Reformative cannula electrodes for His bundle electrogram recording in isolated rat hearts

His bundle electrogram (HBE) recording is an important method for the study of the atrioventricular conduction system. However, the current HBE recording methods in isolated animal hearts have some disadvantages, such as unstable recording due to the difficulty in fixing electrodes as a result of intense heart beat, the small amplitude of the His signal or the possibility to destroy the integrity of heart structure. To overcome these disadvantages, we designed and manufactured reliable, inexpensive and easy-made bipolar cannula electrodes, which combine the functions of Langendorff-perfusion aortic cannula and recording electrodes. With the cannula electrodes, the operation of HBE recording becomes easier and clearer; hence, more stable recordings can be obtained in isolated rat hearts.