Device Reprogramming Research Articles

Incidence of myopotential induction in subcutaneous implantable cardioverter-defibrillator patients: Is the oversensing issue really solved?

The subcutaneous implantable cardioverter-defibrillator (S-ICD) has established its role in the prevention of sudden cardiac death in a defined population. Inappropriate shocks and device malfunction in S-ICD therapy may be caused by myopotential (MP) oversensing. The purpose of this study was to systematically evaluate a cohort of consecutive S-ICD patients for MP inducibility. After S-ICD implantation, all vectors (primary [PrimV], secondary [SecV], alternative [AltV]) were analyzed during isometric chest press (ICP), lifting and holding a 20-kg weight, and side plank exercise (SPE), supporting the body weight on the left arm. When MPs were induced, signal classification was assessed: adequate noise detection, induced undersensing (R waves classified as noise), and oversensing (noise annotated as R waves). In case of noise induction in the current vector, device reprogramming to a noise-free vector was done. We systematically assessed 41 patients. In nearly all patients (90.2%), MPs were inducible. ICP was the most potent inductor of MPs. Whereas SecV (70.7%) and AltV (75.6%) were most vulnerable during ICP, PrimV was most affected during SPE (51.2%). In only a few cases did the S-ICD software distinguish correctly between MPs and QRS. MPs predominantly led to undersensing (up to 65.9%), but in up to 22% of patients MP-induced oversensing occurred but did not lead to tachycardia detection. No relation was seen between S-ICD lead and generator position and MP inducibility. Induction of MPs during physical exercise was observed frequently. Although in most cases MP noise led to undersensing, oversensing events were commonly observed.

How Well Do Results From Randomized Clinical Trials and/or Recommendations for Implantable Cardioverter-Defibrillator Programming Diffuse Into Clinical Practice?Translation Assessed in a National Cohort of Patients With Implantable Cardioverter-Defibrillators ( ALTITUDE ).

BackgroundInappropriate implantable cardioverter‐defibrillator programming can be detrimental. Whether trials/recommendations informing best implantable cardioverter‐defibrillator programming (high‐rate cutoff and/or extended duration of detection) influence practice is unknown.Methods and ResultsWe measured reaction to publication of MADIT‐RIT (Multicenter Automatic Defibrillator Implantation Trial–Reduce Inappropriate Therapy; 2012) and the Consensus Statement (2015) providing generic programming parameters, in a national cohort of implantable cardioverter‐defibrillator recipients, using the ALTITUDE database (Boston Scientific). Yearly changes in programmed parameters to either trial‐specified or class 1 recommended parameters (≥185 beats per minute or delay ≥6 seconds) were assessed in parallel. From 2008 to 2017, 232 982 patients (aged 67±13 years; 28% women) were analyzed. Prevalence of MADIT‐RIT–specific settings before publication was <1%, increasing to 13.6% in the year following. Thereafter, this increased by <6% over 5 years. Among preexisting implants (91 171), most patients (58 739 [64.4%]) underwent at least 1 in‐person device reprogramming after trial publication, but <2% were reprogrammed to MADIT‐RIT settings. Notably, prevalence of programming to ≥185 beats per minute or delay ≥6 seconds was increased by MADIT‐RIT (57.4% in 2013 versus 40.2% at baseline), but the following publication of recommendations had minor incremental effect (73.2% in 2016 versus 70.8% in 2015). High‐rate cutoff programming was favored almost 2‐fold compared with extended duration throughout the test period. Practice changes demonstrated large interhospital and interstate variations.ConclusionsTrial publication had an immediate effect during 1 year postpublication, but absolute penetration was low, and amplified little with time. Consensus recommendations had a negligible effect. However, generic programming was exercised more widely, and increased after trial publication, but not following recommendations.

