Facilitating Shared Decision Making Among Black Patients at Risk for Sudden Cardiac Arrest : A Randomized Clinical Trial.

BACKGROUND: Racial disparities in implantable cardioverter-defibrillator (ICD) implantation are multifactorial and are partly explained by higher refusal rates. OBJECTIVE: To assess the effectiveness of a video decision support tool for Black patients eligible for an ICD. DESIGN: Multicenter, randomized clinical trial conducted between September 2016 and April 2020. (ClinicalTrials.gov: NCT02819973). SETTING: Fourteen academic and community-based electrophysiology clinics in the United States. PARTICIPANTS: Black adults with heart failure who were eligible for a primary prevention ICD. INTERVENTION: An encounter-based video decision support tool or usual care. MEASUREMENTS: The primary outcome was the decision regarding ICD implantation. Additional outcomes included patient knowledge, decisional conflict, ICD implantation within 90 days, the effect of racial concordance on outcomes, and the time patients spent with clinicians. RESULTS: Of the 330 randomly assigned patients, 311 contributed data for the primary outcome. Among those randomly assigned to the video group, assent to ICD implantation was 58.6% compared with 59.4% in the usual care group (difference, -0.8 percentage point [95% CI, -13.2 to 11.1 percentage points]). Compared with usual care, participants in the video group had a higher mean knowledge score (difference, 0.7 [CI, 0.2 to 1.1]) and a similar decisional conflict score (difference, -2.6 [CI, -5.7 to 0.4]). The ICD implantation rate within 90 days was 65.7%, with no differences by intervention. Participants randomly assigned to the video group spent less time with their clinician than those in the usual care group (mean, 22.1 vs. 27.0 minutes; difference, -4.9 minutes [CI, -9.4 to -0.3 minutes]). Racial concordance between video and study participants did not affect study outcomes. LIMITATION: The Centers for Medicare & Medicaid Services implemented a requirement for shared decision making for ICD implantation during the study. CONCLUSION: A video-based decision support tool increased patient knowledge but did not increase assent to ICD implantation. PRIMARY FUNDING SOURCE: Patient-Centered Outcomes Research Institute.

Clinical Performance of Magnetic Resonance Imaging Conditional and Nonconditional Cardiac Implantable Electronic Devices.

OBJECTIVES: This study compared risks associated with magnetic resonance imaging (MRI) in patients with non-MRI conditional and MRI conditional pacing and defibrillator systems with particular attention to clinically actionable outcomes. BACKGROUND: While recipients of new MRI conditional pacemaker and defibrillator systems may undergo MRI scanning with very low risk, safety and regulatory concerns persist regarding such scanning in recipients of non-MRI conditional systems. METHODS: Patients with any cardiac device who were referred for MRI were prospectively enrolled at a single center and underwent scanning at 1.5 Tesla. Pre- and postscan lead characteristic changes, system integrity, and symptoms were analyzed. A comparison was made between non-MRI conditional and MRI conditional devices. RESULTS: 105 patients were evaluated allowing for comparison of 97 scans with non-MRI conditional devices and 16 scans with MRI conditional devices. The cohort included those with pacemaker dependency, defibrillator, and cardiac resynchronization devices. Small, nonsignificant changes were observed in lead characteristics following scanning, and there was no significant difference when comparing non-MRI and MRI conditional devices. Lead parameter changes did not require lead revision or programming changes. No device reset, failures, or premature scan termination was observed. CONCLUSIONS: 1.5 T MRI scanning in patients with MRI conditional and non-MRI conditional cardiac devices was performed with similar, low clinical risk.

Patient Report and Review of Rapidly Growing Mycobacterial Infection after Cardiac Device Implantation.

Mycobacterial infections resulting from cardiac implantable electronic devices are rare, but as more devices are implanted, these organisms are increasingly emerging as causes of early-onset infections. We report a patient with an implantable cardioverter-defibrillator pocket and associated bloodstream infection caused by an organism of the Mycobacterium fortuitum group, and we review the literature regarding mycobacterial infections resulting from cardiac device implantations. Thirty-two such infections have been previously described; most (70%) were caused by rapidly growing species, of which M. fortuitum group species were predominant.When managing such infections, clinicians should consider the potential need for extended incubation of routine cultures or dedicated mycobacterial cultures for accurate diagnosis; combination antimicrobial drug therapy, even for isolates that appear to be macrolide susceptible, because of the potential for inducible resistance to this drug class; and the arrhythmogenicity of the antimicrobial drugs traditionally recommended for infections caused by these organisms.

