Improved arrhythmia detection in implantable loop recorders.
BACKGROUND
Implantable loop recorders (ILR) have an automatic arrhythmia detection feature that can be compromised by inappropriately detected episodes. This study evaluated a new ILR sensing and detection scheme for automatically detecting asystole, bradyarrhythmia, and tachyarrhythmia events, which is implemented in the next generation device (Reveal DX/XT).


RESULTS
The new scheme employs an automatically adjusting R-wave sensing threshold, enhanced noise rejection, and algorithms to detect asystole, bradyarrhythmia, and tachyarrhythmia. Performance of the new algorithms was evaluated using 2,613 previously recorded, automatically detected Reveal Plus episodes from 533 patients. A total of 71.9% of episodes were inappropriately detected by the original ILR, and at least 88.6% of patients had one or more inappropriate episodes, with most inappropriate detections due to R-wave amplitude reductions, amplifier saturation, and T-wave oversensing. With the new scheme, inappropriate detections were reduced by 85.2% (P < 0.001), with a small reduction in the detection of appropriate episodes (1.7%, P < 0.001). The new scheme avoided inappropriate detections in 67.4% of patients that had them with the original scheme.


CONCLUSIONS
The new sensing and detection scheme is expected to substantially reduce the occurrence of inappropriately detected episodes, relative to that of the original ILR.
Brignole
Michele
M
Department of Cardiology, Arrhythmologic Centre, Ospedali del Tigullio, Lavagna, Italy.
Bellardine Black
Carissa L
CL
Thomsen
Poul E Bloch
PE
Sutton
Richard
R
Moya
Angel
A
Stadler
Robert W
RW
Cao
Jian
J
Messier
Marc
M
Huikuri
Heikki V
HV
D000465:Algorithms; D001145:Arrhythmias, Cardiac / Q000175:diagnosis*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D015716:Electrocardiography, Ambulatory / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D016247:Information Storage and Retrieval / Q000379:methods; D010363:Pattern Recognition, Automated; D019736:Prostheses and Implants; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*