Modern Security Screening And Electromagnetic Interference with Cardiac Implantable Devices: A Cross-Sectional Study

Background: The prevalence of patients with cardiac implantable electronic devices (CIEDs) is increasing and many of these patients will undergo security screening during travel. Currently, patients with CIEDs are advised to request manual security checks as there are concerns about device malfunction due to electromagnetic interference (EMI). The aim of this study was to evaluate the EMI effects and safety of the new security screening millimetre-wave body scanners (MWBSs) for patients with CIEDs. Method: We selected a population of 302 patients with a CIED presenting for routine review at the German Heart Centre, Munich. CIED programming was optimised for the detection of EMI occurrence and high-voltage therapy was disabled. Electrocardiography-monitored patients were then scanned using the body scanner at the recommended distance, as well as in close proximity to the scanner simulating accidental exposure. CIED interrogation was then performed to review for EMI effects. Results: There were no episodes of inhibition of pacing, upper-rate tracking, inappropriate tachycardia detection, or spontaneous device reprogramming. There was no change in pacing or sensing thresholds, or lead impedance measurements after scanning with the MWBS. No CIEDs were identified by the MWBS during the study. Conclusion: No EMI events were detected during the use of MWBSs suggesting that their use is safe and there is no need for specific protocols or precautions. Patients with a CIED need not disclose medical information regarding their device at security checkpoints.

Is ventricular sensing always right, when it is left?

Ventricular sensing in transvenous cardiac implantable electronic devices (CIEDs) occurs conventionally from the right ventricular (RV) channel, though it evolved from epicardial sensing both in pacemakers and implantable cardioverter-defibrillators (ICDs). The objective of this study was to observe the reliability of left ventricular (LV) sensing by transvenous leads placed in coronary veins. LV leads were used for sensing and arrhythmia detection in clinical situations where placement of an RV lead across the tricuspid valve was either not preferred or not feasible, or RV signal was unsuitable for arrhythmia detection, or in the event of sensing failure of an RV lead under advisory in cardiac resynchronization therapy defibrillator (CRTD) recipients. Thirty-seven patients had an IS-1 LV lead connected to the RV port of CIEDs (17 pacemakers, 5 cardiac resynchronization therapy pacemaker [CRTP], 2 ICDs, and 13 CRTDs). Along a median 41 (25-67) months follow-up, lead performance remained stable; there were neither undersensing nor oversensing of non-cardiac signals. VT/VF were correctly detected and terminated by ATP and shocks (one and three patients, respectively); no inappropriate arrhythmia detection. Device reprogramming occurred in four CRTD recipients because of transient counting the QRS (short intervals) when paced in LV-only, and in two with T-wave oversensing. Ventricular sensing by an LV lead is feasible in transvenous devices. Sensing programmability is an unmet need: to fix RV lead sensing issues in cardiac resynchronization therapy (CRT) recipients at no risk of infection (no pocket opening); to avoid interaction with the tricuspid valve; to avoid lead redundancy in the vasculature. Moreover, it will be mandatory owing to the loss of lead interchangeability due to the adoption of DF-4 and quadripolar leads.

Precision of automated QRS duration measurement in patients treated with cardiac resynchronization therapy.

Shortening of the QRS duration (QRSd) is often used to guide device optimization and reprogramming in patients with cardiac resynchronization therapy (CRT). Detecting the small changes expected during reprogramming requires that the QRSd can be measured with high precision, but this has never been studied in patients with CRT. In this study, we wanted to assess the precision of automated QRSd measurement in patients treated with CRT using two commonly available electrocardiographs. Patients treated with CRT were recruited during routine follow-up in our pacemaker clinic. In all participants, a number of immediate successive ECGs were recorded with the GE MAC 5500 (Mac55) and the GE MAC 1600 (Mac16). Data were analyzed with a linear mixed model. A total of 785 12-lead ECGs were recorded in 36 patients with an average of 11.2 and 10.6 ECGs per patient with the Mac55 and Mac16, respectively. The Mac55 measured the QRSd longer by 10.3 milliseconds (ms) (95% CI 7.1-13.5ms, p < 0.001) and with significantly smaller standard deviation for repeated measurements (6.3 vs. 10.4ms, p < 0.001). Limits of agreement were ± 17.5 and ± 28.8ms for the Mac55 and Mac16, respectively. Automated measurement of QRSd in patients with CRT shows low precision with limits of agreement of ± 17.5 and ± 28.8ms for repeated measurements in two commercially available electrocardiographs. Device programming solely by QRSd changes should be done with caution, and clinical effects should be demonstrated in future trials. Device programming based on QRSd changes should be done with caution until the ability of this measure to predict clinical outcome can be demonstrated in prospective study.

