Catheter Ablation for Atrial Fibrillation Using a Zero Fluoroscopy Approach at McLaren Greater Lansing Hospital

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia, affecting approximately 5 million people. Pulmonary vein isolation (PVI) is the most effective rhythm control strategy in patients with symptomatic AF,^1-3 and the number of patients that will undergo PVI will likely increase in the near future. Over the years, the AF ablation procedure has evolved and continued to become safer, effective, and more efficient. AF ablation was initially performed with heavy use of fluoroscopy; however, physicians have begun to limit the use of fluoroscopy by learning to rely on 3-dimensional (3D) mapping and intracardiac echocardiography (ICE). Both technology and physician expertise in acquiring 3D electroanatomic maps and using ICE have improved significantly in the past few years, and there have been multiple reports in which radiofrequency (RF) ablation has been performed with either minimal or complete elimination of fluoroscopy. At McLaren Greater Lansing, we created our zero fluoroscopy program in 2018. We started the zero fluoroscopy technique for our AF ablation and atrial flutter cases, and are now performing ablations of all atrial arrhythmias as well as diagnostic EP studies without the use of fluoroscopy. In this paper, we describe our stepwise approach and strategy of minimizing or eliminating fluoroscopy using the CARTO mapping system (Biosense Webster, Inc., a Johnson & Johnson company).^4-12

Step-by-Step Description

After an overnight fast, patients are brought to the EP laboratory in the post-absorptive state. All patients are instructed to continue their anticoagulation before and after the procedure.

General anesthesia is involved in all cases, and patients are intubated. Three venous accesses are obtained on the right side, and 1 venous access is obtained on the left side.

Step 1: Venous access

One SR0 and 2 SL0 sheaths are inserted in the right femoral vein (RFV), and one 11 French (Fr) short sheath is inserted in the left femoral vein (LFV) using a modified Seldinger technique. Venous access is obtained using a micropuncture needle and ultrasound guidance.

Step 2: Advancing the catheter and creating a map

After obtaining left femoral venous access, a CARTOSOUND catheter (Biosense Webster) is advanced through the LFV using ultrasound guidance. If resistance is felt, the catheter is withdrawn and rotated, and advanced if no further resistance is felt. The catheter is advanced without using any force into the right atrium. Respiratory gating is performed either by placing a catheter in the hepatic vein or in the ventricle. Next, the catheter is placed in the right atrium to obtain the home view (Figure 1). 

A complete clockwise sweep from the home view will bring the coronary sinus, mitral valve, left atrial appendage (LAA), left inferior pulmonary vein (LIPV), and left superior pulmonary vein (LSPV) into view. Further, clockwise rotation brings the left atrial posterior wall, right inferior pulmonary vein (RIPV), pulmonary artery, and right superior pulmonary vein (RSPV) into view.

Step 3: Advancing long wires and sheaths

After obtaining a CARTOSOUND map of the left atrium, the ultrasound catheter is brought back to the home view. Posterior and right-sided tilt will bring the superior vena cava (SVC) into view (Figure 1E). At this time, long wires are advanced into the SVC under direct ultrasound guidance, and long sheaths are advanced over the wires (Figure 1F, Video 1).

Step 4: Advancing catheters

A THERMOCOOL SMARTTOUCH catheter (Biosense Webster) is advanced into the right atrium under direct visualization. Fast anatomical mapping (FAM) of the right atrium, His region, and coronary sinus is created at this time. Subsequently, under electroanatomic map guidance, the decapolar deflectable catheter is advanced and placed in the coronary sinus (Video 2). 

Step 5: Placing esophageal temperature probe

Once the coronary sinus catheter is placed, a multi-sensor esophageal temperature probe is placed under fluoroscopy and ICE guidance, with the most distal placed inferior to the coronary sinus os. The total fluoroscopy time is kept to less than 30 seconds. The fluoroscopy is disabled at this point.

