Lead Fracture Research Articles

Implantable Cardioverter-Defibrillators in Patients with ESRD: Complications, Management, and Literature Review.

Background:Cardiovascular diseases are the leading cause of death among dialysis pa-tients, accounting for about 40% of all their mortalities. Sudden cardiac death (SCD) is culpable for 37.5% of all deaths among patients with end-stage renal disease (ESRD). Implantable cardioverter-defibrillators (ICDs) should be considered in dialysis patients for the primary or secondary preven-tion of SCD. Recent studies on the implementation of ICD/cardiac resynchronization therapy do not exclude patients with ESRD; however, individualized decisions should be made in this group of pa-tients. A thorough evaluation of the benefits of ICD implementation in patients with ESRD requires several large-scale mortality studies to compare and follow up patients with ESRD with and without ICDs. In the present study, we sought to determine and clarify the complications associated with ICD implementation and management thereof in patients suffering from ESRD.Methods:To assess the complications allied to the implementation of ICDs and their management in patients with ESRD, we reviewed available related articles in the literature.Results and Conclusions:ICD implementation in dialysis patients has several complications, which has limited its usage. Based on our literature review, the complications of ICD implementation can be categorized as follows: (1) Related to implantation procedures, hematoma, and pneumothorax; (2) Re-lated to the device/lead such as lead fracture and lead dislodgment; (3) Infection; and (4) Central vein thrombosis. Hence, the management of the complications of ICDs in this specific group of patients is of vital importance.

Quantification of Electromechanical Coupling to Prevent Inappropriate Implantable Cardioverter-Defibrillator Shocks.

ObjectivesThis study sought to test specialized processing of laser Doppler signals for discriminating ventricular fibrillation (VF) from common causes of inappropriate therapies.BackgroundInappropriate implantable cardioverter-defibrillator (ICD) therapies remain a clinically important problem associated with morbidity and mortality. Tissue perfusion biomarkers, implemented to assist automated diagnosis of VF, sometimes mistake artifacts and random noise for perfusion, which could lead to shocks being inappropriately withheld.MethodsThe study tested a novel processing algorithm that combines electrogram data and laser Doppler perfusion monitoring as a method for assessing circulatory status. Fifty patients undergoing VF induction during ICD implantation were recruited. Noninvasive laser Doppler and continuous electrograms were recorded during both sinus rhythm and VF. Two additional scenarios that might have led to inappropriate shocks were simulated for each patient: ventricular lead fracture and T-wave oversensing. The laser Doppler was analyzed using 3 methods for reducing noise: 1) running mean; 2) oscillatory height; and 3) a novel quantification of electromechanical coupling which gates laser Doppler relative to electrograms. In addition, the algorithm was tested during exercise-induced sinus tachycardia.ResultsOnly the electromechanical coupling algorithm found a clear perfusion cut off between sinus rhythm and VF (sensitivity and specificity of 100%). Sensitivity and specificity remained at 100% during simulated lead fracture and electrogram oversensing. (Area under the curve running mean: 0.91; oscillatory height: 0.86; electromechanical coupling: 1.00). Sinus tachycardia did not cause false positive results.ConclusionsQuantifying the coupling between electrical and perfusion signals increases reliability of discrimination between VF and artifacts that ICDs may interpret as VF. Incorporating such methods into future ICDs may safely permit reductions of inappropriate shocks.

MANAGING A “KNOTTY” LEAD

As the number of ICD implantations increases, so do device complications. Implanters need a variety of approaches to deal with the different possibilities. A 64-year-old woman who underwent initial biventricular ICD placement in 2012 presents with atrial lead fracture. Venography revealed a mildy

Long-term performance of right ventricular pacing leads: risk factors associated with permanent right ventricular pacing threshold increase

