Dr. Jeff Williams' Discussion forum for biotechnology, pacemakers, defibrillators, and electrophysiology studies including ablation.
Author: Heart Rhythm Center
Dr. Williams obtained his undergraduate degree with a double major in Biomedical and Electrical Engineering at Vanderbilt University. He was then awarded a Keck Fellowship for graduate school at the University of Pittsburgh where he obtained his Master’s degree in Bioengineering.
Dr. Williams went on to obtain his medical degree at Drexel University in Philadelphia and completed 5 years of Fellowship training in both Cardiovascular Diseases and Clinical Cardiac Electrophysiology at the University of Pittsburgh Medical Center.
His unique background and extensive knowledge of both engineering and cardiology have earned Dr. Williams many accolades in both clinical and academic settings. He’s published over 20 manuscripts and abstracts in the field of cardiology/electrophysiology and has received awards from both the American College of Cardiology Foundation and the National Institutes of Health.
Dr. Williams started in the Invasive Electrophysiology Laboratory at The Good Samaritan Hospital in 2008 and, in the last three years, the Heart Rhythm Center has published outcomes on pacemaker and defibrillator implantations as well as the safety and efficacy of high frequency jet ventilation during EP studies with ablation under his direction.
Thanks to all the faculty and attendees of the 2018 Lakeland Regional Health Cardiovascular Symposium! We appreciate the time away from family and hope the education proves to be worthwhile. You will find link to PDF’s of all lectures below; please note that faculty may have altered their presentations from these files.
The following PA and Lateral CXR was obtained the day after an uneventful dual chamber pacemaker implantation placed via left cephalic cutdown.
One can see a radiopaque ribbon near the pacemaker can in both views raising the suspicion of a retained operative sponge. All skin dressings were removed and repeat CXR was performed.
Repeat PA CXR performed after dressing removed leaving steri-strips in place reveals that wound dressing had inadvertently used a radiopaque lap sponge as part of a pressure dressing. Nice case of “pseudo” sponge in the pocket but certainly caused some initial stress during CXR reading!
This PA and Lateral CXR was taken the day after an uneventful defibrillator implantation. I have saved these images for close to a decade as I never wanted to forget this is always a possibility. In full disclosure, this was not a procedure I performed.
This was an eye opening case of an operative sponge left in the pocket. As I recall, the patient was very gracious and sponge was extracted uneventfully the following day. Years later a practice partner of mine called me about an interesting case he was doing on a generator change in a can that went ERI at 8 years. He found an oddly healing pocket and ultimately dissected this sponge (see following picture) out from the pocket. Amazing that the pocket healed at all though clearly the pocket was very abnormal.
Introduction: From the initial report of intraoperative radiofrequency (RF) ablation causing esophageal injury,GIL01 atrioesophageal fistulas (AEF) have been reported in percutaneous atrial fibrillation RF ablations.SCA04,PAP04 Atrioesophageal fistulas have been estimated to occur in as many as 1% of AF ablationsDOL03 but a commonly accepted event rate is 0.1%.PAP04,SCA04,CUM06 The mortality associated with AEF is devastating and found to be 100% in the largest published registry of AEF.CUM06 This is in stark contrast to a near zero death rate of atrial perforations during RF ablation.BUN05 An article by Müller et al (http://www.heartrhythmjournal.com/article/S1547-5271(15)00418-X/abstract) examined the high incidence of esophageal lesions after atrial fibrillation ablations related to the use of esophageal temperature probes. Multivariate analysis revealed the use of the temperature probe was the only independent predictor of esophageal lesions. Finally, recently published data in Heart Rhythm examined the rate of atrioesophageal fistula formation with contact force (CF) sensing catheters versus non-CF-sensing catheters. Black-Maier et al found the “occurrence of atrioesophageal fistula formation accounted for a 5-fold higher proportion of all MAUDE medical device reports of injury or death with CF-sensing catheters compared with non-CF-sensing catheters.”
