Intracardiac shear-wave elastography quantitatively mapped RFCA-induced thermal lesions, showing a large increase in stiffness in ablated ex vivo regions (99 ± 17 kPa vs 22 ± 5 kPa in normal tissue).
Does intracardiac shear-wave elastography accurately map the stiffness of RFCA-induced thermal lesions in cardiac tissues?
Intracardiac shear-wave elastography is a feasible real-time imaging technique to quantitatively evaluate thermal ablation lesions during RFCA.
Effect estimate: increase ratio 4.5
Absolute Event Rate: 99% vs 22%
Purpose: Radio frequency catheter ablation (RFCA) is a well‐established clinical procedure for the treatment of atrial fibrillation (AF) but suffers from a low single‐procedure success rate. Recurrence of AF is most likely attributable to discontinuous or nontransmural ablation lesions. Yet, despite this urgent clinical need, there is no clinically available imaging modality that can reliably map the lesion transmural extent in real time. In this study, the authors demonstrated the feasibility of shear‐wave elastography (SWE) to map quantitatively the stiffness of RFCA‐induced thermal lesions in cardiac tissues in vitro and in vivo using an intracardiac transducer array. Methods: SWE was first validated in ex vivo porcine ventricular samples ( N = 5). Both B‐mode imaging and SWE were performed on normal cardiac tissue before and after RFCA. Areas of the lesions were determined by tissue color change with gross pathology and compared against the SWE stiffness maps. SWE was then performed in vivo in three sheep ( N = 3). First, the stiffness of normal atrial tissues was assessed quantitatively as well as its variation during the cardiac cycle. SWE was then performed in atrial tissue after RFCA. Results: A large increase in stiffness was observed in ablated ex vivo regions (average shear modulus across samples in normal tissue: 22 ± 5 kPa, average shear‐wave speed ( c t ): 4.5 ± 0.4 m s −1 and in determined ablated zones: 99 ± 17 kPa, average c t : 9.0 ± 0.5 m s −1 for a mean shear modulus increase ratio of 4.5 ± 0.9). In vivo , a threefold increase of the shear modulus was measured in the ablated regions, and the lesion extension was clearly visible on the stiffness maps. Conclusions: By its quantitative and real‐time capabilities, Intracardiac SWE is a promising intraoperative imaging technique for the evaluation of thermal ablation during RFCA.
Kwiecinski et al. (Tue,) conducted a other in Atrial fibrillation (RFCA lesions) (n=8). Intracardiac shear-wave elastography (SWE) vs. Normal cardiac tissue (before RFCA) was evaluated on Shear modulus (stiffness) of cardiac tissue (increase ratio 4.5). Intracardiac shear-wave elastography quantitatively mapped RFCA-induced thermal lesions, showing a large increase in stiffness in ablated ex vivo regions (99 ± 17 kPa vs 22 ± 5 kPa in normal tissue).