Cardiac pacemakers and implantable defibrillators in terminal care.

The use of cardiac pacemakers and arrhythmia control devices is increasingly common. The presence of a previously placed pacemaker or implantable cardioverter-defibrillator (ICD) in a terminally ill patient may result in medical and ethical issues for the patient, family, and healthcare provider. Two cases are presented to illustrate the complex issues that may arise in the terminally ill with a pacemaker or an ICD. Based on these cases and a review of published data, it is likely that the disabling of a previously placed pacemaker will neither hasten nor prolong the natural history of the underlying illness in most instances. There are uncommon but potentially severe adverse effects of disabling the pacemaker; therefore, pacemakers should generally be left intact in terminally ill patients. It is more difficult to generalize as to whether deactivation of an ICD is appropriate; in this case death may be hastened and the decision concerning an ICD will depend on the specific clinical scenario. Patient and family education regarding palliative care treatment goals and the function of pacemakers and other implanted arrhythmia control devices can help to alleviate anxiety surrounding the impact of this technology at the end of life.     

An Update on Pacemakers and Defibrillators

The aging population coupled with comorbidities lead to the growing number of pacemaker and implantable cardioverter defibrillator (ICD) implants each year. Newer studies give way to revisions in device guidelines, whereas innovations in electrophysiology provide promising therapies, such as leadless cardiac pacemakers, subcutaneous ICDs, and magnetic resonance imaging–conditional devices. This article summarizes current device guidelines, reviews novel therapies, and discusses practical applications for nurse practitioners. It is paramount for nurse practitioners in all specialties to remain up to date with the latest trends in device therapy given the prevalence of patients with cardiac implantable electronic devices.     

Implantable Cardioverter‐Defibrillator Recipient Attitudes towards Device Deactivation: How Much do Patients Want to Know?

Background: Patients receiving implantable cardioverter‐defibrillators (ICDs) often have severely impaired left ventricular function and a poor prognosis. Having an ICD in situ effectively denies them the possibility of a quick, arrhythmic death. It is still unclear if and when the end of life and device deactivation should be discussed with patients and how much patients want to know prior to ICD implantation. Methods: Patients with an active ICD for chronic heart failure were interviewed regarding their attitude toward the ICD, their recollection of the consent procedure, and how they felt the end of life should be discussed with ICD patients (n = 54). Patients who had received ICD therapies (n = 25) were reviewed as a subgroup with extended questions regarding attitudes toward device deactivation. Results: Fifty‐four patients were recruited. Most patients were not aware that the ICD could be deactivated. The vast majority of patients (84%) wanted to be involved in the deactivation decision; 40% felt this discussion should be prior to ICD implantation but others felt the discussion should only occur if the patient was terminally ill (16%) or in the last few days of life (5%). Conclusion: Patients with ICDs are routinely counseled about the benefits of ICDs, but options for device deactivation are not well understood by patients. Most patients would like to be involved in deactivation decisions and we feel this should be discussed well in advance. (PACE 2011; 34:1628–1633)     

Urgent implantable cardioverter defibrillator deactivation by unconventional means

Increasing numbers of patients are receiving implantable cardioverter defibrillators (ICDs); the devices remain fully functional in most terminally ill patients at the time of death. We describe a case of a terminally ill patient with repeated defibrillations who requested urgent ICD deactivation. Nonmedical magnets available in the facility were used to deactivate the ICD and terminate the defibrillations. We then studied various magnetic field sources commonly available in homes, such as ceramic magnets, cell phones, computer hard drives, headsets, and earbuds that potentially may be used to temporarily deactivate an ICD until a device technician is available for reprogramming. We conclude that commonly available magnetic sources may potentially be used to deactivate an ICD. The clinical usefulness of this is speculative and limited to conditions when the need to turn off the device is urgent, and a delay in reprogramming is anticipated.     

