Variability in Implantable Cardioverter Defibrillator Pulse Generator Longevity Between Manufacturers

ELLINOR, P.T., et al .: Variability in Implantable Cardioverter Defibrillator Pulse Generator Longevity Between Manufacturers. ICDs are used frequently to treat malignant ventricular arrhythmias. Despite the expanding role of these devices, little is known about the manufacturer variability in the performance of ICD generators. The purpose of this study is to explore the indications for ICD pulse generator replacement and to examine performance differences between the three major manufacturers of ICDs in the United States. The authors performed a retrospective review of ICD pulse generators that were implanted and replaced at Massachusetts General Hospital between February 1998 and March 2002. During the study period, 50 (7%) of the 707 devices in the study cohort were replaced. The most common indication for pulse generator replacement was related to battery performance followed by device recall, upgrade to a dual chamber device, and pulse generator malfunction. After exclusion of the recalled devices, a significantly higher number of pulse generators manufactured by St. Jude Medical (14/229) required replacement for battery depletion or prolonged charge times during the study period compared with devices from Guidant (2/220) or Medtronic (0/273),  P = 0.003  and  P < 0.0001  , respectively. This difference was attributable to reduced longevity in the Angstrom series of defibrillators. (PACE 2003; 26[Pt. I]:71–75)     

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.     

Cardiac defibrillation and resynchronization therapies: principles, therapies, and management implications

Patients with heart failure remain at high risk for sudden cardiac death (SCD) and death due to heart failure progression, despite the incorporation of pharmacologic agents into clinical practice that have been shown to decrease mortality in clinical trials. Most patients experience SCD as their first dysrrhythmic event. The implantable cardioverter defibrillator (ICD) effectively terminates ventricular tachycardia/fibrillation (VT/VF) aborting SCD. Cardiac resynchronization therapy (CRT) complements pharmacologic therapy improving cardiac performance, quality of life, functional status, and exercise capacity in patients with systolic dysfunction despite optimal medical therapy who have a prolonged QRS duration; furthermore, it decreases mortality when compared with optimal medical therapy alone. Implantation of a combination CRT and ICD device, a CRT-D, reduces mortality by aborting SCD and providing the functional benefits of CRT. This article discusses the evolution of CRT-D therapy, the mechanism of operation of a CRT-D device, and nursing implications.     

Effect of Extracorporeal Shock Wave Lithotripsy on Implantable Cardioverter Defibrillator

Extracorporeal shock wave Jithotripsy (ESWL) is frequently used for nephrolithiasis of the upper urinary tract. Because of the powerful shock wave and electromechanical forces created, this therapy has been contraindicated in the patient with an implantable cardioverter defibrillator (ICD). To determine whether or not ESWL affects ICD devices, we subjected ten devices to a full course of ESWL. The devices were then returned to the manufacturer to undergo bench analysis, which revealed no abnormalities in function. Additionally, one device was placed in the pathway of the shock wave, resulting in a discharge of the device despite a frequency of ESWL of 100 shocks/min (well below the rate cutoff of that device). Manufacturer analysis of this device, likewise, revealed no abnormalities even though the device had been exposed to the focal point of the shock wave. We conclude that contralateral ESWL is not contraindicated for the patient with an ICD. We do, however, recommend a postprocedure evaluation to ensure appropriate function of the ICD.     

Gender disparity in the use of cardiac resynchronization therapy in the United States

