Subcutaneous Lead Research Articles

Reevaluación del diagnóstico y el tratamiento de las infecciones de dispositivos de electroestimulación cardiaca mediante [18F]FDG-PET/TC

Introduction and objectivesThe role of [18F]FDG-PET/CT in cardiac implantable electronic device (CIED) infections requires better evaluation, especially in the diagnosis of systemic infections. We aimed to determine the following: a) the diagnostic accuracy of [18F]FDG-PET/CT in each CIED topographical region, b) the added value of [18F]FDG-PET/CT over transesophageal echocardiography (TEE) in diagnosing systemic infections, c) spleen and bone marrow uptake in differentiating isolated local infections from systemic infections, and d) the potential application of [18F]FDG-PET/CT in follow-up. MethodsRetrospective single-center study including 54 cases and 54 controls from 2014 to 2021. The Primary endpoint was the diagnostic yield of [18F]FDG-PET/CT in each topographical CIED region. Secondary analyses described the performance of [18F]FDG-PET/CT compared with that of TEE in systemic infections, bone marrow and spleen uptake in systemic and isolated local infections, and the potential application of [18F]FDG-PET/CT in guiding cessation of chronic antibiotic suppression when completed device removal is not performed. ResultsWe analyzed 13 (24%) isolated local infections and 41 (76%) systemic infections. Overall, the specificity of [18F]FDG-PET/CT was 100% and sensitivity 85% (79% pocket, 57% subcutaneous lead, 22% endovascular lead, 10% intracardiac lead). When combined with TEE, [18F]FDG-PET/CT increased definite diagnosis o fsystemic infections from 34% to 56% (P=.04). Systemic infections with bacteremia showed higher spleen (P=.05) and bone marrow metabolism (P=.04) than local infections. Thirteen patients without complete device removal underwent a follow-up [18F]FDG-PET/CT, with no relapses after discontinuation of chronic antibiotic suppression in 6 cases with negative follow-up [18F]FDG-PET/CT. ConclusionsThe sensitivity of [18F]FDG-PET/CT for evaluating CIED infections was high in local infections but much lower in systemic infections. However, accuracy increased when [18F]FDG-PET/CT was combined with TEE in endovascular lead bacteremic infection. Spleen and bone marrow hypermetabolism could differentiate bacteremic systemic infection from local infection. Although further prospective studies are needed, follow-up [18F]FDG-PET/CT could play a potential role in the management of chronic antibiotic suppression therapy when complete device removal is unachievable.

Reappraisal of [18F]FDG-PET/CT for diagnosis and management of cardiac implantable electronic device infections

Introduction and objectivesThe role of [18F]FDG-PET/CT in cardiac implantable electronic device (CIED) infections requires better evaluation, especially in the diagnosis of systemic infections. We aimed to determine the following: a) the diagnostic accuracy of [18F]FDG-PET/CT in each CIED topographical region, b) the added value of [18F]FDG-PET/CT over transesophageal echocardiography (TEE) in diagnosing systemic infections, c) spleen and bone marrow uptake in differentiating isolated local infections from systemic infections, and d) the potential application of [18F]FDG-PET/CT in follow-up. MethodsRetrospective single-center study including 54 cases and 54 controls from 2014 to 2021. The Primary endpoint was the diagnostic yield of [18F]FDG-PET/CT in each topographical CIED region. Secondary analyses described the performance of [18F]FDG-PET/CT compared with that of TEE in systemic infections, bone marrow and spleen uptake in systemic and isolated local infections, and the potential application of [18F]FDG-PET/CT in guiding cessation of chronic antibiotic suppression when completed device removal is not performed. ResultsWe analyzed 13 (24%) isolated local infections and 41 (76%) systemic infections. Overall, the specificity of [18F]FDG-PET/CT was 100% and sensitivity 85% (79% pocket, 57% subcutaneous lead, 22% endovascular lead, 10% intracardiac lead). When combined with TEE, [18F]FDG-PET/CT increased definite diagnosis o fsystemic infections from 34% to 56% (P=.04). Systemic infections with bacteremia showed higher spleen (P=.05) and bone marrow metabolism (P=.04) than local infections. Thirteen patients without complete device removal underwent a follow-up [18F]FDG-PET/CT, with no relapses after discontinuation of chronic antibiotic suppression in 6 cases with negative follow-up [18F]FDG-PET/CT. ConclusionsThe sensitivity of [18F]FDG-PET/CT for evaluating CIED infections was high in local infections but much lower in systemic infections. However, accuracy increased when [18F]FDG-PET/CT was combined with TEE in endovascular lead bacteremic infection. Spleen and bone marrow hypermetabolism could differentiate bacteremic systemic infection from local infection. Although further prospective studies are needed, follow-up [18F]FDG-PET/CT could play a potential role in the management of chronic antibiotic suppression therapy when complete device removal is unachievable.

