No abstract
Background-Fetal long QT syndrome (LQTS) is associated with complex arrhythmias including torsades de pointes and 2°atrioventricular block. Sinus bradycardia has also been associated with fetal LQTS, but little is known of this rhythm manifestation. Our purpose was to characterize the fetal heart rate (FHR)/gestational age (GA) profile of fetal LQTS. Methods and Results-We ascertained fetal LQTS subjects by family history (Group 1) or fetal arrhythmia referral (Group 2). We compared FHR in LQTS subjects versus normal fetuses. To identify FHR predictors of LQTS, we calculated a bradycardia index as % of LQTS FHR recordings either Յ110 beats per minute (obstetric standard) or Յ3 rd percentile for GA. Among 42 LQTS subjects, 26 were in Group 1 and 16 in Group 2. There were 536 normal fetuses. The bradycardia index was only 15% for FHR Յ110 beats per minute, but 66% for FHR Յ3rd percentile for GA. Ten fetuses with complex arrhythmias also had severe and sustained sinus bradycardia throughout gestation. Identifying a fetal proband in Group 2 resulted in LQTS diagnosis in 9 unsuspected members of 6 families. Conclusions-FHR varies by GA in both normal and LQTS fetuses. Postnatal evaluation of neonates with FHR Յ3rd percentile for GA may improve ascertainment of LQTS in fetuses, neonates, and undiagnosed family members. (Circulation. 2012;126: 2688-2695.) Key Words: arrhythmias, cardiac Ⅲ fetus Ⅲ long-QT syndrome L ong QT syndrome (LQTS) is reported to have an incidence of 1 in 2500 individuals. Although QT interval prolongation may be an incidental finding, LQTS typically presents in adolescence or young adult life with syncope, sudden death, or cardiac arrest. 1,2 Less frequently, LQTS presents in the perinatal (fetal/neonatal) period; in this setting morbidity and mortality are high, and torsades de pointes (TdP) and 2°atrioventricular (AV) block are signature rhythms. [3][4][5][6] Sinus bradycardia is also a manifestation of fetal LQTS and is reported to be more common than TdP and 2°AV block. For example, as many as 44% to 66% of fetuses diagnosed with LQTS presented with sinus bradycardia at 26 to 40 weeks of gestation. 3,6 -8 In most reports, a fetal heart rate (FHR) Յ110 beats per minute (bpm) at any gestational age (GA) raised suspicion of LQTS. Indeed, FHR of Յ110 bpm at any GA is the obstetric definition of sinus bradycardia. 9 However, little is known of the sensitivity of this finding and how it relates to the subsequent diagnosis of LQTS. Clinical Perspective on p 2695It is well known that FHR in the normal fetus decreases during gestation from about 175 bpm at 10 weeks to 138 bpm at 40 weeks. This phenomenon is believed to be attributable to the increasing dominance of the parasympathetic nervous system on heart rate control as gestation progresses. 10,11 Despite the association between fetal bradycardia and LQTS, the FHR/GA profile, or the range of FHRs of subjects with LQTS, has not been defined. We wondered whether there might be a pathological FHR in the setting of 1:1 AV conduction that was below n...
This paper describes a computational approach for accurately determining the location of human eyes in unconstrained monoscopic gray level images. The proposed method is based on exploiting the flow field characteristics that arise due to the presence of a dark iris surrounded by a light sclera. A novel aspect of the proposed method lies in its use of both spatial and temporal information to detect the location of the eyes. The spatial processing utilizes flow field information to select a pool of potential candidate locations for the eyes. Temporal processing uses the principle of continuity to filter out the actual location of the eyes from the pool of potential candidates. Extensions for gaze angle determination, and the tracking of human point-of-regard are indicated.
Figure 1: Left: A car model rendered with smooth ACC. Right: The same model with creases and corners added. AbstractWe present an extension of recently developed Loop and Schaefer's approximation of Catmull-Clark surfaces (ACC) for surfaces with creases and corners which are essential for most applications. We discuss the integration of ACC into Valve's Source game engine and analyze performance of our implementation.
We present a set of artistic choices and novel real-time shading techniques which support each other to enable the unique rendering style of the game Team Fortress 2. Grounded in the conventions of early 20th century commercial illustration, the look of Team Fortress 2 is the result of tight collaboration between artists and engineers. In this paper, we will discuss the way in which the art direction and technology choices combine to support artistic goals and gameplay constraints. In addition to achieving a compelling style, the shading techniques are designed to quickly convey geometric information using rim highlights as well as variation in luminance and hue, so that game players are consistently able to visually "read" the scene and identify other players in a variety of lighting conditions.
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