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 AIGIS(Rx)(®) 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. METHODS: This study enrolled consecutive CIED procedures utilizing the antibacterial envelope at 10 US academic, community, and Veterans Affairs medical centers. Procedures following an explantation for a prior CIED infection or off-label use of the antibacterial envelope were excluded. RESULTS: The 624 eligible procedures (age 70 ± 13 years, 68.1% men, 27.2% renal insufficiency, 35.4% oral anticoagulant use, 67.8% replacement/revision procedures) utilized pacemakers (35%), implantable cardioverter-defibrillators (ICD)(29%), and cardiac resynchronization therapy with defibrillator devices (CRT-D)(36%). Nearly half of the patients (49%) had at least three predefined risk factors for CIED infection. CIED implantation was successful in 621 procedures (99.5%[95% confidence interval (CI) 98.8-99.9]). There were three major infections (0.48%[95%CI 0.17-1.40]) after 1.9 ± 2.4 months follow-up. The infections followed one ICD revision and two CRT-D replacements. There were seven deaths; none was a result of the antibacterial envelope or the CIED procedure. CONCLUSIONS: CIED procedures that utilized an antibacterial envelope had a high rate of CIED implantation success (>99%). Although the follow-up to date is short, there was also a low rate of infection (<0.50%) in this population at high risk for CIED infection.

Renal insufficiency predicts the time to first appropriate defibrillator shock.

BACKGROUND: Indications for implantable cardioverter defibrillator (ICD) implantation are expanding, but many primary and secondary ICD trials have excluded patients with advanced renal insufficiency. We investigated the effect of renal function on the incidence and time to first appropriate ICD shock. METHOD: We analyzed data from all new ICD implantations at a tertiary care center from July 2001 to December 2002. RESULTS: During a mean follow-up time of 445 +/- 285 days, 29 (13%) of 230 patients (age 63 +/- 14 years, 79% men, 77% white, 75% coronary artery disease, left ventricular ejection fraction 0.28 +/- 0.14) received 41 appropriate shocks. Patients were divided into tertiles according to their serum creatinine level. The 1-year incidence of appropriate ICD shock was 3.8%, 10.8%, and 22.7% in the first, second, and third tertiles, respectively (P = .003). Using the same cut off values of serum creatinine, the 1-year incidence of appropriate ICD therapy (shock and antitachycardia pacing) was 8.8%, 20.8%, and 26.3% (P = .02). After correcting for age, sex, race, left ventricular ejection fraction, indication for ICD implantation, and use of beta-blockers in a Cox regression model, serum creatinine was still an independent predictor of the time to first appropriate ICD shock (hazard ratio 6.0 for the third compared with the first tertile, P = .001). CONCLUSION: Renal insufficiency is a strong predictor of appropriate ICD shocks. Defibrillator therapy should therefore not be withheld based on the presence of this comorbidity. The mechanisms underlying the relationship between renal function and ventricular arrhythmias deserve further investigation.

Epidemiology and determinants of outcome of admissions for atrial fibrillation in the United States from 1996 to 2001.

Despite numerous epidemiologic studies, few data exist on recent trends in admissions to United States hospitals of patients with atrial fibrillation (AF) as a primary diagnosis and on the determinants of outcome of these hospitalizations. In the present study, we investigated recent trends in the incidence of AF admissions to United States hospitals from 1996 to 2001 using a representative sample of all acute-care hospital admissions in the United States provided by the Centers for Disease Control, with special attention to the importance of age, gender, race, and other determinants of outcome, namely, in-hospital mortality.

Utilization of implantable cardioverter-defibrillators in survivors of cardiac arrest in the United States from 1996 to 2001.

