[Pacemaker ECG Quiz No. 23: Pacemaker malfunction or arrhythmia?].

In a 69-year-old patient, a DDDR pacemaker was implanted for sinus node disease with syncope due to sinus arrest with pauses > 4 s. Programming was performed carefully including measures to prevent unnecessary ventricular pacing. Approximately 6 months after implantation, the patient who was asymptomatic in the meantime presented for pacemaker control because the ECG had raised the question of pacemaker malfunction.