sick sinus syndrome and indication for first-time implantation of a ddd pacemaker: symptomatic sinus pauses (>2 sec) or bradycardia with or without paroxysmal af.

age ≥18 years.

patient informed consent.

permanent or persisting (>7 days) af prior to implantation.

persisting symptomatic sinus bradycardia and/or chronotropic incompetence where ddd-pacing at a frequency of >40 bpm is indicated (verified with long term ecg monitoring).

persisting second or third degree av block.

life expectancy <2 years.

participation in another interventional research study.

indication for implantable cardioverter defibrillator (icd) or cardiac resynchronization therapy (crt).

pregnancy.