Seigo Yamashita

Driver Domains in Persistent Atrial Fibrillation

Background— Specific noninvasive signal processing was applied to identify drivers in distinct categories of persistent atrial fibrillation (AF). Methods and Results— In 103 consecutive patients with persistent AF, accurate biatrial geometry relative to an array of 252 body surface electrodes was obtained from a noncontrast computed tomography scan. The reconstructed unipolar AF electrograms acquired at bedside from multiple windows (duration, 9±1 s) were signal processed to identify the drivers (focal or reentrant activity) and their cumulative density map. The driver domains were catheter ablated by using AF termination as the procedural end point in comparison with the stepwise-ablation control group. The maps showed incessantly changing beat-to-beat wave fronts and varying spatiotemporal behavior of driver activities. Reentries were not sustained (median, 2.6 rotations lasting 449±89 ms), meandered substantially but recurred repetitively in the same region. In total, 4720 drivers were identified in 103 patients: 3802 (80.5%) reentries and 918 (19.5%) focal breakthroughs; most of them colocalized. Of these, 69% reentries and 71% foci were in the left atrium. Driver ablation alone terminated 75% and 15% of persistent and long-lasting AF, respectively. The number of targeted driver regions increased with the duration of continuous AF: 2 in patients presenting in sinus rhythm, 3 in AF lasting 1 to 3 months, 4 in AF lasting 4 to 6 months, and 6 in AF lasting longer. The termination rate sharply declined after 6 months. The mean radiofrequency delivery to AF termination was 28±17 minutes versus 65±33 minutes in the control group (P<0.0001). At 12 months, 85% patients with AF termination were free from AF, similar to the control population (87%,); P=not significant. Conclusions— Persistent AF in early months is maintained predominantly by drivers clustered in a few regions, most of them being unstable reentries.

Repeated provocation of time- and ATP-induced early pulmonary vein reconnections after pulmonary vein isolation: eliminating paroxysmal atrial fibrillation in a single procedure.

Background— Recurrence of atrial fibrillation (AF) after successful pulmonary vein isolation (PVI) occurs mainly due to the reconnection of the once isolated PV. Although provocation and elimination of the early pulmonary vein reconnection (EPVR) soon after PVI has been widely performed to improve the outcome, AF recurrence due to subsequent PV reconnections still occurs. In this study, we repeatedly provoked and eliminated the EPVR to determine the appropriate procedural end point. Methods and Results— Seventy-five patients with paroxysmal AF underwent PVI. EPVR was provoked by both time and ATP induction every 30 minutes until 90 minutes after the individual isolation of all PVs. The number of reconnected atrio-PV gaps were evaluated and reablated at each provocation step. Although both time- and ATP-dependent EPVR was induced most frequently at 30 minutes after PVI (75 and 76 gaps, respectively), the prevalence of induced EPVR at 60 minutes was still high (64 and 36 gaps induced by time and ATP, respectively). Only a small number of EPVR appeared at 90 minutes after the elimination of all EPVR by 60 minutes (8 gaps, P<0.01). During the mean follow-up period of 370 days, 92% of cases were free from AF without antiarrhythmic drugs. Conclusions— Provocation and elimination of time- and ATP-induced EPVR not only at 30 minutes but also at 60 minutes is recommended after PVI to improve its efficacy.Background— Recurrence of atrial fibrillation (AF) after successful pulmonary vein isolation (PVI) occurs mainly due to the reconnection of the once isolated PV. Although provocation and elimination of the early pulmonary vein reconnection (EPVR) soon after PVI has been widely performed to improve the outcome, AF recurrence due to subsequent PV reconnections still occurs. In this study, we repeatedly provoked and eliminated the EPVR to determine the appropriate procedural end point. Methods and Results— Seventy-five patients with paroxysmal AF underwent PVI. EPVR was provoked by both time and ATP induction every 30 minutes until 90 minutes after the individual isolation of all PVs. The number of reconnected atrio-PV gaps were evaluated and reablated at each provocation step. Although both time- and ATP-dependent EPVR was induced most frequently at 30 minutes after PVI (75 and 76 gaps, respectively), the prevalence of induced EPVR at 60 minutes was still high (64 and 36 gaps induced by time and ATP, respectively). Only a small number of EPVR appeared at 90 minutes after the elimination of all EPVR by 60 minutes (8 gaps, P <0.01). During the mean follow-up period of 370 days, 92% of cases were free from AF without antiarrhythmic drugs. Conclusions— Provocation and elimination of time- and ATP-induced EPVR not only at 30 minutes but also at 60 minutes is recommended after PVI to improve its efficacy.

Role of electrophysiological studies in predicting risk of ventricular arrhythmia in early repolarization syndrome.