PurposeRight ventricular pacing threshold (RVPT) may rise over time accompanied by the increased use of implantable cardiac pacemakers. However, risk factors for permanent RVPT increase are not fully clarified in patients without definite lead fracture and dislodgment. We aimed to evaluate the long-term performance of RV pacing leads and identify risk factors associated with the occurrence of permanent RVPT increase in this population.MethodsPatients with first implantation of cardiac pacemakers from January 2008 to June 2016 were consecutively enrolled. Follow-up for RVPT increase was until December 2017. The clinical data, specific data on the pacemaker implantation, and routine follow-up were retrieved.ResultsDuring a follow-up duration of 5.4 ± 2.1 years, permanent RVPT increase (except lead fracture and dislodgment) was found in 8.4% (87/1033) patients. Patients with permanent RVPT increase had higher prevalence of myocardial infarction (MI), diabetes, and the use of amiodarone. The risk factors independently associated with permanent RVPT increase were MI (HR = 1.094, 95% CI 1.014–1.180, p = 0.031), diabetes (HR = 2.804, 95% CI 1.064–3.775, p = 0.003). MI patients with RVPT increase had higher prevalence of multivessel disease and atrioventricular block. Diabetic patients with RVPT increase exhibited higher serum fasting blood glucose (FBG) and hemoglobin A1c (HbA1c) levels, which were correlated with the maximum RVPT (p < 0.001).ConclusionsOur data showed that permanent RVPT increases (except lead fracture and dislodgement) during long-term follow-up after pacemaker implantation. The likely risk factors predisposing to chronic permanent RVPT increase are MI and diabetes with higher FBG and HbA1c levels.

Use and outcomes of subcutaneous implantable cardioverter-defibrillator (ICD) after transvenous ICD extraction: An analysis of current clinical practice and a comparison with transvenous ICD reimplantation

The subcutaneous implantable cardioverter-defibrillator (S-ICD) does not require the insertion of any leads into the cardiovascular system. The aims of the study were to describe current practice and to measure outcomes associated with S-ICD or standard single-chamber transvenous ICD (TV-ICD) use after TV-ICD explantation. We analyzed all consecutive patients who underwent transvenous extraction of an ICD and subsequent implantation of an S-ICD or a single-chamber TV-ICD at 12 Italian centers from 2011 to2017. A total of 229 patients were extracted and subsequently reimplanted with an S-ICD (90; 39%) or a single-chamber TV-ICD (139; 61%). S-ICD implantation increased from 9% in 2011 to 85% in 2017 (P< .001). Patients reimplanted with an S-ICD were younger (53 ± 13 years vs 60 ± 18 years; P = .011) and more frequently had undergone extraction owing to infection (73% vs 52%; P<.001). The rates of complications at follow-up were comparable between groups (hazard ratio 0.97; 95% confidence interval 0.49-1.92; P = .940). No lead failures, systemic infections, or system-related deaths occurred in the S-ICD group. In the TV-ICD group, 1 lead fracture occurred and 2 systemic infections were reported, resulting in death in 1 case. In the S-ICD group, the rate of complications was lower when the generator was positioned in a sub- or intermuscular pocket (hazard ratio 0.21; 95% confidence interval 0.05-0.87; P = .048). Our results show an increasing use of S-ICD over the years in patients undergoing TV-ICD explantation. An S-ICD is preferably adopted in young patients, mostly in the case of infection. The complication rate was comparable between groups and decreased when a sub- or intermuscular S-ICD generator position was adopted.

