A guiding introducer system for use in the treatment of arrhythmia associated with the left ventricle from the ventricular side comprising an inner guiding introducer and an outer guiding introducer wherein the inner guiding introducer is comprised of a first and second section and the outer guiding introducer is comprised of a first and second sections. The guiding introducer system is for use in sensing, pacing, and ablating procedures in the left ventricle.