Ventricular tachycardia. Chipping away at finding curative therapy.

In clinical cardiology, therapy for the most part is still primarily palliative, whereas relatively few procedures are truly curative. In the early days of invasive electrophysiology, clinicians were excited about the ability to induce supraventricular tachycardia with single, critically timed atrial extrastimuli.1 Soon thereafter, a whole array of mechanisms that induced these tachycardias became evident. Tachycardia circuits could be categorized as those that were due to atrioventricular (AV) nodal reentrant circuits,2 those that incorporated extranodal bypasses,3 and those that included nodoventricular tracts.4 From this deeper understanding of reentrant circuits followed impressive surgical5 and, more recently, catheter ablative techniques6 designed as totally curative therapy. Now, for example, ablation of an accessory AV pathway without change to the normal AV node-His axis is an accepted, almost routine, surgical technique in many medical centers, and it allows for return of patients to a totally normal lifestyle without need for long-term antiarrhythmic therapy. Recently, techniques have been developed allowing for reproducible induction of ventricular tachycardia, which has allowed for application of remarkable surgical7 and, in some instances, catheter ablative procedures8 for tachycardia control. These techniques, though often effective, still require openheart surgery and extensive endocardial mapping during tachycardia. In a remarkable report in this issue of Circulation, Tchou et a19 have summarized