Effectiveness of Medtronic CareLink Express System in identifying patients with high-energy electrotherapy devices requiring clinically significant intervention.

The number of patients with implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy and defibrillator (CRT-D) is growing. This results in high workloads for centers performing standard controls (SC) of these systems. Medtronic CareLink Express® (MCLE) is a solution enabling remote controls (RC) of implantable devices. In cases of detecting arrhythmias or device malfunctioning, it automatically generates alarms transmitted to the controlling physician. The objective of the study was to evaluate the effectiveness of alarms generated by MCLE in identification of patients that require clinically significant intervention during SC. A total of 119 patients (age 64 ± 14, 17 women) implanted with ICD/CRT-D were included in the trial. Device reprogramming or pharmacological treatment modifications during SC were as-sessed as significant if they were required for optimal clinical management of the patient (effectiveness of antiarrhythmic and resynchronization therapy, also patient safety). Analysis of generated alarms was then performed to assess the effectiveness (sensitivity and specificity) of MCLE in identifying patients that require changes in therapy. Data from 129 transmissions and 129 subsequent SCs were analyzed. 179 alarms were recorded during 96 (74%) transmissions. A total of 333 program changes of implanted devices took place during 107 (83%) SCs. Device reprogramming was considered clinically significant in 27 cases Additionaly, 13 pharmacological treatment modifications were performed. Sensitivity and specificity of alarms generated by MCLE with regards to identification of patients requiring clinically significant intervention was 87% and 31%, respectively. Finally, a statistically significant difference was observed in the number of clinically significant interventions among patients with and without MCLE alarms (33 [86.8%] vs. 5 [13.2%], p = 0.037). Medtronic CareLink Express® is an RC system enabling high-sensitivity supervision of patients with cardiac.

From in-clinic to fully remote follow-up model for pacemaker patients: A four-year experience

BackgroundGuidelines on remote monitoring (RM) still suggest at least 1 in-person visit per year for all remotely followed patients, including pacemaker patients. MethodsThe RM of pacemaker patients was systematically introduced in our clinic since January 2013. Patients without RM were visited 2 months after implantation and afterwards annually. Subjects with RM had in-person visit only at 2-month follow-up and at device replacement. ResultsAt the end of 2016 a total of 2233 patients (mean age 81.4 ± 9.9 years, 55% male) were followed by our centre. The patient population had a mean annual growth of 2.8 ± 2.3% with an incidence of RM increasing from 0% in 2012 to 45% in 2016. The in-clinic visits significantly decreased from the second year (I year: −12, 0%; II year: −324, −17%; III year: −276, −17%, IV year: −127, −10%).The annual incidence of unscheduled ambulatory visit for patients with RM was 15.9 ± 2.9%, mainly triggered by device reprogramming, transmission problems and autocapture deactivation. There was no effect on the incidence of serious adverse events and mortality. ConclusionsThis fully remote follow-up model for pacemaker patients reduced in-clinic visits since the second year from its implementation in our clinical practice. This strategy may increase the organizational benefits of RM in low-risk patients.

New generation implantable cardiac rhythm devices allow safe radiotherapy treatments: A large single centre study

