparinized saline and (b) no exchange of all catheters over the sheaths. RESULTS: SCEs were detected in 67 patients (54.5%), and the incidence of SCEs did not significantly differ between groups SP and CP (55.7% vs 53.2%; P = .780). A multivariate analysis demonstrated that an older age, non-paroxysmal AF, and radiofrequency (RF) power output were independent positive predictors of SCEs (odds ratios: 1.079, 5.613, and 1.405; P = .005, <.001, and .012). On the follow-up MR imaging, 83.5% of the SCEs in group SP and 87.7% in group CP disappeared (P = .398). CONCLUSIONS: Strict prevention of LA air intrusion may have no additional effect for reducing the incidence of SCEs after local impedance-guided AF ablation using a mini-basket catheter. An older age, non-paroxysmal AF, and high-power RF applications may increase the risk of SCEs.

Impact of the size of non-ablated left atrial posterior wall area on outcomes after extensive encircling pulmonary vein isolation.

The aim of this study was to evaluate the impact of the size of the isolated surface area and non-ablated left atrial posterior area after extensive encircling pulmonary vein isolation (EEPVI) for non-paroxysmal atrial fibrillation (AF) on arrhythmia recurrence. This study included 132 consecutive persistent AF patients who underwent EEPVI guided by Ablation Index (AI). The isolated antral surface area (IASA) excluding the pulmonary veins, the non-ablated left atrial (LA) posterior wall surface area (PWSA), the ratio of IASA to LA surface area (IASA/LA ratio), and the ratio of PWSA to LA surface area (PWSA/LA ratio) were assessed using CARTO3 and the association with AF and atrial tachycardia (AT) recurrence was examined. At a mean follow-up of 13.2 ± 7.3 months, sinus rhythm was maintained in 115 (87%) patients. In the univariate Cox regression analysis, the factors that significantly predicted AT/AF recurrence were a history of heart failure, a higher CHA2DS2-VASc score, a larger LA diameter, and a larger PWSA/LA ratio. Multivariate Cox regression analysis revealed that the independent predictors of AT/AF recurrence were LA diameter [hazard ratio (HR) 1.120 per 1 mm increase; 95% confidence interval (CI) 1.006-1.247; P = 0.039] and PWSA/LA ratio (HR 1.218 per 1% increase; 95% CI 1.041-1.425; P = 0.014). Receiver operating characteristics curve analysis yielded an optimal cut-off value of 8% for the PWSA/LA ratio. The Kaplan-Meier survival curve showed that patients with a larger PWSA/LA ratio had poorer clinical outcomes (Log-rank P = 0.001). A larger PWSA/LA ratio was associated with a high AT/AF recurrence rate in patients with non-paroxysmal atrial fibrillation.

Hypertrophic Cardiomyopathy Complicated by Cardiac Sarcoidosis Diagnosed by Both the Morphological Abnormalities and the Time Course of the Disease.

The definite diagnosis of cardiac sarcoidosis (CS) can be difficult because it mimics other cardiomyopathies and morphological abnormalities during its time course. Distinguishing CS isolated cardiac sarcoidosis from other cardiomyopathies is very important for the introduction of immunosuppressive therapy.In this study, we report a patient who had initially been diagnosed with hypertrophic obstructive cardiomyopathy (HOCM). The patient developed complete atrioventricular block (CAVB) and morphological abnormalities, which led to his primary diagnosis being re-conducted. Moreover, we made a definite diagnose of isolated CS (ICS) based on the guideline for the diagnosis and treatment using 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT)1) and performed tailor-made treatment including immunosuppressive therapy.

What are the post-ablation insular residual electrograms in the posterior left pulmonary veins electrically connected to?

