In this interview, we speak with Dr. Hany Demo, a cardiac electrophysiologist with Swedish Covenant Hospital in Chicago, Illinois.
Tell us about your EP program at Swedish Covenant Hospital.
We have a strong and robust EP program at Swedish Covenant Hospital. We treat a wide variety of arrhythmias and perform a wide range of complex ablations, including radiofrequency and cryoablation for atrial fibrillation, typical and atypical atrial flutter, SVT, PVC, and ventricular tachycardia ablation. We perform all kinds of device implants. We are building a new electrophysiology laboratory with state-of-the art technology to help us continue to carry out our commitment of delivering the best care for our patients.
We also have a very busy device clinic with thousands of patients enrolled in remote monitoring. We are in the process of starting a dedicated atrial fibrillation clinic that will be centered around patient education and engagement while providing state-of-the-art care.
What is your case volume? How many catheter ablations are performed each month?
Our lab case volume has been steadily and strongly growing over the past two years. We average around 40 to 45 EP cases monthly, with about 30 ablation cases.
How long have you been performing fluoroless catheter ablation at Swedish Covenant Hospital? What percentage of your ablations are fluoroless?
I have been performing fluoroless catheter ablation since January 2016, when I first joined Swedish Covenant Hospital. All of our ablations are performed fluorolessly. So far, I have performed more than 750 zero fluoroscopy ablations.
What made you decide to adopt a fluoroless approach at Swedish Covenant Hospital?
I was fortunate to be trained and mentored during my electrophysiology fellowship by Dr. Mansour Razminia, who is considered one of the pioneers in fluoroscopy reduction and elimination techniques. In 2017, we published our five-year experience showing fluoroless ablations can be performed without compromising safety, efficacy, or procedural duration.1 Because of the advantages of fluoroless ablations, including eliminating risk of radiation to the patients and lab personnel while not compromising patient safety or outcomes, I started to perform all endocardial ablations at Swedish Covenant Hospital using a fluoroless approach.
What is your approach to fluoroless ablation? Describe your technique for performing a completely fluoroless ablation procedure.
My approach to fluoroless ablations relies mainly on the use of intracardiac echocardiography (ICE) and a three-dimensional electroanatomical mapping system (EAM).
To perform fluoroless cryoballoon ablation (CBA), I start by obtaining percutaneous femoral venous access using a modified Seldinger technique guided by vascular ultrasound. A 14 French (Fr) sheath is placed in the right femoral vein, and a 10 Fr long sheath and 7 Fr sheath are placed in the left femoral vein. A 9 Fr ICE catheter (ViewFlex, Abbott) is inserted through the 10 Fr long sheath in the left femoral vein and advanced to the right atrium (RA).
The 6 Fr decapolar catheter (Inquiry Diagnostic Catheter, Abbott) is inserted into the left femoral vein and advanced to the inferior vena cava (IVC) under the guidance of the EAM system (EnSite Precision Cardiac Mapping System, Abbott). Under ICE and EAM guidance, 3D geometries of the IVC, superior vena cava (SVC), right atrium, and coronary sinus are collected.
To perform transseptal puncture, starting from the home view on ICE, clockwise rotation is added to visualize the interatrial septum and left atrium (LA). Then, a posterior tilt is added and minimal counterclockwise rotation is applied to visualize the SVC. Next, through the 14 Fr sheath, a 180 cm 0.032 Fr J-wire is advanced inside the SVC under direct visualization of ICE (Figure 1). The transseptal sheath-dilator assembly (SL-0, Abbott) is inserted through the 14 Fr sheath and advanced over the wire into the SVC. The wire is then withdrawn from the body. The transseptal needle (NRG RF Transseptal Needle, Baylis Medical) is placed in the sheath-dilator assembly, which is then withdrawn minimally to expose the blunt tip of the RF transseptal needle. The transseptal assembly is withdrawn into the RA while tracked on ICE, until tenting of the interatrial septum is seen on ICE (Figure 2). Transseptal puncture is performed using radiofrequency. Hemodynamic pressure monitoring is used to confirm entry into the LA along with direct ICE visualization.
In preparation for sheath exchange, the J-wire is advanced through the transseptal sheath into the left superior pulmonary vein (LSPV), the location of which is confirmed under ICE (Figure 3). While maintaining the J-wire in the LSPV, the SL-0 sheath is withdrawn from the body along with the short 14 Fr access sheath and exchanged for a 15 Fr steerable sheath (FlexCath Advance, Medtronic). The 10.5 Fr, 28 mm cryoballoon (Arctic Front Advance, Medtronic) and a 10-pole circular mapping catheter (Achieve, Medtronic) are placed through the 15 Fr steerable sheath into the LA.
The ostia of the pulmonary veins (PVs), as visualized by ICE, are delineated on the mapping system using the circular mapping catheter. Three-dimensional geometry of the PVs and LA on the mapping system is created as we sequentially isolate the pulmonary veins.