Vagal Nerve Stimulation: Indications for Revision in Adult Refractory Epilepsy

The goal of this study was to assess the indications of revision for vagal nerve stimulation at a single institution in an adult population with drug-resistant epilepsy. This was a retrospective review of a prospectively collected database who underwent vagal nerve stimulator implantation for drug-resistant epilepsy during 1992-2017. Patients receiving vagal nerve stimulation (VNS) implants were monitored throughout their perioperative and postoperative course and were classified according to type of seizure at the time of diagnosis and indications for VNS revision. In addition, response to dysfunctional VNS devices or adverse effects were noted. Most patients receiving VNS implants were given a diagnosis of complex partial seizures (CPSs) before implantation (95.1%). Other epileptic conditions identified requiring implantation included generalized seizures, generalized-atonic seizures, Lennox-Gastaut syndrome, CPS or generalized seizures, and tuberous sclerosis (with generalized characteristics). High lead impedance was the most common indication for revision (5.6%), whereas device ineffectiveness leading to continued seizures was the most common indication for removal (2.3%). Infection, lead fracture, and dual- to single-pin lead battery changes occurred at an incidence of 1.9%, requiring either implant removal or revision. Other events that occurred, albeit rarely, included skin extrusion (0.5%), postoperative hematoma (0.5%), and implant rejection (0.5%) necessitating removal. VNS implantation in adults was shown to be a well-tolerated procedure. In addition, indications for revision or removal of the VNS device was low in this population with lead fracture rates lower than the incidence reported in pediatric population literature.

Lead fracture of peripheral nerve stimulator for brachial plexopathy -a case report.

Peripheral nerve stimulation (PNS) is a useful treatment for chronic pain, but it can cause damage depending on its application site. Here, we describe the case of a 54-year-old man who underwent PNS for brachial plexopathy in 2015. One lead was implanted on the left medial cord to stimulate the medial antebrachial cutaneous nerve, and the other was implanted on the radial nerve to stimulate the posterior antebrachial cutaneous nerve. Both leads were inserted near the shoulder joint but did not cross it. Before PNS, the patient did not move his shoulder and elbow because of severe pain, but the treatment greatly alleviated this pain. Twenty months after the operation, both leads were fractured, and the severe pain returned. Repetitive motion near the joint was closely related to the lead fractures. In conclusion, large joints as the insertion sites of PNS leads should be avoided to prevent lead fractures.

The Long-Term Durability of Multilumen Concentric Percutaneous Spinal Cord Stimulator Leads.

Lead fracture is a well-known complication of cylindrical spinal cord stimulator leads. In order to reduce this complication, anchor design and techniques have been modified, but internal lead design has received little attention. The goal of this study was to study the impact of lead design by a retrospective determination of the fracture rate of multilumen concentric (MLC) 8-contact leads. Retrospective chart review. University teaching hospital. A registry of spinal cord stimulator implants and corresponding billing data were used to identify patients. Procedural details were reviewed for technique, lead insertion, anchoring details, manufacturer, and lead longevity from 2002 to 2014. Data storage was in RedCap data-capturing software (REDCap eData Collection web-based application). All analyses were performed using SAS 9.3 (SAS Institute, Cary, NC, U.S.A.). In a near 12"-year time period, 172 patients received 305 permanently implanted 8-contact leads, with an overall fracture rate of 4.3%. Of these, 191 leads were of the MLC design. No lead fracture was observed in the MLC leads over an average 4.5years of follow-up. Retrospective single center. MLC lead design has the potential to significantly mitigate lead fracture.

Decreased inappropriate shocks with new generation ICDs in children and patients with congenital heart disease

Inappropriate implantable cardioverter defibrillator (ICD) shocks in children and patients with congenital heart disease (CHD) remain a major complication of device therapy, occurring in as many as 50% of children with ICDs. New generation devices include algorithms designed to minimize inappropriate shocks. This study aimed to evaluate the effect of new generation ICDs on the incidence of inappropriate shocks in the pediatric and CHD population. Retrospective study of patients with CHD or under age 25 receiving ICDs between 2000 and 2015. New generation ICDs were defined as those with Medtronic "SmartShock" algorithms. Two hundred eight devices were implanted in 146 patients. Rates of inappropriate shocks were similar between diagnoses (P = .71). The rate of inappropriate shock was 15% over median 5.8 years follow-up. In the 36 patients (25%) with new generation ICDs, the rate of inappropriate shock was 6.3% over 4 years. Comparing old to new generation ICDs, freedom from first inappropriate shock was 90.6% versus 97.1% at 1 year and 80.4% versus 97.1% at 3 years (P = .01). Lead fracture was associated with having inappropriate shock (hazard ratio 8.5, P < .0001), and there was no significant difference between the device groups when lead fractures were excluded. Clinical actions were taken in 69% of patients after initial inappropriate shock (such as medication or program change, system revision, or explant). When an action was taken, subsequent inappropriate shock was reduced (5.3% vs 49.2% at 1 year; P = .002). Pediatric and CHD patients are experiencing reduced inappropriate shocks with new generation ICD systems, though reduced lead fracture may account for this improvement. Clinical interventions after inappropriate shock favorably impact the subsequent rate of shocks once an inappropriate shock occurs.

