Methods, implantable medical devices and systems configured to perform analysis of captured signals from implanted electrodes to identify cardiac arrhythmias. Various components fabricated from a reducible-ion-containing glass are selectively exposed to a reducing atmosphere such that they are reduction-blackened prior to at least one heating and drawing step relative to the bundle into which they are to be fusedly incorporated. Control logic can generate first code values in response to the difference between the voltage of the first substrate portion and the target voltage. The artificial is preferably formed from hot glue. \u2018SAVaworry\u2019 will grow and bloom well in the greenhouse or outdoors, in the ground or in containers.