Background: Although several studies have shown the effectiveness of cardiac resynchronization therapy (CRT) for advanced congestive heart failure (CHF), gender differences in utilization of CRT are not known.
Methods: We used the Healthcare Cost and Utilization Project (HCUP) to study national rates for admissions due to CHF along with procedures for initial CRT implantation, including both CRT-defibrillator (CRT-D) and CRT-pacemakers (CRT-P) during the years of 2002–2004. Chi-square tests were used for comparison between number of women and men. A P < 0.05 was considered significant.
Result: Women had consistently higher rates of admission for CHF during each year (574,037 (54%) vs 482,005 (46%), 2002; 601,181 (54%) vs 517,202 (46%), 2003; and 580,913 (53%) vs 521,280 (47%), 2004). The number of initial CRT device implantations (both CRT-D and CRT-P) was significantly lower during each year for women compared to men (659 (25%) vs 1,931 (75%), 2002; 6,928 (26%) vs 19,646 (74%), 2003; and 11,286 (27%) vs 42,196 (73%), 2004; P < 0.01 for all). Both CRT-P and CRT-D were used less frequently in women compared to men; however, this difference was consistently less prominent during each year with CRT-P compared to CRT-D (301 (41%) CRT-P vs 358 (19%) CRT-D, 2002; 659 (39%) CRT-P vs 2,530 (28%) CRT-D, 2003; and 2,891 (39%) CRT-P vs 8,395 (24%) CRT-D, 2004; P < 0.05).
Conclusion: Our data clearly demonstrate a significant gender disparity in utilization of CRT devices. Further studies are needed to find possible reasons behind this disparity.     

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.     

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.     

Changing trends in pacemaker and implantable cardioverter defibrillator generator advisories

Pacemaker and implantable cardioverter defibrillator (ICD) generator recalls and safety alerts (advisories) occur frequently, affect many patients, and are increasing in number and rate. It is unknown if advances in device technology have been accompanied by changing patterns of device advisory type. Weekly FDA Enforcement Reports from January 1991 to December 2000 were analyzed to identify all advisories involving pacemaker and ICD generators. This article represents additional analysis of previously cited advisories and does not contain additional recalls or safety alerts over those that have been previously reported. The 29 advisories (affecting 159,061 devices) from the early 1990s (1991-1995) were compared to the 23 advisories (affecting 364,084 devices) from the late 1990s (1996-2000). While the annual number of device advisories did not change significantly, ICD advisories became more frequent and a three-fold increase in the number of devices affected per advisory was observed. The number of devices affected by hardware advisories increased three-fold, due primarily to a 700-fold increase in electrical/circuitry abnormalities and a 20-fold increase in potential battery/capacitor malfunctions. Other types of hardware abnormalities (defects in the device header, hermetic seal, etc.) became less common. The number of devices recalled due to firmware (computer programming) abnormalities more than doubled. The remarkable technological advances in pacemaker and ICD therapy have been accompanied by changing patterns of device advisory type. Accurate, timely physician and patient notification systems, and routine pacemaker and ICD patient follow-up continue to be of paramount importance.     

植入型心律转复除颤器在心脏性猝死一级预防中的应用

目的随访观察植入型心律转复除颤器（ICD）／心室再同步心律转复除颤器（CRT．D）在中国单中心心脏性猝死（SCD）高危患者一级预防中的临床应用。方法入选2009年1月至2011年12月入住浙江大学医学院附属第一医院心内科符合一级预防适应证并植入ICD／CRT．D的患者共80例,其中33例植入单腔／双腔ICD,47例植入CRT．D。基础病因主要为扩张性心肌病（55．0％）和冠状动脉性心脏病（27．5％）。植入ICD／CRT．D后第1个月末和第3个月末各随访1次,以后每6个月随访1次,若患者发生电击等ICD治疗事件,则即时进行检查。结果80例患者平均随访（23±7）个月,非计划性再入院11例（13．7％）,死亡4例（5．0％）。记录ICD治疗事件共38次,其中有26次（68．4％）为ICD识别持续性VT／VF发作而进行的适当治疗,12次（31．6％）为由于心房颤动而进行的不适当治疗事件。结论ICD,CRT—D能在短时间内对发生恶性快速性心律失常的患者进行识别及实施治疗,在SCD一级预防中疗效明确,可使SCD的高危患者获益。     

