Expecting the Expected

A n invariable hallmark of an experienced invasive electro- physiologist is his or her ability to thoroughly examine preprocedural data so as to anticipate the likely site of successful ablation.Indeed, teaching rounds for electrophysiology at any institution is likely replete with examples of how careful analysis of the ECG and structural imaging data are used to anticipate not only where to ablate but also the specific anatomic hurdles that may be encountered, facilitating planning to avoid complications.Although advanced imaging has become increasingly useful to understand substrate abnormalities, the mainstay for preprocedural prediction of successful ablation remains the ECG. See Article by Namdar et al ECG and the Electrophysiologist: Best Friends ForeverFrom the outset, the field of electrophysiology has relied heavily on the ECG for clinical and invasive diagnoses.Every student's knowledge base includes ECG localization for accessory pathways and detailed ECG vector analysis to diagnose the origin of monomorphic ventricular tachycardia and atrial tachycardia. 1 In this installment of Teaching Rounds in Cardiac Electrophysiology, Namdar et al 2 add to this legacy instructing us on an advanced multielectrode surface ECG analysis system that allowed a surprisingly high degree of spatial resolution in identifying a coronary venous epicardial ventricular tachycardia focus.The authors elegantly instruct us on the use of the new system, but, more importantly, provide a perspective on analyzing the different kinds of information-ECG, structural integration with the refined electrocardiographic data, and knowledge of the relevant anatomy when mapping epicardially and within the venous system.We also need to understand, however, the limitations inherent in the ECG even despite with sophisticated processing and image integration.