A Clinical Trial of the Use of Remote Heart Rhythm Monitoring With a Smartphone After Cardiac Surgery

A predefined subgroup analysis of the outcomes described below will be performed in the following subgroups: * Subjects not on anticoagulation drug therapy (for a planned duration of \>45 days) at discharge. * Subjects with no history of AF prior to surgery and no POAF lasting \>24h in hospital. * Subjects with a CHADSVASC score ≥ 4 or a CHADSVASC score ≥ 2 with at least one additional risk factor associated with the risk of developing POAF. additional risk factors include: * chronic obstructive pulmonary disease * sleep apnea * impaired renal function * left atrial enlargement * elevated body mass index * combined CABG with valve repair or replacement