Abstract
BackgroundRadiofrequency (RF) ablation has become a mainstay of treatment for ventricular tachycardia, yet adequate lesion formation remains challenging. This study aims to comprehensively describe the composition and evolution of acute left ventricular (LV) lesions using native-contrast cardiovascular magnetic resonance (CMR) during CMR-guided ablation procedures.MethodsRF ablation was performed using an actively-tracked CMR-enabled catheter guided into the LV of 12 healthy swine to create 14 RF ablation lesions. T2 maps were acquired immediately post-ablation to visualize myocardial edema at the ablation sites and T1-weighted inversion recovery prepared balanced steady-state free precession (IR-SSFP) imaging was used to visualize the lesions. These sequences were repeated concurrently to assess the physiological response following ablation for up to approximately 3 h. Multi-contrast late enhancement (MCLE) imaging was performed to confirm the final pattern of ablation, which was then validated using gross pathology and histology.ResultsEdema at the ablation site was detected in T2 maps acquired as early as 3 min post-ablation. Acute T2-derived edematous regions consistently encompassed the T1-derived lesions, and expanded significantly throughout the 3-h period post-ablation to 1.7 ± 0.2 times their baseline volumes (mean ± SE, estimated using a linear mixed model determined from n = 13 lesions). T1-derived lesions remained approximately stable in volume throughout the same time frame, decreasing to 0.9 ± 0.1 times the baseline volume (mean ± SE, estimated using a linear mixed model, n = 9 lesions).ConclusionsCombining native T1- and T2-based imaging showed that distinctive regions of ablation injury are reflected by these contrast mechanisms, and these regions evolve separately throughout the time period of an intervention. An integrated description of the T1-derived lesion and T2-derived edema provides a detailed picture of acute lesion composition that would be most clinically useful during an ablation case.
Highlights
Radiofrequency (RF) ablation has become a mainstay of treatment for ventricular tachycardia, yet adequate lesion formation remains challenging
RF lesion temporal evolution The native T1-derived lesion and T2-derived edema were clearly visualized and reflected the characteristic teardrop shape of RF lesions observed in corresponding contrast-enhanced images, gross pathology, and histopathology (Fig. 2)
Elevated T2 indicating edema surrounding the ablation site was evident in the first T2 maps acquired as early as 3 min after the start of ablation
Summary
Radiofrequency (RF) ablation has become a mainstay of treatment for ventricular tachycardia, yet adequate lesion formation remains challenging. Once the critical isthmus of a VT circuit is isolated, radiofrequency (RF) ablation is performed with the hope of creating a necrotic lesion (permanent injury) at the putative isthmus, rendering VT non-inducible. The insult of ablation leads to edema (reversible injury) surrounding the ablation site [4,5,6,7,8] This reversible injury is thought to result in transient conduction block, with conduction recovering once the edema has resorbed [9,10,11], potentially leading to late arrhythmia recurrence. The ability to detect whether the arrhythmogenic substrate has been permanently destroyed, as evidenced by the presence of a lesion at a critical ablation site, may be invaluable and provide an additional intra-procedural endpoint to gauge long-term procedural success
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
