Department of Cardiology, Asklepios Klinik St. Georg, Hamburg, Germany.
Heart Rhythm. 2012 Mar;9(3):407-13. doi: 10.1016/j.hrthm.2011.09.072. Epub 2011 Oct 4.
High-intensity frequency ultrasound (HIFU) can achieve pulmonary vein isolation (PVI), but severe complications have happened. An esophageal temperature (ET)-guided safety algorithm was implemented. We investigated medium-term outcome.
After left atrial access, HIFU was applied until complete PVI. The safety algorithm was as follows: ≤3 complete ablations per pulmonary vein, early abortion when ET ≥40.0°C, use of Power Modulation at ET >39.0°C or when after 20 to 30 seconds no change in PV electrograms: to reduce the ablation temperature in the surrounding tissue, acoustic power is switched on and off with a frequency of 1 Hz; in all first ablations, use of Power Modulation after 50% of programmed time. Touch-up radiofrequency ablation when PVI failed. Follow-up included interviews and Holter electrocardiograms. Recurrence was defined as atrial fibrillation (AF) >30 seconds without a blanking period.
A total of 28 symptomatic patients (18 males, age 63 years), with paroxysmal AF (n = 19) and persistent AF (n = 9) were included. After a median follow-up of 738 days, 22 of the 28 patients (79%) were free of AF without antiarrhythmic drugs. After 1 repeat procedure with radiofrequency ablation, 5 patients remained free of AF. The complications were as follows: 1 lethal atrial-to-esophageal fistula at day 31, 1 pericardial effusion at day 48, 1 unexplained death at day 49, and 2 persistent phrenic nerve palsies with full recovery within 12 months.
Two-year follow-up after PVI using HIFU and an ET-guided safety algorithm shows success rates similar to those of radiofrequency-based procedures but with higher complication rates. Importantly, the ET-guided safety algorithm failed to prevent severe complications. HIFU does not meet safety standards required for the treatment of AF, and this led to a halt of its clinical use.
高强度频率超声（HIFU）可实现肺静脉隔离（PVI），但会发生严重并发症。我们实施了食管温度（ET）引导的安全算法，并对中期结果进行了研究。
经左心房入路后，应用 HIFU 直至完全实现 PVI。安全算法如下：每个肺静脉的完全消融次数≤3 次，当 ET≥40.0°C 时早期中止，当 ET>39.0°C 或在 20 至 30 秒内 PV 电图无变化时使用功率调制：为降低周围组织的消融温度，声能以 1Hz 的频率开启和关闭；在所有初次消融中，在程控时间的 50%后使用功率调制。当 PVI 失败时进行射频消融补点。随访包括访谈和动态心电图。复发定义为无空白期的房颤（AF）>30 秒。
共纳入 28 例有症状患者（18 例男性，年龄 63 岁），阵发性 AF（n=19）和持续性 AF（n=9）。中位随访 738 天后，28 例患者中的 22 例（79%）无抗心律失常药物且无 AF。在进行 1 次射频消融重复手术后，5 例患者仍无 AF。并发症如下：第 31 天发生 1 例致死性心房-食管瘘，第 48 天发生 1 例心包积液，第 49 天发生 1 例原因不明的死亡，2 例持续性膈神经麻痹，12 个月内完全恢复。
HIFU 联合 ET 引导的安全算法行 PVI 术后 2 年随访显示，成功率与基于射频的手术相似，但并发症发生率更高。重要的是，ET 引导的安全算法未能预防严重并发症。HIFU 不符合治疗 AF 的安全标准，因此其临床应用已停止。