Inappropriate Shock Due to Subcutaneous Lead Body Fracture: Extraction and Reimplantation

Subcutaneous Implantable Cardioverter Defibrillator (S-ICD) has been developed as an alternative to Transvenous (TV) devices to reduce lead-related complications leaving the heart and vasculature untouched. Recently, Boston Scientific published a safety notice in December 2020 regarding a subcutaneous electrode risk of fracture. In the following case report, we describe a case report experiencing this complication and present how we proceeded for lead extraction and reimplantation. The procedure remained safe and easy.

Peripheral Neuromodulation for the Management of Headache.

ContextNeuromodulation is an expanding field of study for headache treatment to reduce pain by targeting structures within the nervous system that are commonly involved in headache pathophysiology, such as the vagus nerve (VNS), occipital nerves, or sphenopalatine ganglion (SPG) for stimulation. Pharmaceutical medical therapies for abortive and prophylactic treatment, such as triptans, NSAIDs, beta-blockers, TCAs, and antiepileptics, are effective for some individuals, but the role that technology plays in investigating other therapeutic modalities is essential. Peripheral neuromodulation has gained popularity and FDA approval for use in treating certain headaches and migraine headache conditions, particularly in those who are refractory to treatment. Early trials found FDA approved neurostimulatory implant devices, including Cephaly and SpringTMS, improved patient-oriented outcomes with reductions in headaches per month (frequency) and severity.Evidence AcquisitionThis was a narrative review. The sources for this review are as follows: Searching on PubMed, Google Scholar, Medline, and ScienceDirect from 1990 - 2019 using keywords: Peripheral Neuromodulation, Headache, vagus nerve, occipital nerves, sphenopalatine ganglion.ResultsThe first noninvasive neurostimulator device approved for migraine treatment was the Cefaly device, an external trigeminal nerve stimulation device (e-TNS) that transcutaneously excites the supratrochlear and supraorbital branches of the ophthalmic nerve. The second noninvasive neurostimulation device receiving FDA approval was the single-pulse transcranial magnetic stimulator, SpringTMS, positioned at the occiput to treat migraine with aura. GammaCore is a handheld transcutaneous vagal nerve stimulator applied directly to the neck at home by the patient for treatment of cluster headache (CH) and migraine. Several other devices are in development for the treatment of headaches and target headache evolution at different levels and inputs. The Scion device is a caloric vestibular stimulator (CVS) which interfaces with the user through a set of small cones resting in the ear canal on either side and held in place by modified over-ear headphones. The pulsante SPG Microstimulator is a patient-controlled device implanted in the patient’s upper jaw via an hour-long oral procedure to target the sphenopalatine ganglion. The occipital nerve stimulator (ONS) is an invasive neuromodulation device for headache treatment that consists of an implanted pulse generator on the chest wall connected to a subcutaneous lead with 4 - 8 electrodes that is tunneled the occiput.ConclusionsThe aim of this review is to provide a comprehensive overview of the efficacy, preliminary outcomes, and limitations of neurostimulatory implants available for use in the US and those pending further development.

