Electrophysiology Clinical Research and Innovation, Regenerative Medicine Research, and Cullen Cardiovascular Surgery Research, Texas Heart Institute (M.D.M., B.G., A.E., M.J., D.A.T., L.C.S., M.R.).
CHI-Baylor St. Luke's Medical Center (M.D.M., B.G., A.E., D.A.T., L.C.S., M.R.).
Circ Arrhythm Electrophysiol. 2019 Aug;12(8):e007256. doi: 10.1161/CIRCEP.119.007256. Epub 2019 Aug 12.
Impaired myocardial conduction is the underlying mechanism for re-entrant arrhythmias. Carbon nanotube fibers (CNTfs) combine the mechanical properties of suture materials with the conductive properties of metals and may form a restorative solution to impaired myocardial conduction.
Acute open chest electrophysiology studies were performed in sheep (n=3). Radiofrequency ablation was used to create epicardial conduction delay after which CNTf and then silk suture controls were applied. CNTfs were surgically sewn across the right atrioventricular junction in rodents, and acute (n=3) and chronic (4-week, n=6) electrophysiology studies were performed. Rodent toxicity studies (n=10) were performed. Electrical analysis of the CNTf-myocardial interface was performed.
In all cases, the large animal studies demonstrated improvement in conduction velocity using CNTf. The acute rodent model demonstrated ventricular preexcitation during sinus rhythm. All chronic cases demonstrated resumption of atrioventricular conduction, but these required atrial pacing. There was no gross or histopathologic evidence of toxicity. Ex vivo studies demonstrated contact impedance significantly lower than platinum iridium.
Here, we show that in sheep, CNTfs sewn across epicardial scar acutely improve conduction. In addition, CNTf maintain conduction for 1 month after atrioventricular nodal ablation in the absence of inflammatory or toxic responses in rats but only in the paced condition. The CNTf/myocardial interface has such low impedance that CNTf can facilitate local, downstream myocardial activation. CNTf are conductive, biocompatible materials that restore electrical conduction in diseased myocardium, offering potential long-term restorative solutions in pathologies interrupting efficient electrical transduction in electrically excitable tissues.
心肌传导受损是折返性心律失常的潜在机制。碳纳米管纤维（CNTfs）结合了缝线材料的机械性能和金属的导电性，可能为受损的心肌传导提供一种修复解决方案。
在绵羊（n=3）中进行急性开胸电生理学研究。使用射频消融术在心脏外膜上造成传导延迟，然后应用 CNTf 和丝线缝线对照。在啮齿动物中，通过手术将 CNTf 缝合穿过右房室结，进行急性（n=3）和慢性（4 周，n=6）电生理学研究。进行了啮齿动物毒性研究（n=10）。对 CNTf-心肌界面进行了电分析。
在所有情况下，大型动物研究均表明 CNTf 可改善传导速度。急性啮齿动物模型在窦性节律时表现出心室预激。所有慢性病例均恢复房室传导，但需要心房起搏。没有明显的大体或组织病理学毒性证据。离体研究表明接触阻抗明显低于铂铱。
在这里，我们证明在绵羊中，缝合在心外膜瘢痕上的 CNTfs 可在急性情况下改善传导。此外，在没有大鼠炎症或毒性反应的情况下，CNTF 在房室结消融后 1 个月仍能保持传导，但仅在起搏状态下。CNTF/心肌界面的阻抗如此之低，以至于 CNTF 可以促进局部下游心肌的激活。CNTF 是一种导电、生物相容的材料，可以恢复病变心肌的电传导，为中断电兴奋组织有效电传导的病理提供潜在的长期修复解决方案。
