Translational Pathway for Catheter Ablation



Gregory K. Feld, MD

Since the initial description of radiofrequency catheter ablation techniques for the treatment of supraventricular tachyarrhythmias (SVT) in the late 1980s (i.e., radiofrequency catheter ablation for atrioventricular nodal reentrant tachycardia and atrioventricular reentrant tachycardia due to accessory pathways), extensive advances and refinements have occurred in the systems and methods used to ablate these arrhythmias and prevent them from recurring. These include testing a wide variety of parameters such as catheter thrombegenicity, durability, steerability, flexibility and tortional rigidity, temperature sensing capabilities (i.e., with various sensors including thermocouples, thermistors, etc.), and the development of contact-force sensing (i.e., measuring grams of tissue contact force using physical spring-loaded force sensors, optical sensors, etc.), all with the intent of producing the transmural ablation lesions necessary for curing cardiac arrhythmias, and to do so safely; that is, to reduce risk of systemic embolization, cardiac perforation, and collateral tissue damage. This development and testing typically has been first performed in in vitro models, then in animal models, and then in humans, prior to U.S. Food and Drug Administration approval of the use of these various ablation systems and refinements to treat specific cardiac arrhythmias. During this period of ablation catheter development and testing, alternative energy sources for ablating cardiac tissue have also been studied and employed for treating cardiac arrhythmias (e.g., catheter and balloon cryoablation, laser balloon, hot balloon, and even a microwave antenna).

Additionally, it has been necessary to develop sophisticated three-dimensional cardiac mapping systems that can generate an internal or external cardiac geometry (i.e., endocardial and/or epicardial geometry), define critical tissue characteristics (i.e., voltage amplitude, impedance, conduction velocity, etc.) and display these parameters on the geometry as is it created (i.e., typically by moving the ablation and/or mapping catheters over the endocardial and/or epicardial surface of the heart), and to localize the ablation and mapping catheters within this geometry to increase the accuracy and durability of tissue ablation, in order to modify or cure these cardiac arrhythmias. While discussion of mapping system testing and development will not be the primary focus of this section of the document, it is nonetheless highly complex and integral to the advancement of catheter ablation techniques for the future treatment of cardiac arrhythmias.

As the methods for catheter ablation of common SVTs (i.e., atrioventricular nodal reentry, atrioventricular reentry due to an accessory pathway, atrial tachycardia, and even atrial flutter) have become relatively well established and commonplace, the development of ablation techniques for more complex cardiac arrhythmias, specifically atrial fibrillation and ventricular tachycardia or fibrillation, has become the primary focus of research and development in this area, including that of industry, basic researchers, and clinicians. Currently this is an area of extensive research, and an area for major advances in the future, particularly as the proportion of these specific arrhythmias increases in our aging and sicker population. Thus, progress in treatment of atrial fibrillation and ventricular tachycardia with ablation, will require major advances in both ablation and mapping technology.

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