Myopotential sensing by a dual chamber implantable cardioverter defibrillator: two case reports.
BACKGROUND
Inappropriate discharges and/or improper inhibition of bradycardia pacing due to oversensing of extraneous signals in implantable cardioverter defibrillators (ICDs) have been described. With one exception, no previous report involving an intact lead system has cited myopotential oversensing as the cause.


RESULTS
Two case reports of myopotential oversensing by a dual chamber ICD system are reported. In the first patient suffering from chronic pulmonary obstructive disease, intermittent myopotential sensing during labored respiration resulted in episodic inhibition of bradycardia pacing. In the second patient, oversensing of sustained myopotentials generated during strenuous isometric activity resulted in an inappropriate ICD discharge. For both, the ICD system consisted of a CPI model 1810 Ventak AV used in conjunction with a model 0125 Endotak lead, incorporating integrated bipolar sensing.


CONCLUSIONS
Although modern ICDs have proven to be highly effective in detecting and terminating malignant tachyarrhythmias, the opportunity for improving their detection specificity remains.
Cardiology Division, Robert Packer Hospital, Sayre, Pennsylvania 18840, USA.
P
P
Deshmukh
K
K
Anderson
D000368:Aged; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D006339:Heart Rate; D006801:Humans; D008297:Male; D008564:Membrane Potentials; D009200:Myocardial Contraction; D012449:Safety; D017180:Tachycardia, Ventricular / Q000503:physiopathology / Q000628:therapy*