A 26 year old male patient with arrhythmogenic right ventricular cardiomyopathy (ARVC) was referred for catheter ablation of drug refractory ventricular tachycardia (VT). A 12 lead ECG of the VT (CL 190 ms, intermediate axis, left bundle branch block morphology) suggested a right ventricular outflow tract origin (RVOT).
The ablation procedure was guided by a three dimensional Real-time Positioning Management System (RPM). This system uses sonomicrometry to determine the three dimensional location of an ablation catheter relative to two reference catheters positioned into the right atrium and right ventricle. At the onset of the mapping procedure, the right ventricle was depicted as a spherical body. After induction of VT, this spherical body was adjusted to the shape and size of the RVOT by dragging the ablation catheter over the endocardium of the RVOT (below left). Simultaneously, electrograms were recorded sequentially at multiple sites and the local activation time (relative to the surface ECG) was marked automatically. In this way, a colour coded activation map was superimposed on the RVOT model (below right). At the site of earliest endocardial activity (anterior part of the RVOT), a small area of fragmented electrograms (2 × 3 cm2) was found. The three dimensional endocardial position of this area could accurately be delineated using the RVOT model (white dots). This entire area was ablated. Ablation of this localised area of fragmented electrograms resulted in termination and non-inducibility of the VT after ablation.
This presentation demonstrates facilitation of ablation of VT in a patient with ARVC by accurate delineation of the arrhythmogenic substrate thereby using a three dimensional mapping technique.