Gautham Kalahasty

Management of the Patient With Implantable Cardioverter-Defibrillator Lead Failure

52-year-old man was brought to the emergency department because of multiple implantable cardioverter-defibrillator (ICD) shocks. His existing dual-chamber pacemaker was upgraded from a biventricular ICD 4 years ago. The ECG in the emergency department showed sinus tachycardia with left bundle-branch block at a rate of 135 bpm. In the emergency department, the patient received 5 additional shocks without a change in rhythm. A donut magnet was placed over the ICD. Interrogation revealed evidence of a lead fracture, and tachycardia therapies were disabled. The high-voltage lead was a Medtronic Sprint Fidelis ICD lead. Admission to the hospital was recommended for definitive correction of his problem. This case illustrates the most common presentation of an ICD lead failure and the resulting management challenges. Lead failure is typically thought of as an intrinsic design or construction defect leading to an adverse clinical event. However, any adverse clinical event mediated through malfunction of an ICD lead represents lead failure. An ICD lead failure can occur in any patient, even with leads that have a proven record of reliability. The overall incidence of ICD lead failure is difficult to assess because of its underreporting and the absence of strict reporting requirements. Random component failures in individual patients are especially difficult to quantify, but some studies suggest a failure rate of ≈0.58%/y among modern ICD leads.1 Leads that have undergone manufacturer advisory or Food and Drug Administration alerts have a much higher incidence of failure. Examples of ICD leads with high failure rates include the Guidant Endotak DSP (model 0125) and the Medtronic Transvene (model 6936). The 6936 lead had a 90% survival rate at 4 to 5 years and a nearly 60% survival rate at 8 to 9 years. Therefore, lead failure rates are not linear over time. The recent recall of the Medtronic …

An alternative technique of implanting a nontransvenous implantable cardioverter-defibrillator system in adults with no or limited venous access to the heart

BACKGROUND In some patients at high risk for sudden cardiac death, a transvenous implantable cardioverter-defibrillator (ICD) cannot be implanted owing to limited vascular access. These patients can benefit from a nontransvenous defibrillation system consisting of a rate-sensing lead attached to the epicardium and a subcutaneous (SQ) array. OBJECTIVE We examine the feasibility, safety, and clinical circumstances requiring implant of nontransvenous defibrillation system in adults. METHODS Eight patients received an ICD system composed of an SQ array and either a chronic endocardial rate/sense lead (n = 5) or a new epicardial rate/sense lead (n = 3) for primary (n = 2) or secondary (n = 6) prevention. The obstacles to transvenous ICD implantation included recurrent endovascular lead infections (n = 1), congenital heart disease (n = 4), and superior vena cava occlusion (n = 3). The array was tunneled posteriorly, and the epicardial rate-sensing leads were implanted by left lateral minithoractomy. Four patients also required left ventricular pacing. RESULTS Successful defibrillation was obtained in all patients at 29 ± 2.6 J. There were no major cardiovascular complications. Over a mean follow-up of 545 ± 204 days there was one appropriate and no inappropriate shocks. None of the patients required system revision. There were no significant changes in impedance, pacing threshold, or ventricular sensing observed with the epicardial leads and no change in high-voltage impedance. CONCLUSIONS The nontransvenous defibrillation system described is an effective technique in an adult population with acceptable pacing and defibrillation threshold.

Simpler is better: new lessons learned from the 12-lead electrocardiogram.

“It has long been an axiom of mine that the little things are infinitely the most important” — —Sherlock Holmes in “A Case of Identity” by Arthur Conan Doyle Cardiac resynchronization therapy (CRT) can have a profound therapeutic impact on appropriately selected patients. However, even when the current clinical guidelines for CRT1 are rigorously applied, the response rate is ≈70%. Nearly a third of patients who undergo implantation of a CRT device are clinical nonresponders and more may be “remodeling nonresponders.” An extensive body of literature reports on a wide variety of methods that can be better used to identify potential responders by measurement of mechanical dyssynchrony. Factors responsible for nonresponse include comorbid conditions, cardiac substrate, left ventricular (LV) lead location, and device programming. Comorbid conditions such as obstructive sleep apnea, right-sided heart failure, and type of intraventricular conduction delay should be considered at the preprocedural stage. Device programming may help minimize the number of nonresponders. Prediction of responders by invasive hemodynamic assessment is impractical for daily clinical practice. Cardiac magnetic resonance imaging is too expensive for routine use and is not an option for many patients who already have devices and need upgrades. The appeal of echocardiography for predicting responders by identifying mechanical dyssynchrony has been dampened by its limited reproducibility and poor predictive value.2 It is also impractical to perform echocardiography during implantations. The prolonged QRS duration (QRSd; electric dyssynchrony), as measured on a standard 12-lead ECG, remains the best method for identifying candidates for CRT. In an elegant and important study reported in this issue of Circulation , Sweeney and colleagues3 use the 12-lead ECG and show that, despite its apparent simplicity, analysis of the standard 12-lead ECG can yield both pitfalls and impressive rewards. Article see p 626 Current clinical guidelines specify a …

An Unusual Source of Electromagnetic Interference: A Device-Device Interaction

Introduction:  Implantable cardioverter‐defibrillators (ICDs) are susceptible to oversensing of extracardiac signals, also known as electromagnetic interference (EMI). We report a case of an unusual source of electrical interference of only the high voltage (HV) impedance measurement in the Teligen™ ICD (Boston Scientific, St. Paul, MN, USA) caused by electrical interference from an electrosurgical generator with an electrocautery patch located in close proximity to the ICD pulse generator.

