Electrophysiology procedures rely heavily on fluoroscopy for visualization of diagnostic catheters, ablation catheters, and pacing and defibrillator leads. In fact, the modern EP lab is generally centered around the fluoroscopy unit. Over time, fluoroscopic imaging has improved, allowing electrophysiologists to see things in greater detail with less radiation exposure to patients and staff. Recently, there has been a move towards performing EP procedures with little to no fluoroscopy at all. This advance is made possible with the use of three-dimensional electroanatomical mapping systems which allow the physician to visualize a diagnostic or ablation catheter within a 3D model of the cardiac chamber with a great degree of accuracy and in near real-time with minimal latency. In addition to the advances in three-dimensional electroanatomical mapping, intracardiac echocardiography (ICE) has also advanced our ability to visualize catheters and cardiac structures during EP procedures. Using these tools in combination allows us to perform both routine and advanced EP procedures completely without fluoroscopy.
The problem with fluoroscopy is that it exposes our patients and staff to radiation. Although the exposure during a routine ablation may be minimized, the American Cancer Society acknowledges that there is no dose of radiation that can be considered safe. Fortunately, the EP community has started to work towards reducing the exposure to fluoroscopy during our procedures. In 2017, Dr. Mansour Razminia published his 5-year experience with fluoroless ablations. He reported on 500 consecutive patients who underwent ablations for SVT (including AVNRT, AVRT, and atrial tachycardia), atrial fibrillation, VT, and PVCs. In all but one patient (who required 0.3 minutes of fluoroscopy to confirm venous access), fluoroscopy was not used.1 More recently, a report on 1000 consecutive patients who underwent near-zero fluoroscopic atrial fibrillation ablation was published, showing that atrial fibrillation ablations could be performed with very low fluoroscopy times (<6 minutes) without compromising safety or efficacy.2
In our lab, I have adopted a completely fluoroless approach for all ablations. My first fluoroless procedure was performed on October 19, 2017. We were fortunate to have Dr. Razminia give us a presentation on his approach and technique. Based on his lecture, I was able to adopt his techniques to our EP lab. Since that time, my total fluoroscopy time for all ablations has been zero. I have now performed 113 ablations without fluoroscopy, including 58 atrial fibrillation ablations using the cryoballoon and over 50 ablations using remote magnetic navigation. I have not seen an increase in procedure times or complications. As others have reported, I have been able to perform fluoroless ablations with the same safety and efficacy as expected.
Our first step in starting this program was to start a case without wearing lead and without bringing the fluoroscopy unit over the patient. This helps to remove the temptation to step on fluoroscopy during the case, even for a few seconds. We rely heavily on ultrasound and three-dimensional mapping, and find that we actually are able to see more anatomy than we could with fluoroscopy. We routinely use ultrasound for femoral access. This allows us to see the needle as we gain access. We also can use the ultrasound to confirm that our guidewires are in the proper vessel.
Once femoral access is obtained, EP catheters may be advanced into the heart. At this time, we use three-dimensional electroanatomical mapping to create a 3D representation of the IVC (and aorta when appropriate) as we advance our catheters. With this technique, we can actually see more than fluoroscopy allows (Figure 1). Once we are in the heart, a three-dimensional model can be quickly created. This model is then used to guide placement of the EP catheters in the appropriate positions.
Once the EP catheters are in place, the ICE catheter is advanced. This can be advanced safely by using the ultrasound to visualize the IVC as it is being advanced. Once in the right atrium, it can be used to guide transseptal puncture. I routinely perform transseptal puncture using ICE alone. By visualizing the SVC, I can deploy a transseptal sheath over a J-wire. I can see the sheath and needle assembly engage the fossa ovalis, and I can accurately select an optimal site for transseptal puncture. (Video 1)
ICE is essential for performing pulmonary vein isolation with the cryoballoon system. During these procedures, the ICE catheter is generally passed into the left atrium, which allows for an excellent view of the pulmonary veins. Color Doppler is used to evaluate the flow around the cryoballoon prior to ablation. In addition to color Doppler, the PV pressure waveform is monitored to ensure that the balloon is completely occluding the pulmonary vein. Using these two techniques, intravenous contrast is not necessary to perform this procedure. (Figure 2, Video 2)
I use ICE to guide placement of our multipolar basket catheter during focal impulse and rotor modulation (FIRM) mapping. The left atrial diameter can be directly measured, which helps us choose an appropriately sized basket catheter. The catheter can be clearly seen as it is deployed through the transseptal sheath and into the left atrium. (Video 3)
Intracardiac echocardiography is surprisingly helpful in guiding ablation of atrial flutter. During these procedures, the ICE catheter is used to visualize the TV-IVC isthmus. The ablation catheter can be seen throughout the entire ablation procedure. Ridges and sulci can be easily identified and ablated. These areas are frequently missed when using electroanatomical mapping techniques or fluoroscopic guidance. (Video 4)
Ventricular tachycardia ablations are also performed with ICE visualization. During ablation in the left ventricle, the mapping and ablation catheters can be visualized directly by placing the ICE catheter into the right ventricle and posteriorly turning the catheter. This is especially useful during ablation around the papillary muscles.
I have performed fluoroless ablations in patients with pacemakers and ICDs in place. Leads are easily seen using ICE. There have been no lead dislodgements during these ablations. I routinely perform threshold tests before and after ablation procedures.
There are clear advantages to performing these procedures without fluoroscopy. There is obviously no exposure to radiation, even during lengthy procedures. In addition, there is no need to wear lead, which reduces the risk of orthopedic problems that are frequently reported amongst interventional cardiologists and radiologists.
Unfortunately, we are not yet able to perform all EP procedures without fluoroscopy. The obvious example is a device (pacemaker or ICD) implant. It is possible to visualize pacing and defibrillator leads using electroanatomical mapping systems. This can certainly aid in positioning leads, especially during His bundle pacing. However, we currently have no technique for assessing the slack in the lead. Furthermore, bipolar pacing leads are not rendered as accurately as a multipolar EP catheter. Finally, sheaths cannot be visualized at all, which is a hindrance during CS cannulation or deployment of a leadless pacemaker. Hopefully, newer lead and sheath designs will allow better visualization to allow us to perform these procedures without fluoroscopy.
In summary, it is possible to perform all ablation procedures, including atrial fibrillation ablations, completely without fluoroscopy. I believe that this is the beginning of a new mindset for electrophysiology, as it is clear that more and more electrophysiologists are adopting these techniques. We are grateful for the efforts of visionaries such as Dr. Razminia, who have developed this field and acted as teachers and mentors for those of us who want to be "unleaded."
Disclosure: Dr. Dell'Orfano has no conflicts of interest to report regarding the content herein. Outside the submitted work, he reports that he is on the Speakers' Bureau for Abbott Medical.
Follow Dr. Dell'Orfano on Twitter at @jdellorf
1. Razminia M, Willoughby MC, Demo H, et al. Fluoroless Catheter Ablation of Cardiac Arrhythmias: A 5‐Year Experience. Pacing Clin Electrophysiol. 2017;40(4):425-433.
2. Sommer P, Bertagnolli L, Kircher S, et al. Safety profile of near-zero fluoroscopy atrial fibrillation ablation with non-fluoroscopic catheter visualization: experience from 1000 consecutive procedures. Europace. 2018;20(12):1952-1958.