This 71-year-old man received a Biotronik Lumax 540 HF-T triple chamber defibrillator in the context of ischemic cardiomyopathy with left bundle branch block. He was followed by remote monitoring and a periodic EGM was transmitted.
This tracing shows a transitory decrease in the percentage of BiV stimulation due to atrial undersensing, revealed by the transmission of a periodic EGM without alert. As the percentage of BiV stimulation does not decrease below the threshold, a specific alert is not emitted. The tracing is not consistent with the sensing of a PVC, which must, by definition, be premature, unlike in this case. It might, on the other hand, be a ventricular escape in the context of sinus node dysfunction. This patient’s sinus node function was normal and atrial sensing in an average range, with a 0.6-mV P wave amplitude, characteristics consistent with atrial undersensing, which was corrected by reprogramming of the atrial sensitivity.