Long-term follow-up of paediatric patients with a subcutaneous implantable cardioverter-defibrillator

Abstract Background Inherited channelopathies, cardiomyopathies and structural heart diseases are known to increase the risk of sudden cardiac death in children and are occasionally treated with an implantable cardioverter-defibrillator (ICD). Due to their physical growth and higher level of activity, children experience more adverse events than adults, such as lead fractures, vascular problems and infections. The subcutaneous ICD (S-ICD) was introduced to avoid these lead-related complications and is expected to be especially beneficial for children who require ICD therapy. However, long-term follow-up data of this population are lacking. Purpose To evaluate long-term clinical outcomes of the S-ICD in the paediatric population. Methods Follow-up data were prospectively collected of all paediatric patients (age <18 years) who received their S-ICD in our tertiary centre between November 2009 and June 2019. Clinical outcomes that were assessed were appropriate or inappropriate shocks and complications that required surgical intervention. Results A total of 21 paediatric patients received an S-ICD, with a median age of 15 years (ranged 8–17) and a median body mass index of 18.8 kg/m2 (ranged 15.5–28.8, lowest weight 30kg). The indication for ICD implantation was mostly idiopathic ventricular fibrillation (38.1%) or genetic arrhythmic disease (28.6%). The subcutaneous lead was implanted in an S-shape to accommodate for growth in small patients, and straightening of the lead could be observed on successive chest X-rays (see figure). There was no need for lead or device revisions in this cohort. After a median follow-up of 4.3 years (IQR 2.7–6.5), five patients (23.8%) received an appropriate shock for ventricular arrhythmias and six patients (28.6%) received an inappropriate shock for supraventricular tachycardia (n=4) or double-counting (n=2). Complications that required device extraction occurred in three patients after 0.8±1.1 years and was the result of inappropriate shocks (n=1) and pocket infection (n=2). In two patients the S-ICD was extracted due to progression of their cardiac disease, of whom one needed biventricular pacing and one underwent heart transplantation. Conclusions The S-ICD appears efficacious in this heterogeneous paediatric population. Although higher than reported in adults, the long-term complication rate in paediatric S-ICD recipients is similar to the paediatric transvenous ICD population. Funding Acknowledgement Type of funding source: None

Patient comfort factors associated with the chronically implanted extravascular ICD (EV ICD): retrospective analysis of the first-in-human EV ICD trial

Abstract Background The extravascular ICD (EV ICD) utilizes a lead positioned within the substernal space and a device placed along the left midaxillary line to provide pacing and defibrillation therapies. Since substernal implantation positions the lead close to the heart, a lower energy for defibrillation is needed for the EV ICD relative to an ICD with subcutaneous lead placement. With lower energy requirements, the EV ICD system requires only a 33 cubic centimeter (cc) device, whereas the commercially available subcutaneous ICD utilizes a ∼60 cc device. The smaller form factor for EV ICD may require a smaller device incision site with smaller pocket, potentially resulting in less post-operative pain. Figure 1 illustrates the comparative sizes of the EV ICD and a subcutaneous device. While issues related to patient comfort have been published for the subcutaneous ICD, patient comfort factors associated with the EV ICD system have not been described previously. Purpose To characterize post-operative factors related to patient comfort associated with the EV ICD system. Methods The EV ICD first-in-human study was conducted at four sites in Australia and New Zealand. Data from chronically implanted patients were retrospectively analyzed for changes in analgesics in the post-operative window between implant and the two-week follow-up. Adverse events were collected between implant and six months related to patient-reported pain/discomfort, need for system revision based on discomfort, impaired wound healing and seroma formation. Results In total, 21 patients underwent implantation of the EV ICD system. Three patients had initiated pain control medications prior to enrollment, including one patient with fractured ribs. Overall, 12 patients (57.1%) received no anesthetic or analgesic medications besides acetaminophen beyond the day of implant. For the remainder of patients, post-operative medications included fentanyl (1), discontinued after two days; morphine (4), discontinued the day of implant (1) or after ≤2 days (3); or oxycodone (10), discontinued after ≤1 day (7) or ≤1 week (3). There were no intraprocedural complications. There were four non-serious, early-onset (≤1 week post-implant) adverse events identified, which included swelling (1), impaired healing at the xiphoid incision site (1), and two instances of inspiratory pain ≤1 day post-implant, all of which resolved without sequelae. There were no system revisions or removals associated with incision sites or pocket discomfort, and there were no reports of seroma formation through six months of follow-up. Conclusions Analysis of factors related to patient comfort indicate that the EV ICD system has generally been well tolerated across patients. A larger data set is needed to more fully characterize whether the smaller device size of the EV ICD relative to the subcutaneous defibrillator results in improved patient comfort. Sizes of extravascular devices Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Medtronic plc

