Assessment of primary prevention patients receiving an ICD - Systematic evaluation of ATP: APPRAISE ATP.

BACKGROUND: The value of antitachycardia pacing (ATP) in the overall cohort of primary prevention patients who receive implantable cardioverter-defibrillators (ICDs) remains uncertain. ATP success reported in prior trials potentially included a large number of patients receiving unnecessary ATP for arrhythmias that may have self-terminated owing to the prematurity of the intervention. Although some patients derive benefit from initial ATP in terminating rapid ventricular arrhythmias and thereby preventing shocks, there are limited data allowing us to identify those patients a priori. OBJECTIVE: The purpose of APPRAISE ATP is to understand the role of ATP in primary prevention patients currently indicated for ICD therapy in a large prospective randomized controlled trial with modern programming parameters. METHODS: The study is a global, prospective, randomized, multicenter clinical trial conducted at up to 150 sites globally, enrolling approximately 2600 subjects The primary endpoint of the trial is time to first all-cause shock in a 2-arm study with an equivalent study design in which the incidence of all-cause shocks will be compared between primary prevention subjects programmed with shocks only vs subjects programmed to standard therapy (ATP and shock). RESULTS: An Electrogram and Device Interrogation Core Laboratory will review interrogation data to determine primary endpoints that occur in APPRAISE ATP. Their decisions are based on independent physician review of the data from device interrogation. CONCLUSION: The ultimate purpose of the study is to aid clinicians in the selection of ICD technologies based on hard endpoint evidence across the spectrum of indications for primary prevention implantation.

Periprocedural imaging and outcomes after catheter ablation of atrial fibrillation.

OBJECTIVE: Catheter ablation of atrial fibrillation (AF) has become an increasingly safe and effective therapy. This has been partly attributed to the use of adjunctive imaging modalities. We aimed to describe the use and associated outcomes of periprocedural imaging for AF ablation. METHODS: We studied all Medicare fee-for-service claims for AF ablation from July 2007 to December 2009, and identified associated imaging studies before and during ablation, including transoesophageal echocardiography (TEE), intracardiac echocardiography (ICE), CT and MRI. The primary outcomes were death, stroke or transient ischaemic attack (TIA), repeat ablation, and bleeding (pericardial or vascular) at 6 months. RESULTS: 11 525 patients underwent AF ablation during the study period. There was significant variation in imaging use at the practice level. In addition to electroanatomic mapping, 53% (n=6060/11 525) underwent TEE, 67% (n=7715/11 525) received ICE, and 50% (n=5724/11 525) underwent a preprocedure CT or MRI. Imaging generally increased from 2007 to 2009. After adjustment, the use of preablation CT or MRI was associated with a significantly lower risk of stroke or TIA (0.4% vs 0.9%, adjusted HR 0.46, 95% CI 0.28 to 0.74, p=0.002), and the use of ICE was associated with a lower risk of repeat ablation (5.7% vs 8.5%, adjusted HR 0.59, 95% CI 0.37 to 0.92, p=0.02) but higher risk of bleeding (1.1% vs 0.7%, adjusted HR 1.76, 95% CI 1.15 to 2.70, p=0.009). CONCLUSIONS: Periprocedural imaging for AF ablation is increasingly used, although practice patterns vary widely. Our data suggest that periprocedural imaging is associated with better outcomes after catheter ablation; however, prospective studies of periprocedural imaging strategies are warranted.

Association between myocardial substrate, implantable cardioverter defibrillator shocks and mortality in MADIT-CRT.

OBJECTIVE: The aim of the present study was to assess a possible association between myocardial substrate, implantable cardioverter defibrillator (ICD) shocks, and subsequent mortality. METHODS: Within the multicentre automatic defibrillator implantation trial-cardiac resynchronization therapy (MADIT-CRT) population (n = 1790), we investigated the association between myocardial substrate, ICD shocks and subsequent mortality using multivariate Cox regression analyses and landmark analyses at 1-year follow-up. RESULTS: The 4-year cumulative probability of ICD shocks was 13% for appropriate shock and 6% for inappropriate shock. Compared with patients who never received ICD therapy, patients who received appropriate shock had an increased risk of mortality [HR = 2.3 (1.47-3.54), P < 0.001], which remained increased after adjusting for echocardiographic remodelling at 1 year (HR = 2.8, P = 0.001). Appropriate anti-tachycardia pacing (ATP) only was not associated with increased mortality (P = 0.42). We were not able to show an association between inappropriate shocks (P = 0.53), or inappropriate ATP (P = 0.10) and increased mortality. Advanced myocardial structural disease, i.e. higher baseline echocardiographic volumes and lack of remodelling at 1 year, was present in patients who received appropriate shocks but not in patients who received inappropriate shocks or no shocks. CONCLUSION: In the MADIT-CRT study, receiving appropriate ICD shocks was associated with an increased risk of subsequent mortality. This association was not evident for appropriate ATP only. These findings, along with advanced cardiac structural disease in the patients who received appropriate shocks, suggest that the compromised myocardium is a contributing factor to the increased mortality associated with appropriate ICD shock therapy. Clinical trials.gov identifier: NCT00180271.

Outcomes of Medicare beneficiaries undergoing catheter ablation for atrial fibrillation.

BACKGROUND: Atrial fibrillation is common among older persons. Catheter ablation is increasingly used in patients for whom medical therapy has failed. METHODS AND RESULTS: We conducted a retrospective cohort study of all fee-for-service Medicare beneficiaries ≥65 years of age who underwent catheter ablation for atrial fibrillation between July 1, 2007, and December 31, 2009. The main outcome measures were major complications within 30 days and mortality, heart failure, stroke, hospitalization, and repeat ablation within 1 year. A total of 15 423 patients underwent catheter ablation for atrial fibrillation. Mean age was 72 years; 41% were women; and >95% were white. For every 1000 procedures, there were 17 cases of hemopericardium requiring intervention, 8 cases of stroke, and 8 deaths within 30 days. More than 40% of patients required hospitalization within 1 year; however, atrial fibrillation or flutter was the primary discharge diagnosis in only 38.4% of cases. Eleven percent of patients underwent repeat ablation within 1 year. Renal impairment (hazard ratio, 2.07; 95% confidence interval, 1.66-2.58), age ≥80 years (hazard ratio, 3.09; 95% confidence interval, 2.32-4.11), and heart failure (hazard ratio, 2.54; 95% confidence interval, 2.07-3.13) were major risk factors for 1-year mortality. Advanced age was a major risk factor for all adverse outcomes. CONCLUSIONS: Major complications after catheter ablation for atrial fibrillation were associated with advanced age but were fairly infrequent. Few patients underwent repeat ablation. Randomized trials are needed to inform risk-benefit calculations for older persons with drug-refractory, symptomatic atrial fibrillation.