Cardiac Mapping: Utility or Futility?

Introduction: Cardiac mapping is a broad term that covers several modes of mapping such as body surface,1 endocardial,2 and epicardial3 mapping. The recording and analysis of extracellular electrograms, reported as early as 1915, forms the basis for cardiac mapping.4 More commonly, cardiac mapping is performed with catheters that are introduced percutaneously into the heart chambers and sequentially record the endocardial electrograms with the purpose of correlating local electrogram to cardiac anatomy. These electrophysiological catheters are navigated and localized with the use of fluoroscopy. Nevertheless, the use of fluoroscopy for these purposes may be problematic for a number of reasons, including: 1) the inability to accurately associate intracardiac electrograms with their precise location within the heart; 2) the endocardial surface is invisible using fluoroscopy and the target sites can only be approximated by their relationship with nearby structures such as ribs, blood vessels, and the position of other catheters; 3) due to the limitations of two-dimensional fluoroscopy, navigation is not exact, time consuming, and requires multiple views to estimate the three-dimensional location of the catheter; 4) inability to accurately return the catheter precisely to a previously mapped site; and 5) exposure of the patient and medical team to radiation. Newer mapping systems have revolutionized the clinical electrophysiology laboratory in recent years and have offered new insights into arrhythmia mechanisms. They are aimed at improving the resolution, three-dimensional spatial localization, and/or rapidity of acquisition of cardiac activation maps. These systems use novel approaches to accurately determine the threedimensional location of the mapping catheter and local electrograms are acquired using conventional, well-established methods. Recorded data of the catheter location and intracardiac electrogram at that location are used to reconstruct in real-time a representation of the threedimensional geometry of the chamber, color-coded with relevant electrophysiological information. However, these mapping systems are very expensive and not required for the commoner clinical arrhythmias like atrioventricular nodal reentry (AVNRT), accessory pathway mediated tachycardia (WPW syndrome and concealed pathways) and typical atrial flutter. The purpose of this article is to discuss the possible contribution of newer cardiac mapping system to treat various arrhythmias.