Thinking about the future – data on adolescent patients with a subcutaneous ICD

Abstract Background Implantable cardioverter-defibrillator (ICD) systems are established for the prevention of sudden cardiac death. Long-term data on ICD function in children and adolescents is rare and has suggested higher rates of lead failure as well as oversensing, both leading to inappropriate therapy. The present study displays a long-term single-center follow-up of young patients having received an S-ICD. Methods and results The present study represents a single-center experience of patients younger than 25 years who received an S-ICD (n=49). Follow-up data included regular in-house follow-up as well as unscheduled hospitalisations in our center. Mean age at implantation was 19.2±4.1 years and 33 patients (67.4%) were male. In 21 patients (42.9%) electrical heart disease or idiopathic ventricular fibrillation represented the underlying condition of ICD implantation. 15 patients suffered from HCM (30.6%). Median follow-up duration was 2 years. No patient died during the observation period. Appropriate shocks occurred in 7 patients (14.3%). Inappropriate shock delivery was recorded in 6 patients (12.3%). T-wave oversensing was the main cause for inappropriate shock delivery (5/6 patients), in the other patient myopotentials were the reason for inappropriate therapy. In one patient, operative refixation of the subcutaneous lead was necessary due to hypermobility leading to oversensing. After modification of the sensing vector as well as activation of the SMART pass filter no further oversensing episodes occurred in any patient. Conclusion ICD therapy in children and adolescents is effective for prevention of sudden cardiac death. Every episode was terminated by the first therapy. The rate of appropriate shock as well as inappropriate therapies was quite high compared to typical ICD cohorts. In particular T-wave oversensing seems to be challenging for the S-ICD detection algorithms also in this cohort. Funding Acknowledgement Type of funding source: None

Partial Fracture of a Subcutaneous ICD Lead from Mechanical Trauma

Transvenous implantable cardioverter-defibrillators (TV-ICD) have electrode failure rates as high as 20% over a 10 year followup with 12% as a result of lead fractures. [1] The development of the Boston Scientific subcutaneous ICD (S-ICD) promoted the benefit of significantly reduced post-implant complication rates. [4] We present the first reported case of a S-ICD electrode failure secondary to partial fracture as a result of mechanical trauma.

A Randomized Controlled Trial of Subcutaneous Nerve Stimulation for Back Pain Due to Failed Back Surgery Syndrome: The SubQStim Study

