Failure of impedance monitoring to prevent adverse clinical events caused by fracture of a recalled high-voltage implantable cardioverter-defibrillator lead

Sporadic high pacing and shock impedance on remote monitoring in hybrid implantable cardioverter-defibrillator systems: Clinical impact and management

BACKGROUND

Sporadic high impedance values without other anomalies detected by remote monitoring of hybrid cardiac implantable electronic device systems have been described recently. The clinical significance and related hazard of this phenomenon are not fully understood.

OBJECTIVE

The purpose of this study was to describe the prevalence, management, and outcomes associated with hybrid implantable cardioverter-defibrillator (ICD) systems.

METHODS

We collected data on patients with sporadic high lead impedance alert on remote monitoring who had undergone implantation with a hybrid ICD system between January 2015 and December 2019. Pacing thresholds, sensing and impedance values, and temporal pattern of impedance values were collected by remote monitoring, at implantation, and during an in-office visit.

RESULTS

Among 92 patients receiving a hybrid ICD, 15 (16.3%) had high impedance alert on remote monitoring (14 Boston Scientific and 1 St. Jude Medical ICD canisters paired with Medtronic or Biotronik DF-1 leads). Four patients had a cardiac resynchronization therapy-defibrillator (CRT-D), 7 a dual-chamber ICD, and 4 a single-chamber ICD. Three patients presented with high atrial lead impedance, 7 high right ventricular lead impedance, 1 high left ventricular impedance, and 2 high shock impedance values. All patients underwent follow-up by remote monitoring. Sporadic high impedance values were not associated with an adverse outcome or need for revision in all but 1 patient, who had continuously increasing pacing thresholds due to lead microfracture.

CONCLUSION

In the absence of clear signs of lead fracture or connection issues, sporadic high pacing and shock impedance in hybrid implantable defibrillator systems can be safely managed by close follow-up.

Implantable cardioverter-defibrillator lead revision following left ventricular assist device implantation

INTRODUCTION

Lead dysfunction can lead to serious consequences including failure to treat ventricular tachycardia or fibrillation (VT/VF). The incidence and mechanisms of lead dysfunction following left ventricular assist device (LVAD) implantation are not well-described. We sought to determine the incidence, mechanisms, timing, and complications of right ventricular lead dysfunction requiring revision following LVAD implantation.

METHODS

Retrospective observational chart review of all LVAD recipients with pre-existing implantable cardioverter-defibrillator (ICD) from 2009 to 2018 was performed including device interrogation reports, laboratory and imaging data, procedural reports, and clinical outcomes.

RESULTS

Among 583 patients with an ICD in situ undergoing LVAD implant, the median (interquartile range) age was 62.5 (15.7) years, 21% were female, and the types of LVADs included HeartWare HVAD (26%), HeartMate II (52%), and HeartMate III (22%). Right ventricular lead revision was performed in 38 patients (6.5%) at a median (25th, 75th) of 16.4 (3.6, 29.2) months following LVAD. Mechanisms of lead dysfunction included macrodislodgement (n = 4), surgical lead injury (n = 4), recall (n = 3), insulation failure (n = 8) or conductor fracture (n = 7), and alterations in the lead-myocardial interface (n = 12). Undersensing requiring revision occurred in 22 (58%) cases. Clinical sequelae of undersensing included failure to detect VT/VF (n = 4) and pacing-induced torsade de pointes (n = 1). Oversensing occurred in 12 (32%) and sequelae included inappropriate antitachycardia pacing ([ATP], n = 8), inappropriate ICD shock (n = 6), and ATP-induced VT (n = 1).

CONCLUSION

The incidence of right ventricular lead dysfunction following LVAD implantation is significant and has important clinical sequelae. Physicians should remain vigilant for lead dysfunction after LVAD surgery and test lead function before discharge.

Physician decision making in anticoagulating atrial fibrillation: a prospective survey of a physician notification system for atrial fibrillation detected on cardiac implantable electronic devices of patients at increased risk of stroke

OBJECTIVES

The objectives of this study were to evaluate the effectiveness of a physician notification system for atrial fibrillation (AF) detected on cardiac devices, and to assess predictors of anticoagulation in patients with device-detected AF.

