Pacemaker failure

Abstract: Importance Risk stratification and management paradigms for patients with cardiovascular implantable electronic devices (CIEDs) requiring radiotherapy (RT) vary widely and are based on limited clinical data. Objective To identify the incidence and predictors of CIED malfunction and describe associated clinical consequences in a large cohort of patients treated with photon- and electron-based RT. Design, Setting, and Participants Retrospective analysis of all patients with a functioning CIED who underwent RT between August 2005 and January 2014 with CIED interrogation data following RT at an academic cancer center. We identified 249 courses of photon- and electron-based RT in 215 patients (123 pacemakers [57%]; 92 implantable cardioverter-defibrillators [43%]). Substantial neutron production was generated in 71 courses (29%). Exposure Implantation of CIED with subsequent therapeutic radiation treatment (neutron producing with 15- or 18-MV photons and non–neutron producing with electrons, GammaKnife, or 6-MV photons). Main Outcomes and Measures Malfunction of CIED, characterized as single-event upset (data loss, parameter resets, unrecoverable resets), and delayed effects including signal interference, pacing threshold changes, and premature battery depletion. Results Malfunction of CIED attributable to RT occurred during 18 courses (7%), with 15 CIEDs experiencing single-event upsets, and 3, transient signal interference. All single-event upsets occurred during neutron-producing RT, at a rate of 21%, 10%, and 34% per neutron-producing course for CIEDs, pacemakers, and implantable cardioverter-defibrillators, respectively. No single-event upsets were found among 178 courses of non–neutron-producing RT. Incident CIED dose did not correlate with device malfunction. Patients treated to the abdomen and pelvis region were more likely to undergo a single-event upset (hazard ratio, 5.2 [95% CI, 1.2-22.6]; P = .03). Six patients with a CIED parameter reset developed clinical symptoms: 3 experienced hypotension and/or bradycardia, 2 experienced abnormal chest ticking consistent with pacemaker syndrome, and 1 developed congestive heart failure. The 3 episodes of signal interference did not result in clinical effects. No delayed malfunctions were directly attributed to RT. Conclusions and Relevance In a cohort of contemporary CIEDs, all cases of single-event upset malfunction occurred in the setting of notable neutron production, at a rate of 21% for neutron-producing RT and 0% for non–neutron-producing RT. Where clinically feasible, the use of non–neutron-producing RT is recommended. Given the lack of correlation between CIED malfunction and incident dose observed up to 5.4 Gy, invasive CIED relocation procedures in these settings can be minimized.

Abstract: We report a case of electrocautery-induced pacemaker failure that resulted in asystole in a 15-year-old girl scheduled for cardiac surgery. Her pacemaker was converted to the asynchronous mode the night before surgery. Electromagnetic interference from the unipolar electrocautery caused a reduction in the battery voltage, which allowed the digital circuitry, but not the voltage control oscillator (VCO), to work properly. Eventually the battery current drain caused VCO "lock-out," and pacemaker and battery failure. This report demonstrates that electrocautery-induced pacemaker failure can occur, even after conversion to asynchronous mode.

Abstract: Pacemaker malfunction occurred after a patient was given 3000–3600 rads to an area occupied by an A-V sequential pacemaker. Analysis of the removed generator showed that there was malfunction of the large scale integrated circuit and the type of damage was consistent with radiation-induced effects. The newer muJtiprogram-mable units may be more sensitive to ionizing radiation than those previously available. (PACE, Vol. 5, March-April, 1982)

Abstract: Patients with implanted pacemakers and ICDs can be safely managed for surgery and anaesthesia. Anaesthetic management of such patients should be planned first according to the patient's underlying medical status with particular emphasis on ventricular function and electrolyte balance. The anaesthetist must understand the various modes of pacemakers and ICDs available in the patient population. These devices are safe and well shielded form most electromagnetic interference in the operating room. Some precautions are nevertheless necessary. A magnet should not be placed routinely over a programmable pacemaker or ICD in the operating room, especially in the presence of electrocautery. Rate-responsive pacemakers should have rate adaptive modes disabled before surgery whenever possible. The mechanism of rate response should be known, so that inappropriate changes in heart rate can be avoided in the perioperative period if the rate responsive mode cannot for some reason be disabled. Antitachycardia pacemakers, should have the antitachycardia function disabled preoperatively. Methods for the provision of alternate emergency pacing should be available when dealing with patients at risk of bradyarrhythmias or pacemaker failure in the operating room. The anaesthetist should have a safe, practical plan of action that suites his/her experience and capabilities. ICDs should have automatic cardioverter-defibrillator functions disabled for surgery and external modes of cardioversion/defibrillation should be available.