Inappropriate Shock Due to T‐Wave Oversensing by a Subcutaneous ICD after Alcohol Septal Ablation for Hypertrophic Cardiomyopathy

A 53‐year‐old female patient with hypertrophic obstructive cardiomyopathy (HOCM) was admitted for alcohol septal ablation (ASA). A subcutaneous internal cardioverter defibrillator (S‐ICD) was implanted for primary prevention. After ASA, the patient developed a right bundle branch block, and the S‐ICD delivered a total of five inappropriate shocks due to T‐wave oversensing (TWOS). TWOS is a relatively frequent cause of inappropriate shocks in S‐ICD patients. After invasive treatment for HOCM, there is a risk of developing intraventricular conduction delay and subsequent changes in QRS and T‐wave morphology. This should be taken into consideration when ICD indication is evaluated in HOCM patients.     

Ancillary tools in pacemaker and defibrillator lead extraction using a novel lead removal system

A previous report described our preliminary experience with a highly successful pacing lead removal system (VasoExtor). Extending this experience, we found it necessary to use additional tools to enhance the success of percutaneous lead extraction with this system. In the present series, we used the standard locking stylets (S and K), and recently, one newer type of stylet (Magic) over the last 3 years in 34 patients to extract 48 pacemaker leads in 31 patients and 3 defibrillator (ICD) leads in 3 patients. Lead extraction was carried out in 23 men and 11 women (aged 64 +/- 17 years) because of pacemaker infection (n = 21), pacemaker (n = 8) or ICD (n = 3) lead malfunction, or prior to ICD implant (n = 2). Leads were in place for 3.5 +/- 3.7 years. Infections, involving pocket and lead(s), were due to S. epidermidis (n = 13), S. aureus (n = 6), S. aureus plus E. coli (n = 1), for fungi (n = 1). Of the 48 pacing leads, 31 were ventricular, 15 atrial, and 2 were VDD leads. The ICD leads were two double-coil leads (CPI) and one single-coil lead (Telectronics). Using the S (n = 12), K (n = 8), or Magic (n = 3) stylets, all pacing leads in 23 patients and the ICD leads in 2 patients were successfully removed from a subclavian approach using the locking stylets. However, in nine (26.5%) patients ancillary tools were required. In four patients, lead fragments were captured with use of a noose catheter, a pigtail catheter, and a bioptome from a right femoral approach. In two patients, locking could not be effected and a noose catheter from the right femoral vein was used, aided by a pigtail and an Amplatz catheter and a bioptome to remove three leads. In a patient with an ICD lead, a combined subclavian (stylet S) and right femoral approach (noose catheter) was required. In a patient with a dysfunctional ventricular lead 12 years old, a motor drive unit was used to facilitate the exchange of locking stylets, but extraction failed. In another patient, a fragment of a dysfunctional ventricular lead remained intravascularly despite resorting to a femoral approach. Finally, lead removal was completely (32/34, 94%) or partially (1/34, 3%) successful in 33 (97%) of 34 patients for 50 (98%) of 51 leads without complications. In conclusion, to enhance the success of pacing or ICD lead extraction with use of the VascoExtor locking stylets, an array of ancillary tools were required in more than one fourth of patients.     

Nailed It: Conservative Management of Penetrating Injury and Potential Infection of a Cardiovascular Implantable Electronic Device

A 47‐year‐old man with a history of ischemic cardiomyopathy and chronic systolic heart failure presented after he inadvertently shot himself in the left upper chest with a pneumatic nail gun, penetrating his implantable cardioverter defibrillator (ICD) generator. The device was noninterrogable, consistent with device failure. A new ICD was attached to the existing right ventricular lead, which showed no evidence of traumatic damage and normal lead parameters on interrogation. Aggressive debridement and antibiotic irrigation of the ICD pocket was performed and an antibacterial envelope was used. Bacterial culture of the ICD pocket grew Bacillus species. The patient completed a course of at least 14 days of oral clindamycin. At follow‐up, there were no signs or symptoms of systemic or local wound infection.     

