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Drug-Coated Devices for Peripheral Arterial Disease Recent analyses provide reassurance about using paclitaxel-coated devices in patients with peripheral arterial disease, but the FDA believes that...

The issue of conflicts of interest held by physicians and other caregivers has drawn increased attention in recent years. In response, some commentators and institutions have proposed policies intended to protect patients' rights, including disclosure of relationships with for-profit companies. Conflicts of interest policies must balance the need for transparency and patient safety, but must also take into account the positive aspects of such relationships, including innovative product development. This article discusses various types of conflicts that can and do occur in healthcare delivery and potential policy options that may address these issues. The case history, device, physician, and patient described below do not represent actual people or events, but are intended to be emblematic of the challenges faced in the current medical marketplace.

A device interrogation for a 32-year-old woman with arrhythmogenic right ventricular cardiomyopathy and an implantable cardioverter-defibrillator capable of monitoring intrathoracic impedance demonstrated a dramatic increase in her OptiVol Fluid index levels in the absence of clinical heart failure. The timing of her intrathoracic impedance changes correlated with plasma volume changes during an uneventful pregnancy without cardiovascular complications. The strengths and limitations of intrathoracic impedance are described in the context of the physiology of pregnancy.

BACKGROUND Little is known about the magnetic field strength of portable headphones and their potential to cause magnetic interference with implanted pacemakers (PMs) and implantable cardioverter-defibrillators (ICDs). OBJECTIVE The purpose of this study was to evaluate the magnetic field strength of portable headphones and to determine if they can cause clinically relevant magnetic interference. METHODS PM or ICD function was assessed in 100 patients during exposure to eight different models of portable headphones to determine the incidence of clinically relevant magnetic interference. The magnetic field strength of the headphones also was measured in vitro. RESULTS Clinically relevant magnetic interference from portable headphones occurred in 30 (30%) of 100 patients and more commonly affected ICD than PM patients (21/55 [38.2%] vs 9/45 [20.0%]; P .048). All patients affected by magnetic interference experienced a magnet response, characterized by asynchronous pacing in PM patients and by inhibition of tachyarrhythmia detection in ICD patients. In all but one of the 30 cases of magnetic interference, removal of the headphones from the patient’s chest immediately restored normal device function. Headphones with a measured magnetic field strength 10 gauss at 2 cm were much more likely to cause magnetic interference than were those with lower magnetic field strength (30/100 [30%] patients vs 0/100 [0%] patients; P .0001). Magnetic interference was not observed when headphones were placed 3 cm from the skin surface. CONCLUSION Clinically significant magnetic interference can occur when portable headphones are placed in close proximity to implanted PMs and ICDs. Patients with such a device should be advised to keep portable headphones at least 3 cm from their device.

Protecting implantable medical devices against attack without compromising patient health requires balancing security and privacy goals with traditional goals such as safety and utility. Implantable medical devices monitor and treat physiological conditions within the body. These devices - including pacemakers, implantable cardiac defibrillators (ICDs), drug delivery systems, and neurostimulators - can help manage a broad range of ailments, such as cardiac arrhythmia, diabetes, and Parkinson's disease. IMDs' pervasiveness continues to swell, with upward of 25 million US citizens currently reliant on them for life-critical functions. Growth is spurred by geriatric care of the aging baby-boomer generation, and new therapies continually emerge for chronic conditions ranging from pediatric type 1 diabetes to anorgasmia and other sexual dysfunctions. Moreover, the latest IMDs support delivery of telemetry for remote monitoring over long-range, high-bandwidth wireless links, and emerging devices will communicate with other interoperating IMDs.

Coronary drug-eluting stents (DES) were first approved for use in the United States in 2003 (Cypher Coronary Sirolimus-Eluting Stent [SES], Cordis Corporation, Miami Lakes, Fla) and 2004 (Taxus Express Paclitaxel-Eluting Stent [PES], Boston Scientific Corporation, Natick, Mass) on the basis of randomized, blinded, controlled studies that demonstrated reduced target vessel failure (Cypher) and target vessel revascularization (TVR) (Taxus) at 9 months. Major adverse cardiac events were also significantly reduced for both DES when compared with bare metal stents (BMS). Presentations at national and international meetings in 2006 suggested that DES use may be associated with an increase in late (≥1 year after implantation) stent thrombosis (ST). Other studies suggested that there may be a significant increase in the combined end point of death and myocardial infarction (MI) compared with BMS. In response to these safety concerns, the US Food and Drug Administration (FDA) convened a meeting of the Circulatory System Medical Devices Advisory Panel. Advisory Panels make nonbinding recommendations to the FDA. Panelists recognized the need for a method to assess the true frequency of ST. However, one of the challenges in the assessment of DES ST risk is that the ST definition varies from study to study (Table 1). Differences in these on-protocol definitions of ST make it difficult to pool studies for analysis and to compare one stent to another (sirolimus-eluting versus paclitaxel-eluting). Furthermore, it is important to note that the on-protocol definition of ST for some of the clinical trials that support DES approval in the United States censored events that occurred after target lesion and/or target vessel revascularization (TLR/TVR). This means that an ST that occurs after TLR/TVR may not be counted as an ST by the on-protocol definition. Because BMS patients are more likely to experience restenosis and TLR/TVR than DES patients, more BMS patients …

