Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (A.S.-D., M.B., H.Y., J.S., E.A.).
Helmsley Center for Electrophysiology, Department of Cardiology, Icahn School of Medicine at Mount Sinai, NY (V.Y.R.).
Circ Arrhythm Electrophysiol. 2019 Nov;12(11):e007661. doi: 10.1161/CIRCEP.119.007661. Epub 2019 Nov 11.
Ventricular tachycardia ablation is often limited by insufficient lesion creation. A novel radiofrequency catheter with an expandable lattice electrode has a larger surface area capable of delivering higher currents at a lower density to potentially increase lesion dimensions without overheating.
This 8F bidirectional irrigated catheter (Sphere-9, Affera Inc) has a 9 mm spherical lattice tip ("lattice") with an effective surface area 10-fold larger than standard linear catheters. Nine surface thermocouples provide temperature feedback to a proprietary high-current generator operating in a temperature-controlled mode. Ex vivo phase: in 11 bovine hearts, unipolar ablation at 30, 60, and 120 seconds was compared between the lattice (Tmax60°C) and a standard linear irrigated-tip catheter (40 W) at contact force of 10 g. In 5 porcine hearts, bipolar ablation was compared between the catheters (Tmax60°C versus 40 W; 60 seconds). In vivo phase: in 9 swine, ventricular ablation at Tmax60°C versus 40 W was performed for 60 seconds. In addition, direct tissue temperature at 3- and 7-mm tissue depth was measured in a thigh muscle preparation.
Ex vivo: lattice produced deeper lesions at 30, 60, and 120 seconds application duration (6.7±1.3 versus 4.8±1.2 mm; 8.3±1.4 versus 5.4±0.8 mm; 10.0±1.6 versus 6.1±1.6 mm, respectively, ≤0.001 for all). Bipolar lesions were deeper (15.8±4.1 versus 10.5±1.4 mm, <0.001) and more likely to be transmural (80% versus 0%, =0.002). In vivo: lattice produced deeper lesions (10.5±1.4 versus 6.5±0.8 mm, ≤0.001). Tissue temperature at 7 mm was higher with the lattice (+15.1±2.4°C; <0.001). The steam-pop occurrence was lower with the lattice (total: 4% versus 18%, =0.02; in vivo 0% versus 14.2%, =0.13).
This novel radiofrequency system produces larger ventricular lesions compared with standard irrigated catheters and at a lower risk of tissue overheating. This may improve the efficacy of ventricular tachycardia ablation procedures while reducing the number of applications and procedural duration.
室性心动过速消融术常因病灶形成不足而受限。一种新型的具有可扩张网格电极的射频导管具有更大的表面积，能够以更低的密度输送更高的电流，从而有可能在不使导管过热的情况下增加病灶的尺寸。
这种 8F 双向灌流导管（Sphere-9，Affera Inc）具有一个 9 毫米的球形网格尖端（“网格”），其有效表面积是标准线性导管的 10 倍。九个表面热电偶为专有的高电流发生器提供温度反馈，该发生器以温度控制模式运行。
在 11 只牛心，在接触力为 10 g 时，分别比较了网格（Tmax60°C）和标准线性灌流尖端导管（40 W）在 30、60 和 120 秒的单相消融。在 5 只猪心，比较了两种导管之间的双相消融（Tmax60°C 与 40 W；60 秒）。
在 9 只猪中，Tmax60°C 与 40 W 进行 60 秒的心室消融。此外，还在大腿肌肉准备中测量了 3-7 毫米组织深度的直接组织温度。
离体：网格在 30、60 和 120 秒的应用时间内产生更深的病灶（分别为 6.7±1.3、8.3±1.4 和 10.0±1.6 毫米，均<0.001）。双相病灶更深（15.8±4.1 毫米与 10.5±1.4 毫米，<0.001）且更有可能透壁（80%与 0%，=0.002）。在体内：网格产生的病灶更深（10.5±1.4 毫米与 6.5±0.8 毫米，均<0.001）。网格的组织温度更高（7 毫米时+15.1±2.4°C，<0.001）。网格的蒸汽弹出发生率更低（总发生率为 4%与 18%，=0.02；体内为 0%与 14.2%，=0.13）。
与标准灌流导管相比，这种新型的射频系统产生的心室病灶更大，组织过热的风险更低。这可能提高室性心动过速消融术的疗效，同时减少应用次数和手术时间。
