Rationale and design of the Apixaban for the Reduction of Thrombo-Embolism in Patients With Device-Detected Sub-Clinical Atrial Fibrillation (ARTESiA) trial.

BACKGROUND: Device-detected subclinical atrial fibrillation (AF) refers to infrequent, short-lasting, asymptomatic AF that is detected only with long-term continuous monitoring. Subclinical AF is common and associated with an increased risk of stroke; however, the risk of stroke with subclinical AF is lower than for clinical AF, and very few patients with subclinical AF alone have been included in large AF anticoagulation trials. The net benefit of anticoagulation in patients with subclinical AF is unknown. DESIGN: ARTESiA is a prospective, multicenter, double-blind, randomized controlled trial, recruiting patients with subclinical AF detected by an implanted pacemaker, defibrillator, or cardiac monitor, and who have additional risk factors for stroke. Patients with clinical AF documented by surface electrocardiogram will be excluded from the study. Participants will be randomized to receive either apixaban (according to standard AF dosing) or aspirin 81mg daily. The primary outcome is the composite of stroke, transient ischemic attack with diffusion-weighted magnetic resonance imaging evidence of cerebral infarction, and systemic embolism. Approximately 4,000 patients will be enrolled from around 230 clinical sites, with an anticipated mean follow-up of 36months until 248 adjudicated primary outcome events have occurred. SUMMARY: ARTESiA will determine whether oral anticoagulation therapy with apixaban compared with aspirin reduces the risk of stroke or systemic embolism in patients with subclinical AF and additional risk factors

Post Traumatic Myocardial-infarction

We report the history of a young man who developed an acute anterolateral myocardial infarction secondary to blunt chest trauma in an automobile accident. Arteriography demonstrated that the patient had sustained a left anterior descending artery tear and a coronary-ventricular fistula from the first septal branch. Different pathogenetic mechanisms with their specific complications and diagnostic features are discussed

Use of Exercise Electrocardiography, Technetium-99m-mibi Perfusion Tomography, and 2-dimensional Echocardiography for Coronary-disease Surveillance in a Low-prevalence Population of Heart-transplant Recipients

Background: Coronary artery disease has been reported to be a significant cause of long-term morbidity and mortality after heart transplantation. However, the diagnosis of coronary disease by means of noninvasive procedures has shown disappointing accuracy, and many centers currently recommend an annual surveillance coronary angiogram. Methods: We prospectively studied the accuracy and feasibility of a symptom-limited upright bicycle exercise, combined with computerized electrocardiogram analysis, echocardiography, and perfusion scintigraphy in 37 consecutive heart transplant recipients at 2.8 +/- 1.4 years after transplantation for routine follow-up coronary angiography. Results: No patient had any hemodynamically significant (> 50% diameter) coronary stenosis, but luminal irregularities were detectable in four patients. The exercise electrocardiogram was interpretable in only 22 patients (59%), and two of the remaining patients (9%) had false-positive results. The feasibility of perfusion tomography (100%) and two-dimensional echocardiography (97%) were greater than for stress electrocardiogram (p < 0.001 and p < 0.01 respectively). False-positive results were obtained at stress echocardiography in one patient (3%), and at scintigraphy in six patients (16%, p = not significant). None of these methods detected coronary artery stenoses of less than 50% diameter. Conclusions: Both exercise perfusion tomography and two-dimensional echocardiography are feasible and can be used with adequate specificity for the noninvasive diagnosis of coronary artery disease in heart transplant recipients. However further studies are needed to determine their respective sensitivity

No evidence of automatic atrial overdrive pacing efficacy on reduction of paroxysmal atrial fibrillation

Aims: Paroxysmal atrial fibrillation (PAF) is frequently encountered in pacemaker patients, most commonly in sick sinus syndrome. The combination of site-specific pacing in conjunction with an overdrive algorithm combined with antiarrhythmic drugs on the incidence of PAF in patients with a conventional indication for pacing is unknown. Methods and results: Patients with pacemaker indication and PAF received a DDDR-pacemaker, which included an automatic atrial overdrive (AO) algorithm. The atrial lead was implanted in either the right atrial appendage (RAA) (n = 83) or the right low-atrial septum (LAS) (n = 94). The algorithm was switched on or off in a 3 month, single blind crossover design and antiarrhythmic drugs were kept stable. A control group of 96 patients (LAS, n = 14; RAA, n = 84) without PAF served as controls to assess any proarrhythmic effect of overdrive pacing. Atrial fibrillation (AF) burden defined as cumulative time in mode switch was not reduced during automatic AO from either the RAA or from the LAS. The reduction was not effective both for AF of short (<24 h) and long (≥24 h) duration. There was no atrial proarrhythmia induced by the overdrive algorithm in the control group. Conclusions: We could not demonstrate a reduction of AF burden defined as cumulative time in AF by the AO algorithm, in patients who are paced for standard indications and PAF, neither from the RAA nor from the LAS. © The European Society of Cardiology 2007. All rights reserved.link_to_subscribed_fulltex

Long-term winter warming trend in the Siberian Arctic during the mid- to late Holocene.

Relative to the past 2,000 years1,2, the Arctic region has warmed significantly over the past few decades. However, the evolution of Arctic temperatures during the rest of the Holocene is less clear. Proxy reconstructions, suggest a longterm cooling trend throughout the mid- to late Holocene3–5, whereas climate model simulations show only minor changes or even warming6–8. Here we present a record of the oxygen isotope composition of permafrost ice wedges from the Lena River Delta in the Siberian Arctic. The isotope values, which reflect winter season temperatures, became progressively more enriched over the past 7,000 years, reaching unprecedented levels in the past five decades. This warming trend during the mid- to late Holocene is in opposition to the cooling seen in other proxy records3,5,9. However, most of these existing proxy records are biased towards summer temperatures. We argue that the opposing trends are related to the seasonally different orbital forcing over this interval. Furthermore, our reconstructed trend as well as the recent maximum are consistent with the greenhouse gas forcing and climate model simulations, thus reconciling differing estimates of Arctic and northern high-latitude temperature evolution during the Holocene