Key result
CMR detects ventricular ablation lesions in 50%, limited by scar, ICD artifact, and low LVEF.
Why the study?
Cardiac magnetic resonance characteristics of ventricular radiofrequency ablation lesions have only been incompletely defined.
What are the detectability and temporal imaging characteristics of ventricular radiofrequency ablation lesions on cardiac magnetic resonance?
Observational (n=36)
What are the detectability and temporal imaging characteristics of ventricular radiofrequency ablation lesions on cardiac magnetic resonance?
Ventricular ablation lesions on CMR transition from a 'black' microvascular obstruction appearance to a 'white' late gadolinium enhancement pattern around 1 month post-ablation, but visualization is limited by preexisting scar, ICD artifact, and low ejection fraction.
CMR visualization of ventricular ablation lesions is often unsuccessful; leaves open routine clinical adoption pending technical refinements.
BACKGROUND: Cardiac magnetic resonance (CMR) characteristics of ventricular radiofrequency ablation (RFA) lesions have only been incompletely defined. AIM: To determine the detectability and imaging characteristics of ventricular RFA lesions in an unselected patient cohort undergoing ventricular arrhythmia ablation. METHODS AND RESULTS: A retrospective chart review (n = 249) identified 36 patients with either pre-/postablation CMR (n = 14) or only postablation CMR (n = 22). Ablation lesions could be identified in 50% (n = 18) of patients. Nonvisualized lesions had more preexisting transmural late gadolinium enhancement (LGE) >75% at the ablation sites (21% vs 0.0%, P = .042), more prevalent ICD artifact (50% vs 0%, P = .001), and lower ejection fraction (35.8 ± 14.2% vs 45.3 ± 13.4%, P = .048). Early CMR imaging demonstrated a central "black" signal void (microvascular obstruction [MVO], n = 12, 67%) up to 32 days post-RFA, whereas late imaging showed a homogenously "white" gadolinium enhancement pattern (n = 6, 33%). MVO was only observed in nonfibrotic myocardium without preexisting LGE (n = 12) but was not observed in the scar with preexisting LGE (n = 3, P = .002) suggesting different wash-in/wash-out kinetics in scar/nonscar myocardium. Signal intensity (1909 vs 2534, P = .009) and contrast-to-noise ratio (-7.8 vs 16.3, P = .009) were significantly different between MVO and LGE lesions, respectively. CONCLUSION: Ventricular ablation lesions visualization is negatively affected by preexisting transmural scar, ICD artifact, and low ejection fraction. The transition of "black" MVO appearance to "white" LGE appearance on CMR occurs around 1 month following ablation, suggesting a change in histological characteristics of ablation lesions. This may affect the utility of CMR in the evaluation of the ventricular lesions, when undergoing real-time or repeat VT ablations.
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Vunnam et al. (2020) conducted an observational in Ventricular arrhythmia (n=36). Cardiac magnetic resonance (CMR) was evaluated on Detectability of ventricular RFA lesions. Ventricular ablation lesions were identifiable by CMR in 50% of patients, with visualization negatively affected by preexisting transmural scar, ICD artifact, and low ejection fraction.
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