Heather L. Bloom

Renal insufficiency and the risk of infection from pacemaker or defibrillator surgery.

Background: Pacemakers and implanted cardioverter defibrillator (ICD) infection rates are rising. Renal insufficiency impairs immune function and is known to increase the risk of infection following implantation of orthopedic hardware. The purpose of the current study is to characterize the risk factors for pacemaker and ICD infection and to evaluate the role of renal insufficiency in this complication.

Implantation success and infection in cardiovascular implantable electronic device procedures utilizing an antibacterial envelope.

Background:  Cardiovascular implantable electronic device (CIED) infection rates are increasing faster than implantation rates. More effective antimicrobial prophylaxis may help reduce CIED infections and improve clinical outcomes. The AIGISRx® antibacterial envelope is a polymer mesh implanted in the generator pocket with the CIED. After implantation it releases two antibiotics, minocycline and rifampin, that have been shown to reduce infections associated with other medical devices. The purpose of this retrospective cohort study is to determine the rate of CIED implantation success and CIED infection in procedures utilizing the antibacterial envelope.

Genetic variation in the alternative splicing regulator RBM20 is associated with dilated cardiomyopathy

BACKGROUND Dilated cardiomyopathy (DCM) is a leading cause of heart failure and death. The etiology of DCM is genetically heterogeneous. OBJECTIVES We sought to define the prevalence of mutations in the RNA splicing protein RBM20 in a large cohort with DCM and to determine whether genetic variation in RBM20 is associated with clinical outcomes. METHODS Subjects included in the Genetic Risk Assessment of Defibrillator Events (GRADE) study were aged at least 18 years, had an ejection fraction of ≤30%, and an implantable cardioverter-defibrillator (ICD). The coding region and splice junctions of RBM20 were screened in subjects with DCM; 2 common polymorphisms in RBM20, rs942077 and rs35141404, were genotyped in all GRADE subjects. RESULTS A total of 1465 subjects were enrolled in the GRADE study, and 283 with DCM were screened for RBM20 mutations. The mean age of subjects with DCM was 58 ± 13 years, 64% were males, and the mean follow-up time was 24.2 ± 17.1 months after ICD placement. RBM20 mutations were identified in 8 subjects with DCM (2.8%). Mutation carriers had a similar survival, transplantation rate, and frequency of ICD therapy compared with nonmutation carriers. Three of 8 subjects with RBM20 mutations (37.5%) had atrial fibrillation (AF), whereas 19 subjects without mutations (7.4%) had AF (P = .02). Among all GRADE subjects, rs35141404 was associated with AF (minor allele odds ratio = 0.62; 95% confidence interval = 0.44-0.86; P = .006). In the subset of GRADE subjects with DCM, rs35141404 was associated with AF (minor allele odds ratio = 0.58; P = .047). CONCLUSIONS Mutations in RBM20 were observed in approximately 3% of subjects with DCM. There were no differences in survival, transplantation rate, and frequency of ICD therapy in mutation carriers.

Statin Therapy for the Prevention of Atrial Fibrillation Trial (SToP AF trial)

Statins for Prevention of Atrial Fibrillation. Background: Inflammation and oxidative stress are associated with atrial fibrillation (AF). Statins have antioxidant and anti‐inflammatory properties. We tested if atorvastatin reduced AF recurrence after DC cardioversion (CV) by modifying systemic oxidative stress and inflammation (NCT00252967).

Statins Decrease Oxidative Stress and ICD Therapies

Recent studies demonstrate that statins decrease ventricular arrhythmias in internal cardioverter defibrillator (ICD) patients. The mechanism is unknown, but evidence links increased inflammatory and oxidative states with increased arrhythmias. We hypothesized that statin use decreases oxidation. Methods. 304 subjects with ICDs were surveyed for ventricular arrhythmia. Blood was analyzed for derivatives of reactive oxygen species (DROMs) and interleukin-6 (IL-6). Results. Subjects included 252 (83%) men, 58% on statins, 20% had ventricular arrhythmias. Average age was 63 years and ejection fraction (EF) 20%. ICD implant duration was 29 ± 27 months. Use of statins correlated with lower ICD events (r = 0.12, P = .02). Subjects on statins had lower hsCRP (5.2 versus 6.3; P = .05) and DROM levels (373 versus 397; P = .03). Other factors, including IL-6 and EF did not differ between statin and nonstatin use, nor did beta-blocker or antiarrhythmic use. Multivariate cross-correlation analysis demonstrated that DROMs, statins, IL-6 and EF were strongly associated with ICD events. Multivariate regression shows DROMs to be the dominant predictor. Conclusion. ICD event rate correlates with DROMs, a measure of lipid peroxides. Use of statins is associated with reduced DROMs and fewer ICD events, suggesting that statins exert their effect through reducing oxidation.