METHODS

In 2013, a physician notification system for AF detected on a patient's CIED [including pacemakers, implantable cardioverter defibrillators (ICD) or cardiac resynchronization therapy (CRT) devices] was implemented, with a recommendation to consider oral anticoagulation in high-risk patients. We prospectively investigated the effectiveness of this system, and evaluated both patient and physician predictors of anticoagulation, as well as factors influencing physician decision making in prescribing anticoagulation. Both uni- and multivariable analysis as well as descriptive statistics were used in the analysis.

RESULTS

We identified 177 patients with device-detected AF, 126 with a CHADS2 ⩾2. Only 41% were prescribed anticoagulation at any point within 12 months. On multivariable analysis, stroke risk as predicted by CHADS2 was not a predictor of anticoagulation. ASA use predicted a lower rate of anticoagulation (OR 0.39, 95% CI 0.16-0.97, p = 0.04); physicians in practice for <20 years were more likely to prescribe anticoagulation (OR 3.39, 95% CI 1.28-8.93, p = 0.01); and physicians who believed both cardiologist and family doctor should be involved in managing anticoagulation were more likely to prescribe anticoagulation (OR 3.28, 95% CI 1.02-10.5, p = 0.05).

CONCLUSIONS

Patients on aspirin were less likely to be anticoagulated. Physicians in practice for <20 years and who believed that both the general practitioner and cardiologist should be involved in managing anticoagulants were more likely to prescribe anticoagulation.

Physician decision making in anticoagulating atrial fibrillation: a prospective survey of a physician notification system for atrial fibrillation detected on cardiac implantable electronic devices of patients at increased risk of stroke

OBJECTIVES

The objectives of this study were to evaluate the effectiveness of a physician notification system for atrial fibrillation (AF) detected on cardiac devices, and to assess predictors of anticoagulation in patients with device-detected AF.

METHODS

In 2013, a physician notification system for AF detected on a patient's CIED [including pacemakers, implantable cardioverter defibrillators (ICD) or cardiac resynchronization therapy (CRT) devices] was implemented, with a recommendation to consider oral anticoagulation in high-risk patients. We prospectively investigated the effectiveness of this system, and evaluated both patient and physician predictors of anticoagulation, as well as factors influencing physician decision making in prescribing anticoagulation. Both uni- and multivariable analysis as well as descriptive statistics were used in the analysis.

RESULTS

We identified 177 patients with device-detected AF, 126 with a CHADS2 ⩾2. Only 41% were prescribed anticoagulation at any point within 12 months. On multivariable analysis, stroke risk as predicted by CHADS2 was not a predictor of anticoagulation. ASA use predicted a lower rate of anticoagulation (OR 0.39, 95% CI 0.16-0.97, p = 0.04); physicians in practice for <20 years were more likely to prescribe anticoagulation (OR 3.39, 95% CI 1.28-8.93, p = 0.01); and physicians who believed both cardiologist and family doctor should be involved in managing anticoagulation were more likely to prescribe anticoagulation (OR 3.28, 95% CI 1.02-10.5, p = 0.05).

CONCLUSIONS

Patients on aspirin were less likely to be anticoagulated. Physicians in practice for <20 years and who believed that both the general practitioner and cardiologist should be involved in managing anticoagulants were more likely to prescribe anticoagulation.

Lead Integrity Alert Is Useful for Assessment of Performance of Biotronik Linox Leads

INTRODUCTION

Medtronic's Lead Integrity Alert (LIA) software algorithm is useful for detecting abnormal parameters across various ICD-lead families. However, its utility in the assessment of the Biotronik Linox™ family of high-voltage (HV) leads is unknown.

METHODS

We conducted a retrospective cohort study to assess the performance of the LIA algorithm to detect abnormalities and lead failure in Linox ICD-leads. All LIA-enabled Medtronic devices connected to an active Linox lead were included. The alerts were adjudicated by 2 blinded electrophysiologists and correlated with clinical data.