Value of Imaging: The value of intracardiac imaging via radial intracardiac echo (ICE) cannot be underestimated given the nonuniform thickness and variable course along the posterior wall of the left atrium.SAN05,GOO05,REN06 The proximity of the esophagus to the left pulmonary venous antrum is depicted in Figure 1. Typically, patients with AEF present a mean of 12.3days after their procedure;CUM06 however, presentation within 3-5days of the ablation has been reported.PAP04 Findings on CT scans can be non-specific but, infected pleural and pericardial effusions may suggest esophageal contamination of the pleural spaces. CT scan of the chest (without oral contrast) with the presence of intravenous contrast seen in the esophagus or surrounding posterior mediastinum would imply a fistulous connection.MAL07 Additionally, one may note a narrowed, irregular, and ulcerated pulmonary vein, posterior left atrial wall thickening, posterior mediastinal fat induration, or pneumomediastinum.MAL07
Mechanism of Esophageal Injury: Finite-element analysis supports that esophageal injury is exclusively due to thermal conduction from the atrium.BER05 Esophageal injury can occur despite small electrode size, low power (<30W), and low electrode temperature (34°C). There are two caveats however, irrigated electrodes and electrode-endocardial contact verification (direct visualization with ICE or force-sensing) may increase power delivery to the tissue.
Avoiding Esophageal Injury: There has been much enthusiasm to determine means by which esophageal injury can be avoided. These include echocardiographic monitoring for microbubble formation,CUM05 the use of cryoablation to lower esophageal ulceration,RIP07 plan ablations to avoid esophagus by creating virtual esophageal tube using electroanatomic mapping,SHE07 esophageal irrigation to lower esophageal temperature,TSU07 and physically deflecting the esophagus away from the ablation site.HER06 The study by Muller et alMUL15 suggests the possibility that esophageal temperature probes may increase susceptibility to esophageal lesions. Figure 2 shows ICE images before and after orogastric tube removal. One notes the signature of the OGT at 8 o’clock in the left image. There is a small indentation in the posterior left atrial wall at the site of the OGT. On the right, imaging demonstrates this indentation is resolved after removal of the OGT. I make efforts to remove esophageal instrumentation to avoid any possible displacement of the esophagus towards the left atrium.
CF-sensing catheters have certainly enhanced ability to deliver more consistent lesions however, there are clearly limitations when the operator cannot see real-time electrode-endocardial contact. There have been many times where I have seen left and right atrial tenting due to catheter contact at less than 10g of force. Force sensing has certainly added to our armamentarium but I would caution all that there is more to ablation than contact force.
Note: These radial ICE images would not be possible without my mentor, Dr. David Schwartzman (Pittsburgh, PA).
GIL01 Gillinov AM, Pettersson G, Rice TW, “Esophageal injury during radiofrequency ablation for atrial fibrillation,” J Thor Card Surg, V. 122, No. 6 (December 2001), pp. 1239-1240.
SCA04 Scanavacca MI, D’Avila A, Parga J, Sosa E, “Left Atrial-Esophageal Fistula Following Radiofrequency Catheter Ablation of Atrial Fibrillation,” J Cardiovasc Electrophysiol, V. 15, No. 8 (August 2004), pp. 960-962.
PAP04 Pappone C, Oral H, Santinella V, Vicedomini G, Lang CC, Manguso F, Torracca L, Benussi S, Alfieri O, Hong R, Lau W, Hirata K, Shikuma N, Hall B, Morady F, “Atrio-Esophageal Fistula as a Complication of Percutaneous Transcatheter Ablation of Atrial Fibrillation,” Circulation, V. 109 (June 8, 2004), pp. 2724-2726.
DOL03 Doll N, Borger MA, Fabricius A, Stephan S, Gummert J, Mohr FW, Hauss J, Kottkamp H, Hindricks G, “Esophageal perforation during left atrial radiofrequency ablation: Is the risk too high?” J Thor Cardiovasc Surg, V. 125, No. 4 (April 2003), pp. 836-842.