Sudden and Fatal Malfunction of a Durata Defibrillator Lead due to External Insulation Failure.

Defibrillator lead malfunction can be a disastrous complication, leading to loss of protection from sudden cardiac death in a high-risk patient population. Recognition of lead-specific risk for failure can assist in development of focused screening or surveillance, as in the case of the Riata lead (St. Jude Medical, St. Paul, MN, USA) or the Sprint Fidelis lead (Medtronic Inc., Minneapolis, MN, USA). A case of defibrillation failure secondary to a Durata lead insulation failure is presented. A brief review of the literature and current St. Jude Medical implantable cardiac defibrillator lead design is presented. Identification of arcing is identified as a potential sign of catastrophic insulation failure.

Clinical comparison of ICD detection algorithms that include rapid-VT zones.

INTRODUCTION: The safe use of antitachycardia pacing (ATP) to terminate rapid ventricular tachycardias (VTs) (cycle length 240-320 ms) is predicated on the ability of implantable cardioverter defibrillators (ICDs) to distinguish rapid VT from ventricular fibrillation (VF). We set out to compare the time to device charging following the induction of VF of various ICD multizone detection algorithms for rapid VT/VF discrimination. METHODS AND RESULTS: Data on the time to device charging following the induction of VF at the time to device implantation were collected on 62 consecutive patients in a nonrandomized prospective cohort fashion. Multizone programming for the Boston Scientific, Medtronic, and St. Jude Medical devices was based on prior clinically validated data. Sixty-two subjects were studied (Boston Scientific = 16, Medtronic = 27, St. Jude Medical = 19) and 124 tests for VF detection were performed (Boston Scientific = 32, Medtronic = 54, St. Jude Medical = 38). Mean time to charging was significantly prolonged in the Boston Scientific group as was the percentage of tests where charge initiation occurred >5 seconds from VF-induction: 4.24, 3.99, and 3.00 seconds and 19%, 4%, and 0% for the Boston Scientific, Medtronic, and St. Jude Medical groups, respectively, P < 0.05. ATP was the first therapy administered in 9.4% of tests in the Boston Scientific group. CONCLUSION: The Boston Scientific multizone VT/VF discrimination algorithm results in a prolonged time to VF detection, and consequently, prolonged time to appropriate initiation of device charging. Further studies are needed to determine whether prolonged detection times lead to clinically significant events.

Prospective evaluation of health status, quality of life and clinical outcomes following implantable defibrillator generator exchange.

BACKGROUND: Little is known about health status and quality of life (QoL) after implantable cardioverter-defibrillator (ICD) generator exchange (GE). METHODS: We prospectively followed patients undergoing first-time ICD GE. Serial assessments of health status were performed by administering the 36-Item Short Form Survey (SF-36). RESULTS: Mean age was 67.5 ± 14.3 years, left ventricle ejection fraction (LVEF) was 36.5% ± 15.0% and over 40% of the cohort had improved LVEF to > 35% at the time of GE. SF-36 scores were significantly worse in physical/general health domains compared to domains of emotional/social well-being ( P < 0.001 for each comparison). Physical health scores were significantly worse among those with medical comorbidities including diabetes, chronic obstructive pulmonary disease and atrial fibrillation. Mean follow-up was 1.6 ± 0.5 years after GE. Overall SF-36 scores remained stable across all domains during follow-up. Survival at 3 years post-GE was estimated at 80%. Five patients died during follow-up and most deaths were adjudicated as non-arrhythmic in origin. Four patients experienced appropriate ICD shocks after GE, three of whom had LVEF which remains impaired LVEF (i.e., < 35%) at the time of GE. CONCLUSION: Patients undergoing ICD GE have significantly worse physical health compared to emotional/social well-being, which is associated with the presence of medical comorbidities. In terms of clinical outcomes, the incidence of appropriate shocks after GE among those with improvement in LVEF is very low, and most deaths post-procedure appear to be non-arrhythmic in origin. These data represent an attempt to more fully characterize the spectrum of QoL and clinical outcomes after GE.