INTRODUCTION: Many patients requiring radiotherapy for malignancies have an already implanted cardiac rhythm device. Previous studies reported a variety of device dysfunctions related to high dose radiation. Aim of this study was to assess the impact of current optimal radiotherapy treatment guided by computed tomography on current generation implantable devices. METHODS: Consecutive patients with implanted pacemakers (PMK) and implantable cardioverter defibrillators (ICD) referred for radiotherapy treatment in any district were enrolled at our Centre and followed prospectively with device interrogation before and just after each radiotherapy cycle. A magnet was positioned on the device in patients with implanted defibrillators or pacemaker-dependency. RESULTS: Overall, 48 patients (74.8 years (9.3), 39 males (81.3)) with implantable devices underwent radiotherapy (29 pacemakers and 19 ICDs). Interval between device implant and start of radiation therapy was 2.9 (1.6) years. Radiotherapy was performed under computed tomography guidance, and a mean of 73.5 (45.0) Gy were administered with a mean of 24.8 (14.6) fractionated doses. About half of the patients underwent thoracic radiotherapy, and 9 were treated for a left thoracic malignancy ipsilateral to the implanted device. No device failures were observed at post-treatment device interrogation, nor changes in electrical parameters, inappropriate shocks, device reprogramming or memory reset. None of the patients experienced premature battery failure or other unexpected anomalous findings at the end of the radiation therapy cycle. CONCLUSION: Radiation therapy for malignancies is safe among patients with implanted current generation cardiac rhythm devices.

Pacemaker reprogramming rarely needed after device replacement.

Most outpatient follow-ups after pacemaker implantation do not involve changes in the device settings. Moreover, the need for pacemaker reprogramming declines with time after implantation. Currently, data on the need for changes in pacemaker set-up after replacement owing to battery depletion are lacking. The aim of this study was to determine the rates of pacemaker reprogramming in this patient group. Aretrospective analysis was performed using the files of 217 patients who had undergone pacemaker replacement between 2002 and 2005. The data of 1,407 outpatient follow-up visits between 2002 and 2015 were analyzed. Scheduled and unscheduled visits were marked as visits with "action" or visits "without action", depending on whether pacemaker programming was or was not performed, respectively. Pacemaker programming was performed in only 53(4%) of the 1,234 scheduled visits and in 44(25%) of 173 unscheduled visits. Thus, only 97(7%) of 1,407 visits involved changes in device settings. Of these visits, 446 occurred in the first year after device replacement. The rate of unscheduled visits in the first year was higher (17%) than during the overall period (12%), but the rate of visits involving action was the same: 6% (26 of 446, first year) compared with 7% (97 of 1,407). The vast majority of outpatient visits after pacemaker replacement do not involve subsequent device reprogramming during follow-up. This suggests the potential benefit of remote follow-up for these patients.

102 Pacemaker and Defibrillator Interrogations in the Emergency Department and Hospital Rarely Lead to Device Reprogramming

102 Pacemaker and Defibrillator Interrogations in the Emergency Department and Hospital Rarely Lead to Device Reprogramming

Strategy to manage T-Wave Oversensing in a Biventricular ICD

T-wave oversensing is a relatively prevalent cause of intracardiac signals oversensing in patients with Implantable Cardioverter Defibrillator (ICD). Some of these oversensings are typically corrected with device reprogramming. If reprogramming fails to resolve the issue, invasive options such as repositioning the implanted lead may be necessary. We present a patient with dilated cardiomyopathy and intermittent T wave oversensing by a cardiac resynchronization therapy (CRT) that was managed by altering V-V timing.

Safety and Quality of 1.5-T MRI in Patients With Conventional and MRI-Conditional Cardiac Implantable Electronic Devices After Implementation of a Standardized Protocol.

The purpose of this study was to evaluate the safety and diagnostic utility of 1.5-T MRI examinations of individuals with conventional and MRI-conditional cardiac implantable electronic devices (CIEDs). Patients with a CIED who were referred for MRI were evaluated by radiologists and cardiac electrophysiologists for study participation. CIED interrogation was performed immediately before and after MRI, and cardiac telemetry monitoring was performed during MRI. CIED programming changes, malfunctions, and intraprocedural events were documented. Whether diagnostic questions were answered and whether artifacts related to the CIED were present and negatively affected image interpretation were recorded. One hundred thirteen MRI examinations were performed for 104 patients with CIEDs (74 pacemakers [60 conventional, 14 MRI conditional]; 39 implantable cardiac defibrillators). Device reprogramming was required before MRI for 62.8% of studies (71/113). No significant changes in lead parameters were noted during or after MRI. Electromagnetic noise was detected on at least one lead in 7.1% of studies. Three patients reported transient symptoms (one case each of heating at the pocket site, tingling at the pocket site, and palpitations). All images were considered diagnostic for the original clinical query. Artifacts related to CIEDs were described in 3.5% of MRI reports (4/113) and were present only when the pulse generator was included in the FOV. CIED-related artifacts limited evaluation of tissues immediately adjacent to the pulse generator. Establishment of a multidisciplinary work flow allows individuals with conventional and MRI-conditional CIEDs to safely undergo 1.5-T MRI with diagnostic questions consistently answered.