Pacemaker lead fracture as a cause of pacing failure

Cardiac pacing is a rapidly advancing technique. There are many potential complications of pacemaker implantation. In view of increasing implantations of pacemakers, we must have some insight of possible complications. We describe here a case of pacing lead fracture which was managed by new lead implantation.

New Therapy for Refractory Chronic Mechanical Low Back Pain—Restorative Neurostimulation to Activate the Lumbar Multifidus: One Year Results of a Prospective Multicenter Clinical Trial

ObjectivesThe purpose of the international multicenter prospective single arm clinical trial was to evaluate restorative neurostimulation eliciting episodic contraction of the lumbar multifidus for treatment of chronic mechanical low back pain (CMLBP) in patients who have failed conventional therapy and are not candidates for surgery or spinal cord stimulation (SCS).Materials and MethodsFifty‐three subjects were implanted with a neurostimulator (ReActiv8, Mainstay Medical Limited, Dublin, Ireland). Leads were positioned bilaterally with electrodes close to the medial branch of the L2 dorsal ramus nerve. The primary outcome measure was low back pain evaluated on a 10‐Point Numerical Rating Scale (NRS). Responders were defined as subjects with an improvement of at least the Minimal Clinically Important Difference (MCID) of ≥2‐point in low back pain NRS without a clinically meaningful increase in LBP medications at 90 days. Secondary outcome measures included Oswestry Disability Index (ODI) and Quality of Life (QoL; EQ‐5D).ResultsFor 53 subjects with an average duration of CLBP of 14 years and average NRS of 7 and for whom no other therapies had provided satisfactory pain relief, the responder rate was 58%. The percentage of subjects at 90 days, six months, and one year with ≥MCID improvement in single day NRS was 63%, 61%, and 57%, respectively. Percentage of subjects with ≥MCID improvement in ODI was 52%, 57%, and 60% while those with ≥MCID improvement in EQ‐5D was 88%, 82%, and 81%. There were no unanticipated adverse events (AEs) or serious AEs related to the device, procedure, or therapy. The initial surgical approach led to a risk of lead fracture, which was mitigated by a modification to the surgical approach.ConclusionsElectrical stimulation to elicit episodic lumbar multifidus contraction is a new treatment option for CMLBP. Results demonstrate clinically important, statistically significant, and lasting improvement in pain, disability, and QoL.

Long-term outcome of epicardial implantable cardioverter-defibrillator systems in children: results justify its preference in paediatric patients.

The question of whether transvenous or epicardial implantable cardioverter defibrillator (ICD) system is more beneficial in children and adolescents is controversially discussed. We sought to analyse the long-term outcome after implantation of ICDs using epicardial pacing/sensing and pleural shock leads. Retrospective analysis of 31 consecutive patients undergoing a total of 55 implantations of epicardial/pleural ICD systems below 20 years of age. Median age at implantation was 11.4 years (range 2.2-20) and median follow-up 57 months (range 0.4-127). The ICDs were implanted for primary (n = 17) and for secondary prevention (n = 14). The first defibrillation threshold at implantation was ≤25 J in 94% of the implant procedures. Appropriate shocks occurred in 6 of 31 patients. Inappropriate shocks occurred in 4 of 31 patients triggered by lead fracture, T-wave oversensing, sinus tachycardia, and atrial fibrillation. Freedom from first ICD discharge was 81, 71, and 71% at 3, 6, and 9 years, respectively. Reoperation was indicated in 16 of 31 patients for lead failure (n=11), end of battery life (n=10), generator migration (n=1) and recall (n=1); freedom from reoperation was 74 and 55% at 3 and 6 years. Paediatric epicardial/pleural ICD therapy is feasible, effective, and safe both in the short-term as well as in the long-term perspective at the price of relatively frequent surgical revisions. They do not generally result in an increased burden of inappropriate shocks. This ICD system meets the needs of the paediatric population and can be recommended as a first choice in this age group.