ObjectivesTo compare the effectiveness of peripheral nerve stimulation utilizing a subcutaneous lead implant technique—subcutaneous nerve stimulation (SQS) plus optimized medical management (SQS + OMM arm) vs. optimized medical management alone (OMM arm) in patients with back pain due to failed back surgery syndrome.Patients and MethodsPatients were recruited from 21 centers, in Europe, Israel, and Australia. Eligible patients were randomized (1:1) to SQS + OMM or OMM arms. Those in the SQS arm were implanted with a neurostimulator and up to two subcutaneous percutaneous cylindrical leads in the area of pain. Patients were evaluated pre‐randomization and at one, three, six, and nine months post‐randomization. The primary endpoint was the proportion of subjects with a ≥50% reduction in back pain intensity (“responder”) from baseline to nine months. Secondary outcomes included proportion of responders with a ≥50% reduction in back pain intensity at six months and ≥30% reduction at nine months, and the mean change from baseline in back pain intensity at six and nine months between the two arms.ResultsDue to the slow rate of recruitment, the study was terminated early with 116 subjects randomized. A total of 33.9% (19/56, missing: n = 20 [36%]) of subjects in the SQS + OMM arm and 1.7% (1/60, missing: n = 24 [40%]) in the OMM arm were responders at Month 9 (p < 0.0001). Secondary objectives showed a significant difference in favor of SQS + OMM arm.ConclusionThe results indicate that the addition of SQS to OMM is more effective than OMM alone in relieving low back pain at up to nine months.

Nieskuteczne terapie kardiowertera-defibrylatora spowodowane wzrostem progu defibrylacji

We present the case report of a 28 year-old man with postmyocarditis cardiomyopathy and cardioverter-defibrillator (ICD) implantation in secondary prevention. He survived an episode of circulatory arrest due to ventricular fibrillation/ polymorphic ventricular tachycardia. All high energy therapy delivered by ICD was unsuccessful. The reason for the failure of the therapy was an increase in the defibrillation threshold. The implantation of an additional subcutaneous lead lowered the defibrillation threshold.

The Assessment of Subcutaneous Lead vs. Implanted Lead Electroencephalography and Electromyography

The Assessment of Subcutaneous Lead vs. Implanted Lead Electroencephalography and Electromyography

Four-Wire Interface ASIC for a Multi-Implant Link.

This paper describes an on-chip interface for recovering power and providing full-duplex communication over an AC-coupled 4-wire lead between active implantable devices. The target application requires two modules to be implanted in the brain (cortex) and upper chest; connected via a subcutaneous lead. The brain implant consists of multiple identical “optrodes” that facilitate a bidirectional neural interface (electrical recording and optical stimulation), and the chest implant contains the power source (battery) and processor module. The proposed interface is integrated within each optrode ASIC allowing full-duplex and fully-differential communication based on Manchester encoding. The system features a head-to-chest uplink data rate (up to 1.6 Mbps) that is higher than that of the chest-to-head downlink (100 kbps), which is superimposed on a power carrier. On-chip power management provides an unregulated 5-V dc supply with up to 2.5-mA output current for stimulation, and two regulated voltages (3.3 and 3 V) with 60-dB power supply rejection ratio for recording and logic circuits. The 4-wire ASIC has been implemented in a 0.35-n}{}mu text{m} CMOS technology, occup-ying a 1.5-mm2 silicon area, and consumes a quiescent current of n}{}91.2~mu text{A} . The system allows power transmission with measured efficiency of up to 66% from the chest to the brain implant. The downlink and uplink communication are successfully tested in a system with two optrodes and through a 4-wire implantable lead.

C1-C4 Dorsal Column Stimulation for Refractory Occipital Neuralgia Treatment. Case Report

Introduction Refractory occipital neuralgia is a difficult medical condition, especially when the patient has already been submitted to occipital nerve neurectomy and radiofrequency rhizotomy. There is no case report of spinal cord stimulation in the C1-C4 cervical segments for this condition. Objective To evaluate if C1-C4 dorsal spinal cord stimulation is effective in a patient with refractory occipital neuralgia who was already submitted to neurectomy and rhizotomy. Methods After obtaining the approval from the Ethics Committee of one of our institutions, a unilateral laminectomy was performed between C3 and C4, and a neurostimulator lead was conducted until the posterior portion of the C1 arc was in full view. Then we performed an intraoperative test to evaluate the correspondence between pain location and stimulation-induced paresthesias. We could not put the subcutaneous lead for such condition because of the scar tissue of the area and the previous neurectomy. Results After one year of follow up, we noticed a dramatic improvement in pain control, as well as medication withdrawal. The score of the visual analogue scale was 9 before the surgery, and it dropped to 2 after 1 year of follow-up. Conclusion Spinal cord stimulation between the C1 and C4 cervical segments can be an option for selected cases of refractory occipital neuralgia, including those patients who have already been submitted to neurectomy or rhizotomy.