Physician management of pacemaker and implantable cardioverter defibrillator advisories

This study was designed to determine how physicians manage pacemaker (PM) and implantable cardioverter defibrillator (ICD) recalls and safety alerts (collectively "advisories") and to determine which factors influence physicians' clinical decisions. Although PM and ICD advisories affected over 500,000 patients in the past decade, physician clinical management of advisory devices has not been well studied. Advisories continue to occur frequently and are increasing in number and rate. Five-hundred physician members of the North American Society of Pacing and Electrophysiology (NASPE) were randomly surveyed by mail and were asked to make clinical recommendations regarding the management of various PM and ICD advisory scenarios. One hundred sixty-two physicians (32%) responded to the survey (cardiac electrophysiologist 69%, general cardiologist 22%, surgeon 6%, and other 3%). There was consensus among physicians regarding the management of some PM and ICD advisories but not others. Factors associated with a higher likelihood of physician recommendation for prophylactic advisory device replacement include: ICD implanted for secondary prevention (vs primary prevention, P < 0.001), pacemaker dependence (P < 0.001), prior appropriate ICD therapy (P < 0.001), higher likelihood of device malfunction (P < 0.001), and physician in practice <10 years (P = 0.02). The number of devices implanted or followed per year and physician specialty had no impact on advisory device management. Physician consensus exists regarding the management of some PM and ICD advisories and can be used to guide clinical practice. Substantial differences of opinion, however, are present regarding the management of many other advisories. Evidence based guidelines incorporating the indication for device implantation and the likelihood of device malfunction would greatly facilitate clinical management of PM and ICD advisory devices.     

Use of a transurethral microwave thermotherapeutic device with permanent pacemakers and implantable defibrillators

OBJECTIVE: To determine whether a device (Urologix Targis system) used for transurethral microwave treatment interferes with sensing, pacing, and arrhythmia detection by permanent pacemakers and implantable cardioverter-defibrillators (ICDs). METHODS: We tested 13 pacemakers in both bipolar and unipolar sensing configurations and 8 ICDs in vitro. Pacemakers and ICDs were programmed to their most sensitive settings. Energy outputs of the microwave device were typical of those used clinically. The probe of the microwave device was anchored 1.2 cm from the pacemaker or ICD being tested. RESULTS: No sensing, pacing, or arrhythmic interactions were noted with any ICD or any pacemaker programmed to the bipolar configuration. One pacemaker (Guidant Vigor 1230) showed intermittent tracking when programmed to the unipolar configuration. CONCLUSIONS: Most patients with permanent pacemakers or ICDs can safely undergo transurethral microwave therapy using the device tested. Pacemakers and ICDs should be programmed to the bipolar configuration (if available) during therapy. The pacemaker or ICD should be interrogated before and after therapy to determine whether programming changes occurred as a result of treatment. However, our findings suggest that this is unlikely.     

An analysis of implantable cardiac device reliability. The case for improved postmarketing risk assessment and surveillance

Implantable cardiac devices have become the mainstay of the treatment of patients with heart disease. However, data regarding their reliability and, inferentially, safety have been called into question. We reviewed annual reports submitted to the Food and Drug Administration Office of Device Evaluation by device manufacturers from 2003 to 2007. The annual number of implantable cardiac defibrillators (ICDs) and cardiac resynchronization therapy defibrillator (CRT-D) implants, explants, and returned devices were tabulated along with the cumulative (Cum) number of implants for each device. We derived an annual explantation rate (AER) defined as the ratio of the annual number of explants less the number of normal battery depletions/Cum (×1000). From 2003 to 2007, 256,392 CRT-D and 459,300 ICD devices were implanted in the United States. The overall mean (±SD) AERs for ICD and CRT-D devices were, respectively, 49.5 (15.6) per 1000 ICD devices and 82.6 (35.5) per 1000 CRT-D devices. The AER for each device type significantly decreased over the study period (P for trend <0.001) although the AER for CRT-D devices was 38% higher than that for ICD devices (P < 0.001). On average, 20.3% of CRT-D devices and 22.6% of ICD devices were returned to the manufacturer for analysis after explantation. The rates of explanted CRT-D and ICD devices decreased from 2003 to 2007. Notwithstanding this favorable trend, the AER for CRT-D devices was higher than that for ICD devices. Improved methods for tracking individual device histories are needed for more precise estimates of the risk of device explantation for suspected malfunction. The proportion of devices returned to the manufacturer is suboptimal and needs to be improved to better understand the mechanisms of device malfunction.     