Experience and Solution of Complications of Vagus Nerve Stimulation Therapy in 139 Implant Patients with Medically Refractory Epilepsy

Vagus nerve stimulation(VNS)for patients with intractable epilepsy was approved by the Japan Ministry of Health, Labour and Welfare in 2010. More than 1,500 VNS systems were implanted by the end of August 2016. The aim of the present report is to describe complications we experienced at our department and consider the way to avoid them. We retrospectively reviewed 139 consecutive patients(122 new implantations and 17 reimplantations)between December 2010 and March 2016. Seven patients demonstrated eight complications. Four patients experienced recurrent nerve paralysis with hoarseness and/or cough that did not require device removal. One patient experienced subsequent aspiration pneumonia. The device was removed in one case due to lead fracture and in three owing to surgical site infection(SSI). All recurrent nerve paralysis occurred just after we started VNS implantations. It was presumed that the nerve paralysis was caused by retraction around the vagus nerve. Smaller skin incision and decreased retraction of the surgical field has eliminated this complication. The incidence of infections is reported as 2.2%. Allergic reaction to the VNS device might be one of the causes for SSI in our series. Fracture of the lead was caused by revolving of the pulse generator under the skin. Tight sutures around the pocket or subpectoral placement of a pulse generator is necessary to prevent rotation of the generator depending upon the activity of each patient. This paper provides insight into complications and successful strategies for better outcomes in VNS therapy.

Systematic review of hardware-related complications of Deep Brain Stimulation: Do new indications pose an increased risk?

IntroductionDeep Brain Stimulation (DBS) is an effective treatment extended broadly to many neurological and psychiatric disorders. Nevertheless, complications may arise during DBS procedures or following implantation due to implanted hardware. This may result in both minor and major adverse events that may necessitate hardware removal and/or compromise maximal therapeutic benefit for the patient. Objectives and methodsTo identify relevant literature on hardware-related complications from DBS procedures by performing a systematic review, and propose how to identify at-risk group and possible preventive approaches. ResultsOf 4592 abstract screened, 96 articles fulfilled the selection criteria and were reviewed. Overall, the most common hardware-related complications were infections (5.12% of patients), followed by lead migration (1.60%), fracture or failure of the lead or other parts of the implant (1.46% and 0.73%, respectively), IPG malfunctions (1.06% of patients), and skin erosions without infections (0.48% of patients). New indications for DBS, including Tourette's syndrome, cluster headache, and refractory partial epilepsy, were found to bear a higher incidence of hardware-related infections than established indications such as Parkinson's disease. The highest rate of lead fracture or failure was found in dystonia patients (4.22%). Ultimately, the highest rate of pain at the implantation sites was found in refractory partial epilepsy patients (16.55%). ConclusionOur analysis identified a variety of potential hardware-related complications among patients who underwent DBS procedures. Patients who were at risk of complications, such as patients with dystonia and off-label indications (e.g. Tourette's syndrome) should be informed prior to surgery and closely followed thereafter.

