An electrode for cardiac signal sensing includes an intermediate layer, an iridium-containing layer, an iridium oxide layer, an insulating polymer layer, and a conductive layer formed on a flexible polymer substrate. The intermediate metal layer has a first portion and a second portion, and is formed on the conductive layer. The iridium-containing layer includes at least 50 wt. % iridium and has a first portion and a second portion, and is formed on the first portion of the intermediate metal layer. The iridium oxide layer is formed on the first portion of the iridium-containing layer. The insulating polymer layer is formed on the second portion of the intermediate metal layer and the second portion of the iridium-containing layer. The iridium-containing layer is not formed on the second portion of the intermediate metal layer; and the iridium oxide layer is not formed on the second portion of the iridium-containing layer.