CUM06 Cummings JE, Schweikert RA, Saliba WI, Burkhardt D, Kilikaslan F, Saad E, Natale A, “Brief Communication: Atrial-Esophageal Fistulas after Radiofrequency Ablation,” Ann Int Med, V. 144, No. 8 (18 April 2006), pp. 572-574.
BUN05 Bunch TJ, Asirvatham SJ, Friedman PA, Monahan KH, Munger TM, Rea RF, Sinak LJ, Packer DL, “Outcomes After Cardiac Perforation During Radiofrequency Ablation of the Atrium,” J Cardiovasc Electrophysiol, V. 16, No. 11 (November 2005), pp. 1172-1179.
SCH06 Schwartzman DS, Nosbisch J, and Housel Debra, “Echocardiographically guided left atrial ablation: Characterization of a new technique,” Heart Rhythm, V. 3, No. 8 (August 2006), pp. 930 –938.
SAN05 Sanchez-Quintana D, Cabrera JA, Climent V, Farre J, de Mendonca MC, Ho SY, “Anatomic Relations Between the Esophagus and Left Atrium and Relevance for Ablation of Atrial Fibrillation,” Circulation, V. 112 (September 6, 2005), pp. 1400-1405.
GOO05 Good E, Oral H, Lemola K, Han J, Tamirisa K, Igic P, Elmouchi D, Tschopp D, Reich S, Chugh A, Bogun F, Pelosi F Jr, Morady F, “Movement of the Esophagus During Left Atrial Catheter Ablation for Atrial Fibrillation,” JACC, V. 46, No. 11 (December 6, 2005), pp. 2107-21190.
REN06 Ren J-F, Lin D, Marchlinski FE, Callans DJ, Patel V, “Esophageal imaging and strategies for avoiding injury during left atrial ablation for atrial fibrillation,” Heart Rhythm, V. 3, No. 10 (October 2006), pp. 1156-1161.
MAL07 Malamis AP, Kirshenbaum KJ, and Nadimpalli S, “CT Radiographic Findings: Atrio-esophageal Fistula After Transcatheter Percutaneous Ablation of Atrial Fibrillation,” J Thorac Imaging, V. 22, No. 2 (May 2007), pp. 188-191.
BER05 Berjano EJ and Hornero F, “What affects esophageal injury during radiofrequency ablation of the left atrium? An engineering study based on finite-element analysis,” Physiol Meas, V. 26 (2005), pp. 837-848.
CUM05 Cummings JE, Schweikert RA, Saliba WI, Burkhardt JD, Brachmann J, Gunther J, Schibgilla V, Verma A, Dery MA, Drago JL, Kilicaslan F, Natale A, “Assessment of Temperature, Proximity, and Course of the Esophagus During Radiofrequency Ablation Within the Left Atrium,” Circulation, V. 112 (July 26, 2005), pp. 459-464.
RIP07 Ripley KL, Gage AA, Olsen DB, Van Vleet JF, Lau C-P, Tse H-F, “Time Course of Esophageal Lesions After Catheter Ablation with Cryothermal and Radiofrequency Ablation: Implication for Atrio-Esophageal Fistula Formation After Catheter Ablation for Atrial Fibrillation,” J Cardiovasc Electrophysiol, V. 18, No. 6 (June 2006), pp. 642-646.
SHE07 Sherzer AI, Feigenblum DY, Kulkarni S, Pina JW, Casey JL, Salka KA, Simons GR, “Continuous Nonfluoroscopic Localization of the Esophagus During Radiofrequency Catheter Ablation of Atrial Fibrillation,” J Cardiovasc Electrophysiol, V. 18, No. 2 (February 2007), pp. 157-160.
TSU07 Tsuchiya T, Ashikaga K, Nakagawa S, Hayashida K, Kugimiya H, “Atrial Fibrillation Ablation with Esophageal Cooling with a Cooled Water-Irrigated Intraesophageal Balloon: A Pilot Study,” J Cardiovasc Electrophysiol, V. 18, No. 2 (February 2007), pp. 145-150.
