A 60-Year-Old Man with a Known History of Chronic Obstructive

question 95

Multiple Choice

A 60-year-old man with a known history of chronic obstructive pulmonary disease is brough to the emergency department due to chest palpitation and lightheadeness. He has a histroy of multiple episodes of intermittent chest palpitations. His only medication is a tiotropium-formoterol inhaler. His pulse is 140/min and irregular. respiration is 17/min and blood pressure 118/72. Pulse oximetry on room air shows an oxygen saturation of 96%. Chest examination reveals no murmurs and the lungs are clear on auscultation. There is trace peripheral edema. Cardiac rhythm strip obtained in the emergency department is shown in the exhibit.
Aberrant electrical activity in which of the following anatomic structures is the most likely trigger for this patient's current condition?

• A)Crista terminalis
• B)Papillary muscles
• C)Pulmonary veins
• D)Right ventricular outflow tract
• E)Sinoatrial node
• F)Tricuspid valve annulus

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Definitions:

Thick Filament

A component of muscle fiber primarily made of myosin, responsible for muscle contraction.

Myosin

A type of motor protein found in muscle cells and other cell types, essential for muscle contraction and movement within cells.

Sarcomere

The basic unit of muscle fiber responsible for muscle contraction, consisting of actin and myosin filaments.

Muscle Contraction

The process by which muscle fibers generate force and shorten or lengthen to produce movement.