Electroconvulsive therapy in patients with cardiac pacemakers and implantable cardioverter defibrillators

Electroconvulsive therapy (ECT) is used to treat major depressive illness, especially in elderly and medically frail patients. Not uncommonly, these patients have cardiac pacemakers or implantable cardioverter defibrillators (ICDs). Only a few case reports in the literature describe the use of ECT in such patients. Herein we review our ECT experience treating 26 pacemaker patients and 3 ICD patients. All patients obtained significant antidepressant benefits with ETC. Only one serious cardiac event occurred, a case of supraventricular tachycardia (SVT) requiring a stay on the cardiac intensive care unit. The SVT resolved and the patient went on to receive further uncomplicated ECT treatments. We conclude from this experience that with proper pre-ECT cardiac and pacemaker/defibrillator assessment, ECT can be safely and effectively administered to patients with an implanted cardiac device.     

Ethical analysis of withdrawal of pacemaker or implantable cardioverter-defibrillator support at the end of life

OBJECTIVE: To describe a series of terminally ill patients who requested (or whose surrogates requested) withdrawal of pacemaker or implantable cardioverter-defibrillator (ICD) support and the ethical issues pertaining to these requests. PATIENTS AND METHODS: We performed a retrospective review of the medical records of patients seen at the Mayo Clinic in Rochester, Minn, between January 1996 and June 2002 and identified 6 terminally ill patients who requested (or whose family members requested) withdrawal of pacemaker or ICD support. Potential interventions were an ethics consultation and subsequent withdrawal of pacemaker or ICD support. The study's main outcome measures were death and the context in which it occurred. RESULTS: The mean age of the 6 patients (3 men, 3 women) was 75.5 years. Five had pacemakers, and 1 had an ICD. Five patients had advance directives that indicated a desire to withdraw medical interventions if death was inevitable. Two patients and 4 surrogates requested withdrawal of pacemaker or ICD support. One patient died without withdrawal of support despite an ethics consultation that endorsed its permissibility. Another died while an ethics consultation was in progress. The request to withdraw support was granted in 4 patients, all of whom died within 5 days of withdrawal of support. CONCLUSIONS: Granting terminally ill patients' requests to withdraw unwanted medical support is legal and ethical. Death after withdrawal of support is attributable to the patient's underlying pathology and is not the same as physician-assisted suicide or euthanasia. Clinician familiarity with these concepts may lead to more expeditious withdrawal of unwanted medical support from terminally ill patients.     

Effects of surgical and endoscopic electrocautery on modern-day permanent pacemaker and implantable cardioverter-defibrillator systems

Background: Current guidelines recommend that all implanted pacemakers (PPM) and defibrillators (ICD) be interrogated before and after every invasive procedure. The ability of newer devices to withstand system malfunction or failure during surgery/endoscopy remains unknown.
Objective: To determine the frequency of PPM or ICD malfunction from periprocedural electrocautery.
Methods: Ninety-two consecutive individuals referred for evaluation of a PPM or ICD system prior to noncardiac surgery/endoscopy were enrolled. Devices were preoperatively programmed to a "monitor only" zone to allow for detection of electromagnetic interferences (EMIs). Pacing parameters were maintained without disabling rate responsiveness. The devices were fully interrogated again after surgery. Correlations of inappropriate EMI sensing were made with reference to the distance from the site of electrocautery application to the device system.
Results: All devices withstood periprocedural EMI exposure without malfunction or changes in programming. Minor changes in lead parameters were noted. Three device systems demonstrated brief atrial mode switching episodes, one of which was likely secondary to inappropriate sensing of atrial noise . Two pacemaker devices demonstrated inappropriate sensing of ventricular noise, both of which occurred when the application of electrocautery was within close proximity to the pacemaker generator (<8 cm). No ventricular sensed events were noted in any ICD system.
Conclusions: EMIs during noncardiac surgical/endoscopic procedures pose little threat to current device systems. Rare occasions of inappropriate sensing by devices can be seen in situations where the application of unipolar electrocautery is in close proximity of the system. Routine postsurgical interrogation of PPM or ICDs may not be necessary.     