HER06 Herweg B, Johnson N, Postler G, Curtis AB, Barold SS, Ilercil A, “Mechanical Esophageal Deflection During Ablation of Atrial Fibrillation,” PACE, V. 29 (September 2006), pp. 957-961.
MUL15 Müller P, Dietrich J-W, Halbfass P, Abouarab A, Fochler F, Szöllösi A, Nentwich K, Roos M, Krug J, Schade A, Mügge A, Deneke T, “Higher incidence of esophageal lesions after AF ablation related to the use of esophageal temperature probes,” Heart Rhythm, Published Online: April 03, 2015.
Delivering papers, cutting grass, washing cars and shoveling snow were all formative jobs of mine and I suspect most would jump to their first job out of college or intern year. Given my engineering degrees, my first “real” job should have been selling apps I developed programming in BASIC with my dad’s state-of-the-art Radio Shack TRS-80 but alas there was not a large market for Pong at the time. My first “real” job was bussing tables at Olga’s Diner where I got that first paystub and the reality of paying taxes hit hard. I learned a lot during that summer and certainly it registered enough “likes” in my daughter’s brain to trigger a quick text from her when she was visiting family. My kids have heard me go on and on about this job and my daughter recently sent me a picture showing the South Jersey icon Olga’s Diner being demolished. The picture made me smile thinking about the lessons I learned from that job.
Honesty. The first day on the job I was offered a deal to sneak tips into the bus pan and the dishwashers would split the take with me 50:50. This was an easy first lesson. Don’t steal.
Punctuality. You don’t show up on time, you don’t get those hours on the paycheck.
Humility. It builds character to be the bottom rung of the restaurant ladder and doesn’t hurt to be forced to change before you walk into the house because of the kitchen smell embedded into your clothes.
Interpersonal Communication. At the end of summer, I had to give my 2 weeks notice so I could return to school. My middle-aged boss with a heavy Greek accent initially refused to accept my resignation. Ultimately he did accept my resignation but I translated his first response to mean that I was a hard worker and my absence would be his loss.
Parenting. My parents had to drop me off and pick me up every day (I was only 15 and biking to the corner of Routes 70 and 73 was not a great idea). They knew the lessons the job would teach me were more valuable than that pine-scented tree hanging on the dash to overcome the South Jersey diner kitchen stink that I reeked of.
Career Planning. I learned about career preferences such as air conditioning and whether I not to continue with the hard work and long hours of the restaurant business.
Pride. It’s a good feeling to tell your friends how hard you worked all day. Even nicer to have your work ethic rewarded by a boss who wanted you to abandon school and bus dishes full time.
Work Ethic. The diner was a frenetic place and every job has got to be done efficiently or the whole process breaks down. No dishes or glasses translate into angry patrons. One work-averse employee hurts everyone.
Learning on the job. Like any job, people may just assume you know the nuances but you’ve got to adapt. I was handed a large, gray bus pan and told to get started; I looked around for a server that already seemed to be angry with me and brought my new gray partner. Once I dealt with every dirty table, I then learned the most important 3 lessons in work life: Keep your head down, mouth shut and always be seen working! I can usually follow two of those three at any given time.
Preparing for a job interview. Clearly, my resume at the time was somewhat thin but got my first experience with interview questions such as “Will you show up on time?” “Do you have a ride?” and “Are you a hard worker?”
Respect for others. Simple courtesies like “please” and “thank you” go a long way. Respect servers at a restaurant… especially before you get your meal!
Common sense. I met hard working people who may not have scored well on standardized tests but had tons of common sense… Don’t scoop ice with a glass, only enter the right side of swinging doors, and reward hard work with a tip when appropriate. I learned nonsmokers looked younger and didn’t cough all day.
Great desserts can follow humble meals. To this day, I have never had better cheesecake than Olga’s Diner!
Pay attention to the new young, unfamiliar face at your factory, hospital, or office; this may be their first “real” job and what are you going to teach them?
