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.