Effect of bioimpedance body composition analysis on function of implanted cardiac devices

Background: It is routinely recommended that patients with pacemakers, implantable cardioverter defibrillators (ICD), and cardiac resynchronization therapy‐defibrillators (CRT‐D) avoid bioelectrical impedance analysis (BIA)—a commonly used method to estimate body composition—because of the concern for the potential for BIA interference with pacemaker or ICD function. However, the prevalence of such interference is not known. Objective: Assess for incidence of interference between BIA and ICD or CRT‐D devices. Methods and Results: Twenty patients with heart failure and cardiac implanted electronic devices (50% ICD, 50% CRT‐D) underwent BIA during real‐time device interrogation to detect interference. Study patients were 90% male, with mean age 54 ±14 years, and mean LVEF 23 ± 11%. Devices from all four leading cardiac device manufacturers were included. Device therapies were temporarily disabled to prevent inappropriate shocks. During body composition testing using BIA, no evidence of interference with ICD function was seen in any patient, including no telemetry disruption, no oversensing on any lead, and no patient symptoms. Conclusions: Despite the manufacturers’ recommendation to avoid BIA in patients with ICDs, this study showed no evidence of any interference in 20 patients. Bioimpedance analysis might be safe in such patients, but further confirmatory studies are required. (PACE 2012; 35:681–684)     

Is pacemaker deactivation at the end of life unique? A case study and ethical analysis

Although there has been considerable controversy regarding the deactivation of pacemakers near the end of life, clinicians can expect to face more requests for pacemaker withdrawal as the number of implants grows. Despite a clear ethical and legal precedent, these requests may elicit significant psychological and moral distress on the part of the clinical team. We illustrate some of the difficulties clinicians may face by describing the case of a patient with end-stage heart failure who asked to have her pacemaker turned off near the end of life. We discuss the challenges in determining pacemaker dependency, differing attitudes toward deactivating pacemakers versus other cardiac devices, and how the issues of perceived burden and timing of death may contribute to a clinician's sense of moral distress.     

Survey of cardiac pacing and implanted defibrillator practice patterns in the United States in 1997

A survey of implanters of permanent cardiac pacemakers and ICDs in the United States during 1997 was conducted to identify present and changing patterns in indications for pacing, implantation techniques, pacing-mode selection, follow-up, and opinions regarding pacing and ICD related issues. This report is an update from 1993 of surveys performed every 4 years for the International Cardiac Pacing and Electrophysiology Society (ICPES). Questionnaires were sent to implanting physicians who were members of the North American Society of Pacing and Electrophysiology (NASPE), and who might, therefore, be expected to be more conversant than others with the state of the art. Four major manufacturers also provided estimates of the numbers of pacemakers and ICDs implanted in the United States from 1994 through 1997. In 1997, approximately 182,000 new rhythm management devices, including 153,000 primary pacing systems and 29,000 ICDs, were implanted, an increase of 24% for pacemakers and 90% for ICDs since 1994. In 1997, pacemaker implantations were performed by about 8,600 physicians working in 3,300 hospitals and 1,000 independent "surgi-centers." From 1994 to 1997, sales in the United States of dual chamber pacemakers rose from 58% to 69% of the total, and adaptive rate systems from 74% to 90%. ICD sales increased by about 29% per year from 18,700 to 35,000 units. This study disclosed significant differences among implanter subcategories and between present and earlier practices, and it provided useful insights into trends in pacemaker and defibrillator practice. Future surveys would be facilitated if a standardized implant registry like that used in Europe were established in the United States.     

Ectopy in Patients with Permanent Pacemakers and Implantable Cardioverter-Defibrillators Undergoing an MRI Scan

Background: Recent series suggest that magnetic resonance imaging (MRI) scanning can be performed safely in select patients with pacemakers or implantable cardioverter-defibrillators (ICDs). Limited data have been reported on ectopy during MRI scans in patients with pacemakers or ICDs. This study evaluated increased ectopy observed in patients with permanent pacemakers or ICDs undergoing MRI scanning of any landmark without peak specific absorption rate (SAR) limit.
Methods: Fifty-two patients with a total of 119 leads underwent a total of 59 MRI scans of any landmark using usual protocols with standard peak SAR settings for the scan. No patient was pacemaker dependent. All devices were programmed to single-chamber demand mode (VVI) or dual-chamber demand mode (DDI) with a lower rate of 40 bpm. Both telemetry and pulse oximetry plethysmographic waveform were observed continuously throughout the scans for ectopy.
Results: Increased ectopy was observed during seven scans. The ectopy in four scans was ventricular and had fixed coupling intervals of 1,500 and 3,000, and was likely due to device noise rejection behavior. The etiology of ectopy observed during the other three scans could not be determined. Ectopy could not be predicted by peak SAR, scan time duration, or landmark. No significant changes in pacing thresholds were seen postscan.
Conclusions: The current series suggests that a minority of patients with implanted pacemakers may have MRI-related ectopy. A significant proportion of this ectopy may arise from normal device behavior within the MRI environment.     

