Electrical heaters having serpentine designs and selected dead zones for exhaust aftertreatment systems and assemblies

An electrical heater for treatment of a fluid flow comprising:

• a resistive portion configured to generate heat when electrical current is passed therethrough:
• a pair of electrode attachment portions at opposite ends of the resistive portion:
• a plurality of slots that extend into the resistive portion from an outer periphery of the resistive portion and electrically disconnect segments of the resistive portion from each other to define a serpentine current-carrying path extending through the resistive portion between the pair of electrode attachment portions,
• wherein each of the electrode attachment portions is connected to a respective end segment of the resistive portion that is bounded between an outer periphery of the resistive portion and a respective first slot of the plurality of slots, and
• at least one auxiliary slot in each of the end segments that extends from the outer periphery toward the first slot in a direction transverse to the first slot to bias current flow through a concentrated region adjacent to and extending along the first slot in each end segment.