RESULTS

Between 2008 and 2012, data from 208 patients with 564 patient-years of follow-up were available for analysis. The median follow-up duration was 32 (IQR 21-41 months). Twenty-one LIA triggers were noted in 20 different patients. The median delay until a positive LIA was 32 months (IQR 21-41 months) postimplant with a 5-year lead survival free from LIA of 76%. Ninety-five percent (19/20) LIA alerts were true lead failures. The most common LIA triggers were short V-V intervals (85%) and nonsustained ventricular tachycardia (85%). Abrupt changes of the ICD-lead impedance occurred in 5/20 triggers. Inappropriate ICD-shocks were strongly associated with a positive LIA (30% vs. 7.4%; P = 0.006). Of the explanted Linox leads 53% had visible abnormalities. The sensitivity, specificity, and positive predictive value for lead failure in the presence of a LIA trigger were 87%, 99.5%, and 95.2%, respectively.

CONCLUSIONS

A positive LIA trigger in Biotronik Linox ICD-leads is highly predictive of lead failure. LIA is useful in ongoing surveillance of lead performance.

ICD lead failure detection in chronic soaked leads

Abrasion-induced insulation breach is a common failure mode of silicone-body, transvenous, implantable cardioverter defibrillator leads. It is caused either by external compression or internal motion of conducting cables. The present method of monitoring lead integrity measures low frequency conductor impedance. It cannot detect insulation failures until both the silicone lead body and inner fluoropolymer insulation have been breached completely, exposing conductors directly to blood or tissue. Even then the resistance changes are usually swamped by the baseline values. Thus the first clinical presentation may be either failure to deliver a life-saving shock or painful, inappropriate shocks in normal rhythm. We have previously presented a method for identifying early lead failure based on high frequency transmission line impedance measurements. That work used fresh leads in a liquid simulation bath; we have now demonstrated similar effects in leads soaked for 32 days and hence with saline-saturated silicone lead bodies.

The modern EP practice: EHR and remote monitoring

Cardiac implantable electronic devices (CIEDs) store clinically valuable, time-sensitive information regarding system integrity, arrhythmias, and heart failure parameters. Remote monitoring has impacted clinical practice by reducing scheduled office visits, providing protocols for device recalls and advisories, and facilitating the management of unscheduled encounters. The successful implementation of remote monitoring into clinical practice requires a new work flow and additional staff; the use of the electronic medical record to manage the data emanating from CIEDs poses an additional challenge. Solutions to these issues are discussed, and projections are made regarding the management of CIEDs in a modern electrophysiology practice.

ICD lead failure detection through high frequency impedance

Abrasion-induced insulation breach is a common failure mode of silicone-body, transvenous, implantable cardioverter defibrillator leads. It is caused either by external compression or internal motion of conducting cables. The present method of monitoring lead integrity measures low frequency conductor impedance. It cannot detect insulation failures until both the silicone lead body and inner fluoropolymer insulation have been breached completely, exposing conductors directly to blood or tissue. Thus the first clinical presentation may be either failure to deliver a life-saving shock or painful, inappropriate shocks in normal rhythm. We present a new method for identifying lead failure based on high frequency impedance measurements. This method was evaluated in 3D electromagnetic simulation and bench testing to identify insulation defects in the St. Jude Medical Riata® lead, which is prone to insulation breach.

Remote Monitoring for Follow-up of Patients with Cardiac Implantable Electronic Devices

Follow-up of patients with cardiac implantable electronic devices is challenging due to the increasing number and technical complexity of devices coupled to increasing clinical complexity of patients. Remote monitoring (RM) offers the opportunity to optimise clinic workflow and to improve device monitoring and patient management. Several randomised clinical trials and registries have demonstrated that RM may reduce number of hospital visits, time required for patient follow-up, physician and nurse time, hospital and social costs. Furthermore, patient retention and adherence to follow-up schedule are significantly improved by RM. Continuous wireless monitoring of data stored in the device memory with automatic alerts allows early detection of device malfunctions and of events requiring clinical reaction, such as atrial fibrillation, ventricular arrhythmias and heart failure. Early reaction may improve patient outcome. RM is easy to use and patients showed a high level of acceptance and satisfaction. Implementing RM in daily practice may require changes in clinic workflow. To this purpose, new organisational models have been introduced. In spite of a favourable cost:benefit ratio, RM reimbursement still represents an issue in several European countries.