136-67: Incidence and Predictors of Phrenic Nerve Stimulation following Cardiac Resynchronization Therapy System Implantation of a Quadripolar Lead

Introduction: Quadripolar (quad) left ventricular (LV) pacing leads are routinely used during cardiac resynchronization therapy (CRT). When phrenic nerve stimulation (PNS) occurs in patients with a quad LV lead, reprogramming is often sufficient to eliminate the problem. However, the incidence and predictors of PNS remain less understood. Methods: Patients implanted with CRT-D during a prospective Investigational Device Exemption study of the Boston Scientific ACUITY X4 quad LV lead were evaluated. Electrical performance including pacing capture thresholds (PCT) and PNS were evaluated intra-operatively, at pre-discharge, and 3 months. The IO PNS safety margin was calculated between PNS (tested up to 7.5V) and PCT. Complications were tracked for 6 months. Results: Clinically documented PNS occurred in 58 (8%) of 744 CRT patients. In 14 (24%) of these patients, PNS occurred within the first day of implant; overall, the median time to PNS was 5.5 days [IQR 0.75, 53]. PNS most commonly occurred when the distal electrode was used (30 of 205 [15%] cases vs 28 of 539 [5%] for non-distal pacing, p < 0.001). In 51 (88%) of the 58 patients, PNS was not present intra-operatively at even maximal pacing output. In the remaining 7 patients, a safety margin between PNS and PCT failed to prevent PNS. When the safety margin was < 2 V, there was 35% risk of PNS. Device reprogramming (lowering pacing output or changing pacing electrode) was sufficient to eliminate the issue in 55 (95%) cases. Conclusion: With an ACUITY X4 quad LV lead, PNS was observed in 8% of patients, often within days of device implantation. When possible, avoidance of the distal electrode for pacing and avoidance of accepting a small “safety margin” for pacing output may mitigate against PNS. However, most patients had no measureable PNS at implant, suggesting an inability of current intra-operative techniques to ensure subsequent absence of PNS.

Role of Automatic Wireless Remote Monitoring Immediately Following ICD Implant: The Lumos-T Reduces Routine Office Device Follow-Up Study (TRUST) Trial.

The incidence of unscheduled encounters and problem occurrence between ICD implant and first in-person evaluation (IPE) recommended at 12 weeks is unknown. Automatic remote home monitoring (HM) may be useful in this potentially unstable period. ICD patients were randomized 2:1 to HM enabled post-implant (n = 908) or to conventional monitoring (CM; n = 431). Groups were compared between implant and prior to first scheduled IPE for IPE incidence, causes, and actionability (reprogramming, system revision, medication changes) and event detection time. HM and CM patients were similar (mean age 63 years, 72% male, LVEF 29%, primary prevention 73%, DDD 57%). In the post-implant interval assessed (HM 100 ± 21.3 days vs. CM 101 ± 20.8 days, P = 0.54), 85.4% (776/908) HM patients and 87.7% CM (378/431) patients had no cause for IPE (P = 0.31). When IPE occurred, actionability in HM (64/177 [36.2%]) was greater versus CM (15/62 [24.2%], P = 0.12). Actionable items were discovered sooner with HM (P = 0.025). Device reprogramming or lead revision was triggered following 53/177 (29.9%) IPEs in HM versus 9/62 (14.5%) in CM (P = 0.018). Arrhythmia detection was enhanced by HM: 276 atrial and ventricular episodes were detected in 135 follow-ups in contrast to CM (65 episodes at 17 IPEs). More silent arrhythmic episodes were discovered by HM (7.2% vs. 1.5% [P = 0.15]). Since 27/42 (64.3%) IPEs driven by HM alerts were actionable, event notification was a valuable method for problem detection. Importantly, HM did not increase incidence of non-actionable IPEs (P = 0.72). Activation of automatic remote monitoring should be encouraged soon post-ICD implant.