Clinical judgment versus decision analysis for managing device advisories

Introduction: Implantable cardioverter‐defibrillator (ICD) and pacemaker (PM) advisories may have a significant impact on patient management. Surveys of clinical practice have shown a great deal of variability in patient management after a device advisory. We compared our management of consecutive patients in a single large university practice with device advisories to the “best” patient management strategy predicted by a decision analysis model. Methods: We performed a retrospective review of all patients who had implanted devices affected by an advisory at our medical center between March 2005 and May 2006 and compared our actual patient management strategy with that subsequently predicted by a decision analysis model. Results: Over 14 months, 11 advisories from three different manufacturers affected 436 patients. Twelve patients (2.8%) were deceased and 39 patients (8.9%) were followed at outside facilities. Management of the 385 remaining patients varied based on type of malfunction or potential malfunction, manufacturer recommendations, device dependency, and patient or physician preferences. Management consisted of the following: 57 device replacements (15.2%), 44 devices reprogrammed or magnets issued (11.7%), and 268 patients underwent more frequent follow‐up (71.3%). No major complications, related to device malfunction or device replacement, occurred among any patient affected with a device advisory. Concordance between the decision analysis model and our management strategy occurred in 57.1% of cases and 25 devices were replaced when it was not the preferred treatment strategy predicted by the decision model (43.9%, 37.3% when excluding devices replaced based on patient preference). The decision analysis favored replacement for all patients with PM dependency, but only for four patients with ICDs for secondary prevention. No devices were left implanted that the decision analysis model predicted should have been replaced. Conclusions: We found that despite a fairly conservative device replacement strategy for advisories, we still replaced more devices when it was not the preferred device management strategy predicted by a decision analysis model. This study demonstrates that even when risks and benefits are being considered by experienced clinicians, a formal decision analysis can help to develop a systematic evidence based approach and potentially avoid unnecessary procedures.     

Potential for Personal Digital Assistant interference with implantable cardiac devices

OBJECTIVE: To determine whether the wireless local area network (WLAN) technology, specifically the Personal Digital Assistant (PDA), interferes with implantable cardiac pacemakers and defibrillators. MATERIAL AND METHODS: Various pacemakers and defibrillators were tested in vitro at the Mayo Clinic in Rochester, Minn, between March 6 and July 30, 2003. These cardiac devices were exposed to an HP Compaq IPAQ PDA fitted with a Cisco Aironet WLAN card. Initial testing was designed to show whether the Aironet card radiated energy in a consistent pattern from the antenna of the PDA to ensure that subsequent cardiac device testing would not be affected by the orientation of the PDA to the cardiac device. Testing involved placing individual cardiac devices in a simulator and uniformly exposing each device at its most sensitive programmable value to the WLAN card set to maximum power. RESULTS: During testing with the Cisco WLAN Aironet card, all devices programmed to the unipolar or bipolar configuration single- or dual-chamber mode had normal pacing and sensing functions and exhibited no effects of electromagnetic interference except for 1 implantable cardioverter-defibrillator (ICD). This aberration was determined to relate to the design of the investigators' testing apparatus and not to the output of the PDA. The ICD device appropriately identified and labeled the electromagnetic aberration as "noise." CONCLUSIONS: We documented no electromagnetic interference caused by the WLAN technology by using in vitro testing of pacemakers and ICDs; however, testing ideally should be completed in vivo to confirm the lack of any clinically important interactions.     

Remote, Wireless, Ambulatory Monitoring of Implantable Pacemakers, Cardioverter Defibrillators, and Cardiac Resynchronization Therapy Systems: Analysis of a Worldwide Database