Implantation of a Fully Subcutaneous ICD in Children

The subcutaneous implantable cardioverter defibrillator (S‐ICD) from Cameron Health (San Clemente, CA, USA) does not require a lead to be placed on or in the heart. Such a device, being subcutaneous, has potential benefits in children who require ICDs where problems largely relate to transvenous or epicardial leads and inappropriate shocks. The S‐ICD was approved for use in Europe in June 2009 and recently a study commenced to acquire data in 330 patients in order to submit to the FDA. We shall describe the implantation of the S‐ICD in two children aged 10 and 12 years at our institution. (PACE 2012; 35:e20–e23)     

Pitfalls in electrogram interpretation: Subcutaneous cardioverter defibrillator malfunction in Brugada syndrome

A patient with Brugada syndrome implanted with subcutaneous implantable cardioverter defibrillator (S‐ICD) had oversensing episodes treated with S‐ICD shocks. Comparable artifacts were not evocable with S‐ICD pocket manipulation. The fluoroscopy excluded S‐ICD macroscopic damage. The device extraction revealed undamaged pulse generator and connector, but the lead was inappropriately tunneled under the sixth rib. Then the S‐ICD malfunction was due to lead microscopic damage caused by the lead rubbing the rib surface.     

The azygos defibrillator lead for elevated defibrillation thresholds: implant technique, lead stability, and patient series

Background: Conventional insertion of implantable cardioverter‐defibrillator (ICD) includes an evaluation of the defibrillation threshold (DFT). Implanting an ancillary defibrillation lead in the azygos vein has been introduced as a therapeutic option in patients with “high” DFT. This study reports the efficacy and stability of azygos defibrillation coils implanted for elevated DFTs. Methods: This is a retrospective review of seven consecutive patients with right and left pectoral, single‐ and dual‐chamber, and biventricular ICDs and elevated DFTs, in whom an azygos defibrillation coil was introduced. Results: Addition of an azygos defibrillator lead achieved a satisfactory safety margin during single energy defibrillation efficacy testing in four out of seven patients, with success at maximum device output in two patients. No satisfactory safety margin was achieved in the remaining patient, despite the further addition of a subcutaneous defibrillation coil. No change in lead position was observed over a mean radiographic follow‐up of 8 months. No complications were noted during a mean follow‐up of 14 months, including no deaths, and no ICD shocks. Conclusion: Implanting a defibrillation coil into the azygos vein is feasible and safe. In a majority of patients with failed defibrillation efficacy testing, adding an azygos coil achieves success on repeat testing. Therefore, this technique is one option for lowering the defibrillation threshold in patients who fail DFT testing of their ICD.     

Combination of a subcutaneous ICD in a patient with a baroreceptor activation device: Feasibility,safety, and precautions: A Case Report

We present a case of a patient with a baroreflex activation therapy (BAT) receiving a subcutaneous implantable cardioverter defibrillator (S‐ICD). We anticipated two possible hazardous interactions between the two devices. Stimulation by the BAT could be adjudicated as noise and result in underdetection of ventricular arrhythmias or it might be misinterpreted as ventricular arrhythmias and lead to inappropriate shocks. Postop ensing occurred, the upper limit of pulse width of the BAT was limited because of noise detection by the S‐ICD, but the upper limit of amplitude was limited by patient's discomfort. In this patient, the combination of a BAT and an S‐ICD was safe.     

The innominate vein as alternative venous access for complicated implantable cardioverter defibrillator revisions