Day by day telemetric care of patients treated with cardiac resynchronisation therapy: first Polish experience.

Due to the recent rapid increase in the number of patients implanted with pacemakers, cardioverter-defibrillators (ICD), and cardiac resynchronisation therapy devices (CRT), conventional monitoring at specialist clinics is becoming increasingly difficult. The development of technology has enabled remote device monitoring with the use of teletransmission systems. To assess the effectiveness of transmission and the possibility of using telemetric data for further clinical management of patients with heart failure (HF) treated with CRT-D. The analysis included 305 consecutive patients with chronic HF, New York Heart Association functional classes II-IV, treated with the use of CRT-D by Biotronik or Medtronic in the years 2006-2012. The patients received transmitters, enabling the remote monitoring of the implanted device from the patients' houses. Scheduled reports were automatically sent every month. The triggers for pre-specified emergency alert transmissions were as follows: ventricular tachycardia (VT) or ventricular fibrillation (VF) episodes, CRT-D intervention, ventricular extrasystoles > 110/h, any episode of atrial fibrillation (AF), atrial flutter (AFL) or supraventricular tachycardia, mean heart rate (HR) during, mean 24-h HR, CRT pacing < 95%, Elective Replacement Indicator, or End Of Service and device malfunction. The all-cause mortality of the study population has been assessed at the end of the follow-up period (mean of 20.5 months). Devices manufactured by Biotronik were provided to 71% of the study population, while 29% received devices by Medtronic. In 97.3% of cases, the monitors were wireless, fully automatic, and capable of immediate data transmission whenever a pre-specified alert notification was fulfilled. The analysis of long-term outcomes revealed that all-cause mortality of the whole study population was 13%. The effectiveness of report transmission was 98%. During follow-up a total of 31,198 transmissions were received and analysed, which constituted, on average, 4.9 transmissions per patient per month. Among analyses, 30% were reports generated by scheduled remote follow-ups, and 70% were caused by unscheduled device alerts. Correct functioning of the system was confirmed; the quality of the received data was 100%. In 63.9% of patients, decisions based on the information obtained from telemonitoring reports were made to modify the therapy, refer the patients to cardiology or electrophysiology clinics, or hospitalise them urgently. The most common medical reaction was device reprogramming (46.8%). Pharmacotherapy was modified in 33.7% of patients: beta-blocker dose increase (25.9%), anticoagulant treatment inclusion (15.7%), amiodarone inclusion (1.9%), or digoxin inclusion (4.5%). The remaining medical responses were referring patients for atrioventricular junction ablation (8.1%), VT ablation (2.9%), or AF/AFl ablation (1.6%). Remote monitoring of implantable devices is feasible, safe, and effective in supervising patients with CRT-D devices. Daily-based remote monitoring of a large population of HF patients allows continuous "triage" of high-risk patients and selection of individuals who require urgent intervention.

Implantable defibrillators versus medical therapy for cardiac channelopathies.