Study Objective: To describe the daily routine application of a new telemonitoring system in a large population of cardiac device recipients.
Methods: Data transmitted daily and automatically by a remote, wireless Home Monitoring™ system (HM) were analyzed. The average time gained in the detection of events using HM versus standard practice and the impact of HM on physician workload were examined. The mean interval between device interrogations was used to compare the rates of follow-up visits versus that recommended in guidelines.
Results: 3,004,763 transmissions were made by 11,624 recipients of pacemakers (n = 4,631), defibrillators (ICD; n = 6,548), and combined ICD + cardiac resynchronization therapy (CRT-D) systems (n = 445) worldwide. The duration of monitoring/patient ranged from 1 to 49 months, representing 10,057 years. The vast majority (86%) of events were disease-related. The mean interval between last follow-up and occurrence of events notified by HM was 26 days, representing a putative temporal gain of 154 and 64 days in patients usually followed at 6- and 3-month intervals, respectively. The mean numbers of events per patient per month reported to the caregivers for the overall population was 0.6. On average, 47.6% of the patients were event-free. The mean interval between follow-up visits in patients with pacemakers, single-chamber ICDs, dual chamber ICDs, and CRT-D systems were 5.9 ± 2.1, 3.6 ± 3.3, 3.3 ± 3.5, and 1.9 ± 2.9 months, respectively.
Conclusions: This broad clinical application of a new monitoring system strongly supports its capability to improve the care of cardiac device recipients, enhance their safety, and optimize the allocation of health resources.     

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.     

Indications for predismissal testing with arrhythmia-induction in patients receiving an implantable cardioverter defibrillator

Arrhythmia induction during implantation of cardioverter defibrillators (ICD) is a standard procedure. However, controversy exists regarding the need for routine arrhythmia induction before discharge from hospital (pre-hospital discharge (PHD) test). In order to reduce the number of tests we identified risk factors that predict relevant ICD malfunction. METHODS AND RESULTS: 965 patients receiving a first device implantation (n=724) or device/system replacement (n=241) between 1998 and 2004 were analysed. During implantation 176 (18%) complications (intraoperative undersensing of induced arrhythmias, unsuccessful arrhythmia-therapy or low DFT safety margin) occurred. Frequent (>4 times) intraoperative lead repositioning due to low sensing values was present in 44 patients (5%). 9% of the patients with first ICD implantation, 21% with device replacement and 27% with system replacement developed complications during PHD testing with arrhythmia induction. Intraoperative complications, although corrected during implantation, were independent risk factors for malfunction during PHD testing (p<0.05). Additional predictors for malfunction were intraoperative lead repositioning (>4 times) and a history of both VF and VT (p<0.05). Patients without intraoperative complications rarely developed malfunction during PHD testing (3.7% first device, 6.25% system replacement). Only in patients undergoing device replacement was a higher risk for failure (13%) evident. No risk factors could be identified for these subgroups. CONCLUSION: Routine arrhythmia induction during PHD is recommended in ICD patients with intraoperative complications, although corrected during implantation, as well as frequent intraoperatives lead repositioning. Patients undergoing device/system replacement uncomplicated implantation are not generally at low risk for device failure.     

Significant differences in the expected versus observed longevity of implantable cardioverter defibrillators (ICDs)

Background

Implantable cardioverter defibrillator (ICD) is a life-saving therapy for patients at risk of ventricular arrhythmias. Due to its high cost, its cost-effectiveness is highly dependent on its longevity, which is currently only based upon the manufacturer’s predicted device life span.

Aim

We sought to assess the ICDs’ longevity and the factors influencing it, and to compare the observed (real life) to the expected (manufacturer’s prediction) life span at a device level.

Methods

We retrospectively identified all patients who underwent an ICD implantation in a tertiary care medical center. For each device, an expected longevity was assigned based on the manufacturer/model, pacing percentage, and number of shocks per year. We defined device failure if the observed survival was shorter than 80 % of the expected. Only devices with follow-up time that exceeded the expected longevity were included.

Results

Of the 275 devices in the cohort, 79 (29 %) failed. Median device longevity was 5 years and varied markedly between manufacturers (4.3, 4.8, 5.1, and 6.3 years for Biotronik, St. Jude Medical, Boston Scientific, and Medtronic, respectively). There were significant differences among the manufacturers in device failure rates: 48, 17, 22, and 14 % for Biotronik, St. Jude Medical, Boston Scientific, and Medtronic, respectively). In multivariate analysis, manufacturer, earlier year of implantation, congestive heart failure and chronic renal failure significantly predicted device failure.