Unanswered Questions — Drug-Eluting Stents and the Risk of Late Thrombosis By the end of 2004, drug-eluting stents were used in nearly 80% of percutaneous coronary interventions in the United States, and within 3 years, several million drug-eluting stents had been implanted worldwide. Dr. William Maisel writes that, unfortunately, much remains uncertain about the long-term safety of the devices.

Although implantable cardioverter defibrillators (ICDs) are increasingly used in advanced (class III/IV) heart failure, their benefits may be limited by death from pump failure and data are limited. The aim of this study was to assess the impact of QRS duration and disease etiology on survival and rehospitalization in advanced heart failure patients with ICDs.A retrospective study of 438 patients with heart failure (age 56 +/- 15, ejection fraction 29 +/- 15, 76% class III/IV) discharged between 1996 and 2000 was performed.An ICD was placed in 94 of the 438 patients for nonsustained (51.1%) or sustained (24.4%) ventricular arrhythmia, syncope (16.0%), or prophylaxis (8.5%). Patients with ICDs had a lower mean baseline ejection fraction (25% vs 30%, P = .007) but a trend toward fewer class IV symptoms (33% vs 44%, P = .164). Patients with ICDs had better survival (RR 0.48, P = .001) but increased rehospitalization (RR 1.41, P = .031). In both the ischemic and nonischemic subgroups, survival was superior in patients with ICDs (RR 0.38, P = .003 and RR 0.54, P = .042). Patients with QRS120 milliseconds had a trend toward better survival with an ICD (RR 0.42, P = .119) but increased rehospitalization (RR 2.13, P = .021). Patients with QRSor = 120 milliseconds had better survival with an ICD (RR 0.45, P = .001) without increased risk of rehospitalization (RR 1.22, P = .314).Patients with advanced heart failure selected to receive ICDs have better survival trends but shorter time to rehospitalization than patients without ICDs. Benefit appears greater for those with prolonged QRS duration.

Post-cardiac surgery atrial fibrillation (AF) places patients at risk for thromboembolism and stroke, while the surgery and cardiopulmonary bypass alter the multiple factors of coagulation and may increase the tendency to bleed. It is in the context of this complex clinical picture that the physician must make decisions regarding the risks and benefits of anticoagulation therapy to lower the risk for thromboembolism and stroke associated with postoperative AF. Physicians must also weigh the usually transient and self-limited duration of new-onset postoperative AF against the potential for postoperative bleeding if anticoagulation therapy is started. No randomized, controlled clinical trials are available that specifically address the problem of anticoagulation therapy for the postoperative AF. In that context, recommendations are based on the established therapy for nonsurgical situations modified by the potential risk of bleeding in the postoperative patient.

Introduction: Wavefront direction is a determinant of bipolar electrogram amplitude that could influence identification of low amplitude regions indicating infarction or scar. Methods: To assess the importance of activation sequence on electrogram amplitude 11 patients with prior infarction and ventricular tachycardia were studied. At 819 left ventricular sites bipolar electrograms were recorded during atrial pacing and ventricular pacing, followed by unipolar pacing with a stimulus of 10 mA at 2 ms. Sites with a pacing threshold > 10 mA were designated electrically unexcitable scar. Results: Areas of low voltage (≤1.5 mV) were present in all patients. Atrial paced and ventricular paced electrogram amplitudes were strongly correlated (r = 0.77; P < 0.0001). Changing the activation sequence (from atrial pacing to ventricular pacing) produced a > 50% change in electrogram amplitude at 28% of sites and a > 100% change at 10% of sites, but only 8% of sites had an electrogram amplitude classified as abnormal (≦1.5 mV) with one activation sequence and normal (> 1.5 mV) with the other activation sequence. Electrically unexcitable scar (6% of sites) was associated with lower electrogram amplitude but could not be reliably identified based on electrogram amplitude alone for either activation sequence. Conclusion: Voltage maps created with bipolar recordings using these methods should be relatively robust depictions of abnormal ventricular regions despite variable catheter orientation and activation sequences that might be produced by different rhythms