Sudden cardiac death is a significant cause of mortality in both the US and globally. However, 5% to 15% of people with sudden cardiac death have no structural abnormalities, and most of these events are attributed to underlying cardiac ion channelopathies. Rates of cardiac ion channelopathy diagnosis are increasing. However, the optimal treatment for such people is poorly understood and current guidelines rely primarily on expert opinion. To compare the effect of implantable cardioverter defibrillators (ICD) with antiarrhythmic drugs or usual care in reducing the risk of all-cause mortality, fatal and non-fatal cardiovascular events, and adverse events in people with cardiac ion channelopathies. We searched the Cochrane Central Register of Controlled Trials (CENTRAL, 2015, Issue 6), EMBASE, MEDLINE, Conference Proceedings Citation Index - Science (CPCI-S), ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) in July 2015. We applied no language restrictions. We included all randomized controlled trials of people aged 18 years and older with ion channelopathies, including congenital long QT syndrome, congenital short QT syndrome, Brugada syndrome, or catecholaminergic polymorphic ventricular tachycardia. Participants must have been randomized to ICD implantation and compared to antiarrhythmic drug therapy or usual care. Two authors independently selected studies for inclusion and extracted the data. We included all-cause mortality, fatal and non-fatal cardiovascular events, and adverse events for our primary outcome analyses and non-fatal cardiovascular events, rates of inappropriate ICD firing, quality of life, and cost for our secondary outcome analyses. We calculated risk ratios (RR) and associated 95% confidence intervals (CIs) for dichotomous outcomes, both for independent and pooled study analyses. From the 468 references identified after removing duplicates, we found two trials comprising 86 participants that met our inclusion criteria. Both trials included participants with Brugada syndrome who were randomized to ICD versus β-blocker therapy for secondary prevention for sudden cardiac death. Both studies were small, were performed by the same investigators, and exhibited a high risk of bias across multiple domains. In the group randomized to ICD therapy, there was a nine-fold lower risk of mortality compared with people randomized to medical therapy (0% with ICD versus 18% with medical therapy; RR 0.11, 95% CI 0.01 to 0.83; 2 trials, 86 participants). There was low quality evidence of a difference in the rates of combined fatal and non-fatal cardiovascular events, and the results were imprecise (26% with ICD versus 18% with medical therapy; RR 1.49, 95% CI 0.66 to 3.34; 2 trials, 86 participants). The rates of adverse events were higher in the ICD group, but these results were imprecise (28% with ICD versus 10% with medical therapy; RR 2.44, 95% CI 0.92 to 6.44; 2 trials, 86 participants). For secondary outcomes, the risk of non-fatal cardiovascular events was higher in the ICD group, but these results were imprecise and were driven entirely by appropriate ICD-termination of cardiac arrhythmias (26% with ICD versus 0% with medical therapy; RR 11.4, 95% CI 1.57 to 83.3; 2 trials, 86 participants). Approximately 25% of the ICD group experienced inappropriate ICD firing, all of which was corrected by device reprogramming. No data were available for quality of life or cost. We considered the quality of evidence low using the GRADE methodology, due to study limitations and imprecision of effects. Among people with Brugada syndrome who have survived a prior episode of sudden cardiac death, ICD therapy appeared to reduce mortality when compared to β-blocker therapy, but the true magnitude may be substantially different from the estimate of the effect because of study limitations and imprecision. Due to the large magnitude of effect, it is unlikely that there will be additional studies evaluating the role of ICDs for secondary prevention in this population. Further studies are necessary to determine the optimal treatment, if any, to prevent an initial episode of sudden cardiac death in people with cardiac ion channelopathies.

Management of patients with implantable cardioverter-defibrillators and pacemakers who require radiation therapy

Radiation therapy (RT) may pose acute and long-term risks for patients with cardiac implantable electronic devices (CIEDs), including pacemakers (PMs) and implantable cardioverter-defibrillators (ICDs). However, the frequency of these problems has not been accurately defined. The purpose of this study was to determine the prevalence of CIEDs among patients requiring RT and report the common CIED-related problems when patients are managed according to a standard clinical care path. In a single tertiary-care center, we prospectively screened all patients requiring RT and identified patients with ICDs or PMs. We collected clinical data about their cancer, RT treatment plan, and CIED. Radiation dose to the device was estimated in all patients, and any device malfunction during RT was documented. Of the 34,706 consecutive patients receiving RT, 261 patients (0.8%, mean age 77.9 ± 9.4 years) had an implantable cardiac device: 54 (20.7%) ICDs and 207 (79.3%) PMs. The site of RT was head and neck (27.4%), chest (30.0%), and abdomen/pelvis (32.6%). Using our care path, 63.2% of patients required continuous cardiac monitoring, 14.6% required device reprogramming, 18.8% required magnet application during RT, and 3.4% required device repositioning to the contralateral side before RT. Four patients (1.5%) had inappropriate device function during RT: 3 experienced hemodynamically tolerated ventricular pacing at the maximum sensor rate, and 1 experienced a device power-on-reset. No patient died or suffered permanent device failure. Nearly 1% of patients receiving RT in this series has a PM or ICD. However, with a systematic policy of risk assessment and patient management, significant device-related complications are rare.