BACKGROUND: Venous complications of implantable cardioverter defibrillator (ICD) systems may cause significant problems when the need for system revision or upgrades arises. Such revisions require venous access close to the site of the previous ICD implantation. The internal and external jugular vein have disadvantages due to a long subcutaneous course crossing the clavicle and problems with lead extraction if infection occurs. METHODS: In seven patients with ICD revisions due to lead dysfunction (n = 4) and upgrade to a biventricular device (n = 2) and status after system removal due to infection with new device implantation (n = 1) conventional venous access could not be obtained. Intraoperative contrast venography demonstrated an occluded left subclavian and/or left innominate vein in all patients. In all patients, we gained venous access through puncture of the right innominate vein and tunneled the new lead subcutaneously to the ICD pocket on the left. RESULTS: No intraoperative complications were observed. All patients are followed in our ICD clinic. Mean follow-up is 16 +/- 4 months now. So far, no clinical or lead complications with this access have been observed. CONCLUSIONS: We have demonstrated that ICD lead placement through puncture of the right innominate vein is feasible. We propose the innominate vein as an alternative route for establishing venous access in patients requiring ICD revisions or upgrades who suffer from venous obstruction. ICD implanting physicians should acquaint themselves with the technique of right innominate vein puncture to use this vein as a bail-out strategy in patients with complicated venous access.     

Human experience with transvenous biventricular defibrillation using an electrode in a left ventricular vein

This study investigated the safety and feasibility of transvenous biventricular defibrillation in ICD patients. Some patients may have high DFTs due to weak shock field intensity on the LV. Animal studies showed a LV shocking electrode dramatically lowered DFTs. This approach might benefit heart failure patients already receiving a LV lead or conventional ICD patients with high DFTs. A modified guidewire was used as a temporary left venous access defibrillation electrode (LVA lead). In 24 patients receiving an ICD, the LVA lead was advanced through a guide catheter in the coronary sinus (CS) and into a randomized LV vein (anterior or posterior) using a venogram for guidance. Paired DFT testing compared a standard right ventricular defibrillation system to a biventricular defibrillation system. There were no complications or adverse events. As randomized, LVA lead insertion success was 87% and 71% for anterior and posterior veins, respectively, and 100% after crossover. Total insertion process time included venogram time (32.5 +/- 26.9 minutes, range 5-115, mode 15 minutes) and LVA lead insertion time (15 +/- 14 minutes, range 1-51, mode 7 minutes). An apical LVA lead position was achieved in 11 (45%) of 24 patients and 7 (64 %) of these 11 displayed a DFT reduction; however, mean DFTs were not statistically different. Transvenous biventricular defibrillation is feasible and was safe under the conditions tested. Additional clinical studies are justified to determine if optimized LV lead designs, lead placement, and shock configurations can yield the same large DFT reductions as observed in animals.     

Evaluation oF FactORs ImpacTing CLinical Outcome and Cost EffectiveneSS of the S-ICD: design and rationale of the EFFORTLESS S-ICD Registry

Background: Leads in and on the heart of the transvenous implantable cardioverter defibrillator (ICD) form the Achilles’ heel of this system due to potential for peri‐ and postimplant complications. The S‐ICD is a newer generation of the ICD that does not require leads on the heart or in the vasculature. We present the rationale and study design of the Evaluation oF FactORs ImpacTing CLinical Outcome and Cost EffectiveneSS of the S‐ICD (EFFORTLESS S‐ICD) Registry which was designed to evaluate the long‐term performance of the S‐ICD including patient quality of life and long‐term resource utilization. Methods: The Registry is an observational, nonrandomized, standard of care evaluation to be conducted at approximately 50 investigational centers in Europe and New Zealand where the S‐ICD is approved for use and distribution. Clinical Registry endpoints include perioperative (30 days postimplant) complication‐free rate, 360‐day complication‐free rate, and percentage of inappropriate shocks for atrial fibrillation and supraventricular ventricular tachyarrhythmia. Other endpoints include patient‐reported outcomes (e.g., quality of life) and hospital personnel implant and follow‐up experience with the S‐ICD system. Conclusions: Results from EFFORTLESS will build on and expand the initial published experience with the S‐ICD, which demonstrated that the device successfully and consistently detects and treats episodes of sustained ventricular tachyarrhythmias. The Registry will also evaluate the patients’ perspective of how it is to live with an S‐ICD as compared to a contemporary transvenous system and track the experience of implanting physicians and personnel performing patient follow‐up with a completely subcutaneous system. (PACE 2012; 1–6)     