To the Editor: Cardiac resynchronization therapy (CRT) improves symptoms and decreases hospitalizations in selected patients with heart failure ([1,2][1]). With CRT, pacing from the left ventricle (LV) alters the ventricular activation (VA) sequence, changing the QRS morphology. In responders

Methods for determining if an ablation lesion has been created by RF current application are limited, but needed. This study sought to determine if a change in pacing threshold at the ablation site might be used to assess creation of an ablation lesion. Peak-to-peak amplitude of the bipolar electrogram (EGM) and the unipolar pacing threshold were determined before and after creation of RF lesions using irrigated tip (63 lesions in 11 patients) or conventional ablation catheters (33 lesions in 9 patients) in infarct scars for ablation of ventricular tachycardia. The threshold was measured during continuous pacing at a cycle length of 600 ms by a decrementing output current at a pulse width of 2 ms. The unipolar pacing threshold increased by 254 +/- 248% (from 5.7 +/- 3.5 to 15.1 +/- 6.7 mA, P

Heart failure (HF) affects almost 5 million patients in the United States and is a leading cause of morbidity and mortality. Atrial fibrillation (AF), like HF, affects millions of patients and markedly increases in prevalence with age. As the US population ages, the number of patients afflicted with HF and AF will continue to grow. HF with preserved ejection fraction is particularly common in the elderly population. The prevalence of AF in patients with HF increases from

Pacemaker and implantable cardioverter defibrillator (ICD) generator recalls and safety alerts (advisories) occur frequently, affect many patients, and are increasing in number and rate. It is unknown if advances in device technology have been accompanied by changing patterns of device advisory type. Weekly FDA Enforcement Reports from January 1991 to December 2000 were analyzed to identify all advisories involving pacemaker and ICD generators. This article represents additional analysis of previously cited advisories and does not contain additional recalls or safety alerts over those that have been previously reported. The 29 advisories (affecting 159,061 devices) from the early 1990s (1991-1995) were compared to the 23 advisories (affecting 364,084 devices) from the late 1990s (1996-2000). While the annual number of device advisories did not change significantly, ICD advisories became more frequent and a three-fold increase in the number of devices affected per advisory was observed. The number of devices affected by hardware advisories increased three-fold, due primarily to a 700-fold increase in electrical/circuitry abnormalities and a 20-fold increase in potential battery/capacitor malfunctions. Other types of hardware abnormalities (defects in the device header, hermetic seal, etc.) became less common. The number of devices recalled due to firmware (computer programming) abnormalities more than doubled. The remarkable technological advances in pacemaker and ICD therapy have been accompanied by changing patterns of device advisory type. Accurate, timely physician and patient notification systems, and routine pacemaker and ICD patient follow-up continue to be of paramount importance.

Background The thrombolysis in myocardial infarction (TIMI) frame count and TIMI perfusion grade are measures of epicardial and microvascular ventricular coronary artery blood flow, respectively. Similar angiographic methods for measuring atrial coronary artery blood flow have not been developed. Objective To utilize two new angiographic measures of atrial blood flow (ABF), the atrial frame count (AFC) and the atrial perfusion score (APS), to determine whether ABF differs between patients with and without coronary artery disease (CAD). Methods The AFC was defined as the number of frames for dye to reach standardized, distal atrial arterial landmarks during coronary angiography. The APS was utilized as a measure of microvascular atrial perfusion. AFCs were measured in 36 patients prior to isolated coronary artery bypass grafting (CABG), isolated valve surgery or in control patients (with neither CAD nor valvular disease). Results Sinus node artery and left atrial branch AFCs were higher (that is, ABF was reduced) in patients with CAD undergoing CABG than in those undergoing valve surgery (P < 0.05) or in control patients (P < 0.05). The APS was reduced in 63% of CAD patients but in only 5% of those without CAD (P < 0.001). The severity of CAD was a significant predictor of decreased ABF independent of the degree of proximal epicardial stenosis (P < 0.03). Conclusions ABF is measurable with the AFC and APS. A significant reduction in ABF is present in patients with CAD undergoing CABG compared to patients without CAD. This reduction appears to be related to the overall severity of CAD independent of the degree of proximal stenosis.

Introduction: Successful RF ablation of VT late after MI can involve multiple applications and long lines of RF lesions. The impact on left ventricular function is potentially important, but not well defined. Quantitative echocardiography was used to determine the effect of radiofrequency (RF) ablation on left ventricular function in patients with ventricular tachycardia (VT) after myocardial infarction (MI).

