A membrane-electrode assembly for solid polymer electrolyte fuel cell that exhibits superior dimensional stability to high temperature of hot water generated on power generation, and that has both excellent power generation performance and durability in a low temperature environment is provided. The drive mechanism 64 has a first hub 82, a second hub 84 that is biased relative to the first hub 82, and a pivotal latch member 66 that is biased towards an engaged position with the second hub 94. The middle segment is pivotably attachable to at least one of the male and female segments. The ambulatory medical device can program a stimulation using the desired device parameter value, and deliver the programmed stimulation to one or more target sites to achieve desired therapeutic effects.