Subcutaneous Implantable Cardioverter Defibrillator: Early Experience.

IntroductionThe implantable cardioverter defibrillator had been increasing the survival of patients at high risk for sudden cardiac death. The subcutaneous implantable cardioverter defibrillator was developed to mitigate the complications inherent to lead placement into cardiovascular system.ObjectiveTo report the initial experience of 18 consecutive cases of subcutaneous implantable cardioverter defibrillator implantation showing the indications, potential pitfalls and perioperative complications.MethodsBetween September 2016 and March 2017, 18 patients with indication for primary and secondary prevention of sudden cardiac death, with no concomitant indication for artificial cardiac pacing, were included.ResultsThe implantation of the subcutaneous implantable cardioverter defibrillator successfully performed in 18 patients. It was difficult to place the subcutaneous lead at the parasternal line in two patients. One patient returned a week after the procedure complaining about an increase in pain intensity at pulse generator pocket site, which was associated with edema, temperature rising and hyperemia. Two patients took antialgic medication for five days after surgery. A reintervention was necessary in one patient to replace the lead in order to correct inappropriate shocks caused by myopotential oversensing.ConclusionIn our initial experience, although the subcutaneous implantable cardioverter defibrillator implantation is a less-invasive, simple-accomplishment procedure, it resulted in a bloodier surgery perhaps requiring an operative care different from the conventional. Inappropriate shock by oversensing is a reality in this system, which should be overcame in order not to become a limiting issue for its indication.

Intraoperative Defibrillation Testing Should Not Be Generally Abandoned for All ICD Procedures-A Multicenter Study on 4,572 Consecutive Patients.

Background The ongoing technical advances in development of new implantable cardioverter defibrillator (ICD) systems led some investigators to question the routine use of intraoperative defibrillation testing (DT). Therefore, we evaluated retrospectively in a multicenter study effectiveness, safety, and usefulness of intraoperative DT on unbiased large patient population. Methods Data from 4,572 consecutive patients undergoing any ICD intervention were retrospectively analyzed. Besides efficacy of DT, risk factors for DT failure were identified in a multiple logistic regression analysis. Results Overall 5,483 shock data from 4,532 patients were available. Not tested for medical reasons were 13.5%. DT-associated complications were not noted. Primary DT effectiveness was 95.8%, whereas 4.2% were ineffective. Optimization (51.6% increase of DT energy, 10.1% subcutaneous lead array (SQ array), 2% generator exchange, 4.8% lead reposition, 9.3% lead exchange, and 22.2% change of shock parameters) led to successful DT in 152 patients (96.2%). Subanalyses and logistic regression identified implantation of generator in any other position than left subpectoral, age, body mass index and left ventricular ejection fraction as independent predictors for primary DT failure. Conclusion The number of patients, including those undergoing generator exchange, system upgrade, or system revision, with inappropriate intraoperative testshock is relatively high. The results of recent prospective clinical trials can be extrapolated only on first ICD implantations with high-energy generators. For patients undergoing subcutaneous ICD implantation, right-sided implantation, patients with channelopathies and hypertrophic cardiomyopathy, as well as for procedures on already implanted ICD systems, the intraoperative DT might still be recommended.

