Constanciel Elodie, N'Djin W Apoutou, Bessière Francis, Chavrier Françoise, Grinberg Daniel, Vignot Alexandre, Chevalier Philippe, Chapelon Jean Yves, Lafon Cyril
IEEE Trans Ultrason Ferroelectr Freq Control. 2013 Sep;60(9):1868-83. doi: 10.1109/TUFFC.2013.2772.
Atrial fibrillation (AF) is the most frequent cardiac arrhythmia. Left atrial catheter ablation is currently performed to treat this disease. Several energy sources are used, such as radio-frequency or cryotherapy. The main target of this procedure is to isolate the pulmonary veins. However, significant complications caused by the invasive procedure are described, such as stroke, tamponade, and atrioesophageal fistula, and a second intervention is often needed to avoid atrial fibrillation recurrence. For these reasons, a minimally-invasive device allowing performance of more complex treatments is still needed. High-intensity focused ultrasound (HIFU) can cause deep tissue lesions without damaging intervening tissues. Left atrial ultrasound-guided transesophageal HIFU ablation could have the potential to become a new ablation technique. The goal of this study was to design and test a minimally-invasive ultrasound-guided transesophageal HIFU probe under realistic treatment conditions. First, numerical simulations were conducted to determine the probe geometry, and to validate the feasibility of performing an AF treatment using a HIFU mini-maze (HIFUMM) procedure. Then, a prototype was manufactured and characterized. The 18-mm-diameter probe head housing contained a 3-MHz spherical truncated HIFU transducer divided into 8 rings, with a 5-MHz commercial transesophageal echocardiography (TEE) transducer integrated in the center. Finally, ex vivo experiments were performed to test the impact of the esophagus layer between the probe and the tissue to treat, and also the influence of the lungs and the vascularization on lesion formation. First results show that this prototype successfully created ex vivo transmural myocardial lesions under ultrasound guidance, while preserving intervening tissues (such as the esophagus). Ultrasound-guided transesophageal HIFU can be a good candidate for treatment of AF in the future.
心房颤动（AF）是最常见的心律失常。目前采用左心房导管消融术治疗该疾病。使用了多种能量源，如射频或冷冻疗法。该手术的主要目标是隔离肺静脉。然而，已报道了由侵入性手术引起的严重并发症，如中风、心包填塞和心房食管瘘，并且通常需要进行二次干预以避免心房颤动复发。由于这些原因，仍然需要一种能够进行更复杂治疗的微创设备。高强度聚焦超声（HIFU）可在不损伤中间组织的情况下造成深部组织损伤。左心房超声引导经食管HIFU消融术有可能成为一种新的消融技术。本研究的目的是在实际治疗条件下设计并测试一种微创超声引导经食管HIFU探头。首先，进行数值模拟以确定探头几何形状，并验证使用HIFU迷宫（HIFUMM）手术进行房颤治疗的可行性。然后，制造并表征了一个原型。直径18毫米的探头头部外壳包含一个3兆赫的球形截顶HIFU换能器，分为8个环，中心集成了一个5兆赫的商用经食管超声心动图（TEE）换能器。最后，进行了体外实验，以测试探头与待治疗组织之间的食管层的影响，以及肺和血管化对病变形成的影响。初步结果表明，该原型在超声引导下成功地在体外创建了透壁心肌病变，同时保留了中间组织（如食管）。超声引导经食管HIFU未来可能是治疗房颤的良好选择。