A 67-year-old man underwent a third ablation procedure for a recurrent atrial tachycardia (AT) after an extensive pulmonary vein (PV) isolation, linear ablation along the left atrial (LA) roof and posterolateral mitral isthmus (MI), and defragmentation of persistent atrial fibrillation and an induced perimitral AT. High-resolution mapping during the clinical AT using the Rhythmia system (Boston Scientific) suggested that the AT was a ridge-related reentrant AT and exhibited a reconnection of the left PVs (LPVs). The residual electrograms in the posterior LPVs were surrounded by endocardial scar, which was like an island consisting of residual LPV electrograms. Retrograde venography of the vein of Marshall (VOM) demonstrated that the VOM reached the posterior left superior PV through the ridge between the LA appendage and left inferior PV and then the LPV carina. An ethanol infusion into the VOM resulted in a simultaneous AT termination and complete electrical isolation of the LPVs, that is, the disappearance of the residual LPV electrograms. The insular residual LPV electrograms in the present case did not appear to be endocardially connected to the LA, because the LPV electrograms were surrounded by endocardial scar and there was a large time gap between the earliest activation in the posterior LPVs and activation in the surrounding area. The VOM course on the venography and elimination of the residual LPV electrograms with an ethanol infusion into the VOM suggested that the insular residual LPV electrograms were electrically connected to the posterolateral LA via the VOM and its branches.

Halo-shape technique for leadless pacemaker implantations: A case report.

A 92-year-old woman underwent an implantation of a leadless pacemaker (Micra; Medtronic, Inc, Minneapolis, MN) for complete atrioventricular block after a transvenous lead extraction due to a pocket infection of a dual chamber pacemaker. Marked scoliosis and a humpback due to an advanced age made it impossible to direct the tip of the pacemaker delivery catheter towards the right ventricular septum or apex and shape the catheter into a gooseneck-shape. Thus, by attaining a halo-catheter shape of the delivery catheter, the catheter tip could be directed toward the infero-basal portion of the right ventricular septum. The pacemaker was successfully deployed at that site without any complications, and good device parameters were achieved. The halo-shape technique may be also an alternative method for delivering a leadless pacemaker in patients with an unsuccessful delivery of a leadless pacemaker to the right ventricular septum using the conventional gooseneck-shape technique.

Multiple epicardial connections during extensive pulmonary vein isolation.

A 76-year-old male underwent a pulmonary vein isolation (PVI) of atrial fibrillation. The first-pass encirclement did not isolate the left superior PV (LSPV). High-resolution activation mapping during LSPV pacing identified the earliest activation site (EAS) on the left atrial (LA) roof outside the PVI line. A radiofrequency application on the roof isolated the LSPV. Thereafter, an LSPV reconnection occurred. Second activation mapping during LSPV pacing identified the EAS at the bottom of the ridge outside the PVI line. Radiofrequency applications targeting the EAS eliminated the LSPV reconnection. The multiple residual connections may be associated with spared epicardial PV-LA connections.

Postablation cerebral embolisms in balloon-based atrial fibrillation ablation with periprocedural direct oral anticoagulants: A comparison between cryoballoon and HotBalloon ablation.

INTRODUCTION: This prospective observational study aimed to investigate the incidence of symptomatic and silent cerebral embolisms after balloon-based ablation of atrial fibrillation (AF) in patients receiving periprocedural anticoagulation with direct oral anticoagulants (DOACs), and compare that between cryoballoon and HotBalloon ablation (CBA and HBA). METHODS AND RESULTS: We enrolled 123 consecutive AF patients who underwent a balloon-based pulmonary vein isolation (PVI) and brain magnetic resonance (MR) imaging after the ablation procedure (CBA, n = 65; HBA, n = 58). The DOACs were continued in 62 patients throughout the periprocedural period and discontinued in 61 on the procedural day. Intravenous heparin was infused to maintain an activated clotting time of 300 to 400 seconds during the procedure. No symptomatic embolisms occurred in this series. Silent cerebral ischemic lesions (SCILs) were observed on MR imaging in 22 patients (17.9%), and the incidence of SCILs did not significantly differ between the CBA and HBA groups (21.5 vs 13.8%; P = 0.263). According to a multivariate logistic regression analysis, an older age was an independent positive predictor of SCILs (odds ratio, 1.062; 95% CI, 1.001-1.126; P = 0.046), but neither the balloon catheter type nor periprocedural continuation or discontinuation of the DOACs were significant predictors. The incidence of major and minor bleeding complications was comparable between the CBA and HBA groups (1.5 vs 0%, P = 0.528; 7.7 vs 5.2%, P = 0.424). CONCLUSIONS: Both CBA and HBA of AF revealed a similar incidence of postablation cerebral embolisms. Elderly patients may be at a risk of SCILs after a balloon-based PVI with periprocedural DOAC treatment.