Clinical analysis of pacing therapy and treatment of complications during follow-up in children

Objective: To analyze characteristics of permanent pacemaker implantation in children as well as treatment and prognosis of complications. Method: Clinical data of children who underwent endocardial or epicardial permanent pacemaker implantation between April 2000 and June 2016 in Shanghai Xinhua Hospital and Shanghai Children's Medical Center were analyzed retrospectively. These patients were discharged 5 days after implantation. Electrocardiogram, chest X ray, echocardiography and pacemaker programming were performed during follow-up. Treatment regimes, complication management and prognosis were analyzed retrospectively. Result: Data of a total of 193 cases were collected. One hundred and six patients were male and 87 patients were female.The average age was (5.09±4.05) years(0.4-16 years)and the average weight was (20.47±11.62) kg.133(68.9%); patients were implanted with endocardial pacemakers and 60(31.1%)patients were implanted with epicardial pacemakers; 135(69.9%)patients were single-chamber paced with 87 from RVA and 48 from RVOT. fifty-eight(30.1%)patients were dual chamber paced. These included 122(63.2%)postoperative third degree AV block(Ⅲ-AVB), 38 (19.7%)congenital complete AV block (CCAVB), 3(1.6%)post ventricular septal defect (VSD) interventional therapy AV block, 23 (11.9%)sick sinus syndrome (SSS) and 7(3.6%)Ⅲ-AVB after fulminant myocarditis. One hundred and thirty-seven(71%)patients were followed up for an average duration of 5.32 years(0.3-10 years). Pacemaker exchange were performed in 46 patients due to battery exhaustion.The average life of battery was 5.4 years (1-9 years). Sixteen patients underwent lead exchange due to dislocation or separation.One patient underwent lead extraction due to recovery of AV conduction 21 days after surgery for complete transposition of great arteries (D-TGA/VSD). Skin abrasion, infection or dehiscence occured in 6 patients. Heart failure occurred in 2 patients at 6 and 8 years after implantation whose heart functions improved after switching from VVI to DDD or adding ACEI . One patient died suddenly due to ineffective pacing caused by lead fracture. Another patient under DDD pacing was found to have atrial myocardial perforation with normal sensing and pacing so that no intervention was performed. Conclusion: The pacing mode and path through which leads are implanted for permanent pacemaker implantation in children have their peculiar characteristics.Some complications might occur during follow-up with good prognosis if appropriately treated.

Sacral Neuromodulation Device Heating During Lumbar and Pelvic Magnetic Resonance Imaging—a Phantom Study

To evaluate radiofrequency-induced temperature rises associated with performing lumbar and pelvic magnetic resonance imaging (MRI) studies with an implanted sacral neuromodulation device using a phantom model. An accepted phantom model of radiofrequency-induced heating in human tissue was used to measure the temperature rise in the stimulator lead electrodes and impulse generator under the conditions used during routine clinical lumbar and pelvic MRIs in a 1.5Tesla MRI scanner. Testing configurations included an intact device (tined lead connected to generator), an intact lead, and a lead fragment (model of lead fracture). Variations in the position of the phantom relative to the scanner were also tested. During testing with the intact device or the lead fragment no significant heating was detected. In contrast, the isolated intact lead model showed heating up to 5°C. These tests provide preliminary evidence that the risk of heating is low for clinical lumbar and pelvic MRI at 1.5-Tesla with an intact sacral neuromodulation device system and with a fractured lead. However, there is a significant temperature change in the intact lead model.

In silico assessment of biomedical products: The conundrum of rare but not so rare events in two case studies.

In silico clinical trials, defined as "The use of individualized computer simulation in the development or regulatory evaluation of a medicinal product, medical device, or medical intervention," have been proposed as a possible strategy to reduce the regulatory costs of innovation and the time to market for biomedical products. We review some of the the literature on this topic, focusing in particular on those applications where the current practice is recognized as inadequate, as for example, the detection of unexpected severe adverse events too rare to be detected in a clinical trial, but still likely enough to be of concern. We then describe with more details two case studies, two successful applications of in silico clinical trial approaches, one relative to the University of Virginia/Padova simulator that the Food and Drug Administration has accepted as possible replacement for animal testing in the preclinical assessment of artificial pancreas technologies, and the second, an investigation of the probability of cardiac lead fracture, where a Bayesian network was used to combine in vivo and in silico observations, suggesting a whole new strategy of in silico-augmented clinical trials, to be used to increase the numerosity where recruitment is impossible, or to explore patients' phenotypes that are unlikely to appear in the trial cohort, but are still frequent enough to be of concern.