Anesthesia for subcutaneous implantable cardioverter‐defibrillator implantation: Perspectives from the clinical experience of a U.S. panel of physicians

1 Background and objective

Worldwide adoption of the subcutaneous implantable cardioverter‐defibrillator (S‐ICD) for preventing sudden cardiac death continues to increase, as longer‐term evidence demonstrating the safety and efficacy of the S‐ICD expands. As a relatively new technology, comprehensive anesthesia guidance for the management of patients undergoing S‐ICD placement is lacking. This article presents advantages and disadvantages of different periprocedural sedation and anesthesia options for S‐ICD implants including general anesthesia, monitored anesthesia care, regional anesthesia, and nonanesthesia personnel administered sedation and analgesia.

2 Methods

Guidance, for approaches to anesthesia care during S‐ICD implantation, is presented based upon literature review and consensus of a panel of high‐volume S‐ICD implanters, a regional anesthesiologist, and a cardiothoracic anesthesiologist with significant S‐ICD experience. The panel developed suggested actions for perioperative sedation, anesthesia, surgical practices, and a decision algorithm for S‐ICD implantation.

3 Conclusions

While S‐ICD implantation currently requires higher sedation than transvenous ICD systems, the panel consensus is that general anesthesia is not required or is obligatory for the majority of patients for the experienced S‐ICD implanter. The focus of the implanting physician and the anesthesia services should be to maximize patient comfort and take into consideration patient‐specific comorbidities, with a low threshold to consult the anesthesiology team.     

S‐ICD is effective in preventing sudden death in arrhythmogenic cardiomyopathy athletes during exercise

Here, we describe the cases of two elite athletes, with a diagnosis of arrhythmogenic cardiomyopathy (ACM), in which a subcutaneous implantable cardioverter defibrillator (S‐ICD) has been implanted. Both patients experienced a ventricular tachycardia during exercise and received effective S‐ICD shocks that interrupted arrhythmias. This report reveals for the first time that the S‐ICD is effective in reverting arrhythmias in ACM patients, even during exercise. Moreover, these cases may confirm that competition/physical activity is associated with ICD shocks.     

Effects of a Thin-Sized Lead Body of a Transvenous Single Coil Defibrillation Lead on ICD Implantation

SCHUCHERT, A., et al. : Effects of a Thin‐Sized Lead Body of a Transvenous Single Coil Defibrillation Lead on ICD Implantation. In the interest of patients receiving implantable cardioverter defibrillators (ICDs), the clinical benefits of newer and thinner transvenous defibrillation leads have to be determined. The aims of this study were to evaluate the ICD procedure duration and the frequency of lead dislocation at the 3‐month follow‐up of a new defibrillation lead with a thin‐sized lead body and its conventionalsized predecessor. The thin‐sized single coil defibrillation lead (Kainox RV, Biotronik; lead body 6.7 Fr) was implanted in 61 patients and the conventional‐sized defibrillation lead (SPS, Biotronik; lead body 7.8 Fr) in 60 patients. Both leads were connected to a left‐sided, prepectorally implanted Phylax ICD (Biotronik) with active housing. The lead implantation time and total procedure duration were determined. Lead implantation time was defined as the time from lead insertion to the end of the pacing measurements. The total procedure duration spanned skin incision to closure. The incidence of lead repositioning during the lead implantation time and during ventricular fibrillation conversion testing was also assessed. The frequency of lead dislocations was recorded at the 3‐month follow‐up. Mean lead implantation time and total procedure duration of the thin‐sized lead (23 ± 22 minutes 76 ± 37 minutes ) were not statistically different from the time needed for the conventional‐sized lead (22 ± 20 minutes 81 ± 34 minutes ). The number of lead repositionings during the lead implantation time was similar (thin‐sized lead: 1.4 ± 2.4 ; conventional‐sized lead: 1.1 ± 1.9 ). An additional lead repositioning was not necessary during ventricular fibrillation conversion testing in 93.4% of the patients with thin‐sized and in 94.4% with conventional‐sized leads (not significant). At the 3‐month follow‐up, there were four (6.6%) lead dislocations in the thin‐sized and four (6.7%) in the conventional‐sized lead group. In conclusion, the downsized lead body of the new defibrillation lead influenced neither ICD procedure duration nor the incidence of lead dislocation during follow‐up.     

