Escartin Terenz, Terricabras Maria, Sheagren Calder, Krahn Philippa, Roifman Idan, Wright Graham, Cheung Christopher C
Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; Sunnybrook Research Institute, Toronto, Ontario, Canada.
Sunnybrook Research Institute, Toronto, Ontario, Canada; Department of Cardiology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
Heart Rhythm. 2025 Jun 20. doi: 10.1016/j.hrthm.2025.06.024.
Late gadolinium enhancement magnetic resonance imaging (MRI) has been shown to reliably locate radiofrequency ablation (RFA) lesions with microvascular obstruction (MVO) as a broadly accepted signature. However, MVO volume depends on the time elapsed after gadolinium contrast injection. Native T1-weighted (Tw) MRI has recently been shown to accurately characterize RFA lesions in preclinical models.
This study aimed to demonstrate the feasibility of wideband native Tw MRI in characterizing lesion dimensions in patients within 7 days of ventricular tachycardia RFA.
Postablation wideband native Tw and 3-dimensional late gadolinium enhancement MRI was performed within 7 days of RFA. RFA lesion surface area (mm), volume (mm), and native Tw maximum lesion depth were calculated. Average catheter contact force (g), ablation duration (seconds), and impedance drop (Ω) were calculated. Patients with and without implantable cardioverter-defibrillators were included.
Ten patients (median age = 64.5 years, 60% ischemic) underwent ventricular tachycardia RFA (80% endocardial, 20% epicardial RFA) and postablation cardiac MRI within 7 days of RFA (median = 4.5 days). There was a significantly greater mean MVO surface area and volume than mean native Tw lesion surface area and volume (P = .0108, P = .0376, P < .05), respectively. There were strong positive correlations between average surface area and average volume measured by MVO and native Tw (r = 0.71, P = .0237, r = 0.70, P = .0265, P < .05), respectively. Average maximum native Tw lesion depth correlated with average ablation duration and average impedance drop (r = 0.73, P = .02, r = 0.68, P = .04, P < .05), respectively.
Native Tw MRI can effectively characterize lesion dimensions in patients with and without implantable cardioverter-defibrillators within 7 days after ablation. This emerging biomarker may facilitate early prediction of RFA efficacy and ablation success particularly in patients demonstrating contraindications to gadolinium contrast agents.
钆延迟增强磁共振成像（MRI）已被证明能够可靠地定位伴有微血管阻塞（MVO）的射频消融（RFA）病灶，MVO是广泛认可的标志。然而，MVO体积取决于钆造影剂注射后的时间。最近研究表明，在临床前模型中，天然T1加权（Tw）MRI能够准确地对RFA病灶进行特征描述。
本研究旨在证明宽带天然Tw MRI在表征室性心动过速RFA术后7天内患者病灶大小方面的可行性。
在RFA术后7天内进行消融后宽带天然Tw和三维钆延迟增强MRI检查。计算RFA病灶表面积（mm）、体积（mm）以及天然Tw最大病灶深度。计算平均导管接触力（g）、消融持续时间（秒）和阻抗下降（Ω）。纳入植入式心脏复律除颤器患者和未植入患者。
10例患者（中位年龄 = 64.5岁，60%为缺血性）接受了室性心动过速RFA（80%为心内膜RFA，20%为心外膜RFA），并在RFA术后7天内（中位时间 = 4.5天）接受了消融后心脏MRI检查。MVO的平均表面积和体积分别显著大于天然Tw病灶的平均表面积和体积（P = 0.0108，P = 0.0376，P < 0.05）。MVO和天然Tw测量的平均表面积与平均体积之间分别存在强正相关（r = 0.71，P = 0.0237，r = 0.70，P = 0.0265，P < 0.05）。天然Tw平均最大病灶深度分别与平均消融持续时间和平均阻抗下降相关（r = 0.73，P = 0.02，r = 0.68，P = 0.04，P < 0.05）。
天然Tw MRI能够有效表征消融术后7天内植入或未植入植入式心脏复律除颤器患者的病灶大小。这种新兴的生物标志物可能有助于早期预测RFA疗效和消融成功率，特别是对于那些对钆造影剂有禁忌证的患者。
