Optimization of decrementing evoked potential mapping for functional substrate identification in ischaemic ventricular tachycardia ablation
Jaffar Al-Sheikhli, James Winter, Ivo Roca‐Luque, Pier D. Lambiase, Michele Orini, Andreu Porta‐Sánchez, Tarvinder Dhanjal
Abstract
Ventricular tachycardia (VT) ablation approaches based on high-density mapping, which enable the rapid acquisition of thousands of mapping points in order to delineate slow conduction zones, have been widely adopted.1 The identification of functionally relevant substrates has been advanced by the identification of potentials participating in the initiation and/or maintenance of scar-dependent VT. During right ventricular apical (RVA) pacing with an extra-stimulus (S2), these potentials display delayed conduction (decremental) behaviour (DeEP).2 This methodology has been shown to be more specific in identifying the critical isthmus of re-entrant VT.3 An important factor accounting for decrement is conduction velocity (CV) restitution.2 With a short-coupled S2, CV will decrease, and further delay occurs in the near-field signal with respect to the far-field signal, creating DeEPs. Conventionally, the S2 has been delivered at ventricular effective refractory period (VERP) + 20 ms to elicit decrement.3–5 However data are lacking on justifying the delivery of the S2 at VERP + 20 ms, which may result in areas defined as DeEP due to intrinsic CV restitution properties, thus creating larger-than-required ablation target areas. We hypothesized that DeEPs are better identified with longer S2 coupling intervals. The second hypothesis was to consider the definition of a DeEP as the range of decrement beyond 10 ms has not been previously explored and to identify the best combination of these parameters. \n \n