Treatment of Arrhythmias

This heavily trafficked poster session featured posters focused on left atrial pressure waveform analysis, intracardiac echocardiography, pressure-guided cryoballon isolation of the pulmonary veins, radiofrequency ablation, atrial fibrillation due to mitral valve disease, a non-contact mapping system, and the mechanism of chronic atrial fibrillation. MDNG had the pleasure of meeting with some of the presenters, and summaries of their posters are provided below.

Atrial Mechanical Function Using Left Atrial Pressure Waveform Analysis in Persistent and Paroxysmal Atrial Fibrillation PatientsZhongwei Cheng, Peking Union Medical College Hospital, Beijing, China; and Ronald Lo, Anurag Gupta, Marco Perez, Paul Zei, Henry H Hsia, Mintu Turakhia, Mamin Al-Ahmad, and Paul J Wang, Stanford University School of Medicine, Stanford, CA.

This team of researchers examined left atrial (LA) "mechanical function in paroxysmal and persistent [atrial fibrillation (AF)] patients and the predictors of impaired LA function," as the felt that "LA pressure measurements at the time of ablation may give insight into LA mechanical function in AF patients." After enrolling 52 consecutive AF patients with clear LA pressure waveform and dividing them in to paroxysmal and persistent AF groups, they found that those in the former group "have elevated A wave pressure, possibly reflecting impaired left atrial compliance." On the other hand, those in the latter group "have markedtly elevated LA pressures, suggesting alterations in LA function. They concluded that "LA pressure measurement during ablation procedures may lead to significant insights into the changes in hemodynamic function in AF patients.

Intracardiac Echo for Registration of Rotational Angiography Based Left Atrial Reconstructions: A Novel Approach Integrating Two Intraprocedural 3D Imaging Techniques in Atrial Fibrillation AblationGeorg Nölker, Klaus J Gutleben, Guido Ritscher, Johannes Heintze, Juergen Vogt, and Dieter Horstkotte, Heart and Diabetes Center North Rhine-Westphalia, Ruhr University Bochum, Bad Oeynhausen, Germany; Ani Sinha and Johannes Brachmann, Coburg Hospital, Coburg, Germany; and Nassir Marrouche, University of Utah, Salt Lake City, UT.

Nölker and colleagues conducted their study to "quantify the accuracy of intraprocedural rotation angiography (RA) based" left atrial (LA) and pulmonary vein (PV) reconstructions (RC) "registered by spatial RC of intracardiac echocardiography (ICE)," as image "integration of 3D RC in electroanatomical mapping (EAM) plays a major role in atrial fibrillation (AF)" and point-by-point "EAM is commonly used for registration of imported" LA and PV anatomy. After finding that all PV were successfully isolated and that "3D reconstructions of LA and PV were feasible in every patient by both modalities," the researchers concluded that intraprocedural "3D reconstruction of LA and PV for ablation of AF is feasible based on RA as well as based on ICE," as is registration "of LA reconstructions based on RA by 3D ICE reconstructions." They also noted that minimal deviation was seen between the two modalities, which couldn't be improved upon with the "integration of additional EAM points into the 3D ICE reconstructions."

Pressure-guided Cryoballoon Isolation of the Pulmonary Veins for the Treatment of Paroxysmal Atrial FibrillationClaudia Herrer Siklódy, Jan Minners, Martin Allgeier, Jürgen Allgeier, Nikolaus Jander, Jochen Schielbelling-Römer, Cornelius Keyl, Reinhold Weber, Dietrich Kalusche, Thomas Arentz, Herz-Zentrum, Bad Krozingen, Germany

The researchers who conducted this study aimed to "correlate mechanical PV occlusion with changes in a pressure curve recorded at the distal tip of the cryoballoon catheter," as complete "PV occlusion during balloon ablation has been shown to predict successful electrical isolation." They found that occlusion "and therefore electrical isolation of PVs during cryoballoon ablation can be predicted by the appearance of a PV wedge curve at the tip of the catheter," and that this new "parameter may facilitate the procedure."

Atrial Fibrillation Due to Mitral Valve Disease, but Not Lone Atrial Fibrillation Is Associated with Increased Left Atrial FibrosisGuillaume S. Geuzebroek, Norbert M. Van Hemel, Peter C. De Bruin, and Wim-Jan Van Boven St. Antonius Hospital, Nieuwegein, Netherlands; and Shirley C. Van Amersfoorth, Mark G. Hoogendijk, Jacques M. De Bakker, and Ruben Coronel, Academical Medical Center Amsterdam, Amsterdam, Netherlands

Geuzebroek and colleagues sought to test their hypothesis that "left atrial fibrosis is more pronounced in patients with AF and mitral valve disease (AF+MVD) compared to patients without AF or with lone AF," based on the knowledge that atrial fibrosis constitutes a substrate of AF." The research team found that patients with AF and MVD "have more atrial fibrous tissues than patients with lone AF and controls, especially in the" left atrial appendages, but that no difference exists between patients with lone AF and controls in regards to the amount of fibrous tissue. They concluded that "(1) AF secondary to MVD is more dependent of structural remodeling than lone AF and (2) that decreased anti-arrhythmic surgical efficacy for AF with MVD is likely explained by extensive atrial structural changes.

Mechanisms Responsible for the Termination of Atrial Fibrillation Assessed by Non-contact Mapping SystemNaoki Yoshida, Yasuya Inden, Tomohiro Uchikawa, Tomoya Kitamura, Hiromi Kamiya, Masayuki Shimano, and Toyoaki Murohara, Nagoya University Graduate School of Medicine, Nagoya, Japan; and Makoto Hirai, Nagoya University School of Health Sciences, Nagoya, Japan.

The purpose of this study was to "assess the termination mechanisms of AF by evaluating the relationship between AF termination and the left atrial anatomical structures." Yoshida and fellow researchers found that the ablation line of PV isolation "and the specific anatomical structures such as" left atrium roof or the ridge between left PVs and LA appendage "may be associated with the spontaneous wave breakup and may play an important role in termination of AF."

New Insights into the Mechanism of Chronic Atrial Fibrillation in PatientsIvan Cakulev, Jayakumar Sahadeven, and Alberto Waldo, University Hospital Case Medical Center, Cleveland, OH; and Seungyup Lee and Celeen Khrestian, Case Western Reserve University, Cleveland, OH.

Cakulev and colleagues "performed epicardial mapping of chronic AF in patients undergoing open heart surgery to test the hypothesis that chronic AF is due to 1 or more drivers." When looking at the mechanism of chronic AF in seven patients with the condition, the authors found that "1) sites of prolonged regularity, some lasting 60 seconds, is not consistent with a multiple reentrant wavelet mechanism; 2) the simultaneous presence of several sites with regular activation at different CLs, speaks against the single driver hypotheis; 3) multiple unstable drivers best explains the mechanism of chronic AF in all but one of these patients."