Background —Saline cooling of the electrode during radiofrequency (RF) ablation increases lesion size in animal models. If cooled RF also increases lesion size in human infarcts, it should facilitate the termination of ventricular tachycardia (VT). Methods and Results —In 66 patients with VT due to prior infarction, 366 ablation sites, which were classified by entrainment and isolated potentials followed by ablation during VT with either standard RF energy (247 sites) or cooled RF (119 sites), were retrospectively reviewed to compare the efficacy for terminating VT. RF energy was applied at 259 isthmus sites, 62 bystander sites, 28 inner loop sites, and 17 outer loop sites. Compared with standard RF, cooled RF terminated VT more frequently at isthmus sites where an isolated potential was present (89% versus 54%, P =0.003), isthmus sites without an isolated potential (36% versus 21%, P =0.04), and at inner loop sites (60% versus 22%, P =0.04). Termination rates were similarly low for cooled and standard RF at bystander sites (14% versus 9%, P =0.56) and outer loop sites (13% versus 11%, P =0.93). Conclusions —Greater efficacy of cooled RF for terminating VT is consistent with the production of a larger lesion in human infarctions, which should facilitate successful ablation.

From the Medical Device Safety Institute, Beth Israel Deaconess Medical Center, Boston, MA (Maisel); and the Department of EmergencyMedicine, Harbor-UCLA Medical Center, the Los Angeles Biomedical Research Institute, Torrance, CA, and the David Geffen School of Medicine atUCLA, Los Angeles, CA (Lewis).

Implantable cardioverter-defibrillators (ICDs) have revolutionized the treatment of patients at risk for sudden cardiac death. In the nearly 3 decades since the first human ICD implant,1 millions of devices have been implanted worldwide and innumerable lives have been saved. Successful resuscitation of a potentially lethal ventricular arrhythmia by an ICD system depends on successful arrhythmia detection and timely delivery of therapy. Both the ICD generator and the ICD lead are critical components of this system. The lead, in particular, is literally a lifeline whose purpose is to convey critical information about the heart’s rhythm to the ICD generator and, in turn, to deliver life-sustaining therapy when needed. Failure of an ICD lead may result in significant clinical events, including failure to pace, failure to defibrillate, inappropriate shocks, and even death. Article p 2727 ICD leads, like many medical technologies, have undergone a remarkable transformation. Epicardial leads, which necessitated a thoracotomy for lead placement, have given way to transvenous leads, which are easier to implant, less costly, and associated with decreased morbidity and mortality.2 Important advances in transvenous lead technology, such as the development of steroid elution, smaller diameter leads, novel insulations, and multipolar leads, have translated into meaningful clinical benefits for patients. Although modern ICD leads consist primarily of electrodes, conductors, insulation, and a fixation mechanism to attach the lead to the myocardium, lead design and performance vary from model to model. Indeed, monitoring of performance is critical not only to identify products with increased failure rates but also to provide physicians and patients with realistic expectations of device performance. In the current issue of Circulation , Eckstein et al add to our understanding of ICD lead performance.3 The investigators conducted a retrospective analysis of 1317 consecutive patients who received ICD systems (including 38 different ICD lead …

In October, after 38 months on the U.S. market and 268,000 implantations worldwide, the Medtronic Sprint Fidelis was voluntarily recalled because of its propensity to fracture. Dr. William Maisel writes that the controversy highlights the shortcomings of the regulatory system for medical devices and underscores the urgent need for legislation that will ensure adequate protection for patients.

Transvenous implantable cardioverter-defibrillator (ICD) lead development was an important advance in arrhythmia management. Their evolution has been critical to the wide acceptance of ICDs for the treatment of ventricular arrhythmias and the prevention of sudden cardiac death. Indeed, it is unlikely that the 20-fold increase in annual ICD implants observed during the past 15 years would have occurred without the advent of these leads.1 Compared with their epicardial predecessors, transvenous ICD leads are easier to implant, are less costly, and result in substantially decreased morbidity and mortality.2 Article p 2474 Modern ICD leads consist primarily of electrodes, conductors, and insulation, with a fixation mechanism and a connector to attach the lead to the myocardium and the ICD generator, respectively. ICD leads must withstand hundreds of millions of repetitive cardiac cycles, survive in the hostile environment of the human body, and allow high-voltage energy delivery for defibrillation at a moment’s notice. In total, the demands placed on ICD leads are unparalleled among implantable medical devices. Successful resuscitation of a potentially lethal ventricular arrhythmia by an ICD system depends on successful arrhythmia detection and timely delivery of therapy. Both the ICD generator and the lead are critical components of this system. Although ICD generator malfunctions have recently garnered much attention, failure of an ICD lead also can result in significant clinical events.1,3,4 Oversensing can cause inhibition of pacing or inappropriate shocks, and failure to capture, premature battery depletion, or failure to defibrillate also can occur.5 Unlike ICD generators, which can be explanted and returned for manufacturer analysis when malfunction is suspected, ICD leads cannot be easily removed, because of the extensive scarring and fibrosis that occurs around the lead in the vasculature and heart. Verification of suspected lead malfunction is uncommon because of the substantial risks of lead …

