ECG Cardiac Anatomy 4

Question 1

Which coronary artery territory is represented by ST changes in leads II, III, and aVF?

Accepted Answer

Right coronary artery

Answer

Inferior leads II, III, and aVF face the inferior wall, which is predominantly supplied by the right coronary artery.

Question 2

The sinus node (SA node) is typically located at the junction of which structures?

Accepted Answer

Superior vena cava and right atrium

Answer

The SA node sits at the superior cavoatrial junction near the crista terminalis in the right atrium.

Question 3

Tricuspid valve regurgitation most directly increases volume load in which chamber?

Accepted Answer

Right atrium

Answer

Systolic backflow through an incompetent tricuspid valve floods the right atrium, causing right atrial dilation.

Question 4

Which valve is located at the origin of the pulmonary artery and prevents backflow into the right ventricle?

Accepted Answer

Pulmonic valve

Answer

The pulmonic (pulmonary) valve is a semilunar valve that opens during right ventricular systole and closes to prevent regurgitation.

Question 5

The left ventricle forms which border of the heart on the standard frontal chest X-ray?

Accepted Answer

Left cardiac border

Answer

The left ventricular free wall forms the left cardiac silhouette on a PA chest X-ray.

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