Conclusions

In conclusion, there is a significant device failure rate among ICDs, with variability among manufacturers, impacting both patients and the medical economic systems.     

Psychological distress in patients with ICD recall

BACKGROUND: Multiple clinical trials have shown that a properly functioning implantable cardioverter-defibrillator (ICD) is capable of interrupting sudden death caused by ventricular tachyarrhythmias. However, ICDs are complex medical devices, and they do not always perform as expected or they may fail completely. Exposure of ICD recipients to professional or media reports that their specific device type is potentially malfunctioning could negatively influence their psychological status. METHODS: This study aimed to evaluate and quantify psychological distress in patients implanted with an ICD-recall device. Thirty patients implanted with ICD-recall devices (ICD-recall group) and 25 patients with unaffected ICD devices (ICD-control group) were interviewed using the Brief Symptom Inventory (a psychological self-report symptom scale). RESULTS: Mean values of all primary psychiatric distress symptom dimensions and global indices were within the normal range for both the ICD-recall and the ICD-control group. New York Heart Association (NYHA)class was a predictor of higher distress symptoms in all categories, independently of the ICD group. NYHA II group patients tended toward higher stress levels than the NYHA I group, but only somatization was significantly different. An upward, but not significant, trend in 7 of the 12 scales was associated with symptomatic shock experience. CONCLUSION: This study demonstrates that psychological distress was not significantly increased in patients recently informed about a potential malfunction of their device.     

Role of transvenous implantable cardioverter-defibrillators in preventing sudden cardiac death in children, adolescents, and young adults

OBJECTIVE: To evaluate the indications, underlying cardiac disorders, efficacy, and complications involved with transvenous implantable cardioverter-defibrillators (ICDs) in pediatric patients at the Mayo Clinic. PATIENTS AND METHODS: The records of all patients aged 21 years or younger who underwent transvenous ICD placement at the Mayo Clinic, Rochester, Minn, were reviewed retrospectively. RESULTS: Between March 1992 and September 2000, 16 patients (7 females; mean age, 15.4 years; range, 10-21 years) underwent transvenous ICD placement. The ICD was implanted for primary prevention of sudden cardiac death in 7 and for secondary prevention in 9. The underlying cardiac disorders included hypertrophic cardiomyopathy in 6 patients and congenital long QT syndrome in 6 patients. The mean +/- SD follow-up was 36+/-29 months (range, 5-108 months). There was no mortality. Seven patients (44%) received appropriate ICD therapy, including 6 of 9 who had ICDs placed for secondary prevention. Median time free from appropriate ICD discharge was 3 years (range, 0.2-9 years). Three patients (19%) experienced inappropriate ICD discharge. Two patients needed device replacement because of technical problems (lead fracture and device malfunction). Two patients developed pocket infection that required removal and reimplantation of the ICD. CONCLUSION: In adolescents and young adults, transvenous ICDs may prevent sudden death but are not free of complications. Forty-four percent of this cohort received potentially life-saving ICD therapy, including two thirds who received an ICD for secondary prevention.     

Randomized Clinical evaluatiON of wireless fluid monitoriNg and rEmote ICD managemenT using OptiVol alert-based predefined management to reduce cardiac decompensation and health care utilization: The CONNECT-OptiVol study

