I see this as being a love song. 'Hearbeat City' is a place inside the singer (or subject of the song, as it is sung from his POV). Jackie is back in his life and now he can start feeling again, as some who are in love will say that they lose the ability to feel (ie, feel dead inside - a form of defensive separation from one's feelings and internal state, which can lead sometimes to severe depression) when they are heartbroken-- or living outside Heartbeat City. The subject could just be very in love and thus very relieved when Jackie comes back or he could be a codependent who without someone in his life loses his own internal focus and sense of being, as well as a loss of being in touch with his feelings, or if a codependent, his identity. The heart is metaphorically the place of both one's feelings and true sense of self - one with a 'big heart' has both a good sense of their own feelings as well as a solid sense of self. The subject gets his Jackie back, he gets his heart back, his sense of self and his source of happiness-- and so he is back in 'Heartbeat City'.
I see this as being a love song. 'Hearbeat City' is a place inside the singer (or subject of the song, as it is sung from his POV). Jackie is back in his life and now he can start feeling again, as some who are in love will say that they lose the ability to feel (ie, feel dead inside - a form of defensive separation from one's feelings and internal state, which can lead sometimes to severe depression) when they are heartbroken-- or living outside Heartbeat City. The subject could just be very in love and thus very relieved when Jackie comes back or he could be a codependent who without someone in his life loses his own internal focus and sense of being, as well as a loss of being in touch with his feelings, or if a codependent, his identity. The heart is metaphorically the place of both one's feelings and true sense of self - one with a 'big heart' has both a good sense of their own feelings as well as a solid sense of self. The subject gets his Jackie back, he gets his heart back, his sense of self and his source of happiness-- and so he is back in 'Heartbeat City'.