The purpose of this study was to determine propafenone's effectiveness in terminating and suppressing supraventricular arrhythmias using meta-analytic techniques. Published abstracts and manuscripts with these goals were selected and data abstracted on conversion and maintenance of sinus rhythm. Data were pooled using standard meta-analytic techniques and analyzed according to observation times, trial design (randomized versus nonrandomized), and route of drug administration. Propafenone successfully terminated 83.8% (95% confidence interval 78.1-89.7%) of supraventricular tachycardias. For supraventricular tachycardias, the proportion of patients remaining in sinus rhythm without recurrent arrhythmia was 64.6% (58.1-71.1%) at 1 year. The likelihood of converting a paroxysm of atrial fibrillation (AF) increased over time, with 76.1% (72.8-79.4%) of patients in sinus rhythm 24 hours after initiation of therapy. Patients receiving intravenous therapy were more likely to convert to sinus rhythm in the first 4 hours after drug administration. The treatment benefit of propafenone versus placebo in converting sinus rhythm was greatest in the first 8 hours after treatment (treatment benefit of 31.5% [24.5-38.5%] at 4 hours and 32.9% [24.3-41.5%] at 8 hours, p

New-onset atrial fibrillation (AF) occurs frequently after cardiac surgery. The utility of prophylactic atrial pacing to prevent AF following cardiac surgery has been investigated in a number of trials, but clinical guidelines for its use are lacking. Trials of prophylactic atrial pacing to prevent AF following cardiac surgery were identified by searching PubMed, the Cochrane database, selected medical journals, and references in selected articles. Nine randomized controlled trials were identified that addressed prophylactic atrial pacing after cardiac surgery to prevent AF. Prophylactic right atrial pacing and prophylactic left atrial pacing have yielded inconclusive results. Prophylactic biatrial pacing (BAP) reduced the incidence of AF significantly in four studies, reduced it nonsignificantly in one study, and had no effect in one study. On the basis of the literature that was reviewed and graded for quality, it was concluded that prophylactic atrial pacing to prevent AF after cardiac surgery is safe. We recommend that BAP be considered, particularly in patients who are at high risk for the development of postoperative AF.

The US Food and Drug Administration (FDA) Circulatory System Devices Panel met to discuss the type of data required to effectively evaluate the performance of cardiopulmonary resuscitation (CPR) and hypothermia devices for cardiac arrest patients. Advisory panels make nonbinding recommendations to the FDA. The era of modern CPR began in the 1960s, when mouth-to-mouth ventilation combined with forceful chest compressions were first used together to attempt to resuscitate victims of cardiopulmonary arrest. Unfortunately, despite the promise of a variety of pharmacological, electrical, and mechanical therapies during and after administration of CPR, meaningful improvements in cardiac arrest survival have been difficult to achieve. Earlier generations of CPR devices are designed to assist the rescuer in the performance of CPR. These devices, for example, may compress the chest at a fixed rate and compression depth, or they may provide audible or visual indicators to assist the rescuer with compliance with published CPR guidelines. In general, regulatory guidelines do not require clinical data for these devices as long as they are similar in design and technology to previously marketed “predicate” devices. More than 30 devices for external compression and/or timing assistance during CPR have been cleared for marketing by the FDA. Devices intended to enhance a clinical aspect of CPR, in contrast to devices designed simply to assist the rescuer in the performance of CPR, require clinical data to support approval of the device. These devices, such as those providing interposed abdominal compression, circumferential chest compression, or active compression-decompression, have focused primarily on enhancing hemodynamics during CPR. Despite great interest in improving CPR survival rates, no device intended to enhance hemodynamics during CPR has been approved by the FDA for marketing in the United States. The Circulatory System Devices Panel was asked to discuss and make recommendations about the type of clinical data …

