ECG Cardiac Anatomy 5

Question 1

The left main coronary artery bifurcates into which two vessels?

Accepted Answer

LAD and LCx

Answer

The left main coronary artery divides into the left anterior descending (LAD) and left circumflex (LCx) arteries.

Question 2

Which structure prevents the AV valves from prolapsing into the atria during ventricular contraction?

Accepted Answer

Papillary muscles and chordae tendineae

Answer

Papillary muscles contract simultaneously with the ventricle, tensing the chordae tendineae to hold valve leaflets in place.

Question 3

In a right-dominant coronary circulation (most common), the posterior descending artery (PDA) arises from which vessel?

Accepted Answer

Right coronary artery

Answer

In ~85% of individuals, the RCA gives rise to the PDA, making the circulation 'right dominant.'

Question 4

Which ECG finding is characteristic of right ventricular hypertrophy related to cor pulmonale?

Accepted Answer

Right axis deviation with tall R in V1

Answer

RVH produces right axis deviation and a dominant R wave in V1 due to increased right ventricular mass shifting the electrical axis rightward.

Question 5

The fibrous skeleton of the heart serves which primary function?

Accepted Answer

Provides electrical insulation between atria and ventricles

Answer

The fibrous skeleton electrically isolates the atria from the ventricles so the only conduction pathway is the AV node–His axis.

ECG Certification Practice Test