Disclosed is a sustained-release preparation of ivabradine or pharmaceutically acceptable salts thereof. The reciprocating bar is protruded from the handle and received in the actuator receiving recess. Between adjacent ones of the mounting portions, there are formed abutment portions in which the circuit board is superposed on and placed in abutment with the negative terminal side heat sink or the positive terminal side heat sink, and the abutment portions are fixed to each other by rivets. A wrapper module is operable to handle selecting and loading of the one or more plugin modules.