The concept of specialized cardiovascular care is not new. Nearly 4 decades ago, Killip and Kimball1 reported the results of their study of the treatment of 250 patients with myocardial infarction in a coronary care unit. With continuous ECG monitoring at a centralized nursing station, defibrillators at each bedside, and nurses authorized to deliver precordial shocks if physicians did not respond fast enough, the mortality rate was reduced from 26% to 7%.1 A classification scheme for heart failure severity was developed, and the authors ultimately concluded that the coronary care unit was critical to the timely recognition and treatment of potentially lethal arrhythmias. See p 3636 During the ensuing decades, expert coronary care has been extended to the emergency department, where specialized units or critical pathways are used to provide expedited, high-quality care for a variety of cardiovascular symptoms and diagnoses, including chest pain, unstable angina, myocardial infarction, heart failure, and stroke. The goals of this specialized care are to provide more efficient, higher-quality health care for less money by reducing unnecessary hospital admissions, hastening diagnosis, increasing diagnostic yield, and decreasing adverse outcomes. For a specialized plan of care to be realistic, the diagnosis should be relatively common, require immediate evaluation, and have significant associated morbidity, mortality, or both if left untreated or misdiagnosed. As an example, critical pathways for the management of acute chest pain have succeeded at improving care for patients at low or intermediate risk for myocardial ischemia. A strategy of early diagnostic testing including the measurement of serum cardiac enzymes and the performance of exercise testing in selected patients within 6 hours of presentation can lead to clinically important reductions in admission rates and number of hospital days without increasing adverse outcomes.2,3 Like chest pain, syncope is a common symptom among patients presenting …

Syncope is the sudden and transient loss of consciousness accompanied by a loss of postural tone. The term derives from the Greek word synkoptein, meaning “to cut short,” and purportedly, Hippocrates himself provided the first description of a patient with the disorder.1 Syncope accounts for 3 percent of emergency room visits and 1 to 6 percent of all hospital admissions, and it costs $750 million per year to diagnose and treat.2,3 The causes of syncope range from the benign to the lethal. Rational patient care is facilitated by an understanding of the pathophysiology and epidemiology of syncope, as well . . .

Background— Sprint Fidelis (Fidelis) implantable cardioverter-defibrillator leads are prone to fractures that have caused adverse events, primarily inappropriate shocks, and a few reported deaths. More than 100 000 patients have Fidelis leads. No independent multicenter long-term performance information exists for this lead, and single-center studies suggest that certain patients are at increased risk for Fidelis failure. Our aim was to assess the longevity of Fidelis leads and to evaluate clinical variables and adverse events associated with Fidelis failure. The results were compared with like data for Quattro Secure (Quattro) implantable cardioverter-defibrillator leads implanted at our centers. Methods and Results— This 3-center study included adults ≥18 years of age who received Fidelis or Quattro leads for the prevention of sudden cardiac death. From November 2001 to January 2009,1023 Fidelis and 1668 Quattro leads were implanted and followed up. The failure rate for Fidelis leads was 2.81%/y compared with 0.43%/y for Quattro leads ( P P P =0.041). Conclusions— Compared with Quattro leads, the survival of Fidelis leads continues to decline, and Fidelis failure is notably higher in younger patients, women, individuals with hypertrophic cardiomyopathy, and patients with arrhythmogenic right ventricular dysplasia or channelopathies. These findings have significant implications for the management of patients who have Fidelis leads, and they demonstrate the importance of weighing clinical variables in assessments of implantable cardioverter-defibrillator lead performance.

Little is known about patients' views surrounding the ethical and legal aspects of managing pacemakers (PMs) and implantable cardioverter-defibrillators (ICDs) near the end of life. Patients with hypertrophic cardiomyopathy (HC) are at heightened risk of sudden cardiac death and are common recipients of such devices. Patients with HC recruited from the membership of the Hypertrophic Cardiomyopathy Association were surveyed about their clinical histories, advance care planning, legal knowledge, and ethical beliefs relating to the withdrawal of PM and ICD therapy. The mean age of the 546 patients was 49.1 years, 47% were women, and 57% had ICDs. Only 46% of the respondents had completed an advance directive, only 51% had a healthcare proxy, and cardiac implantable electrical devices (CIEDs) were commonly not addressed in either (92% and 58%, respectively). Many patients characterized deactivating PMs or ICDs as euthanasia or physician-assisted suicide (29% for PMs and 17% for ICDs), and >50% expressed uncertainty regarding the legality of device deactivation. Patients viewed deactivation of ICDs and PMs as morally different from other life-sustaining therapies such as mechanical ventilation and dialysis, and these views varied substantially according to the CIED type (p