Subcutaneous Implantable Cardioverter Defibrillator Lead Failure due to Twiddler Syndrome

We present a case of Twiddler syndrome in a patient with a subcutaneous implantable cardioverter defibrillator (S‐ICD). The patient presented herself to the outpatient clinic with pain in the left chest. Chest x‐ray confirmed Twiddler syndrome and ICD read‐out revealed lead failure resulting in absent heart rhythm sensing in one vector. The lead and pulse generator were extracted and a new S‐ICD system was reimplanted submuscular underneath the serratus anterior muscle to prevent reoccurrence. Lead investigation revealed an insulation defect caused by excessive mechanical stress.     

Noise Detection During Bradycardia Pacing with a Hybrid Nonthoracotomy Implantable Cardioverter Defibrillator System: Incidence and Clinical Significance

The purpose of this study was to prospectively evaluate the incidence of noise detection during bradycardia pacing by an FDA approved hybrid nonthoracotomy ICD system. An illustrative case report which prompted this investigation is provided. Backup bradycardia pacing by tiered therapy cardioverter defibrillators has been useful in preventing postshock bradycardia and occasionally for chronic rate support in bradycardic patients. Unexplained "noise" detected by real-time telemetry has been previously described during bradycardia pacing by a device utilizing automatic gain control for sensing. Eighteen patients were prospectively evaluated for noise detection during ventricular pacing by the ICD. Real-time telemetry was analyzed with each patient: (1) supine, (2) supine with deep inspiration/expiration, (3) supine during Valsalva, and (4) during a change in position from supine to sitting. Analysis of pacing threshold and lead impedance was made in each patient. Eleven of 18 patients bad noise detected on real-time telemetry during bradycardia pacing. In 10 patients this was noted during deep inspiration/expiration, in 2 during Valsalva maneuver, and in 5 with position change. There was no evidence in any patient of lead malfunction nor any difference in pacing threshold or lead impedance between patients with noise detected versus those without it. Noise detection by an approved hybrid ICD system is common and may be due to the automatic gain control which maximizes sensitivity during bradycardia pacing. This may lead to clinically significant events, with both suppression of bradycardia pacing and triggering of tachycardia therapy in the absence of ventricular tachyarrhythmias in pacemaker-dependent patients.     

Nontraditional Implantable Cardioverter Defibrillator Placement in Adult Patients with Limited Venous Access: A Case Series

Background: Conventional transvenous approaches for implantable cardioverter defibrillator (ICD) lead placement are not possible in some patients with limited venous access or severe tricuspid valve dysfunction. Methods: We retrospectively identified six patients who underwent ICD placement or revision requiring nontraditional alternative surgical lead placement at our institution between November 2006 and August 2008. The baseline and operative patient characteristic data were accumulated and reviewed. Results: All the patients (mean age 71 ± 3.4 years) underwent nontraditional surgical placement of epicardial ICD leads and traditional placement of ventricular epicardial bipolar pacing/sensing leads. Five patients had the distal lead tip fixed to the anterior epicardium of the right ventricular outflow tract, which was then looped under and around the ventricles, forming a “sling,” and tunneled to a left subclavicular pocket. One patient had a single unipolar subcutaneous array lead fashioned into a “loop” and placed under the inferior aspect of the ventricles. The average procedure time was 311 ± 115 minutes with a mean defibrillatory threshold (DFT) of ≤ 22 + 3 J. Post‐procedure hospitalization was 9.3 ± 4.4 days and no device‐related complications were encountered. Mean device follow‐up of 451 + 330 days showed normal function and two appropriate successful ICD discharges. Conclusion: Nontraditional alternative surgical methods for the placement of ICD systems in adult patients with limited venous access or TV dysfunction can achieve results similar to those of conventionally placed endovascular leads with limited complications and comparable DFTs in short‐term follow‐up. (PACE 2010; 33:217–225)     

