Evaluating the effects of different dental devices on implantable cardioverter defibrillators.

INTRODUCTION: The implantable cardioverter defibrillator (ICD) is an electronic device that emits electrical signals to the heart via lead wires and electrodes. It is used for cardiac rhythm monitoring and treatment. Because electronic dental devices have been shown to produce electromagnetic fields, we hypothesize that they may interfere with ICD function. METHODS: Nine dental devices (heat carrier, electronic apex locator, electric pulp tester, unipolar electrosurgery unit, electric motor, curing light, and 3 gutta-percha guns) were tested in this study for their ability to interfere with the function of 4 ICDs (2 single-chambered and 2 dual-chambered ICDs). ICD activity was monitored for 30 seconds using an ICD programmer (Medtronic 2090; Minneapolis, MN) and evaluated through an electrogram test strip printout. RESULTS: Electromagnetic interference was detected with the electric motor, curing light, electric pulp tester, and electrosurgery unit although no electromagnetic disturbances were detected with these devices. No electromagnetic interferences were observed for the gutta-percha guns, heat carrier, and apex locator. However, the electrosurgery unit affected the dual-chambered ICD (Consulta CRT-D, Medtronic) and delivered therapies for fibrillation when no ventricular fibrillation was present. CONCLUSIONS: Our results suggest that the electrosurgery unit produces electromagnetic disturbances with unwanted therapy delivery shock and potentially clinically significant outcomes.

Effect of radiofrequency energy emitted from monopolar "Bovie" instruments on cardiac implantable electronic devices.

BACKGROUND: The monopolar "Bovie" instrument emits radiofrequency energy that can disrupt the function of other implanted electronic devices through a phenomenon termed electromagnetic interference. The purpose of this study was to quantify the electromagnetic interference occurring on cardiac implantable devices (CIEDs) resulting from monopolar instrument use in common, modifiable clinical scenarios. STUDY DESIGN: Three anesthetized pigs underwent CIED placement (1 pacemaker and 2 defibrillators). Electromagnetic interference was quantified when changing the monopolar instrument parameters of generator power, generator mode, surgical technique, orientation of active electrode cord, pathway of current vector, and proximity of active electrode to the CIED. RESULTS: Monopolar instrument parameters that decreased the electromagnetic interference occurring on the CIED included decreasing generator power from 60 W to 30 W (p < 0.001), using cut mode rather than coag mode (p < 0.001), using desiccation technique rather than fulguration technique (p < 0.001), orienting the active electrode cord from the feet rather than across the chest wall (p < 0.001), and avoiding the current vector from crossing the CIED system (p < 0.001). Increasing the distance between the active electrode tool and the CIED system decreased electromagnetic interference occurring on the CIED in a dose-response fashion up to a distance of 10 cm (ANOVA, p < 0.001), after which the magnitude of electromagnetic interference remained constant. CONCLUSIONS: Electromagnetic interference occurring on CIEDs resulting from monopolar instruments is minimized by decreasing generator power, using cut mode, using desiccation technique, orienting the active electrode cord from the feet, avoiding the current vector for crossing the CIED system, and increasing the distance between the active electrode and the CIED. Surgeons and operating room staff can minimize electromagnetic interference on CIEDs during monopolar instrument use by accounting for these modifiable clinical factors.

Investigation of hyfrecators and their in vitro interference with implantable cardiac devices.

BACKGROUND: Guidelines exist for minimizing potential electromagnetic interference (EMI) with electrosurgical equipment in patients with cardiac rhythm management (CRM) devices. These guidelines encompass all electrosurgical devices but are not specific for hyfrecators. OBJECTIVE: To investigate the potential interference of CRM devices by hyfrecators. MATERIALS AND METHODS: Using a collagen-based saline gel, three implantable pulse generators (pacemakers) and three implantable cardioverter defibrillators were tested to measure the EMI from two commonly used hyfrecators. The six devices were tested using the hyfrecator under normal use settings and on maximum power. RESULTS: Hyfrecators did not interfere with defibrillators and affected pacemakers only when used in close proximity to the device. For the pacemakers, atrial inhibition was observed at a distance of 3 cm on maximum hyfrecator settings and 1 cm at normal use settings. Ventricular inhibition occurred in very close proximity to the device (<1 cm) or in direct contact. CONCLUSION: Hyfrecators are safe to use in patients with defibrillators and can be used in pacemaker patients within 2 inches of the device perimeter.