Autonomic modulation for the management of patients with chronic heart failure.

Dysregulation of the autonomic nervous system in heart failure (HF) has received considerable attention during the past 3 decades, largely because of the well-recognized association between increased sympathetic activity and the elaboration of biologically active molecules, collectively referred to as neurohormones, that help to maintain cardiovascular homeostasis through increased volume expansion, peripheral arterial vasoconstriction, and increased myocardial contractility. However, high and sustained levels of these biologically active molecules (eg, norepinephrine, angiotensin II, aldosterone) are overtly toxic to the heart and circulation.1 These and other insights have led to the clinical use of neurohormonal antagonists, such as angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, aldosterone antagonists, and β-blockers to treat patients with HF with a reduced left ventricular ejection fraction (LVEF).1 The effectiveness of these pharmacological agents is predominantly because of their ability to directly antagonize the deleterious effects of excessive sympathetic and renin–angiotensin activation. However, the current guideline-directed medical therapy (GDMT) in patients with HF fails to completely restore normal autonomic balance disrupted as a part of HF pathophysiology. During the last decade, a novel approach has generated widespread interest: modulation of the autonomic nervous system as a result of either a one-time intervention (eg, denervation) or of ongoing active therapy (eg, electric stimulation) as a means of further diminishing the sympathovagal imbalance that develops in HF.2,3 Of note, therapeutic neuromodulation with device-based therapies, either with spinal cord stimulation (SCS) or vagal stimulation (VS), has been used safely in patients with chronic pain, epilepsy, and depression, since the 1980s. As noted above, HF with a reduced LVEF is associated with sustained activation of the sympathetic nervous system that is accompanied by a withdrawal of parasympathetic tone. Impaired arterial baroreflexes have been proposed as an important mechanism that contributes to the sympathovagal imbalance present in HF4 …

Effect of daily remote monitoring on pacemaker longevity: a retrospective analysis.

Energy demand of remote monitoring in cardiac implantable electronic devices has never been investigated. Biotronik Home Monitoring (HM) is characterized by daily transmissions that may affect longevity. The aim of the study was to retrospectively compare longevity of a specific dual-chamber pacemaker model in patients with HM on and patients with HM off. Hospital files of 201 patients (mean age 87 ± 10 years, 78 men) who had received a Biotronik Cylos DR-T pacemaker between April 2006 and May 2010 for standard indication were reviewed. In 134 patients (67%), HM was activated. The primary end point was device replacement due to battery depletion. The median follow-up period was 56.4 months (interquartile range 41.8-65.2 months). The estimated device longevity was 71.1 months (95% confidence interval [CI] 69.1-72.3 months) in the HM-on group and 60.4 months (CI 55.9-65.1 months) in the HM-off group (P < .0001). The frequency of inhospital visits with significant device reprogramming was higher in the HM-on group than in the HM-off group (33.3% vs 25.0%, respectively; P = .03). Lower ventricular pulse amplitude (2.3 ± 0.4 V vs 2.7 ± 0.5 V; P < .0001) and pacing percentage (49% ± 38% vs 64% ± 38%; P = .02), both calculated as time-weighted averages, were observed with HM on as compared with HM off. Patient attrition was significantly lower in the HM-on group (9.7%; 95% CI 3.0%-28.7%) than in the HM-off group (45.6%; 95% CI 30.3%-64.3%) (P < .0001). In normal practice, energy demand of HM, if present, was overshadowed by programming optimization likely favored by continuous monitoring. Pacemakers controlled remotely with HM showed an 11-month longer longevity. Patient retention was superior.

Simulation of Intraoperative Pacemaker Failure

Simulation of Intraoperative Pacemaker Failure