Long-Term Efficacy of an Antitachycardia Pacemaker and Implantable Defibrillator Combination

Antitachycardia pacemakers and implantable cardioverter defibrillators (ICD) were implanted in 14 patients to control recurrent hemodynamically stable ventricular tachycardia (VT), All patients underwent extensive preimplant testing in the elecrrophysiology laboratory documenting that in each patient at least 50 episodes of VT could be reliably terminated by an external model of the antitachycardia pacemaker. The burst scanning mode of anfitachycardia pacing was used in all patients. ICDs were implanted solely as a back up should acceleration of VT occur, and all had high nonprogrammable rate cutoffs (mean 191 ± 12 beats/min). During a mean follow-up of 25 ± 6 months, 6,029 episodes of VT were treated in the 14 patients. Only 103 ICD discharges were required (approximately one discharge per 60 episodes of VT). Ten of the 14 patients received discharges from their ICDs. No deaths have occurred. All devices remain active and in the automatic mode. Thus, an antitachycardia pacemaker and ICD combination can safely and effectively terminate VT in highly selected patients who are subjected to extensive preimplant testing. In such patients, the vast majority of episodes of VT can be terminated with antitachycardia pacing, and only rarely is a discharge required from the ICD.     

Left Ventricular Mechanical Assist Devices and Cardiac Device Interactions: An Observational Case Series

Background: Nonpulsatile left ventricular assist devices (LVADs) are increasingly used for treatment of refractory heart failure. A majority of such patients have implanted cardiac devices, namely implantable cardioverter-defibrillators (ICDs) or cardiac resynchronization therapy-pacemaker (CRT-P) or cardiac resynchronization therapy-defibrillator (CRT-D) devices. However, potential interactions between LVADs and cardiac devices in this category of patients remain unknown.
Methods: We reviewed case records and device logs of 15 patients with ICDs or CRT-P or CRT-D devices who subsequently had implantation of a VentrAssist LVAD (Ventracor Ltd., Chatswood, Australia) as destination therapy or bridge to heart transplantation. Pacemaker and ICD lead parameters before and after LVAD implant were compared. In addition, ventricular tachyarrhythmia event logs and potential electromagnetic interference reports were evaluated.
Results: Right ventricular (RV) sensing decreased in the first 6 months post-LVAD. Mean R-wave amplitude preimplant was 10.9 ± 5.25 mV compared with 7.2 ± 3.4 mV during follow-up (P = 0.02). RV impedance also decreased from 642 ± 240 ohms at baseline to 580 ± 212 ohms at follow-up (P = 0.007). There was a significant increase in RV stimulation threshold following implantation of the LVAD from 0.8 ± 0.6 V at baseline to 1.4 ± 1.0 V in the first 6 months postimplant (P = 0.01). A marked increase in ventricular tachyarrhythmia burden was observed in three patients. One patient displayed electromagnetic interference between the LVAD and defibrillator, resulting in inappropriate defibrillation therapy.
Conclusions: LVADs have a definite impact on cardiac devices in respect with alteration of lead parameters, ventricular tachyarrhythmias, and electromagnetic interference.     

The 11th world survey of cardiac pacing and implantable cardioverter-defibrillators: calendar year 2009--a World Society of Arrhythmia's project