Severe tricuspid regurgitation due to interactions with right ventricular permanent pacemaker or defibrillator leads

Although thought to be a rare event, permanent pacemakers and implantable cardioverter‐defibrillators with right ventricular intracardiac leads have the potential to induce tricuspid valve dysfunction. Adverse lead‐valve interactions can take place through a variety of mechanisms including damage at the time of implantation, leaflet pinning, or long‐term fibrosis encapsulating the leaflet tissue. Clinical manifestations can display a wide range of severity, as well as a highly variable time span between implantation and hemodynamic deterioration. This review aims to describe the potential pathophysiologic effects of intracardiac device leads on the tricuspid valve, with a focus on ideal diagnostic strategies and treatment options once lead‐induced valvular dysfunction is suspected.

ICD Lead Design and the Management of Patients with Lead Failure

The implantable cardioverter defibrillator (ICD) lead is critical to the function of the ICD system. The mortality reduction associated with ICDs implanted for primary prevention indications has been made possible by the development of effective and reliable transvenous ICD leads. Mortality rates for implantation of transvenous ICD lead systems are currently less than 0.5%. The reliability and functional characteristics of a lead are often not known until it has been in widespread use. An understanding of the mechanism of lead failure is essential for proper patient management. This article describes the design and construction of ICD leads, discusses lead failure, and reviews subsequent management of patients.

The active fixation coronary sinus lead: more peril than promise?

lead (Model 4195, Medtronic Inc.) is a unipolar pacing lead that has three lobes, which are deployed by advancing the push tubing around the lead. The lobes are designed to retract by pulling the tubing back. The controversy centers primarily around the feasibility and risks of extraction of this lead relative to those of passive fixation CS leads. CS lead placement can be challenging and branch anatomy is often the final arbiter of acute success. The region of latest intrinsic activation is not usually at the left ventricular apex where secondand third-order branches may be accessed to achieve stability. A basilar or midventricular position is associated with more optimal response to cardiac resynchronization therapy (CRT). Acute and late dislodgements often require lead repositioning, increasing the risk of infection. Techniques such as stabilization of the CS lead with stent implantation2 or retention of the stylet to prevent and treat dislocation3 are feasible and novel approaches, but are not appropriate solutions for most cases. The appeal of an active fixation lead to address these issues as well as to facilitate implant ease and acute success is understandable. However, with closer scrutiny of the potential advantages (e.g. lead stability and ability to select anatomy for left ventricular lead

Insights Into Defibrillator Shocks: What OPTION Teaches Us∗

The mortality benefits of implantable cardioverter-defibrillators (ICD) are well established and accepted [(1,2)][1]. It is equally well accepted that inappropriate therapy due to arrhythmia misclassification is associated with increased morbidity and mortality [(3)][2]. It is intuitive to think

Venoplasty: New use for an old technique

In this issue of Heart Rhythm, Worley et al report on their experience with the use of venoplasty to facilitate the implantation of pacemaker or defibrillator leads in patients with partial or total venous obstruction. The authors are to be commended; this report represents the only description of this technique in the electrophysiology literature in a large group of patients, applied by nonradiologists. The outcomes of venoplasty within the branches of the coronary sinus are not included in this report. The authors argue that this is a procedure for which most electrophysiologists should and are likely to seek proficiency. A literature review reveals remarkably few studies and virtually no large series about the use of venoplasty in the context of lead implantation. This study is a retrospective analysis of the experience of a single center with electrophysiologists specifically trained in venoplasty by one electrophysiologist (S.W.) with training in interventional cardiology. Over the course of 11 years, venoplasty was successfully performed on 371 of 373 patients for whom it was attempted. Safety and outcomes were reported on this group of patients, whereas procedurerelated details were reported on a cohort of 152 patients. Venoplasty was initially performed at the discretion of the implanting physician when stenotic lesions could not be opened with progressively larger dilators. Denominators such as total number of implants or total number of stenotic lesions for which venoplasty was not performed or needed (despite some stenosis) were not reported. Most importantly, no clinically significant complications occurred. Contrast extravasation or balloon rupture occurred not uncommonly, but were not associated with significant morbidity. The anticoagulation status of these patients was not reported. No damage to existing leads occurred. The balloons and catheters used for venoplasty of the subclavian vein are commonly available in most interventional vascular suites. There are several other interesting insights that can be drawn from this study. First, although subclavian/distal innominate site occlusions were most common (61%), 22% of occlusions occurred at peripheral and central (innominate/

The role of pacemakers in the management of patients with atrial fibrillation.

This article reviews the wide range of implantable device-based therapies (mainly pacemakers) that are being used in the management of atrial fibrillation (AF), atrial flutter, and atrial tachycardia. The role of pacemakers in the management of patients with AF and in the prevention of AF has been extensively studied. Based on well-designed prospective clinical trials, only a few of these strategies can be recommended for routine clinical use in related subpopulations.