AimsThe CONNECT-OptiVol study is designed to investigate whether wireless fluid monitoring using OptiVol alerts as well as implantable cardioverter–defibrillator (ICD) remote monitoring (RM) reduces cardiac decompensations and health care utilization in ICD patients, as compared to standard clinical care.MethodsPatients undergoing implantation of wireless telemetry-enabled dual chamber (ICD-DR) or cardiac resynchronization therapy/defibrillator (CRT-D) devices with the OptiVol feature are eligible for the study. In a randomized fashion, OptiVol function, its audible alert as well as its remote alert, and other ICD RM alerts are switched ON or OFF. The primary study objective is to estimate an improvement of heart failure status. The primary endpoint is measured as a prolongation of the time to first hospitalization due to worsened heart failure. The secondary objectives are to estimate: a reduction of the time from event to clinical decision, a reduction of the rate of health care utilization, and improved quality of life (QoL) measures (secondary endpoints). The study is designed as a single center pilot study with 180 patients randomized 1:1 to the two study arms.ConclusionThe CONNECT-OptiVol study aims to answer whether wireless fluid monitoring integrated into RM may reduce cardiac decompensations and health care utilization in ICD patients. The results can be used to adequately power future studies evaluating the benefit of these features. Study enrollment has been completed, and follow-up is expected to be finished in September 2012.     

Effects of scatter radiation on ICD and CRT function

Background: Effects of direct radiation on implantable cardiac devices have been well studied. However, the effects of scatter radiation are not as clear. Recommendations on management of patients with implantable cardiac devices undergoing radiotherapy are based on limited studies mostly involving pacemakers. We sought to elucidate the effects of scatter radiation on implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy (CRT)-ICDs.
Methods: We exposed 12 ICDs and eight CRT-ICDs to 400 cGy of scatter radiation from a 6-MV photon beam. Devices were programmed with nominal parameters and interrogated prior to radiation, after each fraction, upon completion of the radiation course and again 1 week later. A retrospective review of patients undergoing radiotherapy at the Mayo Clinic–Rochester between 2002 and 2007 in whom the device was outside the radiation field was also performed. There were 13 patients with devices undergoing radiotherapy during this time period, 12 of whom were interrogated prior to and after radiation.
Results: Interrogation reports were reviewed for device reset or parameter changes. There was no evidence of reset or malfunction during or after radiation. Also, no episodes of device reset, inappropriate sensing or therapy, or changes in programmed parameters were found in our review of patients undergoing radiotherapy.
Conclusions: Device reset or malfunction associated with scatter radiation likely represents an unpredictable, rare occurrence. While we see no clear contraindication to radiotherapy in patients with ICDs or CRT-ICDs, precautions should be taken to avoid direct radiation exposure and to closely evaluate patient outcomes before and after the radiation course.     

Deactivating implanted cardiac devices in terminally ill patients: practices and attitudes

Background: Clinicians may receive requests to deactivate pacemakers and implantable cardioverter-defibrillators (ICDs) in terminally ill patients.
Methods: We describe practices and attitudes regarding deactivation of pacemakers and ICDs in terminally ill patients among physicians, nurses, and others who manage treatment of patients with implanted cardiac devices and among field representatives of device manufacturers. A Web-based survey was provided to Heart Rhythm Society members and to representatives of two manufacturers of implantable cardiac devices. Measurements were the answers of 787 respondents.
Results: Of the respondents, 86.8% reported involvement in requests for ICD deactivation and 77.6% reported involvement in pacemaker deactivation (P < 0.001). Having cared for a terminally ill patient for whom the respondent or a physician had ordered device deactivation was common (95.4% for ICDs vs 84.8% for pacemakers; P < 0.001). Having personally deactivated a device was also common (92.4% for ICDs vs 76.6% for pacemakers; P < 0.001). More respondents said they were comfortable with personally deactivating an ICD than deactivating a pacemaker (56.7% for ICDs vs 34.4% for pacemakers; P < 0.001). Respondents reported that the industry representative is the individual who deactivates the device most of the time (59.3% for ICDs and 49.7% for pacemakers).
Conclusions: Deactivation of implanted cardiac devices in terminally ill patients is common. Practices and attitudes associated with pacemaker deactivation differ significantly from those associated with ICD deactivation. Professional groups should develop guidelines for managing requests for implanted cardiac device deactivation and should clarify the role of device industry representatives in these deactivations.