Step 6: Transseptal puncture

Next, the long sheaths (SL0) are advanced over the ablation catheter into the SVC under ultrasound guidance and using the 3D map. A Brockenbrough transseptal needle is advanced along with dilators into the SVC. The dilator and needle/dilator-sheath assembly is withdrawn as a unit under direct ICE visualization. The engagement of the fossa ovalis with the dilator is noted, and transseptal puncture is performed with the tip of the dilator tenting the intra-atrial septum (IAS) towards the left-sided veins (Figure 1). Entry into the left atrium is confirmed by injecting saline into the left atrium. Subsequently, the needle and dilator are withdrawn while advancing the sheath. The procedure is repeated for a second transseptal as well. Throughout the procedure, ACT is maintained between 350 to 400 seconds using heparin boluses.

Step 7: Creating FAM of the left atrium, appendage, and pulmonary veins

The PENTARAY catheter (Biosense Webster) and ablation catheters are advanced through the transseptal sheaths into the left atrium. An extensive FAM, voltage, and activation map of the left atrium, LAA, and pulmonary veins is performed using the PENTARAY multipolar mapping catheter. 

Step 8: Ablation

Pulmonary vein isolation is performed by circumferential ablation around each pulmonary vein. Additional ablation (including roof, floor, mitral isthmus, or left atrial tachycardia ablation) is performed depending on the clinical scenario of each patient. PVI is assessed by confirming entrance (electrical silence in each vein) and exit block (pacing in pulmonary vein) in each pulmonary vein. A voltage map is also performed in each pulmonary vein (Video 3, Figure 2). After PVI and additional ablations are performed, dormant conduction in each vein is confirmed by placing the PENTARAY catheter in each vein and administering an IV injection of adenosine (12 mg) for each vein. After completing the left atrial ablation, including left atrial flutter (Figure 3), the catheters are withdrawn from the left atrium and placed in the right atrium. 

Step 9: Cavotricuspid isthmus (CTI) ablation

Depending on the clinical presentation, patients undergo CTI ablation as well, with confirmation of bidirectional block across the isthmus (Figure 4, Video 4). 

Step 10: Checking for pericardial effusion

After completing the ablation, the ICE catheter is placed in the right ventricle, and clockwise rotation is performed to visualize the left ventricle and rule out any pericardial effusion.

Step 11: Reversal of heparin, removal of sheaths, and hemostasis

Heparin is reversed using protamine. The sheaths are removed once the ACT is <200 seconds. Hemostasis is obtained using manual compression.

Discussion

There has been an increase in the widespread use of 3D electroanatomic navigation systems to minimize radiation exposure during mapping and RF ablation of tachyarrhythmias.¹¹ Intracardiac echocardiography may also be used to assist in the 3D reconstruction of the heart. Three-dimensional mapping systems have improved in recent years, and now allow contact force measurement as well as simultaneous visualization of multiple catheters. The use of 3D mapping systems in RF ablation procedures results in significantly reduced fluoroscopic times, thus minimizing the risks of ionizing radiation exposure to both patients and medical staff. 

In creating a zero fluoroscopy program, it is important for physicians to understand that the transition to zero fluoroscopy should be slow. Physicians must learn this technique in a stepwise fashion, and have a low threshold of using fluoroscopy when they think it is needed and/or when in doubt. The idea is to minimize the risk of radiation without increasing procedure-related risks or complications to patients. A change in mindset and motivation on the part of electrophysiologists is also important when starting a zero fluoroscopy program. There is a learning curve associated with incorporating this technique in the workflow, but as physicians become more comfortable with zero fluoro, the procedure times will shorten. 

The tools and technologies for implementing a successful zero fluoroscopy ablation program are readily available in almost every EP laboratory that performs AF ablations. The goal is to safely reduce or eliminate the use of fluoroscopy when feasible during most electrophysiology procedures.

Acknowledgments: We would like to acknowledge Jacquelyn Buckley, RN, BSN, CEPS, Senior Clinical Accounts Specialist at Biosense Webster, for her help with the images and pictures.

Disclosures: Dr. Kanjwal has no conflicts of interest to report regarding the content herein. Outside the submitted work, he is a consultant for Biosense Webster, Johnson & Johnson, and Abbott.

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