A 77-year-old female patient with sinus bradycardia and left bundle branch block was implanted with a DDD Biotronik Kairos DR pacemaker in 1999, then a replacement for depleted battery was performed in 2007 (Biotronik Axios DR). During our regularly scheduled follow-ups, we found the atrial and ventricular sensing/pacing function to be satisfactory: P: 3.6 mV, R: 9.9 mV, atrial threshold: 0.7 V/0.4 ms, ventricular threshold: 0.5 V/0.4 ms. Parameters were set as follows: basic rate: 60 bpm, hysteresis: −10 bpm, dynamic AV delay: 225 ms, sense compensation: −45 ms, atrial sensitivity: 1 mV, and ventricular sensitivity: 5 mV. During the latest follow-up (14 years after the first implantation), the following recording was made (Fig. 1). What would be your interpretation of this recording?
Fig. 1.
Ventricular sensing failure, when the QRS is narrow
Answer
You will find the answer elsewhere in this issue.