How does an Atzel's desire kill him?
R. Yonah: An Atzel chooses laziness amidst love of rest. Laziness brings him to the ultimate pain. His desire kills him, for he can never fulfill his desire.
Malbim: Something that is not important to a person, he is lazy to do it. Do not think that the Atzel slackens from working because he does not desire, and worldly matters are light in his eyes, therefore he does not toil to attain them. This is not so! He desires more than one who is not Atzel, for one who has bread in his basket is unlike [one who lacks it; the latter craves it more]. Rather, he does not rule over his hands and other Kelim of action of the body. They do not want to heed the ruling power in the Nefesh. Therefore, his desire kills him.
What do his hands refuse to do?
R. Yonah: When his desire for a matter overpowers, and he seeks to toil to work to get what he desires, his hands refuse to do [the work], for he accustomed his limbs to laziness and rest. Habit rules over them. It is as if his hands refuse what he wants. This is like it says about Zerizus "va'Ta'as b'Chefetz Kapeha" (31:13). When the limbs are habituated to Zerizus, work is not hard for them. It is as if there is desire in them.
Malbim: His hands are prepared to save him from death - via work, he finds his desire. However, the Atzel's hands do not want to listen to him.