Advancements in Pacemaker Technology: The Leadless Device.

Leadless pacemakers will most likely be the future of cardiac pacing. Leadless pacing employs a single-chamber system to pace only the right ventricle and is fully self-contained, which eliminates the need for leads. These systems, implanted by using a transcatheter sheath, are indicated for patients who need right ventricular pacing only. These devices enable patients to avoid lead-related complications, from lead fracture to extraction challenges, as well as pocket-related complications such as infection and disfigurement. Leadless pacemakers also are compatible with magnetic resonance imaging and do not require surgical placement, so patients avoid postoperative mobility restrictions. Because this technology will be increasingly used for cardiac internal electronic devices, commonly seen in critical care nursing, nurses must be knowledgeable about the indications for use of a wireless pacemaker, the implantation procedure, postprocedural care, device interrogation, and follow-up. This article discusses leadless pacemakers, clinical indications for their use, key similarities and differences between the current devices being used, key points for nursing care of patients with a leadless device, and the future of this technology.

Incorporation of stochastic engineering models as prior information in Bayesian medical device trials

ABSTRACTEvaluation of medical devices via clinical trial is often a necessary step in the process of bringing a new product to market. In recent years, device manufacturers are increasingly using stochastic engineering models during the product development process. These models have the capability to simulate virtual patient outcomes. This article presents a novel method based on the power prior for augmenting a clinical trial using virtual patient data. To properly inform clinical evaluation, the virtual patient model must simulate the clinical outcome of interest, incorporating patient variability, as well as the uncertainty in the engineering model and in its input parameters. The number of virtual patients is controlled by a discount function which uses the similarity between modeled and observed data. This method is illustrated by a case study of cardiac lead fracture. Different discount functions are used to cover a wide range of scenarios in which the type I error rates and power vary for the same number of enrolled patients. Incorporation of engineering models as prior knowledge in a Bayesian clinical trial design can provide benefits of decreased sample size and trial length while still controlling type I error rate and power.

Multicenter investigation of an implantable cardioverter-defibrillator algorithm to detect oversensing

The SecureSense right ventricular (RV) lead noise discrimination algorithm is designed to detect lead fracture and other types of oversensing in order to decrease inappropriate therapy. We studied the real-life accuracy of the SecureSense algorithm in implantable cardioverter-defibrillator (ICD) patients followed by remote monitoring across multiple centers. Across 3 French centers, we studied 486 patients with a St Jude Medical device who were followed by remote monitoring and who had the SecureSense algorithm activated. We reviewed ≤10 of the most recent remote monitoring-transmitted electrograms of nonsustained oversensing, RV lead noise, and ventricular tachycardia/ventricular fibrillation that received therapy. SecureSense inhibited 22 inappropriate therapies (lead dysfunction in 10 cases, P-wave oversensing in 12 cases). A total of 57 patients (12%) sent ≥1 nonsustained oversensing episode (total of 393 episodes) with multiple etiologies: noise on the near-field channel (38%), oversensing of T waves during ventricular pacing (33%), oversensing of the sinus P wave (12%), and oversensing of the paced P wave (6%). Two episodes (0.5%) of nonsustained VTwere undersensed by the far-field channel. Of 336 analyzed episodes of ventricular tachyarrhythmia, 15 episodes (4%) in 4 patients were related to oversensing of intrinsic P waves in 11 episodes or oversensing of external noise due to electrical cautery for the remaining 4 episodes. Of ICD patients equipped with SecureSense, 12% developed episodes of oversensing. The SecureSense algorithm prevented inappropriate ICD therapies with accurate diagnosis of oversensing (caused by lead dysfunction or oversensing of physiological signals). P-wave oversensing in integrated bipolar leads, electrical cautery, and electromagnetic interference are prone to be missed by SecureSense.