Pseudo-Focal Atrial Tachycardia Case Series
Short title: Nakatani, et al. Macroreentries with epicardial bypass
Yosuke Nakatani, MD; Takashi Nakashima, MD; Josselin Duchateau, MD; Konstantinos Vlachos, MD; Philipp Krisai, MD; Takamitsu Takagi, MD; Tsukasa Kamakura, MD; Clémentine André, MD; Cyril Goujeau, MD; F. Daniel Ramirez, MD; Remi Chauvel, MD; Romain Tixier, MD; Masateru Takigawa, MD; Takeshi Kitamura, MD; Ghassen Cheniti, MD; Arnaud Denis, MD; Frédéric Sacher, MD; Mélèze Hocini, MD; Michel Haïssaguerre, MD; Pierre Jaïs, MD; Nicolas Derval, MD; Thomas Pambrun, MD
Hôpital Cardiologique du Haut-Lévêque, CHU Bordeaux, L’Institut de RYthmologie et modélisation Cardiaque (LIRYC), Université Bordeaux, France.
Data availability statement: The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.
Funding statement: Dr. Nakatani is supported by the JHRS-EHRA Fellowship. Dr. Krisai is supported by the University of Basel, the Mach-Gaensslen foundation, and the Bangerter-Rhyner foundation. Dr. Ramirez is supported by the Canadian Institutes of Health Research Banting Postdoctoral Fellowship. This work is supported by the Agence Nationale de la Recherche (grant number; IHU LIRYC ANR-10-IAHU-04).
Conflict of interest disclosure: Drs. Haïssaguerre, Hocini, Jaïs, Derval, Sacher and Pambrun have received lecture fees from Biosense Webster. Drs. Derval, Sacher and Jaïs have received lecture fees from Boston Scientific.
Address for correspondence: Yosuke Nakatani, MD
Hôpital Cardiologique du Haut-Lévêque, Avenue de Magellan, 33604 Bordeaux-Pessac, France. Telephone: +33-5-57656542; E-mail:yosuke3gbst@gmail.com
ABSTRACT
Introduction: Human atria comprise distinct epicardial layers, which can bypass endocardial layers and lead to downstream centrifugal propagation at the ”epi-endo” connection. We sought to characterize anatomical substrates, electrophysiological properties, and ablation outcomes of ”pseudo-focal” atrial tachycardias (ATs), defined as macroreentrant ATs mimicking focal ATs.
Methods and Results: We retrospectively analyzed ATs showing centrifugal propagation with post-pacing intervals (PPIs) after entrainment pacing suggestive of a macroreentry. A total of 26 patients had pseudo-focal ATs consisting of 15 perimitral, 7 roof-dependent, and 5 cavotricuspid isthmus (CTI)-dependent flutters. A low-voltage area was consistently found at the collision site and co-localized with epicardial layers like the: (1) coronary sinus-great cardiac vein bundle (22%); (2) vein of Marshall bundle (15%); (3) Bachmann bundle (22%); (4) septopulmonary bundle (15%); (5) fossa ovalis (7%); and (6) low right atrium (19%). The mean missing tachycardia cycle length (TCL) was 67 ± 29 ms (22%) on the endocardial activation map. PPI was 9 [0-15] ms and 10 [0-20] ms longer than TCL at the breakthrough site and the opposite site, respectively. While feasible in 25 pseudo-focal ATs (93%), termination was better achieved by blocking the anatomical isthmus than ablating the breakthrough site [24/26 (92%) vs. 1/6 (17%); p < 0.001].
Conclusion: Perimitral, roof-dependent, and CTI-dependent flutters with centrifugal propagation are favored by a low-voltage area located at well-identified epicardial bundles. Comprehensive entrainment pacing maneuvers are crucial to distinguish pseudo-focal ATs from true focal ATs. Blocking the anatomical isthmus is a better therapeutic option than ablating the breakthrough site.
Keywords: Atrial tachycardia; Macroreentry; Epicardial connection; Catheter ablation; Entrainment pacing.