Same-day discovery of implantable cardioverter defibrillator dysfunction in the TRUST remote monitoring trial: influence of contrasting messaging systems

Aims

Assess whether automatic remote home monitoring (HM) permits same-day evaluation of implantable cardioverter defibrillator (ICD) system dysfunction.

Methods and results

Compromised ICD system integrity (generator/lead) demands prompt evaluation. Home monitoring promises earlier discovery but may be limited by technological differences and follow-up mechanism. We tested whether HM enabled event review within 24 h, and contrasted differing messaging mechanisms. Nine hundred and eight patients in the TRUST prospective multicentre trial were followed by HM for 15 months. ICD system problems automatically triggered notifications: repeatedly (‘redundant’) for impedance deviations and elective replacement indication (ERI), but only a single transmission for ‘30 J ineffective’. Detection time from event onset to physician evaluation was measured. Forty-three system-related alerts occurred; 42% were asymptomatic, 42% were actionable, and 22 of 43 (51%) were viewed within 24 h. Redundant notifications were: 1 ERI, 9 shock impedance, 2 ventricular and 6 atrial pacing impedance. Most (11/18; 61%) were detected in <24 h. Others elicited daily notifications without interruption until resolution. For single transmissions, 11 of 25 (44%) events were detected on the same day. Most (56%, 14/25) were detected between 1 and 39 days (mean 10.0 ± 13.0 days). Ten of 14 events were detected by HM and 4 at the time of office visits. These observations suggest single transmissions were vulnerable to detection failure. Mean detection time of redundant events was 1.1 ± 1.8 vs. single transmission 5.6 ± 10.9 days (P = 0.05). Hence, redundant notification avoided late detection.

Conclusion

Same-day discovery of ICD dysfunction, even if asymptomatic, was achievable. For those events not evaluated within 24 h, repetitive messaging promoted earlier discovery. Reorganization of clinical follow-up methods may maintain early reaction ability.

Clinical Trials registration information

ClinicalTrials.gov; NCT00336284.

Telemedicine and cardiac implants: what is the benefit?

Cardiac implantable electronic devices are increasing in prevalence. The post-implant follow-up is important for monitoring both device function and patient condition. However, practice is inconsistent. For example, ICD follow-up schedules vary from 3 monthly to yearly according to facility and physician preference and availability of resources. Recommended follow-up schedules impose significant burden. Importantly, no surveillance occurs between follow-up visits. In contrast, implantable devices with automatic remote monitoring capability provide a means for performing constant surveillance, with the ability to identify salient problems rapidly. Remote home monitoring reduces the volume of device clinic visits and provides early detection of patient and/or system problems.

Psychological impact of surveillance in patients with a defibrillator lead under advisory: a prospective evaluation

BACKGROUND

Implantable cardioverter defibrillator (ICD) leads are subject to technical failures and the impact of the resulting public advisories on patient welfare is unclear. The psychological status of patients who received an advisory for their Medtronic Fidelis ICD lead (Medtronic Inc., Minneapolis, MN, USA) and followed either by self-surveillance for alarm or home monitoring with CareLink was evaluated prospectively and compared to patients with ICDs not under advisory.

METHODS

One hundred sixty consecutive consenting patients (90 alarms, 24 Carelinks, 46 controls) were recruited within 1.5 years of advisory notification. Advisory patients were seen immediately before being told that the automatic lead surveillance utilized since the advisory had been inadequate in warning of impending fracture, as well as 1 and 6 months after programming was optimized. Depression, anxiety, quality of life (QoL), and ICD-related concerns were assessed.

RESULTS

Symptoms of depression and state anxiety were experienced by 31% and 48% of patients, respectively. QoL was impaired on all subscales. No significant group differences in distress and ICD-related concerns emerged at baseline or at follow-up. At baseline, alarm patients reported greater limitations because of body pain compared to controls (P < 0.05). All patients showed a significant reduction in body pain-related QoL at the final versus first two evaluations (P < 0.001). Advisory patients were significantly less satisfied with surveillance at follow-up than at baseline (P < 0.05).