Radial intracardiac echocardiography adds significant anatomic correlation during invasive EP studies. In particular, coronary sinus (CS) anatomy can be evaluated during CS access or ablation of the slow AV nodal pathway during AVNRT ablations. A steerable sheath (Agilis, St. Jude Medical) flushing with saline holds a 9MHz radial ICE catheter (UltraICE, Boston Scientific Corporation) and is positioned along the inferoseptal aspect of the tricuspid annulus.
The left image shows the posterior aspect of the CS os and you can often visualize the right coronary artery (RCA) in this view. One can see a thickened roof of CS (or often a prominent Eustachian ridge). As the steerable sheath holding the ICE probe is advanced toward the right ventricle (RV), the main CS is brought into view as seen in the middle image. As you move more ventricular, the septal insertion of the tricuspid valve leaflet is brought into view. Finally, the right image depicts the radial ICE view when the anterior aspect of the CS os is brought into view as the probe is advanced even closer to the RV. This is where the traditional position of the slow AVN pathway is found – the slow AV node pathway is generally located at the anterior edge of the CS os near the septal insertion of the tricuspid leaflet.
A nice anatomic study from Choure et al (“In Vivo Analysis of the Anatomical Relationship of Coronary Sinus to Mitral Annulus and Left Circumflex Coronary Artery Using Cardiac Multidetector Computed Tomography: Implications for Percutaneous Coronary Sinus Mitral Annuloplasty,” JACC, Vol. 48, No. 10, 2006) shows some detailed CT imaging of the relation between the coronary arteries and coronary sinus. The following image (taken from Choure et al) gives a nice visualization of the CS os and its relation to the RCA. One can see the circumflex crossing the mid-distal CS. They found the circumflex artery crossed the CS at a variable distance from the CS os (ranging 37 to 123 mm).
For more information about the use of radial ICE during EP studies:
Atrial fibrillation ablations can be accomplished using radial intracardiac echocardiographic (ICE) guidance and can help minimize fluoroscopic use. ICE imaging is initially used during left-sided ablations by facilitating transeptal punctures. Next, radial ICE can be placed in the left atrium to guide atrial fibrillation ablations and demonstrate stable ablation electrode-endocardial contact. Clearly, contact force-sensing ablation catheters have helped assess electrode-endocardial contact but radial ICE allows the operator to directly visualize contact. Furthermore, direct ICE visualization permits assessment of endocardial tissue deflection as well as anatomic guidance to help make left-sided ablations safer (e.g., location of esophagus, thickness of left atrial regions, etc). A full description of radial ICE-guided atrial fibrillation ablation has been previously described (1,2,3) but we will take a more detailed ICE tour of the ablative process.
Radial ICE Guided Transeptal Puncture:
Transseptal Punctures can be safely performed using radial ICE guidance. A suitably sized Mullins introducer sheath (10-11 French) can be used to position the radial ICE catheter along the interatrial septum as shown in Figure 1. The Mullins sheath provides enough maneuverability to adjust the ICE catheter position in both inferior-superior and anterior-posterior directions to optimize the location of transseptal puncture in the fossa ovalis. Once ICE localization of transseptal needle showing tenting of the septum in suitable fossa is obtained LAO fluoroscopy is then used to guide the transseptal puncture and advancement of left atrial sheath.
Figure 1 Radial ICE Guidance of Transeptal Puncture for Left Atrial Access. The left and right atria are well-visualized with the ICE catheter in the right atrium along the interatrial septum in the fossa ovalis. One can see the tenting evident when transseptal needle is in good contact with the interatrial septum.
The following video shows the interatrial septum with radial ICE located in the right atrium. You see tenting of the septum and subsequent transeptal puncture facilitating left atrial ablation. Once transeptal access is achieved using an 8F Mullins sheath, a long wire exchange is performed to allow placement of the steerable sheath through which radial ICE is placed. An additional transeptal puncture is performed and wire exchange placement of 8.5Fr SRO sheath through which an irrigated tip ablation catheter is placed.