Chronotropic incompetence, beta-blockers, and functional capacity in advanced congestive heart failure: time to pace?

BACKGROUND: Chronotropic incompetence (CI) is often seen in subjects with chronic congestive heart failure (CHF). The prevalence of CI, its mechanisms and association with beta-blocker use as well as exercise capacity have not been clearly defined. METHODS AND RESULTS: Cardiopulmonary exercise tolerance testing data for 278 consecutive patients with systolic CHF was analyzed. CI, defined as the inability to reach 80% of maximally predicted heart rate was present in 128 of 278 subjects (46%). The prevalence of CI was highest in those with most impaired exercise capacity (72, 48, and 24% for subjects with a VO(2) of <14.0, 14.0-20.0, and >20.0 ml/kg/min respectively; p=0.001). While subjects with CI had lower peak exercise heart rate (114 vs. 152 bpm), and lower peak VO(2) (15.4 vs. 19.9 ml/kg/min), they were equally likely to be on chronic beta-blocker therapy (74% vs. 71%; p=0.51). Heart rate and norepinephrine (NE) levels were measured during exercise in a separate cohort of 24 subjects with CHF. There was no difference in beta-blocker dose between subjects with and without CI, however, exercise induced NE release and Chronotropic Responsiveness Index, a measure of post-synaptic beta-receptor sensitivity to NE, were lower in subjects with CI (1687+/-911 vs. 2593+/-1451 pg/ml p=0.08; CRI 12.7+/-5.7 vs. 22.1+/-4.7, p=0.002). CONCLUSIONS: CI occurs in >70% of subjects with advanced systolic CHF irrespective of beta-blocker use and is associated with a trend toward impaired NE release, post-synaptic beta-receptor desensitization and reduced exercise capacity.

Differential effects of carvedilol and metoprolol succinate on plasma norepinephrine release and peak exercise heart rate in subjects with chronic heart failure.

Dosing equivalency of carvedilol and metoprolol remains a debate. Degree of beta 1-blockade is best assessed by blunting of the exercise-induced heart rate. Accordingly, the authors have investigated dosing equivalency by examining baseline and peak exercise heart rates and norepinephrine levels in subjects with chronic heart failure treated with carvedilol or metoprolol. Thirty-seven subjects treated with carvedilol (32.9 +/- 3.5 mg; n = 23) or metoprolol succinate (XL) (96.4 +/- 15.9 mg; n = 14) referred for cardiopulmonary exercise testing were studied prospectively. Carvedilol versus metoprolol XL subjects did not differ with respect to baseline heart rate (73 +/- 2 vs 70 +/- 3 bpm), or baseline plasma norepinephrine levels (597.5 +/- 78.3 vs 602.1 +/- 69.6 pg/mL), P = NS. However, despite similar peak exercise norepinephrine levels (2735.8 +/- 320.1 vs 2403.1 +/- 371.6 pg/mL), heart rate at peak exercise was higher in subjects receiving carvedilol (135 +/- 4 bpm) than those receiving metoprolol XL (117 +/- 6 bpm), P = 0.02. Similar norepinephrine release and more complete beta 1-blockade is observed in well-matched subjects with chronic heart failure treated with a mean daily dose of metoprolol XL 96.4 mg compared with carvedilol 32.9 mg.

Magnetic resonance imaging safety in nonconditional pacemaker and defibrillator recipients: A meta-analysis and systematic review.

BACKGROUND: Recommendations regarding performance of magnetic resonance imaging (MRI) in non-MRI conditional pacemaker and defibrillator recipients are evolving. Previous studies have suggested low adverse event rates with MRI in nonconditional cardiac implantable electronic device (CIED) recipients, but low power limits optimal characterization of risk. OBJECTIVE: The purpose of this study was to perform a systematic review and meta-analysis to characterize the clinical risk associated with MRI in CIED recipients in order to improve power. METHODS: PubMed and CINAHL indexed articles from 1990 to 2017 were queried. A random effects model was used for meta-analysis of continuous variables. Safety outcomes were evaluated with descriptive statistics. RESULTS: Seventy studies of non-MRI conditional devices undergoing MRI were identified, allowing for analysis of 5099 patients who underwent a total of 5908 MRI studies. Heterogeneity in lead parameter changes was observed within studies, although smaller variances were noted between studies. All lead characteristics and battery voltages showed very small, clinically insignificant changes when assessed as a pooled cohort, although cases of clinically relevant outcomes were also noted (lead failure 3, implantable cardioverter-defibrillator shock 1, electrical reset 94). Electrical resets were found only in older devices. Defibrillator function was unchanged, and inappropriate shocks were avoided with pre-MRI programming changes. CONCLUSION: This review demonstrated low lead failure and clinical event rates in non-MRI conditional pacemaker and defibrillator recipients undergoing MRI. Observed changes were small and interstudy variance was low, suggesting that the composite event rates offer a reasonable estimate of true effect. The observed adverse events reinforce the need for ongoing vigilance and caution, particularly with older devices.

