In vivo endocardial cardiac transmembrane current determination using a novel catheter mounted microminiature recording array

Complete in vivo electrophysiological mapping of the heart during complex arrhythmias such as ventricular fibrillation (VF) would ideally include information from the entire three dimensional volume of myocardium. To preclude fiber disruption and its potential for pathway disruption, a novel electrode catheter was developed to interrogate endocardial structures from within the ventricular cavities and provide an estimate of cardiac transmembrane current (I_m). This microminiature array, with its ability to provide signals in which electrotonic deflections are readily differentiated from propagated activations, may prove useful in elucidating mechanisms of ventricular fibrillation and defibrillation