In this interview we speak with Mansour Razminia, MD, about his techniques for nonfluoroscopic catheter ablation of cardiac arrhythmias in adults.1 Dr. Razminia and colleagues recently published research from their retrospective analysis performed in two patient groups. Dr. Razminia is the Medical Director of the Cardiac Electrophysiology Lab and Director of Interventional Electrophysiology at Advocate Illinois Masonic Medical Center in Chicago, Illinois.
How long has nonfluoroscopic catheter ablation been utilized in your lab?
Our first nonfluoroscopic catheter ablation was in July 2010. Since December 2010, we have not used any fluoroscopy during our catheter ablations, having performed more than 200 consecutive cases. Arrhythmias that we have treated with fluoroless catheter ablation include atrial fibrillation, atrial tachycardia, left- and right-sided atrial flutter, atrioventricular nodal reentrant tachycardia (AVNRT), and atrioventricular reciprocating tachycardia (AVRT). We have also performed fluoroless ablations for several ventricular tachycardias (VT), including ischemic VT, left- and right-sided outflow tract VT, and coronary cusp VT and fascicular VT.
Tell us about some of the benefits of the nonfluoroscopic approach.
There are numerous benefits to using a nonfluoroscopic approach. Perhaps most important is the elimination of radiation risk to the patient. Whereas a traditional fluoroscopic approach increases the lifetime risk of fatal malignancies, genetic defects, skin injuries, and cataracts, a nonfluoroscopic approach can be used to effectively avoid such risks. This becomes especially important in patients undergoing repeated and prolonged ablations of complex arrhythmias. These risks are relevant to the EP lab staff as well because they work on a regular basis in a radiation-intense environment.
Another benefit of the nonfluoroscopic approach is that it can be used effectively and safely in certain patient groups (e.g., children or pregnant patients) where the traditional fluoroscopic approach carries more risk.
An additional benefit is that the EP staff can avoid the fatigue and orthopedic injuries related to the use of heavy lead protective garments.
An often-overlooked benefit of the nonfluoroscopic approach is that the operator must rely more on the adjunctive imaging technologies of electroanatomical mapping (EAM) and intracardiac echocardiography (ICE). These technologies, especially when used in combination, provide a more precise means of catheter positioning as compared to the two-dimensional views employed when one relies on fluoroscopy. ICE offers direct views of structures not directly seen with fluoroscopy, such as the cavotricuspid isthmus and the pulmonary vein ostia. In addition, tissue apposition is clearly seen during ablation when using ICE.
Tell us about your recent study.
Discuss the two patient groups in this study. What types of arrhythmias were treated in these patient groups?
The first group was a nonfluoroscopy (NF) group consisting of 60 consecutive adult patients, in which catheter positioning was accomplished exclusively with intracardiac electrograms (IE), EAM, and ICE. The NF group was compared to a fluoroscopy (F) group of 60 consecutive patients, in which catheter positioning was guided by fluoroscopy, intracardiac electrograms, EAM and ICE. Both groups included equivalent numbers of the following arrhythmias: atrial fibrillation, atrial flutter, atrial tachycardia, AVNRT, AVRT, and VT.
Give us an example of your techniques for catheter positioning in nonfluoroscopic ablations utilizing intracardiac electrograms, electroanatomic mapping, and/or ICE. What was a typical procedure like?
Our procedures are performed in a standard electrophysiology lab. The fluoroscopy machine is always available but disabled. None of the members of the staff, including the operator, wear lead aprons throughout the procedure. One of the most common procedures we perform is the ablation of atrial fibrillation. We begin by positioning the catheters in the right heart. First an ICE catheter is advanced from the femoral vein to the right atrium by direct ultrasound visualization of the IVC lumen and intracardiac structures. Then, a deflectable decapolar catheter is advanced from the femoral vein to the right atrium under EAM guidance, which is used to collect the geometry of the inferior vena cava (IVC), superior vena cava (SVC), and right atrium before being placed in the coronary sinus.
Next, to perform a transseptal puncture, we insert a 180 cm J-wire 0.032” into the right atrium, with the tip’s location confirmed on ICE. A transseptal sheath-dilator assembly (ACross Transseptal Access System, St. Jude Medical) is then advanced over the wire approximately 4 to 8 inches, depending on patient size. The dilator and J-wire are then withdrawn and the ablation catheter is advanced through the sheath into the SVC. The ablation catheter’s location can be tracked on EAM once the distal electrodes have exited the sheath. The sheath is then advanced over the ablation catheter until a deflection artifact is seen on EAM. This deflection provides confirmation that the sheath has reached the SVC. The ablation catheter is removed.
