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A 36-Year-Old Man Comes to the Emergency Department Due to Loss

question 840

Multiple Choice

A 36-year-old man comes to the emergency department due to loss of consciousness. He was standing in a crowded subway station when he felt lightheaded, had a pounding sensation in his chest, and passed out. On awakening, he felt short of breath for a little while and then was "completely fine." He has had no similar episodes, nor chest pain, confusion, tongue biting, or urinary incontinence. The night before, he was at a party with friends and consumed alcohol. Later he was nauseated and had 3 episodes of vomiting and one episode of diarrhea. In the emergency department, blood pressure is 124/68 mm Hg and pulse is 80/min. There is a small laceration above his right eyebrow. Cardiac examination shows normal heart sounds with regular rhythm. The lungs are clear to auscultation. Neurologic examination shows no abnormalities. ECG is shown in the exhibit.
Which of the following is the most likely cause of this patient's syncope?

Definitions:

Substituted Cyclobutadiene

A derived form of cyclobutadiene where hydrogen atoms are replaced with other atoms or groups, influencing its reactivity and stability.

Computational Methods

Techniques that use computer-based algorithms and simulations to solve complex scientific and mathematical problems.

Resonance Structures

Representations of a molecule where bond arrangements are shown through multiple structures to depict a molecule's electronic structure.

CCC Bond Angles

CCC bond angles refer to the geometric angles between three carbon atoms in a molecular structure, important in determining the shape and properties of molecules.