Utility of Multi-spline Multi-electrode 3D Mapping Catheters in Idiopathic Outflow Tract Ventricular Tachycardia.

We describe two cases of idiopathic VT arising from the postero-septal RVOT in both cases. Each case demonstrates an important learning point and advantage of multi-spline multi-electrode mapping catheters in idiopathic outflow VT. In the first case two dominant PVC morphologies can be clearly seen which we believe originate from a single site of origin with multiple exit sites caused by focal fibrosis. In the second case, focal fibrosis in this region leads to anisotropic conduction of the RVOT in areas of low voltage. We surmise that multi-spline multi-electrode catheters are essential in such cases as extensive point-by-point mapping could significantly prolong procedure time and fail to identify the earliest activation site in the case of anisotropic tissue conduction due to variations in activation latency.