Finally, the J-wire and dilator are advanced through the sheath as a unit so that the J-wire tip is in advance of the
dilator tip by approximately 3 inches. Once the dilator is fully advanced and locked into the sheath, the guide wire is removed. The transseptal needle is inserted into the sheath-
dilator assembly. In the locked position, the entire system is pulled down until the distal tip of the assembly abuts the interatrial septum as visualized by ICE. The system is unlocked, which allows advancement of the needle to approximately 7 mm beyond the tip of the dilator to facilitate transseptal puncture.
To avoid inadvertent puncture of the aorta or the left atrial posterior wall, the puncture is performed under ICE guidance in a view that allows for simultaneous imaging of the tented fossa ovalis and the two left-sided pulmonary veins. The use of ICE allows us to directly visualize the transseptal assembly as it is advanced into the body of the LA. We typically perform two transseptal punctures, with weight-adjusted intravenous heparin initiated prior to the first transseptal puncture.
A circular catheter is inserted through the transseptal sheath and used to create left atrial and pulmonary vein geometries under ICE and EAM guidance. During the ablation, both the circular and ablation catheters are visualized at all times using a variety of ICE views, as well as EAM.
How did procedure times
differ in nonfluoroscopic cases versus ablation cases using
fluoro? What have been the
success rates in the nonfluoroscopy group thus far?
The procedure times, when broken down by specific arrhythmia, were similar in the NF group and the F group. Variations in procedure time for a given arrhythmia were related to situations in which multiple arrhythmias or pathways were ablated. Since the study was completed, we have grown even more comfortable with the nonfluoroscopic approach, and our procedure times have further diminished. As an example, a fluoroless catheter ablation for AVNRT can be performed in one hour and a fluoroless catheter ablation for atrial fibrillation can be completed in two to three hours.
In the study, acute procedural success rates were similar in both the NF and F groups. The success rate was 98 percent (59/60) in the NF group and 100 percent (60/60) in the F group. The single failure in the NF group involved a patient who had a VT that was ultimately thought to have originated from an intraseptal location after extensive mapping was undertaken in the right ventricular and left ventricular tracts and the aortic cusp regions.
Are nonfluoroscopic ablations now being performed by all operators in your lab? What has the learning curve been like in regards to the fluoroless ablation technique?
Nonfluoroscopic ablations are now being performed by all of the members of my team. The idea to pursue nonfluoroscopic catheter ablation came to me after a trip I took to Drs. Ian Law and Nicholas Von Bergen’s electrophysiology lab at the University of Iowa in July 2010. Dr. Law and Dr. Von Bergen are pediatric electrophysiologists who perform fluoroless ablations in the pediatric population. After observing a case of AVNRT ablation and discussing the principles and techniques involved in fluoroless ablation, I was able to perform my first fluoroless atrial flutter ablation the following day. The learning curve has been quite sharp. Within six months after visiting their lab and performing some nonconsecutive fluoroless ablation cases, we had switched over to a strictly nonfluoroscopic approach for all of our cases.
What is significant about this study? How do you see the use of nonfluoroscopic ablation changing the field of EP?
What is significant about this study is that the fluoroscopy-related radiation risk to the patients and staff can be eliminated using a nonfluoroscopic approach that is safe, effective and does not prolong procedure duration. Our study was the first to show how fluoroless ablation could be performed in an unselected patient population presenting with a wide range of arrhythmias. It was also the first to describe fluoroless ablation for ventricular tachycardia.
What tips do you have for others interested in switching to nonfluoroscopic catheter ablation for adult patients?
I would suggest that colleagues who are interested in switching to a nonfluoroscopic approach begin by focusing more on the IE signals as well as the EAM and ICE images during a fluoroscopic ablation. After becoming familiar with how the EAM, ICE, and IE correlate with a particular position on fluoroscopy, gradually less and less fluoroscopy can be used. Perhaps what I found most helpful in learning the fluoroless technique was taking a visit to a lab that is performing fluoroless ablations.
Is there anything you’d like to add?
As the medical community has become increasingly aware of the radiation and orthopedic risks related to using fluoroscopy, many labs are very interested in reducing the amount of total radiation during their procedures. It is my hope that, in the future, the fluoroless ablation technique will be utilized in the majority of — if not all — electrophysiology labs, thus reducing risk to both patients and EP staff.
- Razminia M, Manankil MF, Eryazici PL, et al. Nonfluoroscopic catheter ablation of cardiac arrhythmias in adults: feasibility, safety, and efficacy. J Cardiovasc Electrophysiol. 2012 Oct;23(10):1078-86. doi: 10.1111/j.1540-8167.2012.02344.x. Epub 2012 May 9.