Intra Left Atrial Radial ICE:
Left Atrial Ablations can be enhanced and accomplished using intra left atrial radial ICE (with intraprocedural heparinization for target ACT>300). [1,2,3] Radial ICE is a useful adjunct imaging technique for several reasons. First, direct visualization of the electrode-endocardial interface allows precise positioning of the ablation electrode to guide lesion formation. Second, radial ICE permits the delivery of “focal” left atrial ablative lesions; the electrode kept in same location throughout energy application by manipulating the ablation electrode into firm, stable endocardial contact during continuous ICE imaging of the electrode–endocardial interface. Third, the use of continuous radial ICE during atrial fibrillation ablations allows close monitoring of catheter position and endocardial contact while minimizing dependence on fluoroscopy. Figure 2 depicts a typical view obtained when radial ICE is positioned in the left atrium using a steerable sheath (Agilis, St. Jude Medical, Inc., St. Paul, MN).
Figure 2 Intra Left Atrial Radial ICE Imaging During Atrial Fibrillation Ablation Left Pulmonary Venous Antrum Isolation. The radial ICE catheter is positioned at the entrance to the left PV antrum with the tip of the ablation catheter (Thermocool irrigated tip, Biosense Webster Inc, Diamond Bar, CA) located at ~9 o’clock on the antrum. The inset shows the analogous location of ablation catheter on 3D CT reconstruction of the left PV antrum.
Detailed anatomy of the pulmonary veins can also aid in catheter positioning and stability as well as monitor for procedural complications. Figure 3 provides views of the left and right pulmonary vestibules. The left upper (LUPV) and lower pulmonary veins (LLPV) are visualized as are the saddles. The right intervenous saddle is not as clearly differentiated as the left in this particular example to give the reader a better overall view of the structures surrounding the right pulmonary vestibule such as SVC, main PA, and Waterston’s groove (WG). Waterston’s groove is a fat-filled depression formed as the left and right atria fold into one another; Waterston’s groove is often dissected by surgeons to expose the left atrium. Radial ICE can be carefully placed within each individual pulmonary veins to guide catheter ablation as previously described. [1,2,3]
Figure 3 Radial ICE Anatomy of Left and Right Pulmonary Vestibules. The right pulmonary vestibule is shown with the early portions of the upper and lower pulmonary veins. Superior to the right pulmonary veins one can see the main pulmonary artery and superior vena cava. The approximate location of Waterston’s groove is depicted by the solid line. A more distal view of the left pulmonary vestibule (compared to Figure 2) clearly differentiates the upper and lower PV’s as well as the intervenous saddle.
Intra Left Atrial ICE-Guided Atrial Fibrillation Ablation via Wide Pulmonary Venous Antrum Isolation:
Left Pulmonary Venous Antrum Isolation
Once double transeptal access is obtained, the posterior left atrium pulmonary antrum isolation is started. I generally create a Fast Anatomic Mapping (FAM and CARTO, Biosense Webster, Inc., Diamond Bar, CA) shell of the left atrium trying to capture the anatomy of the left and right pulmonary veins to accurately recreate similar anatomy from the preoperative CT scan. This FAM shell is a complement to the real-time radial ICE that actually guides my ablation catheter placement. The left pulmonary vestibule is first encircled by placing a series of focal lesions applied contigously. Ablation is performed during sinus rhythm. High-frequency ventilation is used to minimize posterior LA motion. Each encircling lesion is composed of a series of contiguously applied (defined by direct contact of adjacent CARTO icons) “focal” (e.g., electrode kept in same location throughout energy application) lesions. For each focal lesion, the ablation electrode is manipulated under ICE guidance into firm, stable endocardial contact. RF energy was delivered during continuous ICE imaging of the electrode–endocardial interface.
The following video shows catheter position while ablating the posterior aspect of the left pulmonary vestibule. Note the appearance of “bubbles;” this is saline irrigation during ablation. The 3D reconstructions CT scan below the video shows the approximate site of ablation catheter and the overall goal ablative lesion set pathway for the primary encircling of the left pulmonary vestibule.