The circular mapping catheter is advanced into the LSPV. The balloon is inflated and moved to the antrum of the vein. ICE is utilized to confirm the alignment of the transseptal sheath and the balloon prior to cryo application (Figure 4). Achievement of a pulmonary capillary wedge pressure waveform on hemodynamic pressure monitoring signifies complete occlusion of the vein (Figure 5). A lack of color-flow Doppler within the targeted PV serves as an additional indicator of adequate PV occlusion. I perform a thorough search for leaks on color-flow Doppler by applying small degrees of clockwise and counterclockwise rotation to evaluate for potential leaks.
In order to maneuver from the left-sided PVs over to the right-sided PVs, the deflated balloon is withdrawn into the sheath, leaving the circular mapping catheter outside of the sheath, which can be seen on ICE and the EAM system. The sheath is then maximally deflected and rotated 180 degrees clockwise. At this point, the circular mapping catheter should be seen close to or within the ostium of the right inferior pulmonary vein (RIPV), and should be maneuvered well into the RIPV as clearly seen on the longitudinal ICE view.
Visualizing longitudinal axis of the right-sided veins on ICE is sometimes challenging. I use different approaches to obtain clear visualization of the right-sided veins prior to performing CBA of such veins. One approach can be achieved while the ICE is in the RA. Start by clockwise rotation of the ICE from home view to visualize the ostium of the right inferior pulmonary vein, then slightly withdraw the ICE catheter while applying minimal anterior and leftward tilts. If faced with a challenging interatrial septum that is encumbering clear visualization of the pulmonary veins while in the right atrium, I routinely place the ICE catheter in the left atrium, SVC, or the coronary sinus for superior visualization.
Prior to CBA for the right-sided PVs, the 6 Fr decapolar catheter is maneuvered to the SVC under ICE and EAM guidance to pace at high output to monitor the integrity of the phrenic nerve during cryo applications. Diaphragmatic capture is monitored through compound motor action potentials (CMAP) and by manual tactile monitoring of right-sided diaphragmatic stimulation. After isolation of each pulmonary vein, the circular mapping catheter is used to confirm entrance and exit block.
Can you describe a recent case in which no fluoroscopy was used?
We recently treated a 45-year-old male who presented with heart failure and systolic dysfunction caused by high-burden ventricular ectopy that was estimated at 45% on a 48-hour Holter monitor. His PVCs originated from the right coronary cusp. With the aid of ICE and using our fluoroless ablation approach, we were able to safely and successfully ablate his PVCs and without the need for coronary angiography. ICE allowed me to visualize the ostium of his right coronary artery (Figure 6) as well as the proximity and safety of my ablation lesions. A few weeks later, his echocardiogram showed normalization of his left ventricular function and he was taken off all heart failure medications.
What tips can you offer for safely monitoring esophageal temperature without fluoroscopy?
We are currently using the single sensor temperature probe in our lab, and plan to start using a multi-sensor self-expandable probe soon.
I make a cross-shaped slit at the tip of the temperature probe while preserving the integrity of the sensor. I insert a quadripolar catheter into the lumen of the probe. Once the proximal tips of the temperature probe and quadripolar catheter are aligned, I use a marker to mark the distal end of the probe. The temperature probe is placed in the esophagus. When the tip of the quadripolar catheter has exited the esophageal temperature probe, the quadripolar catheter tip may be visualized on the cardiac mapping system and geometry of the esophagus is created. In this fashion, the relative location of the temperature probe within the esophagus can be known as the different pulmonary veins are isolated. The temperature probe can also be visualized on ICE.
What refinements do you continue to make to your fluoroless technique?
I continue to refine my fluoroless technique. In addition to traditional ICE views from the right atrium and right ventricle, I now maneuver the ICE catheter into the left atrium, left ventricle, coronary sinus, SVC, and pulmonary artery in order to achieve the best visualization of the different cardiac structures, contact with the ablation catheter, and effect of ablation on the tissue.
I have also recently performed a few select cases of cryoballoon ablation for paroxysmal atrial fibrillation using only ICE and without the use of EAM.
What advice can you offer others about how to adopt a zero fluoroscopy approach (versus a minimal fluoro approach)?
I advise becoming familiar with basic ICE views and gradually building up an understanding of the different views and maneuvers. After observing some cases, one should start with right-sided ablations until they become more comfortable; they can then proceed with left-sided ablations. Dr. Razminia and Dr. Paul Zei also just recently published a great textbook (Fluoroscopy Reduction Techniques for Catheter Ablation of Cardiac Arrhythmias; Cardiotext Publishing) that describes their step-by-step fluoroless ablation technique.
Any final thoughts?
Thank you for the opportunity to discuss fluoroless ablation — it’s a topic that I am very passionate about. I do hope that we will soon have more EP fellowships where fellows can be trained to do fluoroless ablations.
Disclosure: Dr. Demo has no conflicts of interest to report regarding the content herein. Outside the submitted work, he reports personal fees as a consultant for Medtronic and Abbott.
- 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.