Animal Models for Cardiac Arrhythmias

Transgenic and gene-targeted mice are now frequently used to expand the study of cardiac physiology and pathophysiology owing to the ease with which the mouse genome can be manipulated. There are many measures by which an assessment of the phenotypical expression of the transgenic mouse can be made. In the case of cardiac channelopathies and how they relate to cardiac function, telemetry is a technology that utilizes transmitters that are surgically implanted in animals for the purpose of acquiring biopotentials or physioloigical parameters. Electrophysiological techniques have also been used to assess cardiac function at the cellular level, by measuring whole-cell ionic currents and/or transmembrane potentials. This chapter will discuss the surgical procedures involved in successfully implanting the transmitter device in a mouse, as well as highlight the recording of and analysis of electrocardiograms. This chapter will also outline the procedures involved in isolating single-ventricular myocytes from a mouse heart. It is a protocol that was developed in our laboratory for which we have routinely and successfully isolated myocytes from both transgenic and nontransgenic mouse hearts. Although no one isolation protocol is alike, we also present our own observations that have assisted in maximizing myocyte bioavailability and yield.