Despite the high prevalence of pacemakers and implantable cardioverter-defibrillators, little is known about physicians' views surrounding the ethical and legal aspects of managing these devices at the end of life.The purpose of this study was to identify physicians' experiences and views surrounding the ethical and legal aspects of managing cardiac devices at the end of life.Survey questions were administered to internal medicine physicians and subspecialists at a tertiary care center. Physicians were surveyed about their clinical experience, legal knowledge, and ethical beliefs relating to the withdrawal of PM and ICD therapy in comparison to other life-sustaining therapies.Responses were obtained from 185 physicians. Compared to withdrawal of PMs and ICDs, physicians more often reported having participated in the withdrawal or removal of mechanical ventilation (86.1% vs 33.9%, P.0001), dialysis (60.6% vs 33.9%, P.001), and feeding tubes (73.8% vs 33.9%, P.0001). Physicians were consistently less comfortable discussing cessation of PMs and ICDs compared to other life-sustaining therapies (P.005). Only 65% of physicians correctly identified the legal status of euthanasia in the United States, and 20% accurately reported the legal status of physician-assisted suicide in the United States. Compared to deactivation of an ICD, physicians more often characterized deactivation of a PM in a pacemaker-dependent patient as physician-assisted suicide (19% vs 10%, P = .027) or euthanasia (9% vs 1%, P.001).In this single-center study, internists were less comfortable discussing cessation of PM and ICD therapy compared to other life-sustaining therapies and lacked experience with this practice. Education regarding the legal and ethical parameters of device deactivation is needed.

A device interrogation for a 32-year-old woman with arrhythmogenic right ventricular cardiomyopathy and an implantable cardioverter-defibrillator capable of monitoring intrathoracic impedance demonstrated a dramatic increase in her OptiVol Fluid index levels in the absence of clinical heart failure. The timing of her intrathoracic impedance changes correlated with plasma volume changes during an uneventful pregnancy without cardiovascular complications. The strengths and limitations of intrathoracic impedance are described in the context of the physiology of pregnancy.

Implantable medical devices (IMDs) improve patients' quality of life and help sustain their lives. In this study, we explore patient views and values regarding their devices to inform the design of computer security for wireless IMDs. We interviewed 13 individuals with implanted cardiac devices. Key questions concerned the evaluation of 8 mockups of IMD security systems. Our results suggest that some systems that are technically viable are nonetheless undesirable to patients. Patients called out a number of values that affected their attitudes towards the systems, including perceived security, safety, freedom from unwanted cultural and historical associations, and self-image. In our analysis, we extend the Value Sensitive Design value dams and flows technique in order to suggest multiple, complementary systems; in our discussion, we highlight some of the usability, regulatory, and economic complexities that arise from offering multiple options. We conclude by offering design guidelines for future security systems for IMDs.

Dr. William Maisel and Tadayoshi Kohno write that the complex and sophisticated features of medical devices have created a susceptibility to security breaches that could compromise the performance of such devices and the safety and privacy of patients.

ated with subpectoral implantable cardioverter-defibrillator (ICD) implantation may weaken the bond between the header and the titanium case in Cognis cardiac resynchronization therapy defibrillators (CRT-Ds) and Teligen ICDs. Boston Scientific specifically noted that the product advisory did not affect subcutaneous implants. This report contains the details of a patient with a Boston Scientific Cognis CRT-D with a subcutaneous implant who experienced a weakened bond between the device header and case resulting in noise and inappropriate therapies. Case summary

A number of large, well-conducted. placebo-controlled trials have shown that therapy with angiotensinconverting enzyme (ACE) inhibitors improves survival in patients with left ventricular dysfunction and prior myocardial infarction (MI) or symptomatic heart failure (l-3). Part of this benefit seems to be because of a reduction in the incidence of sudden death (4). Although a variety of at-rhythmic and nonarrhythmic mechanisms contribute to sudden death in heart-failure populations, the majority of these deaths are caused by ventricular tachycardia or ventricular fibrillation (VTNF). VTNF can be caused by acute myocardial ischemia, or it may occur in the absence of acute ischemia as a result of electrophysiological abnormalities that develop after MI. Various mechanisms exist by which ACE inhibitors could reduce VTNF. They could prevent arrhythmias caused by recurrent MI and ischemia. The Survival and Left Ventricular Enlargement (SAVE) Trial (l), the Studies of Left Ventricular Dysfunction (SOLVD) (5), and the Heart Outcomes Prevention Evaluation (HOPE) (6) showed a reduction in the risk of MI among patients taking ACE inhibitors. This reduction may be owing to stabilization of atherosclerotic lesions, effects on vascular smooth muscle, inactivation of platelets, and/or increased nitric oxide production (7). In addition, ACE inhibitor-treated patients experience a reduction in sympathetic nervous system activation, which would be expected to reduce the incidence of ventricular arrhythmias. An intriguing but as yet unproven hypothesis relates to the potential for ACE inhibitors to reduce the risk of