Left Ventricular Dilatation Increases the Risk of Ventricular Arrhythmias in Patients With Reduced Systolic Function

Background Reduced left ventricular (LV) ejection fraction increases the risk of ventricular arrhythmias; however, LV ejection fraction has a low sensitivity to predict ventricular arrhythmias. LV dilatation and mass may be useful to further risk-stratify for ventricular arrhythmias. Methods and Results Patients from the Genetic Risk of Assessment of Defibrillator Events (GRADE) study (N =930), a study of heart failure subjects with defibrillators, were assessed for appropriate implantable cardioverter-defibrillator shock and death, heart transplant, or ventricular assist device placement by LV diameter and mass. LV mass was divided into normal, mild, moderate, and severe classifications. Severe LV end-diastolic diameter had worse shock-free survival than normal and mild LV end-diastolic diameter (P =0.0002 and 0.0063, respectively; 2-year shock free, severe 74%, moderate 80%, mild 91%, normal 88%; 4-year shock free, severe 62%, moderate 69%, mild 72%, normal 81%) and freedom from death, transplant, or ventricular assist device compared with normal and moderate LV end-diastolic diameter (P<0.0001 and 0.0441, respectively; 2-year survival: severe 78%, moderate 85%, mild 82%, normal 89%; 4-year survival: severe 55%, moderate 64%, mild 63%, normal 74%). Severe LV mass had worse shock-free survival than normal and mild LV mass (P =0.0370 and 0.0280, respectively; 2-year shock free: severe 80%, moderate 81%, mild 91%, normal 87%; 4-year shock free: severe 68%, moderate 73%, mild 76%, normal 76%) but no association with death, transplant, or ventricular assist device (P =0.1319). In a multivariable Cox proportional hazards analysis adjusted for LV ejection fraction, LV end-diastolic diameter was associated with appropriate implantable cardioverter-defibrillator shocks (hazard ratio 1.22, P =0.020). LV end-diastolic diameter was associated with time to death, transplant, or ventricular assist device (hazard ratio 1.29, P =0.0009). Conclusions LV dilatation may complement ejection fraction to predict ventricular arrhythmias. Clinical Trial Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT02045043.

Long‐Term Evaluation of Biotronik Linox and Linoxsmart Implantable Cardioverter Defibrillator Leads

Expert consensus holds that post‐market, systematic surveillance of ICD leads is essential to ensure confirmation of adequate lead performance. GALAXY (NCT00836589) and CELESTIAL (NCT00810264) are ongoing multicenter, prospective, non‐randomized registries conducted to confirm the long‐term safety and reliability of Biotronik leads.

Automated external cardioversion defibrillation monitoring in cardiac arrest: a randomized trial

BackgroundIn-hospital cardiac arrest has a poor prognosis despite active electrocardiography monitoring. The initial rhythm of approximately 25% of in-hospital cardiopulmonary resuscitation (CPR) events is pulseless ventricular tachycardia/ventricular fibrillation (VT/VF). Early defibrillation is an independent predictor of survival in CPR events caused by VT/VF. The automated external cardioverter defibrillator (AECD) is a device attached by pads to the chest wall that monitors, detects, and within seconds, automatically delivers electric countershock to an appropriate tachyarrhythmia.Study Objectives• To evaluate safety of AECD monitoring in hospitalized patients.• To evaluate whether AECDs provide earlier defibrillation than hospital code teams.MethodsThe study is a prospective trial randomizing patients admitted to the telemetry ward to standard CPR (code team) or standard CPR plus AECD monitoring (PowerHeart CRM). The AECD is programmed to deliver one 150 J biphasic shock to patients in sustained VT/VF. Data is collected using the Utstein criteria for cardiac arrest. The primary endpoint is time-to-defibrillation; secondary outcomes include neurological status and survival to discharge, with 3-year follow-up.ResultsTo date, 192 patients have been recruited in the time period between 10/10/2006 to 7/20/2007. A total of 3,655 hours of telemetry data have been analyzed in the AECD arm. The AECD has monitored ambulatory telemetry patients in sinus rhythm, sinus tachycardia, supraventricular tachycardia, atrial flutter or fibrillation, with premature ventricular complexes and non-sustained VT without delivery of inappropriate shocks. One patient experienced sustained VT during AECD monitoring, who was successfully defibrillated (17 seconds after meeting programmed criteria). There are no events to report in the control arm. The patient survived the event without neurological complications. During the same time period, mean time to shock for VT/VF cardiac arrest occurring outside the telemetry ward was 230 ± 50 seconds.ConclusionAECD monitoring is safe and likely results in earlier defibrillation than standard telemetry monitoring.Trial RegistrationNational Institutes of Health registration ID: NCT00382928

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.

Differential effects of adrenergic antagonists (Carvedilol vs Metoprolol) on parasympathetic and sympathetic activity: a comparison of clinical results

Background Cardiovascular autonomic neuropathy (CAN) is recognized as a significant health risk, correlating with risk of heart disease, silent myocardial ischemia or sudden cardiac death. Beta-blockers are often prescribed to minimize risk. Objectives In this second of two articles, the effects on parasympathetic and sympathetic activity of the alpha/beta-adrenergic blocker, Carvedilol, are compared with those of the selective beta-adrenergic blocker, Metoprolol. Methods Retrospective, serial autonomic nervous system test data from 147 type 2 diabetes mellitus patients from eight ambulatory clinics were analyzed. Patients were grouped according to whether a beta-blocker was (1) introduced, (2) discontinued or (3) continued without adjustment. Group 3 served as the control. Results Introducing Carvedilol or Metoprolol decreased heart rate and blood pressure, and discontinuing them had the opposite effect. Parasympathetic activity increased with introducing Carvedilol. Sympathetic activity increased more after discontinuing Carvedilol, suggesting better sympathetic suppression. With ongoing treatment, resting parasympathetic activity decreased with Metoprolol but increased with Carvedilol. Conclusion Carvedilol has a more profound effect on sympathovagal balance than Metoprolol. While both suppress sympathetic activity, only Carvedilol increases parasympathetic activity. Increased parasympathetic activity may underlie the lower mortality risk with Carvedilol.