CONCLUSIONS

There was limited evidence for worse psychosocial functioning in those at risk for ICD lead fracture, irrespective of surveillance method. However, many control and advisory patients experienced chronic distress for which counseling may prove beneficial.

Use of remote monitoring in the management of system-related complications in implantable defibrillator patients

Remote monitoring of implantable defibrillators (ICDs) is designed to minimise regular follow-up visits and to facilitate early detection of adverse events. With the increased rate of ICD implantations in today's clinical setting and multiple device advisories, which pose management challenges, this approach becomes very attractive. The aim of this article is to present the role of remote monitoring in the detection of system-related complications, its potential benefits and its barriers in the outpatient management of ICD patients.

[Sprint fidelis defibrillation lead: a nine-center experience in Spain]

INTRODUCTION AND OBJECTIVES

Sprint Fidelis defibrillation leads are prone to early failure. Most of the reported series come from a single institution. This paper describes the clinical experience in nine Spanish hospitals.

METHODS

Clinical, implant, and follow-up data of all patients with a Sprint Fidelis lead were analyzed. All cases of lead failure were identified, medium-term lead survival was calculated, and possible predictors for lead failure were determined.

RESULTS

In total, 378 leads in 376 patients were studied. The mean age (male 85.7%) was 64.9 ± 13.6 years. The majority of patients (59.8%) had ischemic heart disease. Mean left ventricular ejection fraction was 33.4% ± 14.5%. Left subclavian vein puncture was used in 74.8%. During a mean follow-up of 30.9 ± 14 months, 16 lead failures have occurred, with a lead survival of 96.1% at 36 months after implantation. Eleven of 16 lead failures were caused by failure of pace/sense conductors, 3 by defects in the high-voltage conductor, and 2 by defects in both types of conductors. A less depressed left ventricular ejection fraction was associated with an increased probability of lead failure (42.4% ± 16% vs. 33% ± 14.3%; P =.011). Three hospitals presented a rate of lead failure higher than 10%; the rate was less than 5% in the remaining 6 hospitals.

CONCLUSIONS

In this multicenter series of 378 leads, the 3-year estimated survival was higher than that reported in prior series. Clinical presentation of lead failures was similar to that reported previously. Left ventricular ejection fraction and hospital of implantation were variables associated to lead failure.

Automatic remote monitoring of implantable cardioverter-defibrillator lead and generator performance: the Lumos-T Safely RedUceS RouTine Office Device Follow-Up (TRUST) trial

BACKGROUND

Monitoring performance of implantable cardioverter-defibrillator (ICD) generators and leads is important. Methods available are with in-person evaluations or by automatic remote home monitoring (HM). These were prospectively evaluated and compared in the TRUST trial. The HM technology tested performed daily self-checks and databasing with rapid event notifications for out-of-range (including asymptomatic) conditions.

METHODS AND RESULTS

Patients (n=1339) were randomly assigned after ICD implant 2:1 to HM or to conventional groups. Both groups underwent scheduled checks every 3 months and were followed for 15 months. In HM, in-person office visits were scheduled at 3 and 15 months. At 6, 9, and 12 months, HM only was used with subsequent office visits if necessary. Between these time points, ICDs triggered event notifications for system integrity problems. Patients randomly assigned to conventional follow-up were evaluated with office visits only. HM and conventional patients were similar (age, 63.3±12.8 versus 64.0±12.1 years; 72.0% versus 73.1% male; New York Heart Association II class, 55.9% versus 60.4%; left ventricular ejection fraction, 29.0±10.7% versus 28.5±9.8%; coronary artery disease, 64.8% versus 71.7%; primary prevention, 72.2% versus 73.8%; DDD devices, 57.8% versus 56.6%). Four patients crossed over from conventional to HM because of advisories. Scheduled checks were more successfully accomplished in HM (92.7% versus 89.2% in conventional, P<0.001). Sixty-two device-related events (53 in HM versus 9 in conventional) were observed in 46 patients (40 [4.4%] in HM versus 6 [1.39%] in conventional, P=0.004). Forty-seven percent were asymptomatic. HM detected generator and lead problems earlier (HM versus conventional: median, 1 versus 5 days; P=0.05). A total of 20 device problems (eg, lead fracture, elective replacement indicators) requiring surgical revision (0.012 per patient-year) were found, 15 in HM and 5 in the conventional groups. Other events were managed nonsurgically (eg, reprogramming, initiation of antiarrhythmics).