The quality of clinical data submitted by manufacturers to support Food and Drug Administration cardiovascular device premarket approval (PMA) applications varies widely and formal quality assessment has not been previously performed. This study evaluated all original cardiovascular device PMAs with Food and Drug Administration decisions between January 1, 2000, and December 31, 2007, to assess the quality of clinical investigations submitted by manufacturers. Effectiveness and safety end points were judged high quality if they were clearly defined and associated with a specific time point for analysis. Subject accounting was high quality if 90% or greater of the original cohort was accounted for at study conclusion. In total, 88 cardiovascular device PMAs (77.3% permanent implants), 132 clinical studies, 37,328 study subjects (age 61.0 +/- 14.5 years, 33.9% women, 86.3% white), and 29,408 device recipients were analyzed. All PMAs contained clinical data. Primary effectiveness end points, primary safety end points, and subject accounting were deemed high quality in 81.8%, 60.2%, and 77.3% of pivotal studies, respectively. Key cardiovascular comorbidities (coronary artery disease 51.1%, diabetes 36.6%, hypertension 35.2%, heart failure 37.5%, tobacco use 31.8%) and race (14.8%) were infrequently reported, and studies rarely included patients younger than 18 years of age (10.2% of studies). Poorly defined safety and effectiveness end points, poor patient accounting, and incomplete collection of important patient comorbidities make device safety and effectiveness assessments more challenging. Women, pediatric, and nonwhite populations are underrepresented in premarket cardiovascular clinical trials. Manufacturers, regulators, and the clinical community should collaborate to address these study shortcomings to ensure that patients are treated with reliable, safe, and clinically useful medical devices.

In August, the FDA granted expedited-review status to the Watchman Left Atrial Appendage Closure Technology, recognizing that the device might represent a breakthrough. Dr. William Maisel discusses the interpretation of the data, the device's proper clinical role, and several important considerations.

Chapter 1: Pathophysiology of Heart Failure Nancy K. Sweitzer, M.D Chapter 2: Medical Therapy for Heart Failure Akshay Desai, MD, MPH Chapter 3: Device Trials in Chronic Heart Failure: Implications of Trial Design Warren K. Laskey, MD Chapter 4: The FDA Perspective on Heart Failure Devices Matthew G. Hillebrenner, M.S.E. Chapter 5: Hemodynamic Monitoring in Heart Failure Anju Nohria, MD Chapter 6: Implantable Cardioverter-Defibrillators Rachel Lampert, MD Chapter 7: Cardiac Resynchronization Therapy Peter J. Zimetbaum, M.D. Chapter 8: Pacing and Defibrillation for Atrial Arrhythmias Joshua M. Cooper, MD Chapter 9: Atrial Fibrillation Ablation John V. Wylie, MD Chapter 10: Percutaneous Treatment of Coronary Artery Disease Roger J. Laham, MD Chapter 11: Percutaneous Management of Peripheral Vascular Disease Lawrence A. Garcia, MD Chapter 12: Percutaneous Management of Valvular Heart Disease Joseph P. Carrozza Jr., MD Chapter 13: Ventricular Assist Devices and Total Artificial Hearts James C. Fang, MD Chapter 14: Device Therapy For Left Ventricular Dysfunction Clyde W. Yancy, MD

The prognostic importance of exercise-induced ventricular arrhythmia (EIVA) may be confounded by the presence of lower-risk idiopathic right ventricular outflow tract arrhythmias with left bundle-branch block (LBBB) morphology.To determine whether right bundle-branch block (RBBB)-morphology EIVA was associated with increased mortality.Retrospective cohort.Academic medical center.585 unique patients with EIVA and 2340 patients without EIVA, matched by age, sex, and risk factor, who were referred for exercise testing in an academic medical center.Deaths and ischemia and infarction found on perfusion scan.During a mean follow-up of 24 months (SD, 13), 31 deaths occurred in the EIVA group compared with 43 deaths in the group without EIVA (5.3% vs. 1.8%; P0.001). Worse survival in patients with RBBB-morphology or multiple-morphology EIVA (6.9%) than in patients without EIVA caused this difference. Patients with LBBB-morphology EIVAs had a mortality rate (2.5%) similar to that of patients without EIVA (P = 0.93, log-rank test). Among patients without known atherosclerotic coronary artery disease, any RBBB-morphology EIVA was associated with death (hazard ratio, 2.73 [95% CI, 1.78 to 4.13]; P0.001), but LBBB-morphology EIVA was not (hazard ratio, 0.82 [CI, 0.18 to 2.04]; P = 0.72).Not all LBBB-morphology EIVA can be dismissed, and not all RBBB-morphology EIVA is high risk. Further evaluation of patients for structural heart disease was clinically driven, not protocol-driven.Right bundle-branch block- or multiple-morphology EIVA is associated with increased mortality. Inclusion of patients with isolated LBBB-morphology EIVA, which often is idiopathic, may contribute to differences in the prognostic importance of EIVA in previous studies.