A method and system improves the effectiveness of cardioversion or defibrillation through the ability to switch shock vectors and to reduce transthoracic impedance. An external multiple patch system comprises at least two options for a shocking vector once external patches are applied and adhered to desired locations on a patient's body. A manual switching mechanism in the system provides the ability to direct current from a defibrillator to either of two or more adhesive electrode patches. A method and system of decreasing transthoracic impedance comprises wrapping material around a patient's body to apply pressure to adhered patches, which further reduces transthoracic impedance by increasing effective pressure on the patches through use of pressure-focusing mechanisms located between a patch and a strap.