Exercise-induced increases in oxidized low-density lipoprotein are associated with adverse outcomes in chronic heart failure.

BACKGROUND: Oxidative stress is an important pathophysiologic feature in chronic heart failure (CHF) and may in part result from the inability to counteract acute surges of circulating oxidant products. Oxidized low-density lipoprotein (oxLDL) is an emerging prognostic marker in CHF. Accordingly, we investigated the effect of exercise-induced oxidative stress on circulating levels of oxLDL and its association with clinical outcomes in CHF. METHODS AND RESULTS: Plasma levels of oxLDL and low-density lipoprotein cholesterol (LDL-c) were measured at rest and after maximal exercise in 48 subjects with CHF and 12 healthy controls. Subjects with CHF had a higher baseline oxLDL (77.7 +/- 3.2 U/L vs 57.9 +/- 5.0 U/L, P = .01) and a higher baseline oxLDL/LDL-c ratio (0.87 +/- 0.04 vs 0.49 +/- 0.04, P < or = .001). Exercise induced an increase in oxLDL in subjects with CHF (77.7 +/- 3.2 U/L to 85.3 +/- 3.0 U/L, P < or = .001) but not in controls (57.9 +/- 5.0 to 61.4 +/- 5.5, P = .17). In 39 subjects for whom follow-up data were available, an increase in oxLDL of more than 11.0 U/L was associated with an increased risk to meet a combined end point of death and need for ventricular assist device or heart transplant during a 19-month follow-up period (hazard ratio 8.6; 95% confidence interval 1.0-73.8, P = .05); this remained significant when adjusted for peak oxygen consumption, left ventricular ejection fraction, New York Heart Association class, sex, and age (hazard ratio 46.6, 95% confidence interval 1.5-1438.1, P = .02). CONCLUSION: Plasma oxLDL and the oxLDL/LDL-c ratio are elevated in subjects with CHF. Whether assessment of oxLDL during maximal exercise allows early identification of subjects at highest risk for adverse outcomes should be systematically investigated.

Cardiac electrophysiology of patients with spinal cord injury.

Spinal cord injury is a clinical syndrome encountered frequently in trauma centers and is accompanied by both acute and chronic heart rhythm abnormalities. The injury is characterized by sympathetic nervous system impairment with preservation of parasympathetic output via the vagus nerve. Severe bradycardia in the form of life-threatening sinus arrest or complete heart block may be observed in the acute recovery phase. Therapy for arrhythmias in the acute phase includes atropine, intravenous chronotropes, methylxanthines for the prevention of episodic bradycardia, and pacemaker implantation in severe cases. In the chronic recovery phase, autonomic dysreflexia in the form of paroxysmal hypertension is often induced by visceral organ distension or other stimuli and can be accompanied by bradycardia or tachycardia. The prognosis for survivors of spinal cord injury is expected to improve with further advances in surgical and medical care, and electrophysiologists will likely be called upon more frequently to help manage heart rhythm disorders in this setting.

Clinical use of antibacterial mesh envelopes in cardiovascular electronic device implantations.

Cardiovascular implantable electronic device system infection is a serious complication of cardiac device implantation and carries with it a risk of significant morbidity and mortality. In the last 15 years, expansions of indications for cardiac devices have resulted in much higher volumes of much sicker patients being implanted, carrying significant risk of infection. Coagulase (-) Staphylococcus and Staphylococcus aureus are responsible for the majority of these infections, and these organisms are increasingly resistant to methicillin. The Aigis™ envelop is a Food and Drug Administration-approved implantable mesh that is impregnated with antibiotics that can be placed in the surgical incision prior to closure. The antibiotics elute off the mesh for 7-10 days, providing in vivo surgical site coverage with rifampin and minocyclin. This paper reviews the three retrospective clinical trials published in peer-reviewed journals and the interim analysis of the two ongoing prospective trials that have been presented at international conferences. Overall consensus is that the Aigis™ offers significant risk reduction for cardiovascular implantable electronic device infection. We then give a comprehensive discussion of how to use the Aigis™ envelop in the clinical setting, comparing the manufacturer's recommendations with our extensive clinical experience.