After deployment of this primary line of encircling lesion, I document that the myocardium subtended by the lesion is electrically isolated using entrance and exit block criteria. The radial ICE catheter is then placed into the left upper pulmonary vein (LUPV) and entrance block is assessed by examining pulmonary vein (PV) potentials; PV potentials in the LUPV are ablated down to the first branch of the LUPV. Exit block is assessed by unipolar pacing from the ablation catheter; any LUPV capture site is ablated as I pull back toward the primary encircling lesion set. The following video shows the ICE catheter inserted into the LUPV with an esophageal probe at 11AM and the ablation catheter at 5PM. The course of the esophagus is a bit unusual in this case and clearly lower power ablative lesions are carefully delivered (and sometimes deferred) to minimize the risk of esophageal damage.
If entrance and exit block are not documented secondary lesions are placed within the primary line to obtain isolation. One can see that radial ICE is used to guide ablation catheter position, maintain catheter stability, and watch for any endocardial damage (such as “heaping”). Once LUPV lesions (if necessary) are completed, the ICE catheter is moved into the LLPV and the PV potential mapping/ablation process is repeated as above. The following video shows the ICE catheter being moved from the LUPV into the LLPV.
The following video shows mapping in the LLPV down to the first branch of the LLPV that is evident on ICE.
After the left pulmonary antrum is isolated, this procedure is repeated for the right pulmonary antrum.
Right Pulmonary Venous Antrum Isolation
Figure 3 depicts still frames of the pulmonary venous antrums. The following video shows a typical view of the right pulmonary venous antrum. The initial portion shows a real-time view of the right pulmonary venous antrum and then the ICE catheter is advanced into the RUPV; towards the end of the video you can see the ablation catheter enter the RUPV and located at the roof ~12P.
Similar to the left pulmonary venous antrum, the right pulmonary vestibule is first encircled by placing a series of focal lesions applied contigously. After deployment of this primary line of encircling lesion, I document that the myocardium subtended by the lesion is electrically isolated using entrance and exit block criteria. The radial ICE catheter is then placed into the right upper pulmonary vein (RUPV) and entrance block is assessed by examining pulmonary vein (PV) potentials; PV potentials in the RUPV are ablated down to the first branch of the RUPV. Exit block is assessed by unipolar pacing from the ablation catheter; any RUPV capture site is ablated as I pull back toward the primary encircling lesion set. Once RUPV lesions (as necessary) are completed, the ICE catheter is moved into the RLPV and the PV potential mapping/ablation process is repeated as above. The following video shows the ICE catheter being moved from the RUPV into the RLPV.
Ultimately, a complete right and left pulmonary venous antrum isolation is completed. The final figure below shows a typical final CARTO lesion set with the analogous course of ablative lesions (including ablation within the pulmonary veins) shown on the 3D CT reconstruction.
Left and right pulmonary venous antrum isolation can be completed using intra left atrial radial ICE guidance with the complementary use of 3D intracardiac mapping. The radial ICE ensures stable endocardial contact and guides catheter/lesion placement. In addition, real-time radial ICE guidance can enhance safety by highlighting esophageal location as well as provide electroanatomic correlation.
Note: Many thanks to my mentor Dr. David Schwartzman who took the time to teach me radial ICE and atrial fibrillation ablations!
1 Schwartzman D, Nosbisch J, Housel D. Echocardiographically guided left atrial ablation: characterization of a new technique. Heart Rhythm, V. 3 (2006), pp. 930–938.
2 Schwartzman D, Williams JL, “On the Electroanatomic Properties of Pulmonary Vein Antral Regions Enclosed by Encircling Ablation Lesions,” Europace , V. 11 (2009), pp. 435–444.
3 Chandhok S, Williams JL, Schwartzman DS, “Anatomical analysis of recurrent conduction after circumferential ablation,” J Intervent Card Electrophysiol, V. 27, No. 1 (January 2010), pp. 41-50.