The goal of the study is to compare whether a center-wide policy of incremental antibiotic therapy will reduce CIED infection rate compared to a policy of conventional antibiotic prophylaxis in high-risk patients undergoing arrhythmia device procedures. All antibiotics used are approved for use and readily available.

This is a randomized prospective cluster crossover trial to track outcomes of high infection risk patients undergoing arrhythmia device procedures. Centres will be randomized to either conventional antibiotic therapy or incremental antibiotic therapy. Patients will not be randomized. Centres will be randomized to one therapy and then cross over to the next after 6 months. At one year they will randomize again and then cross over for the final time at 18 months. During each treatment period the randomized antibiotic therapy will be used on all centre patients undergoing a device implant procedure.

Ethics approval has been obtained in all sites for waiver of consent with notification of the study (i.e. data collection is taking place to track infection rates). A third of sites obtain consent after the procedure for collection of data (but not for care, since either arm is the standard of care).

Inclusion Criteria:

1. Age >= 18 years

2. Received one of the following procedures:

   1. A second or subsequent procedure on the arrhythmia device pocket:

      ICD, pacemaker, CRT-P, CRT-D generator and/or lead replacement

   2. Pocket or lead revision

   3. System upgrade (insertion or attempted insertion of leads)

   4. New cardiac resynchronization therapy device implant (pacemaker or ICD)

3. Patient is not known to have device infection at the time of the surgery