MYOPOTENTIAL SENSING BY A DUAL-CHAMBER IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR - 2 CASE-REPORTS

Introduction: Inappropriate discharges and/or improper inhibition of b radycardia pacing due to oversensing of estraneous signals in implanta ble cardioverter defibrillators (ICDs) have been described, With one e xception, no previous report involving an intact lead system has cited myopotential oversensing as the cause, Methods and Results: Two case reports of myopotential oversensing by a dual chamber ICD system are r eported, In the first patient suffering from chronic pulmonary obstruc tive disease, intermittent myopotential sensing during labored respira tion resulted in episodic inhibition of bradycardia pacing, In the sec ond patient, oversensing of sustained myopotentials generated during s trenuous isometric activity resulted in an inappropriate ICD discharge , For both, the ICD system consisted of a CPI model 1810 Ventak AV use d in conjunction with a model 0125 Endotak lead, incorporating integra ted bipolar sensing, Conclusion: Although modern ICDs have proven to b e highly effective in detecting and terminating malignant tachyarrhyth mias, the opportunity for improving their detection specificity remain s.