Anesthesia care for subcutaneous implantable cardioverter/defibrillator placement: a single-center experience

BackgroundThe recently approved subcutaneous implantable cardioverter/defibrillator (S-ICD) uses a single extrathoracic subcutaneous lead to treat life-threatening ventricular arrhythmias, such as ventricular tachycardia and ventricular fibrillation. This is different from conventional transvenous ICDs, which are typically implanted under sedation. Currently, there are no reports regarding the anesthetic management of patients undergoing S-ICD implantation. Study objectivesThis study describes the anesthetic management and outcomes in patients undergoing S-ICD implantation and defibrillation threshold (DFT) testing. MethodsThe study population consists of 73 patients who underwent S-ICD implantation. General anesthesia (n = 69, 95%) or conscious/deep sedation (n = 4, 5%) was used for device implantation. MeasurementsSystolic blood pressure (SBP) and heart rate were recorded periprocedurally for S-ICD implantation and DFTs. Major adverse events were SBP <90 mm Hg refractory to vasopressor agents, significant bradycardia (heart rate <45 beats per minute) requiring pharmacologic intervention and, “severe” pain at the lead tunneling site and the S-ICD generator insertion site based on patient perception. InterventionsOf the 73 patients, 39 had SBP <90 mm Hg (53%), and intermittent boluses of vasopressors and inotropes were administered with recovery of SBP. In 2 patients, SBP did not respond, and the patients required vasopressor infusion in the intensive care unit. Main resultsAlthough the S-ICD procedure involved extensive tunneling and a mean of 2.5 ± 1.7 DFTs per patient, refractory hypotension was a major adverse event in only 2 patients. The mean baseline SBP was 132.5 ± 22.0 mm Hg, and the mean minimum SBP during the procedure was 97.3 ± 9.2 mm Hg (P < .01). There was also a mean 13–beats per minute decrease in heart rate (P < .01), but no pharmacologic intervention was required. Eight patients developed “severe” pain at the lead tunneling and generator insertion sites and were adequately managed with intravenous morphine. ConclusionsAmong a heterogeneous population, anesthesiologists can safely manage patients undergoing S-ICD implantation and repeated DFTs without wide swings in SBP and with minimal intermittent pharmacologic support.

Subcutaneous defibrillator implantation in pediatric patients.

Objective:Although sudden cardiac death is rare in children, an intracardiac defibrillator system is indicated in children with various types of cardiomyopathy, primary electrical diseases, and after surgical repair of congenital heart defects. The use of transvenous defibrillator lead systems is limited in pediatric patients because of a small body size and/or limited vascular access. Subcutaneous array leads combined with an abdominally placed generator can enable implantation.Method:This is a retrospective study of 13 patients who underwent subcutaneous defibrillator implantation between September 2010 and March 2015. The subcutaneous system was preferred because patients were not amenable to transvenous lead placement.Results:The median patient age was 4.1 years, and the median patient weight was 12.1 kg. Diagnoses of patients were long-QT syndrome in 6, aborted cardiac arrest with left ventricular non-compaction in 3, hypertrophic cardiomyopathy with sustained ventricular tachycardia in 3, and arrythmogenic right ventricular cardiomyopathy in 1. Revision of the subcutaneous lead was required in 5 patients 2–26 months after the implantation. Appropriate shocks were observed in three patients. Inappropriate shock and lead fractures were observed in one patient during the follow-up period. The failure of therapy was observed in one patient. There were no perioperative complications and no early or late deaths.Conclusion:Subcutaneous defibrillator systems are safe and effective in pediatric patients when the transvenous method is risky and contraindicated. Because the high growth rate in this population leads to lead failures, a close follow-up of this population is essential. (Anatol J Cardiol 2016; 16: 630-4)

Clinical experience with subcutaneous implantable cardioverter-defibrillators.

