Section of Cardiac Electrophysiology, Cardiovascular Medicine Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Section of Cardiac Electrophysiology, Cardiovascular Medicine Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
JACC Clin Electrophysiol. 2024 Oct;10(10):2277-2292. doi: 10.1016/j.jacep.2024.08.003. Epub 2024 Oct 2.
Catheter ablation is a well-established and effective strategy for the management of ventricular tachycardia (VT). However, the identification and characterization of arrhythmogenic substrates for targeted ablation remain challenging. Electrogram abnormalities and responses to pacing during VT provide the classical and most validated methods to identify substrates. However, the 3-dimensional nature of the myocardium, nonconductive tissue, and heterogeneous strands of conductive tissue at the border zones or through the nonconductive zones can prohibit easy electrical sampling and identification of the tissue critical to VT. Intracardiac echocardiography is critical for identification of anatomy, examination of catheter approach and contact, assessment of tissue changes during ablation, and even potential substrates as echogenic regions, but lacks specificity with regard to the latter compared with advanced modalities. In recent decades, cardiac magnetic resonance, computed tomography and positron emission tomography have emerged as valuable tools in the periprocedural evaluation of VT ablation. Cardiac magnetic resonance has unparalleled soft tissue and temporal resolution and excels at identification of expanded interstitial space caused by myocardial infarction, fibrosis, inflammation, or infiltrative myopathies. Computed tomography has excellent spatial resolution and is optimal for identification of anatomic variabilities including wall thickness, thrombus, and lipomatous metaplasia. Positron emission tomography excels at identification of substrates including amyloidosis, sarcoidosis, and other inflammatory substrates. These imaging modalities are vital for assessing arrhythmogenic substrates, guiding optimal access strategy, and assessing ablation efficacy. Although clearly beneficial in specific settings, further clinical trials are needed to enhance generalizability and optimize integration of cardiac imaging for VT ablation.
导管消融是治疗室性心动过速（VT）的一种成熟且有效的策略。然而，确定和描述心律失常的靶标消融底物仍然具有挑战性。VT 时电描记图异常和对起搏的反应提供了识别底物的经典和最有效的方法。然而，心肌的 3 维性质、非传导组织以及在交界区或通过非传导区的传导组织的不均匀条纹，可以阻止对 VT 至关重要的组织进行容易的电采样和识别。心内超声心动图对于识别解剖结构、检查导管接近和接触、评估消融过程中的组织变化以及潜在的回声增强区域作为底物都非常重要，但与先进的模式相比，其在后者方面特异性较差。在过去几十年中，心脏磁共振、计算机断层扫描和正电子发射断层扫描已成为 VT 消融围手术期评估的有价值的工具。心脏磁共振具有无与伦比的软组织和时间分辨率，擅长识别心肌梗死、纤维化、炎症或浸润性肌病引起的扩展间质空间。计算机断层扫描具有极好的空间分辨率，是识别解剖变异的最佳方法，包括壁厚度、血栓和脂肪瘤样化生。正电子发射断层扫描擅长识别淀粉样变性、结节病和其他炎症底物。这些成像方式对于评估心律失常的底物、指导最佳的进入策略以及评估消融效果至关重要。尽管在特定情况下明显有益，但仍需要进一步的临床试验来增强可推广性并优化心脏成像在 VT 消融中的整合。
