MicroRNAs and cardiac conduction.

Heart ion-channel function and expression are continuously being regulated on the basis of the hemodynamic state of the cardiovascular system, the neurohumoral milieu and the properties of the ongoing ionic fluxes. These homeostatic forces act through multiple mechanisms at transcriptional, translational and post-translational levels. Of clinical importance is the fact that with adverse stress these regulatory mechanisms can produce arrhythmogenic channel remodelling. Although a great deal is known about the functionality of ion channels and the generation of the action potential, much less is known about the underlying controlling mechanisms and how these become derailed during disease. microRNA-mediated posttranscriptional control is a very recent addition to cardiovascular biology. Here, we outline discoveries pertaining to these new regulators and how they might be involved in cardiac electrophysiology and pathology.