In this interview, we speak with Ashit G. Patel, MD, FACC, FHRS, private practice electrophysiologist with Cascade Cardiology, LLC in Salem, Oregon, about his techniques for managing complex EP procedures. Dr. Patel serves as the Director of Cardiac Electrophysiology at Salem Hospital as well as an Assistant Professor of Medicine at the Oregon Health and Science University.
Tell us about your EP program.
Salem Hospital’s EP program consists of 3 electrophysiologists, 1 EP nurse coordinator, and 3 dedicated EP technologists. In addition, we have cardiac catheterization lab personnel to assist when staffing requires. We have one EP lab that is shared with the 6 labs within the Cardiac Catheterization department. Per month, our program averages 120 procedures, consisting of: ablations (18-20 AFib, 5-7 VT / PVC, and 14-16 SVT),70-75 device implants, and laser lead extractions.
What are your preferred High Density (HD) mapping tools and why?
I have experienced mapping tools from all three current manufacturers over the last 10 years of practice. My HD mapping catheter preference for both atrial and ventricular arrhythmias is the AFocus II Double Loop (Abbott) and the Livewire HD-20 (Abbott). The maps created with the use of these catheters provide me with an accurate, high-resolution, highly dense electroanatomic reconstruction within a short period of time.
What features of the EnSite Precision Cardiac Mapping System do you value most in the diagnosis and treatment of complex cases?
We used CARTO (Biosense Webster, Inc., a Johnson & Johnson company) for the majority of procedures during my EP fellowship at Oregon Health and Science University. The EnSite Array (Abbott) was called upon for the occasional non-sustained rhythms, with the single beat isopotential / voltage mapping applications. EnSite has been my main mapping system of choice since leaving my fellowship. I quickly realized the system’s flexibility and adaptability to map any arrhythmia. Furthermore, it allowed me to develop skills to minimize use of fluoroscopy. In the last 7 years, my procedures have been predominately performed without fluoroscopy. My technique requires an accurate stable navigation, which this system provides. My most valued feature is the system’s ability to create a highly dense geometry, activation, and voltage map without the use of internal timing or positional references.
How important is lateral contact force accuracy in ablating the papillary muscle PVC?
Contact force has been a pivotal advancement for radiofrequency ablation. The lateral contact force indicator of a catheter is extremely important. The majority of the procedures performed are positioned with a lateral catheter tip orientation. The TactiCath catheter (Abbott) has the most accurate real-time contact force on the market in both axial and lateral orientations. This allows for a more effective lesion delivery and minimizes complications related to catheter tip force. When ablating papillary muscle PVC/VTs, there are often times where you feel the tip is in the correct location based on electrograms and the feel of the catheter; however, there is zero grams of force. Based on the anatomic morphology of the papillary muscle, an axial orientation, it is not always possible, and thus, the use of lateral force is important for lesion efficacy. Intracardiac echocardiography (ICE) has been widely used in ablations to visualize endocavitary structures; however, ICE guidance can often be misleading, showing proximal electrodes instead of the ablating tip in contact with the papillary muscle. In such cases, slow retraction of the catheter until achieving an adequate lateral force reading is needed.
How do you utilize the current (side by side) combination of ICE and EnSite Precision Cardiac Mapping System to efficiently map and ablate endocavitary structures?
ICE is an adjunctive imaging tool that can be used in complex ablations, but is not required for mapping of endocardial or endocavitary structures. EnSite Precision allows for rapid high-density electroanatomic reconstructions, including papillary muscles and moderator bands. I use the electrical data, contact force, and ICE to further confirm these structure locations, as well as to increase the efficiency and efficacy of the procedure. In addition, I incorporate ICE to further minimize fluoroscopy to patients and staff.
Disclosure: Dr. Patel has no conflicts of interest to report regarding the content herein. Outside the submitted work, he reports personal fees as a consultant for Abbott.