Introduction
Arrhythmias in the structurally abnormal heart may be precipitated by heterogeneous conduction through regions of fibrosis or scar. In cases of myocardial infarction, the mechanism for arrhythmogenesis is usually due to the presence of viable myocardium interspersed amidst scarred tissue that leads to reentry or enhanced automaticity. Currently, methods to prevent arrhythmia focus on impacting these slow, viable zones through use of either antiarrhythmic medications that alter activation characteristics or ablation to destroy (ie, homogenize) the tissue region. However, both approaches carry significant limitations either due to medication side effects, including the potential for proarrhythmia, or creation of new scar. Furthermore, existing technology is limited by an inability to completely eliminate all arrhythmia circuits (eg, due to circuits deep in the mid-myocardial region).
Regenerative approaches for enhancing conduction through regions of myocardial scar, preventing the fibrotic remodeling that is thought to contribute to arrhythmogenesis, or reversing the damage done from an infarct or other injurious events reflect new approaches to treatment of patients with myocardial disease(1-4). Use of stem cells or biologically compatible, synthetic compounds have been studied extensively, although with greater focus on effects on myocardial contractility and ventricular function rather than arrhythmogenicity. Certain compounds, such as carbon nanotubes, have been studied in a variety of biological approaches, including as a means of potentially enhancing myocardial health(5-11). One promising aspect of carbon nanotubes is that they are highly conductive. We and others have previously shown that applying 3D printed patches composed of carbon nanotubes intermixed with biocompatible compounds could restore conduction across the surface of a previously injured region(12,13). We sought to evaluate whether an injectable, conductive carbon nanotube-based hydrogel would impact conduction properties through a region of iatrogenically disrupted (ablated) myocardium.