A method and system for improving the effectiveness of cardioversion and defibrillation through the ability to reduce transthoracic impedance. A method and system of decreasing transthoracic impedance that allows standardized pressure to be applied directly over desired defibrillator patches. This system reduces transthoracic impedance by increasing effective pressure on desired patches through use of a manual depressor device which incorporates a deformable patient body interface and mechanical and or electronic mechanisms to provide qualitative and or quantitative feedback on the force being applied to said patches. By depressing the device over desired external adhesive electrode patches until an audio and or visual signal indicates sufficient applied pressure, increased patch to skin contact is achieved to decrease the effective transthoracic impedance of a patient upon delivery of a defibrillation shock.