Unexpected Inhibition of Pacing in a Patient with Complete AV Block after Upgrade of a Pacemaker to a Defibrillator: What is the Mechanism?Short Titel: Unexpected inhibition of pacingNicolas Schaerli, MD1, 2; Antonio Madaffari, MD1, 2; Beat Schaer, MD1, 2; Christian Sticherling, MD1,21 Department of Cardiology, University Hospital Basel, Petersgraben 4, 4031 Basel, Switzerland2 Cardiovascular Research Institute Basel, University Hospital Basel, Spitalstrasse 2, 4056 Basel, SwitzerlandDisclosures /Conflict of interest: Nothing to discloseCorresponding author:Christian Sticherling, MDUniversity Hospital Basel, Department of CardiologyPetersgraben 4, 4031 BaselEmail: [email protected]