User-reported abrasion-related lead failure is more common with durata compared to other implantable cardiac defibrillator leads.

BACKGROUND: Following increased rates of inside-out abrasion with the St Jude Medical Riata lead, the Durata implantable cardiac defibrillator (ICD) lead was introduced with modifications intended to increase abrasion resistance. Recent case reports have described insulation failures of the Durata. OBJECTIVE: To determine if increased rates of abrasion-related failure are present with the Durata lead. METHODS: The Food and Drug Administration Manufacturer and User Facility Device Experience database was queried for reports of insulation failure of the Durata lead from 2014. Comparison was made to other ICD leads. Incidence was estimated and case characteristics were compared. RESULTS: The estimated incidence of abrasion was significantly higher for the Durata lead than for the Boston Scientific Endotak or the Medtronic Quattro leads. The mode of abrasion was most often lead-to-can, as compared to "inside-out" abrasion with the Riata lead. Full-thickness abrasion was associated with failure to defibrillate or inappropriate therapy. Four patients had failure of therapy or death. CONCLUSIONS: The findings indicate higher rates of insulation failures of the Durata lead, despite design modifications. External abrasion from the pulse generator to the adjacent lead within the device pocket was the most common etiology. Shocks unmasked previously undetected abrasion, resulting in failure to defibrillate. Data are presented indicating a possible time dependency to abrasion risk. This limited query suggests need for ongoing scrutiny of Durata lead performance. Careful inspection of Durata leads at the time of ICD replacement is warranted, as are vigorous attempts to gather information about terminal events in patients with Durata leads.

A dual wire approach to severe ostial bifurcating renal artery stenosis.

Percutaneous intervention with balloon expandable stents has proven to be an effective measure to enhance renal blood flow and control blood pressure in subjects with severe ostial renal artery lesions. A small cohort of these subjects have an ostial bifurcation, which complicates the approach to revascularization. In these cases there is a concern of creating a total side-branch occlusion during balloon expansion. We report two cases of an ostial lesion at a renal artery bifurcation revascularized by employing a sequential dilatation double guidewire technique. Using a single 7F sheath in each case, both renal artery branches were wired, and each branch was predilated and stented in a sequential fashion. Excellent angiographic results were obtained in both cases.

Association of heart rate recovery and maximum oxygen consumption in patients with chronic congestive heart failure.

BACKGROUND: Peak oxygen consumption (peak VO2) is one of the strongest predictors of mortality in patients with congestive heart failure (CHF). In contrast to measurements of peak VO2, which requires analysis of expired gases, heart rate recovery, defined as maximum heart rate minus heart rate at 1 minute after exercise, is easily obtained. The current study was undertaken to determine the association between peak VO2 and heart rate recovery in patients with CHF. METHODS: Retrospective data on VO2 and heart rate recovery were analyzed in 296 patients with CHF secondary to left ventricular systolic dysfunction (left ventricular ejection fraction [LVEF] <50%) who had undergone cardiopulmonary exercise testing (CPET). Patients exercised on a treadmill using a graded work rate protocol with the work increasing to a symptom-limited maximum. Peak oxygen consumption was defined as the highest value of oxygen uptake attained in the final 20 seconds of exercise when the respiratory exchange ratio was >1.0. RESULTS: Heart rate recovery and peak VO2 correlated moderately (r = 0.47, p < 0.001). The degree of correlation was similar in patients receiving beta-blockers (r = 0.47, p < 0.001) and those not receiving beta-blockers (r = 0.49, p < 0.001). CONCLUSIONS: Although heart rate recovery and peak VO2 correlated moderately, from a clinical standpoint, this finding is probably not strong enough to use heart rate recovery in lieu of peak VO2. This modest correlation of two independent predictors of outcome may suggest their usefulness when combined in a multivariate score.