A worldwide cardiac pacing and implantable cardioverter-defibrillator (ICD) survey was undertaken for calendar year 2009 and compared to a similar survey conducted in 2005. There were contributions from 61 countries: 25 from Europe, 20 from the Asia Pacific region, seven from the Middle East and Africa, and nine from the Americas. The 2009 survey involved 1,002,664 pacemakers, with 737,840 new implants and 264,824 replacements. The United States of America (USA) had the largest number of cardiac pacemaker implants (225,567) and Germany the highest new implants per million population (927). Virtually all countries showed increases in implant numbers over the 4 years between surveys. High-degree atrioventricular block and sick sinus syndrome remain the major indications for implantation of a cardiac pacemaker. There remains a high percentage of VVI(R) pacing in the developing countries, although compared to the 2005 survey, virtually all countries had increased the percentage of DDDR implants. Pacing leads were predominantly transvenous, bipolar, and active fixation. The survey also involved 328,027 ICDs, with 222,407 new implants and 105,620 replacements. Virtually all countries surveyed showed a significant rise in the use of ICDs with the largest implanter being the USA (133,262) with 434 new implants per million population. This was the largest pacing and ICD survey ever performed, because of mainly a group of loyal enthusiastic survey coordinators. It encompasses more than 80% of all the pacemakers and ICDs implanted worldwide during 2009.     

The Psychological Impact of Implantable Cardioverter-Defibrillator Recalls and the Durable Positive Effects of Counseling

Background: It is known that patients with lifesaving devices such as implantable cardioverter-defibrillators (ICDs) may be alarmed and worried by recalls or alerts related to their ICDs.
Objectives: This study aimed to determine whether counseling has any short- or long-term benefits, and to look for characteristics that identify those most worried and those most in need of counseling.
Methods: Among 100 patients with recall or alert ICDs, 14 were pacer dependent; 50 had ICDs for 1° prevention and 22 were women. Patients completed a survey indicating how worried they were on learning of the recall or alert (0–10 scale). After counseling and advice in accordance with manufacturer guidelines, patients were asked to indicate their level of worry, and were again asked after 6 months.
Results: For all patients, the "worry level" at the initial interview was 5.0 ± 3.7, falling to 2.2 ± 3.0 after counseling (P < 0.001) and 1.4 ± 2.3 after 6 months (P < 0.001 vs both earlier levels). There were no significant differences between those implanted for 1° versus 2° prevention or for pacer dependency. Women were initially more worried than men, but not for the long term. The 49 patients whose ICDs could be managed by reprogramming or software fix had significant reduction in worry after counseling and at 6 months compared to others. The 18 patients recommended for operative intervention remained more concerned after counseling (3.5 ± 3.3 vs 1.9 ± 2.9, P = 0.043).
Conclusions: Patients' concerns resulting from ICD recalls or alerts can be reduced by appropriate counseling. Those patients whose ICDs could be reprogrammed to safer parameters had the most reduction in worry levels.     

Combined Third-Generation Implantable Cardioverter Defibrillator with Permanent Unipolar Pacemakers: Preliminary Observations

As implantable Cardioverter defibrillators (ICDs) are strictly contraindicated in the presence of unipolar pacemakers, currently available options in patients having such chronic pacing systems include: abandoning the implanted pacemaker and selecting an ICD with ventricular demand (VVI) pacing; or replacing the chronic (dual chamber) unipolar pacing system with a dedicated bipolar version prior to ICD implantation. In three patients with previously implanted unipolar pacemakers, we challenged the premise that all ICD systems are incompatible by combining with a third-generation transvenous ICD system (Medtronic 7217B PCD® incorporating true bipolar sensing, a self-limiting auto-adjusting sensitivity, and a tolerant VF detection algorithm. The potential for pace-maker-ICD interaction was minimized by separating the tip of the ICDs transvenous right ventricular pace/sense-defihrillation coil lead from that of the chronic pacemaker lead by > 2–3 cm, and by performing “worst case” intraoperative testing. Although ICD double-counting of the dual chamber pacemaker's atrial and ventricular pacing spikes could be provoked at extreme high output settings, it did not occur at clinically appropriate settings. More importantly, continuous high output asynchronous pacing during ventricular fibrillation (VF) did not interfere with ICD detection. During a mean follow-up period of 18 months, one patient has had VF appropriately terminated bv the ICD. In the remaining two patients, proper VF detection and ICD function was reassessed at 3 months and/or at 1 year during noninvasive testing. Conclusion: These preliminary findings demonstrate that this transvenous ICD system's VF sensing and detection features combined with careful implant technique, rigorous “worst case” testing for possible pacemaker-ICD interaction with regular follow-up, may permit implantation of this ICD system in patients with chronic unipolar pacing systems. Further studies are needed to validate the long-term clinical safety of this promising revised approach to a currently contraindicated device combination.