Uninterrupted vs. interrupted periprocedural direct oral anticoagulants for catheter ablation of atrial fibrillation: a prospective randomized single-centre study on post-ablation thrombo-embolic and haemorrhagic events.

AIMS: This prospective, randomized, single-centre study aimed to directly compare the safety and efficacy of uninterrupted and interrupted periprocedural anticoagulation protocols with direct oral anticoagulants (DOACs) in patients undergoing catheter ablation of non-valvular atrial fibrillation (NVAF). METHODS AND RESULTS: We randomly assigned 846 NVAF patients receiving DOACs prior to ablation to uninterruption (n = 422) or interruption (n = 424) of the DOACs on the day of the procedure. The primary endpoint was a composite of symptomatic thromboembolisms and major bleeding events within 30 days after the ablation. Secondary endpoints included symptomatic and silent thromboembolisms and major and minor bleeding events. The primary endpoint occurred in 0.7% of the uninterrupted DOAC group [1 transient ischaemic attack (TIA) and 2 major bleeding events] and 1.2% of the interrupted DOAC group (1 TIA and 4 major bleeding events) (P = 0.480). The incidence of major and minor bleeding was comparable between the two groups (0.5% vs. 0.9%, P = 0.345; 5.9% vs. 5.4%, P = 0.753). Silent cerebral ischaemic lesions (SCILs) were observed in 138 (20.9%) of the 661 patients undergoing post-ablation magnetic resonance (MR) imaging. The uninterrupted and interrupted DOAC groups revealed a similar incidence of SCILs (19.8% vs. 22.0%, P = 0.484) and percentage of SCILs with disappearance on follow-up MR imaging (77.8% vs. 82.1%, P = 0.428). CONCLUSION: Both the uninterrupted and interrupted DOAC protocols revealed a low risk of symptomatic thromboembolisms and major bleeding events and similar incidence of SCILs and minor bleeding events and may be feasible for periprocedural anticoagulation in NVAF patients undergoing catheter ablation.

Pulmonary vein-gap re-entrant atrial tachycardia following atrial fibrillation ablation: an electrophysiological insight with high-resolution mapping.

AIMS: The circuit of pulmonary vein-gap re-entrant atrial tachycardia (PV-gap RAT) after atrial fibrillation ablation is sometimes difficult to identify by conventional mapping. We analysed the detailed circuit and electrophysiological features of PV-gap RATs using a novel high-resolution mapping system. METHODS AND RESULTS: This multicentre study investigated 27 (7%) PV-gap RATs in 26 patients among 378 atrial tachycardias (ATs) mapped with Rhythmia™ system in 281 patients. The tachycardia cycle length (TCL) was 258 ± 52 ms with P-wave duration of 116 ± 28 ms. Three types of PV-gap RAT circuits were identified: (A) two gaps in one pulmonary vein (PV) (unilateral circuit) (n = 17); (B) two gaps in the ipsilateral superior and inferior PVs (unilateral circuit) (n = 6); and (C) two gaps in one PV with a large circuit around contralateral PVs (bilateral circuit) (n = 4). Rhythmia™ mapping demonstrated two distinctive entrance and exit gaps of 7.6 ± 2.5 and 7.9 ± 4.1 mm in width, respectively, the local signals of which showed slow conduction (0.14 ± 0.18 and 0.11 ± 0.10m/s) with fragmentation (duration 86 ± 27 and 78 ± 23 ms) and low-voltage (0.17 ± 0.13 and 0.17 ± 0.21 mV). Twenty-two ATs were terminated (mechanical bump in one) and five were changed by the first radiofrequency application at the entrance or exit gap. Moreover, the conduction time inside the PVs (entrance-to-exit) was 138 ± 60 ms (54 ± 22% of TCL); in all cases, this resulted in demonstrating P-wave with an isoelectric line in all leads. CONCLUSION: This is the first report to demonstrate the detailed mechanisms of PV-gap re-entry that showed evident entrance and exit gaps using a high-resolution mapping system. The circuits were variable and Rhythmia™-guided ablation targeting the PV-gap can be curative.