Introduction: Fluoroscopy is traditionally used in atrial transseptal puncture (TSP); however fluoroscopy exposes patient and physician to excess radiation. Here, we describe a feasibility study of a zero-fluoroscopy transseptal puncture (ZFTSP) technique utilising electroanatomical mapping (EAM) and intracardiac echo (ICE) in a small case series of patients undergoing ablation for atrial fibrillation (AF). We then compare this technique to other established ZFTSP techniques for paroxysmal AF ablation. Methods: Seven patients received ZFTSP. An Acunav™ ICE catheter (Biosense Webster Inc., California, US) was placed in the right atrium, then an Agilis™ sheath (St. Jude Medical, Saint Paul, Minnesota, US) was established into the inferior vena cava. A ThermoCool®
SmartTouch™ catheter (Biosense Webster Inc., California, US) was inserted through the Agilis to map the fossa ovalis. Mapping catheter exchange for dilator and needle allowed for facile ZFTSP. AF outcome, fluoroscopy times, and procedure times were compared with eight age-matched control patients. Results: There were no significant differences in age, body mass index (BMI) or AF duration between the two groups and no immediate complications. ZFTSP procedure time was 183.9±33.7 minutes versus 293.13±129.9 minutes for TSP-only controls (p=0.05). Fluoroscopy time was 17.5±14.1 minutes in ZFTSP patients versus 73.4±50.3 minutes in controls (p=0.01). AF recurrence in ZFTSP patients was 14% versus 25% in controls. Conclusion: ZFTSP utilising ICE and EAM is safe, effective, and time-efficient. There is a small but significant reduction in radiation exposure to patient and physician by the use of this technique.
Atrial fibrillation, transseptal puncture, zero-fluoroscopy, electro-anatomical mapping, intracardiac echocardiography
denotes equal effort by authors. Mark McCauley is supported by an NIH K08 Award 1K08HL130587-01. Mark McCauley owns stock in Nanolinea Inc., Houston, TX. Mehdi Razavi owns stock in Nanolinea Inc. and Saranas Inc., Houston, TX. Nisarg Patel, Scott Greenberg, Joanna Molina-Razavi and Payam Safavi-Naeini have no relevant conflicts of interest to declare.
The authors would like to acknowledge the mentorship and guidance of Dr. Ali Massumi who was a giant in the field of clinical electrophysiology at the Texas Heart Institute, and who recently passed away. His lifetime of contributions to the field have made tremendous impact on his trainees and patients alike.
Compliance with Ethics: Research procedures were followed in accordance with the Institutional Review Boards (IRB) of the Texas Heart Institute and Baylor College of Medicine, and with the Helsinki Declaration of 1975 and subsequent revisions. The IRB did not require informed consent for this retrospective analysis.
Authorship: All named authors meet the International Committee of Medical Journal Editors (ICMJE) criteria for authorship of this manuscript, take responsibility for the integrity of the work as a whole, and have given final approval to the version to be published.
This article is published under the Creative Commons Attribution Noncommercial License, which permits any non-commercial use, distribution, adaptation and reproduction provided the original author(s) and source are given appropriate credit.
August 15, 2016 Accepted
December 12, 2016
Mark D McCauley, Division of Cardiology, Department of Medicine, The University of Illinois at Chicago, 840 S. Wood Street, Ste 920S, Chicago, Illinois 60612. E: firstname.lastname@example.org
The atrial transseptal puncture (TSP) technique is an indispensable procedure in the invasive cardiac catheterisation laboratory. TSP was initially developed in 1959 by Ross, Braunwald and Morrow at the National Institutes of Health, to allow for catheter access to the left atrium (LA) and left ventricle (LV) for the evaluation of valvular heart disease.1 However, today the need for procedural access to the left heart has expanded to include variety of cardiac conditions, which include: electrophysiological mapping of the left heart, catheter ablation of tachycardias, percutaneous mitral valvuloplasty, left atrial appendage exclusion and haemodynamic measurements in chambers with entry limited by prostheses.2 Thus, in recent years there has been an exponential increase in the use of TSP for the treatment of left-sided cardiac disease.
Currently, the most common technique used for TSP is the Brockenbrough technique, which utilises fluoroscopy for sheath placement and septal puncture.3 However, with new imaging technologies including electroanatomical mapping (EAM) and intracardiac echocardiography (ICE), the risk-to-benefit ratio of using fluoroscopic TSP versus standard procedural risk remains unknown. There have been several recent reports of zero-fluoroscopy approaches to the ablation of atrial arrhythmias.4–13 However, the combined use of ICE and EAM to map the interatrial septum and set the TSP needle, has not been described in these procedures. Here, we describe a feasibility study to evaluate a completely zero-fluoroscopy technique for TSP (ZFTSP), in patients undergoing ablation for atrial fibrillation (AF), that takes advantage of the ThermoCool® SmartTouch™ catheter (Biosense Webster Inc., California, US) ablation catheter as a non-traumatic guide for imaging the fossa ovalis, and setting the transseptal sheath for puncture. This technique advances the concept of combined use of ICE and EAM for TSP, and contributes towards a zerofluoroscopy approach to interventional electrophysiology procedures. Finally, we place this technique in perspective of larger, randomised trials examining this important radiation-saving procedure.
