Shocking truths about implantable cardioverter defibrillator monitoring zones.
A 36 year-old man with hypertrophic cardiomyopathy and an ATLAS + DR implantable cardioverter defibrillator (ICD) (St. Jude Medical, Inc., St. Paul, MN, USA) for primary prevention received a shock while cycling. The ventricular fibrillation detection threshold was 182 beats/min. An additional monitoring zone was programmed to 156 beats/min with all discriminators "on" except morphology. On interrogation, the ICD shock followed sinus tachycardia. In the absence of a monitoring zone, device therapy would not have been expected. We explore the mechanisms by which monitoring zones could potentially contribute to inappropriate ICD therapy and offer trouble-shooting tips.
Mansour
Fadi
F
Electrophysiology Service, Montreal Heart Institute, Montreal, Quebec, Canada.
Thibault
Bernard
B
Dubuc
Marc
M
Guerra
Peter G
PG
Macle
Laurent
L
Brugada
Ramon
R
Roy
Denis
D
Talajic
Mario
M
Khairy
Paul
P
D000328:Adult; D002312:Cardiomyopathy, Hypertrophic / Q000517:prevention & control*; D017147:Defibrillators, Implantable / Q000009:adverse effects*; D004554:Electric Countershock / Q000009:adverse effects*; D004868:Equipment Failure; D019544:Equipment Failure Analysis; D006801:Humans; D008297:Male; D017180:Tachycardia, Ventricular / Q000209:etiology* / Q000517:prevention & control*