CONCLUSIONS

ICD lead and generator malfunction was infrequent and often asymptomatic. Only a minority of detected events required surgical intervention. Automatic HM enhanced discovery, permitted prompt detection, and facilitated management decisions. Longitudinal parameter trending, with component function evaluated daily by remote monitoring, may enable long-term performance assessment.

CLINICAL TRIAL REGISTRATION

URL: http://clinicaltrials.gov. Unique identifier: NCT00336284.

Contributions of remote monitoring to the follow-up of implantable cardioverter-defibrillator leads under advisory

Aims

Automatic daily transmission of data from implantable cardioverter–defibrillators (ICDs) enables the remote monitoring of device status and leads function. We report on a 2-year experience with remote monitoring in 40 recipients of high-voltage ICD leads, prone to fracture and under advisory since October 2007.

Methods and results

The ICDs were remotely monitored as well as systematically interrogated in the ambulatory department every 3 months. The patients were also seen in case of abnormal lead impedance, or other manifestations consistent with lead dysfunction. Over a mean follow-up of 22 ± 4 months after ICD implantation, four lead dysfunctions were suspected because of remotely transmitted oversensing of noise artifacts, abrupt rise in pacing impedance, or both. A lead fracture needing lead replacement was confirmed in three patients (7.5%), two of them before any inappropriate therapy and one after the delivery of three inappropriate shocks. No lead failure was observed in the remaining 36 patients, either at the time of ambulatory visits or during remote monitoring.

Conclusion

Remote monitoring allowed the early and reliable detection of ICD leads failure without requiring any patient intervention.

Causes of ventricular oversensing in implantable cardioverter-defibrillators: implications for diagnosis of lead fracture

BACKGROUND

Implantable cardioverter-defibrillator (ICD) ventricular oversensing may result in inappropriate therapy, which may be triggered by lead/connection issues that require surgical revision or physiologic oversensing that may be resolved with reprogramming. The sensing integrity counter (SIC) is an oversensing diagnostic that increments for very rapid ventricular intervals < or =130 ms.

OBJECTIVE

The purpose of this study was to determine the causes of a high SIC and the ability of additional diagnostics to differentiate lead/connection issues from other causes of oversensing for patients with normal impedance.

METHODS

Frequent SICs were identified in patients during routine follow-up visits. To diagnose the cause of oversensing, patients wore a modified 24-hour digital Holter monitor that recorded ECG, ventricular electrogram, and the ICD Marker Channel (Medtronic). Recordings were reviewed to determine the causes of oversensing. Patients with confirmed oversensing and adequate data were analyzed. The number of SICs per day and the presence of a nonsustained tachycardia (NST) episode with ventricular mean cycle length <220 ms were retrieved from stored ICD data.

RESULTS

Forty-eight patients had a median of 13 SICs/day. Presumed lead/connection issues occurred in 23% of patients, whereas physiologic oversensing occurred in 77% of patients. A rapid NST was recorded more commonly in patients with lead/connection issues than in those without (9/11 vs 1/37; P < .0001).

CONCLUSION

Oversensing resulting in frequent, very short intervals typically are caused by either lead/connection issues or physiologic signals. The additional finding of rapid NSTs usually indicates a lead/connection issue, even in the absence of impedance abnormalities.

Remote monitoring and follow-up of pacemakers and implantable cardioverter defibrillators

In the era of communication technology, new options are now available for following-up patients implanted with pacemakers (PMs) and defibrillators (ICDs). Most major companies offer devices with wireless capabilities that communicate automatically with home transmitters, which then relay data to the physician, thereby allowing remote patient follow-up and monitoring. These systems are being widely used in the USA for remote follow-up, and have been more recently introduced in Europe, where their adoption is increasing. In this article, we describe the currently existing systems, review the available evidence in the literature regarding remote follow-up and monitoring of PMs and ICDs, and finally discuss some unresolved issues.