This patient’s device was initially programmed in DDD mode without rate response. The atrial histogram reveals the presence of very high atrial rates which correlate with AF (confirmed on the surface ECG). The pacemaker switched to DDIR mode, explaining the ventricular histogram, which showed a satisfactory rate response (a switch to DDI mode, in this patient, would have caused fixed pacing at the slowest rate).
This pacemaker interrogation raises several questions:
1) this patient presented with a 2 to 3 CHADS score and was a candidate for anticoagulation. The heart rate was well controlled because of her conduction disorder, she was asymptomatic and the diagnosis of AF was made during a routine visit. A systematic remote follow-up by telemedicine should allow a much earlier diagnosis in asymptomatic patients;
2) a conversion of the atrial arrhythmia to sinus rhythm might be considered even if the patient is asymptomatic and the heart rate is well controlled;
3) should a strategy of conversion to sinus rhythm be favored, DDD with switch to DDIR mode in presence of an atrial arrhythmia seems preferable. In this patient, the merits of rate responsiveness during fallbacks are apparent, with preservation of appropriate rates at rest as well as during exercise.
Should a strategy of rate control be favored, the presence of permanent AF would probably justify the programming of VVIR mode.