High altitude retinal hemorrhages are commonly seen at altitudes above 4270 m. While these hemorrhages are generally asymptomatic, macular involvement may result in permanent visual acuity deficit. We present the case of a 29-year-old male recreational skier who traveled to a ski resort at 2930 m, ascended to 3470 m, and developed acute mountain sickness, high altitude pulmonary edema, and bilateral retinal hemorrhages. A funduscopic examination to determine if macular retinal hemorrhage is present may be performed by clinicians in the final assessment of patients following altitude illness.
Uniform success for ablation of focal athaJ tachycardias has been difficult to achieve using standard catheter mapping and ablation techniques. In addition, our understanding of the complex relationship between atrial anatomy, electrophysiology. and surface ECG P wave morphology remains primitive. The magnetic electroanatomical mapping and display system (CARTO) offers an on‐line display of electrical activation and/or signal amplitude related to the anatomical location of the recorded sites in the mapped chamber. A window of electrical interest is established based on signals timed from an electrical reference that usually represents a fixed electrogram recording from the coronary sinus or the atrial appendage. This window of electrical interest is established to include atrial activation prior to the onset of the P wave activity associated with the site of origin of a focal atrial tachycardia. Anatomical and electrical landmarks are defined with limited fluoroscopic imaging support and more detailed global chamber and more focal atrial mapping can be performed with minimal fluoroscopic guidance. A three‐dimensional color map representing atrial activation or voltage amplitude at the magnetically defined anatomical sites is displayed with on‐line data acquisition. This display can be manipulated to facilitate viewing from any angle. Altering the zoom control, triangle fill threshold, clipping plane, or color range can all enhance the display of a more focal area of interest. We documented the feasibility of using this single mapping catheter technique for localizing and ablating focal atrial tachycardias. In a consecutive series of 8 patients with 9 focal atrial tachycardias, the use of the single catheter CARTO mapping system was associated with ablation success in all but one patient who had a left atrial tachycardia localized to the medial aspect of the orifice of the left atrial appendage. Only low power energy deHvery was used in this patient because of the unavaHahiHty of temperature monitoring in the early version of the Navistar catheter, the location of the arrhythmia, and the history of arrhythmia control with flecainide. No attempt was made to Umit fluoroscopy time in our study population. Nevertheless, despite data acquisition from 120–320 anatomically distinct sites during global and more detaHed focal atrial mapping, total fluoroscopy exposure was typically < 30 minutes and was as little as 12 minutes. The detailed display capabilities of the CARTO system appear to offer the potential of enhancing our understanding of atrial anatomy, atrial activation, and their relationship to surface ECC P wave morphology during focal atrial tachycardias.
Two experiments investigated the focusing properties of thematic roles, while a third experiment investigated the view that thematic role preferences reflect a focusing on the consequences of the represented event. Sentence continuation tasks were used in which subjects wrote continuations to sentence fragments containing two antecedents, each occupying a different thematic role. The results of Experiments 1 and 2 showed a preference for referring to a particular thematic role regardless of the presence or absence of a pronoun at the start of the continuation and regardless of whether the continuation was part of a different sentence from the one containing the antecedents (Experiment 1) or part of the same sentence (Experiment 2). These preferences were interpreted as being due to a focus on the consequences of the represented event in a mental model of the sentence. Experiment 3 tested this interpretation by using sentence fragments that ended in so (a connective that reinforces the focus on consequences) or because (a connective that conflicts with the focus on consequences). The results confirmed the interpretation: the observed preferences were maintained with so but modified by because. The results are discussed in terms of the structure of represented events, top-down and bottom-up processes, and thematic hierarchies. The first mention effect in pronoun comprehension is also discussed.
The aim of the two experiments reported here was to distinguish between two heuristic strategies that have been proposed to account for the assignment of pronouns: the subject assignment strategy and the parallel function strategy. According to the subject assignment strategy, a pronoun is assigned to a preceding subject noun phrase, whereas according to the parallel function strategy, a pronoun is assigned to a previous noun phrase in the same grammatical position as the pronoun. These two strategies were tested by examining the interpretation of single object pronouns, first in a reading task and second in an assignment task. In both experiments, there was a strongpreference for assigning an object pronoun to the preceding subject noun phrase, thus supporting the subject assignment strategy. However, this was only the case for pronouns that were linguistically ambiguous. When assignment was constrained by gender, there was no effect of either strategy. It is suggested that heuristic strategies are only used in the absence of other strong cues to assignment.