A more detailed discussion of pacemaker technology is conducted elsewhere. This is a brief point-form summary. Some of these definitions have been asked about in the SAQs before, eg. in Question 29 from the second paper of 2013 and Question 2 from the first paper of 2016.
Reade, M. C. "Temporary epicardial pacing after cardiac surgery: a practical review." Anaesthesia 62.3 (2007): 264-271.
Reade, M. C. "Temporary epicardial pacing after cardiac surgery: a practical review: Part 2: Selection of epicardial pacing modes and troubleshooting."ANAESTHESIA-LONDON- 62.4 (2007): 364.
Gammage, Michael D. "Temporary cardiac pacing." Heart 83.6 (2000): 715-720.
Sanders, Richard S. "The Pulse Generator." Cardiac Pacing for the Clinician. Springer US, 2008. 47-71.