Unusual Marker Annotation: Something Shifty is Going On

Significance of Missing Telemetered Markers in Implanted Cardioverter‐Defibrillators

“…Unusual manifestations of the telemetry function of pacemakers and ICDs have been rarely reported 1,2 . Some experts might consider our observations as curiosities with no clinical significance.…”

“…Unusual manifestations of the telemetry function of pacemakers and implantable cardioverter‐defibrillators (ICDs) are uncommon 1,2 . We have encountered three patients with St. Jude ICDs (St. Jude Medical, Sylmar, CA, USA) where telemetry revealed missing markers.…”

“…Unusual manifestations of the telemetry function of pacemakers and implantable cardioverterdefibrillators (ICDs) are uncommon. 1,2 We have encountered three patients with St. Jude ICDs (St. Jude Medical, Sylmar, CA, USA) where telemetry revealed missing markers. In two cases the missing markers were due to the simultaneous occurrence of two cardiac or device events that interfered with the delivery of the markers by the telemetry system.…”

Electrograms and Marker Delay: Is There a Problem?

“…Marker annotation misalignment is an uncommon occurrence during device system testing and may lead to challenges in interpretation. There has been one published case of misalignment between surface ECG and intracardiac EGM due to a software problem . Another case of misalignment of marker channel and stored events have been reported, also due to software issues as well .…”

“…There has been one published case of misalignment between surface ECG and intracardiac EGM due to a software problem. 1 Another case of misalignment of marker channel and stored events have been reported, also due to software issues as well. 2 In both cases, there was no adverse effect on device function.…”