A 66-Year-Old Man Is Evaluated for Recurrent Syncope

question 347

Multiple Choice

A 66-year-old man is evaluated for recurrent syncope.  He has had 3 episodes of dizziness and palpitations followed by brief loss of consciousness over the last 6 months.  He has no chest pain or dyspnea.  The patient has a history of hypertension and hyperlipidemia.  There is no family history of sudden death.  Initial evaluation shows normal ECG and echocardiogram.  A cardiac electrophysiologic study is performed.  During the study, intravenous infusion of a medication is administered and produces the responses shown below. Which of the following medications was most likely administered to this patient?

• A)Acetylcholine
• B)Adenosine
• C)Clonidine
• D)Esmolol
• E)Isoproterenol
• F)Norepinephrine
• G)Phenylephrine

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Definitions:

Perceptual Parsing

The cognitive process by which the brain segments and organizes sensory input into meaningful units or objects, allowing for the interpretation of the visual and auditory world.

Figure-Ground Relationships

A visual perception principle that involves distinguishing an object (the figure) from its surrounding area (the ground).

Perceptual Organization

The cognitive process by which the brain structures sensory input into meaningful patterns or objects.

Perceptual Constancy

The accurate perception of certain attributes of a distal object, such as its shape, size, and brightness, despite changes in the proximal stimulus caused by variations in our viewing circumstances.