Inappropriate shocks delivered by implantable cardiac defibrillators during oversensing of activity of diaphagmatic muscle

Abstract

Two cases are reported (both men, one 72 and one 54 years old) of inappropriate shocks delivered by an implantable cardiac defibrillator (ICD) device, which oversensed the myopotentials induced by deep breathing and Valsalva manoeuvre. No damage to leads was associated with the oversensing of myopotentials. The mechanism of the inappropriate shocks was determined using real time electrograms. Modification of the duration of ventricular detection and decrease in sensitivity made it possible to avoid the oversensing of myopotentials and to deliver ICD treatment. (Heart 1999;81:94-96) Keywords: implantable cardiac defibrillator; inappropriate shocks; myopotentials Delivery of inappropriate shocks by implantable cardioverter defibrillators (ICDs) is a common complication.1 2 The mostfrequent cause is the occurrence of supraventricular tachycardia that cannot be diVerentiated by the ICD from ventricular tachycardia. 1 2 Other causes are oversensing of T waves, pacing artefacts from a separate pacemaker, and noise from electronic devices, and lead damage. [1][2][3][4][5][6] We report, for the first time, inappropriate shock by oversensing of diaphragmatic muscular activity in two patients implanted with third and fourth generation ICDs. Case 1A 74 year old man with coronary heart disease and recurrent ventricular fibrillation refractory to amiodarone and blocker treatment received a pectoral ICD (Mini1763; CPI Inc, St Paul, Minnesota, USA) with a bipolar endocardial catheter (Endotak model 0125; CPI Inc) in the right ventricular apex. The intraoperatively sensed R wave amplitude was measured at 8 mV and the pacing threshold was 0.7 V at 0.5 ms pulse width. The ICD was programmed

A case of inappropriate implantable cardioverter defibrillator shock due to epileptic seizures: A possible limitation of the Wavelet discrimination algorithm

“…Inappropriate ICD shock is also associated with oversensing of myopotential. Babuty et al reported the occurrence of inappropriate ICD shock due to the oversensing of diaphragmatic myopotential, with integrated bipolar sensing during deep breathing or the Valsalva maneuver, in the absence of lead damages or electrical interference [11]. The incidence of inappropriate detections due to the oversensing of diaphragmatic myopotential was reported to be 8.6%, whereas that of inappropriate ICD shocks was 3% [12].…”

Unusual Cause of Inappropriate Implantable Cardioverter Defibrillators’ Shock: Tremor

“…Bizim olgumuzda tremorun neden olduğu yüksek frekanslı ve güçlü kas kasılmaları ICD tarafından R dalgası olarak algılanmış ve şok vermesine neden olmuştu. Barakpour ve arkadaşları bir cisim fırlat-manın neden olduğu kas kontraksiyonları sırasında görü-len, Babuty ve arkadaşları ise diyafram kasılmaları sonucu gelişen miyopotansiyellere bağlı uygunsuz ICD şoku olguları bildirmişlerdir (8,9) . Miyopotansiyeller genellikle düşük amplitüdlü ve kısa süreli artefaktlara neden olmaktadır.…”

Death Due to an Implantable Cardioverter Defibrillator

“…Late report of death prevented any possibility of lead extraction to determine the exact site of the isolation break. Oversensing is possible without structural lead failure, 4 , 13,14 but this phenomenon must lead to the search for an insulation defect, particularly in the case of inappropriate shocks 1 . To make an early diagnosis of this malfunction, noninvasive parameters such as pacing and sensitivity threshold and pacing impedance should be measured during follow‐up.…”