Right-sided prepectoral implantation of an implantable cardioverter defibrillator in a right pneumonectomized patient

Right-sided prepectoral implantation of an ICD is performed in unusual circumstances only, like in patients with abnormal venous drainage and preexisting left-sided devices. This case report describes a 42-year-old man who had undergone previous right pneumonectomy and who required ICD implantation for symptomatic inducible nonsuppressable hemodynamically unstable ventricular tachycardia. To avoid the small but real possibility of inadvertent iatrogenic left-sided pneumothorax in a patient with previous right pneumonectomy, a dual chamber ICD with an active can was implanted in the right prepectoral position.     

Far-Field R Wave Oversensing in a Dual Chamber Arrhythmia Management Device: Predisposing Factors and Practical Implications

WERETKA, S., et al. : Far-Field R Wave Oversensing in a Dual Chamber Arrhythmia Management Device: Predisposing Factors and Practical Implications. Initial experience with the Medtronic Jewel 7250, the ICD designed to detect and treat ventricular and supraventricular tachyarrhythmias, is very promising. Its effectiveness, however, depends on sensing performance, which has not yet been systematically examined. The aim of the study was to determine the incidence of, predisposing factors for, and practical implications of far-field R wave oversensing (FFRWOS) in this dual chamber ICD. During a total follow-up of 797 months in 48 patients who had the Jewel 7250, follow-up strip charts, 12-channel Holter recordings and, in particular cases, Holter recordings with intracardiac markers were analyzed for the presence of FFRWOS. FFRWOS was documented in ten (21.3%) patients. Compared to other lead locations, the right atrial appendage lead position was most frequently associated with FFRWOS (  7/27 vs 3/21, P < 0.05  ). Patients with FFRWOS had significantly more treated and nontreated atrial episodes, many of which were judged to have been detected inappropriately. In one case, inappropriate atrial antitachycardia pacing due to R wave oversensing triggered sustained ventricular tachycardia, terminated eventually with a high energy shock. In dual chamber ICDs, FFRWOS may represent a frequent phenomenon possibly leading to serious consequences. For atrial leads, a lateral atrial wall position seems to be preferable. In most cases, FFRWOS can be eliminated by optimization of atrial sensing parameters. Given the possibility of ventricular proarrhythmia with atrial pacing therapy, the capability of ventricular backup defibrillation in respective devices is at least reassuring.     

Survival of Transvenous ICD Leads in Young Patients

Background : In adults, transvenous implantable cardioverter defibrillator (ICD) lead failure rates are significant, and their occurrence increases with time from implant. There are limited data in children. The goal of this study was to assess lead survival in young patients undergoing ICD implantation at a single center. Methods : Records of patients under 21 years old with transvenous ICD leads implanted at our center from June 1997 to August 2007 were retrospectively reviewed. Age, weight, height, diagnosis, lead and generator model, venous access technique, generator position, pacing thresholds, lead impedance, and R wave size were recorded. “Lead failure” was defined as any lead problem requiring surgical intervention to restore proper function to the ICD system. Results : Seventy‐one transvenous leads were included (70 patients). Average age at implant was 14.8 years (range 5.7–19.5). All the devices were implanted by a single operator (HMS). Venous access was obtained via cephalic cutdown in 66/71. Mean follow‐up time was 2.8 years (range 0.2–7.8 years, median 2.3 years). There were no infections requiring explantation. There were four lead failures. Three were lead fractures, occurring 12, 13, and 19 months after implant. The fourth lead failed when an arrhythmia was not appropriately detected, and a second dedicated rate‐sensing lead was thus implanted. Univariate analysis did not identify any variable to be a significant predictor of lead failure. Kaplan–Meier survival analysis demonstrated 5‐year lead survival at 89.6%. Conclusions : ICD lead survival in children, when performed by an experienced operator, is similar to that found in adults. (PACE 2010; 33:186–191)