This ECG was recorded from an 87-year old male with a dual chamber pacemaker. What exactly might be going on here? I don’t have a definitive ‘correct’ answer, but it would be interesting to know what people think.
Dr Dave Richley
Dr Dave Richley’s ECG of the Month – September 2020
Atrial undersensing during sustained atrial fibrillation, giving rise to occasional tracking of fibrillation waves interspersed with ineffective atrial pacing during dual chamber pacing at basic or sensor indicated rate. There is also notably one short AV delay (middle complex in V1-3); either a ventricular safety pace following genuine crosstalk from high atrial output, a back-up pulse of AutoCapure, or safety pacing from a sensed intrinsic R-wave shortly following the atrial pace (the QRS is slightly different and therefore possibly fused).
The easy fix is VVIR reprogramming, although due to atrial undersensing we cannot determine from pacing diagnostics if AF is indeed permanent. I’d fix the atrial sensing if possible, or program DDIR; then review in 3 months; or sooner if home monitoring available.
Obviously if AF is a new finding, then start on a DOAC or warfarin if AF considered valvular in nature.
I think Scott’s summed this one up well. We seem to have AF and a pacemaker working in DDD mode with intermittent atrial sensing. Is there anything else that needs commenting on or any alternative explanations for what we see?