The subcutaneous implantable cardioverter-defibrillator (S-ICD) is a novel technology for the treatment of sudden cardiac death. The system consists of a pulse generator implanted in the left axillary position and a single subcutaneous lead for detection and delivery of therapy. Initial clinical trials of S-ICDs demonstrated improved safety and efficacy when compared to transvenous ICD systems, leading to their widespread approval. The main advantage of the S-ICD is the avoidance of vascular access and the complications associated with transvenous leads. Owing to limitations of S-ICDs, patients who require pacing support or antitachycardia pacing are not candidates for the device; instead, this system is currently used most commonly in young patients with previous lead malfunction, limited vascular access, or low risk for subsequent bradycardia or antitachycardia pacing. Findings from device trials support S-ICDs as a viable alternative to transvenous ICDs in certain patients, and the current limitations associated with S-ICDs are likely to be addressed in future iterations of the device, extending its indications and target patient populations.

36 * Experiences from a non-medical, non-cardiac catheter laboratory based implantale loop recorder service

Implantable Loop Recorders (ILR's)are small subcutaneous single lead ECG monitoring devices that are placed in a left pectoral pocket under local analgesia. Traditionally, devices have been implanted by medical staffs (consultants/registrars) in the Cardiac Catheter Laboratory (Cath Lab). Each implant can take between 30–45 minutes depending on operator skill and patient anatomy. This paper details the experiences of 2 nurses and 1 physiologist who have developed a non-medical, non-cardiac catheter laboratory (Cath Lab) implantation service. The development of a non-medical, non-Cath Lab service has had several major patient and organisational benefits that include shorter waiting times, less cancellations, more patient centred clinical environment (many patients find the Cath Lab “scary”/“intimidating” and increased flexibility to implant ‘urgent’ Transient Loss of Consciousness (TLOC) devices. The latter has reduced length of stay within our Emergency Assessment Unit. Moreover, this service means that the department has been able to undertake more procedures in the Cath Lab. Based on 2013-14 data 32 x4 hour Cath Lab sessions were made available for alternative use – potentially an additional 64 angioplasties. When the team commenced the service all patients were cannulated and received Intravenous (IV) antibiotics prophylactically. A literature review did not support this practice and thus a prospective audit (n=100) was undertaken of device implantation without antimicrobial prophylactic cover. There was no statistical difference noted with approximately 1% of implants with or without antimicrobial cover suffering from an erosion or pocket infection (the audit was undertaken on an NNT basis and included patients who were thought to have manipulated their device/wound). This compares favourably with published data suggesting a 1-2% risk of erosion/infection. Devices are also implanted on anti-coagulated patients (NOAC/ warfarin) provided their INR is <3. Physiologists are non-mandatory registered healthcare professionals hence it is illegal for them to use a Patient Group Directions (PGD's) to administer local analgesia. As such we had to amend the Trusts ‘Medicines Management Policy’ to allow ‘named patient’ administration. The service has recently began implanting the Metronic LINQ (an injectable device opposed to a surgically implanted device) that has reduced the procedural time from 30-minutes to 10-minutes. Other advantages are a smaller wounds, less bruising, and less body image concerns in our female clients. There is also a reduced requirement for surgical skills training with his device thus making the transition out of the Cath Lab easier. To conclude; we believe that non-medical ILR implantation outside of the Cath Lab is clinically safe, cost efficacious and delivers significant pathway improvements for the patient.

Mort subite du sujet jeune : le défibrillateur sous-cutané S-ICD est-il une solution alternative aux défibrillateurs conventionnels ?

Implantable cardioverter defibrillator (ICD) is well-recognized therapy to prevent sudden cardiac death. Classic ICD need the use of permanent endocavitary leads, which may cause serious troubles (lead dislodgement, ventricular perforation, lead infections, etc.). The subcutaneous implantable cardioverter defibrillator (S-ICD) is a new device provided by only a subcutaneous lead. It has been developed for the last five years and it is becoming at present a real alternative to classic ICD. We report a clinical case of a 34 y.o. woman who presented a sudden cardiac death and who benefited the implantation of this new technology. This paper deals with the potential indications, usefulness benefits, and problems of the S-ICD.