OBJECTIVES: We analyzed the incidence of implantable cardioverter-defibrillator (ICD) therapy in survivors of cardiac arrest (CA) in the U.S. from 1996 through 2001. BACKGROUND: Cardiac arrest is a class I indication for ICD therapy. The current patterns of ICD utilization in survivors of CA have not been fully examined. METHODS: We searched a representative sample of all hospital discharges for patients admitted with the primary diagnosis of CA who survived to hospital discharge. Patients with a concomitant diagnosis of acute myocardial infarction or previous ICD in situ were excluded. RESULTS: From 1996 to 2001, 113,262 patients were admitted for CA. Of those, 63,745 (56.3%) did not survive to hospital discharge. Of the remaining 49,517 patients, 30.7% received an ICD before discharge, with a gradual increase in implantation rates from 1996 (23.6%) to 2001 (46.3%). Using logistic regression for the years 2000 and 2001, patients who were discharged without an ICD were older (odds ratio [OR] 0.93 for every 10-year increase in age, p < 0.001), more likely to be African American (OR 0.19, p < 0.001), and more likely to be admitted to a smaller hospital (OR 2.24 for each additional 100 beds, p < 0.001). These predictors were independent of other co-morbid illnesses. CONCLUSIONS: Although they are increasing, the rates of ICD therapy after CA remain very low. There are gross discrepancies by race. At a time when newer indications for ICD implantation are emerging, efforts should be focused on identifying the causes of this underutilization and discrepancies in survivors of CA.

Primary prevention of sudden cardiac death.

Sudden cardiac death (SCD) is the leading cause of death in the United States. Although SCD occurs most commonly in patients with established heart disease, SCD can also be the initial manifestation of cardiovascular disease. Efforts to reduce the incidence of SCD include aggressive treatment of heart disease and its risk factors with pharmacologic and nonpharmacologic strategies. Public health measures to improve the response to cardiac arrest, including dissemination of automated external defibrillators in the community, are extremely important. Implantation of implantable cardioverter defibrillators (ICDs) in patients at high risk of SCD improves survival in these patients. Clinical trials have identified patients with ischemic and nonischemic cardiomyopathy who may benefit from prophylactic ICD implantation.

New method for real-time discrimination and management of ventricular and supraventricular tachyarrhythmias applicable to patients with dual-chamber cardioverter-defibrillators.

In this study we describe a highly sensitive and specific method for discriminating between ventricular and supraventricular tachyarrhythmias based on the response to simultaneous atrial and ventricular antitachycardia pacing. This new method, which can terminate supraventricular tachycardias in >50% of patients, can be easily implemented in a new generation of dual-chamber defibrillators.

Selected patients listed for cardiac transplantation may benefit from defibrillator implantation regardless of an established indication.

BACKGROUND: End-stage heart failure (HF) patients are at high risk of sudden cardiac death. This study evaluates the role of implantable cardiac defibrillators (ICDs) in HF patients awaiting cardiac transplantation. METHODS: We identified 194 consecutive patients (age 51 +/- 12 years) with New York Heart Association Class 3 or 4 HF (ejection fraction 22 +/- 9%) listed for cardiac transplantation, 35 of whom underwent ICD implantation. Of the implanted patients, 16 (Group A) had an established indication for ICD implantation (cardiac arrest, n = 10; sustained ventricular tachycardia [VT], n = 3; and positive electrophysiology study, n = 3). Nineteen patients (Group B) underwent ICD implantation for non-established indications (syncope with non-ischemic cardiomyopathy, n = 4; non-sustained VT, n = 15). There were no procedural complications from ICD implantation. RESULTS: During follow-up of 9.2 +/- 10.1 months, there were 3 deaths in the ICD groups (A and B), and 40 in the control group (8.6% vs 25.2%, p = 0.032). Five patients in Group A and 6 in Group B (31%) received appropriate ICD therapy. The number of therapies per patient and the time to the first shock were similar between Groups A and B. Four of 6 Group B patients on outpatient inotropic therapy (67%) received appropriate ICD therapy. CONCLUSIONS: Selected end-stage heart failure patients awaiting heart transplantation, including those without established ICD indications, are at high risk for malignant arrhythmias and may benefit from ICD implantation. Patients with ICD seem to have improved survival compared to those without ICD. Randomized prospective studies are needed to confirm these findings.