Study population and design
We performed a retrospective analysis of patients with paroxysmal or persistent AF who previously elected to have a pulmonary vein isolation procedure due to failure of at least one antiarrhythmic drug (AAD). Outcomes of patients who received fluoroscopy as part of the TSP were compared with patients in which fluoroscopy was not used due to the use of the ZFTSP technique. Seven ZFTSP patients were compared with eight age-matched TSP controls with fluoroscopy. The study protocol was reviewed and approved by the Institutional Review Boards of the Texas Heart Institute at Baylor College of Medicine.
Procedure technique The technique for ZFTSP requires a ThermoCool SmartTouch catheter, Carto® mapping system (Biosense Webster Inc., California, US), Agilis™ Steerable Introducer (St. Jude Medical, Saint Paul, Minnesota, US) or SL-1 transseptal sheath (St. Jude Medical, Saint Paul, Minnesota, US), transseptal needle appropriately sized for the respective sheath, an 0.032” guidewire, ICE catheter (Biosense Webster Inc., California, US) with Vivid™ Echocardiography System (GE Healthcare, Chicago, US) and a decapolar coronary sinus (CS) catheter. First, 8-Fr short and 9-Fr long left common femoral venous (CFV) sheaths are placed without fluoroscopy, as well as two 8-Fr short sheaths in the right common femoral vein (Figure 1A). A decapolar catheter is placed from the left 8-Fr sheath to the CS. Next, an AcuNavTM Intracardiac Echo Catheter (Biosense Webster Inc., California, US) is placed from the left 9-Fr long sheath to the right atrium. The echocardiographic window was then focused on the fossa ovalis, which was located on the inter-atrial septum, posterior to the aorta and anterior to the left pulmonary veins. The placement of the decapolar CS catheter and intracardiac echo catheter can be placed entirely using Carto mapping, and fluoroscopy is not necessary for this portion of the procedure. Often, the CS can be clearly seen by the intracardiac echo catheter, and this may serve as a basis to place the CS catheter.
Through one of the right CFV sheaths, a 0.032” guidewire is passed up the inferior vena cava (IVC) approximately 40 cm, and the sheath is exchanged over wire to a transseptal sheath (either Agilis or SL-1, Figure 1B). The transseptal sheath is advanced into the right CFV, to the IVC about 20–40 cm, and then wire and dilator are removed and the sheath is flushed with heparinated saline (Figure 1C). A flushed ThermoCool SmartTouch catheter is inserted via the introducer tool into the transseptal sheath, and is advanced by 3D Carto imaging to the heart (Figure 1D). The catheter becomes visualised when it exits the sheath and becomes a guide to insertion of both the catheter and sheath into the right atrium (Figure 1E–F). By intracardiac echo guidance and Carto sound mapping, the inter-atrial septum and fossa are visualised, and anatomy is recorded. Additionally, finer detail of the septum is mapped with the ablation catheter.
Once the septum is adequately defined by ICE and mapping such that the fossa ovalis and surrounding myocardium is distinct, the ICE catheter and ablation catheter are fixed, and then the transseptal sheath is advanced over the ablation catheter to the inter-atrial septum (Figure 2A–B). There are two ways to confirm adequate placement of the sheath on the lower third of the septum. First, by intracardiac echo, the sheath sideport is connected to heparinated saline with a flow regulator. Flushing the flow regulator produces microbubbles of saline that can be visualised on echo. Second, with the ablation catheter fixed on the desired area of the septum, advancing the sheath will result in eventual visual loss of the catheter tip on Carto mapping, which coincides with “housing” of the ablation catheter in the sheath and placement of the sheath on the septum. Next, with the sheath position fixed, the ablation catheter is removed and the sheath dilator and transseptal needle are advanced to the tip under intracardiac echo guidance (Figure 2C).
Gentle forward manual pressure is applied to sheath, dilator and needle until the needle crosses the septum by echo and microbubbles are seen on echo (Figure 2D–F). Often, very little pressure is required to puncture the septum given the more exact placement of the sheath by dual imaging, than by fluoroscopy alone. Additionally, left atrial pressure is recorded to confirm left atrial placement and to prevent pressure dampening suggestive of potential perforation risk. Pressure is monitored while the needle is fixed and the dilator and sheath are advanced approximately 2 cm. The dilator is then fixed and the sheath is advanced another 2–3 cm under echo guidance until the sheath is visualised to cross the septum.
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Atrial fibrillation, transseptal puncture, zero-fluoroscopy, electro-anatomical mapping, intracardiac echocardiography