Contact and noncontact electroanatomical mapping

Abstract

Cardiac arrhythmias are traditionally mapped by assessing the timing of electrical activation at various locations in the heart (endocardial, epicardial, or both) under fluoroscopic guidance. These observed timing data are interpreted by the physicians, and the potential sites of ablation are targeted. However, the importance of anatomic structures in the initiation and maintenance of cardiac arrhythmia is increasingly being recognized, mandating a better understanding and defi nition of the patient’s cardiac anatomy for successful electrophysiological procedures. There has been a signifi cant evolution of these electroanatomic systems to considerably enhance the electrophysiologists’ understanding of real-time position management and mapping, thus to enable more precise catheter navigation in different chambers of the heart. Once the image of the cardiac chamber of interest is created, the ablation catheter is moved to the appropriate target sites. Contact mapping technique involves the direct recording of electrical activity with electrodes positioned in selected places within the endocardial surface of the heart or the epicardium. In contrast, noncontact mapping does not require direct contact with the endocardium; the electrograms and the activation sequence are computed based on far-field interpolated voltage differences generated by myocardial depolarization. Image integration of the generated image with an anatomical image of computerized tomography (CT) or magnetic resonance imaging (MRI), although not traditionally included in the arsenal of electrophysiology, could be seen as useful adjuncts for precise and reproducible catheter guidance.