BACKGROUND The early repolarization (ER) pattern is associated with an increased risk of arrhythmogenic sudden death. However, strategies for risk stratification of patients with the ER pattern are not fully defined. OBJECTIVES This study sought to determine the role of electrophysiology studies (EPS) in risk stratification of patients with ER syndrome. METHODS In a multicenter study, 81 patients with ER syndrome (age 36 ± 13 years, 60 males) and aborted sudden death due to ventricular fibrillation (VF) were included. EPS were performed following the index VF episode using a standard protocol. Inducibility was defined by the provocation of sustained VF. Patients were followed up by serial implantable cardioverter-defibrillator interrogations. RESULTS Despite a recent history of aborted sudden death, VF was inducible in only 18 of 81 (22%) patients. During follow-up of 7.0 ± 4.9 years, 6 of 18 (33%) patients with inducible VF during EPS experienced VF recurrences, whereas 21 of 63 (33%) patients who were noninducible experienced recurrent VF (p = 0.93). VF storm occurred in 3 patients from the inducible VF group and in 4 patients in the noninducible group. VF inducibility was not associated with maximum J-wave amplitude (VF inducible vs. VF noninducible; 0.23 ± 0.11 mV vs. 0.21 ± 0.11 mV; p = 0.42) or J-wave distribution (inferior, odds ratio [OR]: 0.96 [95% confidence interval (CI): 0.33 to 2.81]; p = 0.95; lateral, OR: 1.57 [95% CI: 0.35 to 7.04]; p = 0.56; inferior and lateral, OR: 0.83 [95% CI: 0.27 to 2.55]; p = 0.74), which have previously been demonstrated to predict outcome in patients with an ER pattern. CONCLUSIONS Our findings indicate that current programmed stimulation protocols do not enhance risk stratification in ER syndrome.

nMARQ Ablation for Atrial Fibrillation: Results from a Multicenter Study

nMARQ is a multipolar catheter designed to simultaneously ablate at multiple sites around the pulmonary vein (PV) circumference with a single radiofrequency application. We sought to define the safety and efficacy of atrial fibrillation (AF) ablation with the nMARQ catheter.

Postmyocarditis ventricular tachycardia in patients with epicardial-only scar: a specific entity requiring a specific approach.

Nonischemic cardiomyopathy is a heterogeneous condition providing a favorable substrate for ventricular tachycardia (VT).

Image Integration to Guide Catheter Ablation in Scar-Related Ventricular Tachycardia

Although multi‐detector computed tomography (MDCT) and cardiac magnetic resonance (CMR) can assess the structural substrate of ventricular tachycardia (VT) in ischemic cardiomyopathy (ICM), non‐ICM (NICM), and arrhythmogenic right ventricular cardiomyopathy (ARVC), the usefulness of systematic image integration during VT ablation remains undetermined.

Impact of electrode type on mapping of scar‐related VT

Substrate‐based VT ablation is mostly based on maps acquired with ablation catheters. We hypothesized that multipolar mapping catheters are more effective for identification of scar and local abnormal ventricular activity (LAVA).

Substrate mapping and ablation for ventricular tachycardia: the LAVA approach.

Catheter ablation of ventricular tachycardia (VT) is proven effective therapy particularly in patients with frequent defibrillator shocks. However, the optimal endpoint for VT ablation has been debated and additional endpoints have been proposed. At the same time, ablation strategies aiming at homogenizing the substrate of scar‐related VT have been reported.

History and clinical significance of early repolarization syndrome.

The early repolarization (ER) pattern has historically been regarded as a benign ECG variant. However, in recent years this view has been challenged based on multiple reports linking the ER pattern with an increased risk of sudden cardiac death. The mechanistic basis of ventricular arrhythmogenesis in ER syndrome is presently incompletely understood. Furthermore, strategies for risk stratification and therapy for ER syndrome remain suboptimal. The recent emergence of novel mapping techniques for cardiac arrhythmia has ushered a new era of research into the mechanistic basis of ER syndrome. This review provides an overview of current evidence relating to ER and risk of ventricular arrhythmias and discusses potential future areas of research to elucidate the mechanisms of ventricular arrhythmogenesis.

Safety and prevention of complications during percutaneous epicardial access for the ablation of cardiac arrhythmias

Cite this article as: Han S. Lim MBBS, PhD, Frédéric Sacher MD, Hubert Cochet MD, Benjamin Berte MD, Seigo Yamashita MD, Saagar Mahida MBChB, Stephan Zellerhoff MD, Yuki Komatsu MD, Arnaud Denis MD, Nicolas Derval MD, Mélèze Hocini MD, Michel Haïssaguerre MD, Pierre Jaïs MD, Safety and Prevention of Complications during Percutaneous Epicardial Access for the Ablation of Cardiac Arrhythmias, Heart Rhythm, http://dx.doi.org/10.1016/j.hrthm.2014.05.041