Abstract
Small animals like mice or rats are widely used for cardiovascular research and development. The development of cardiovascular drugs requires that electrophysiological studies be conducted using such small animals. Magnetocardiography (MCG) for small animals has not been established yet. In the present study, a newly developed micro-magnetometer array and, 9-channel superconducting quantum interference device (SQUID) with a 2.5-mm diameter pickup-coil were used for MCG measurements. A cryoinjury probe was used to produce regional myocardial injury in mouse and rat hearts, and the specific MCG patterns corresponding to injured locations were recorded with the micro-magnetometer array/SQUID combination. QT prolongation induced by quinidine (60 mg/kg) in mice and rats was recorded. In mice and rats, anterior myocardial injury created a QS pattern. Posterior myocardial injury deepened the depth of the S wave. Thus, the micro-magnetometer array/SQUID combination enabled the in vivo localization of injured myocardium in small animals. Quinidine-induced QT prolongation was successfully measured by MCG. The newly developed miniature magnetometer array system for MCG facilitates the research process of electrophysiological studies of small rodents.
