COMPLETE REAL EXAM QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS) ALREADY
GRADED A+ (BRAND NEW!!)
1. Which coronary artery supplies the sinoatrial (SA) node in
60% of the population?
A. Left anterior descending (LAD)
B. Right coronary artery (RCA)
C. Left circumflex (LCx)
D. Posterior descending artery (PDA)
Correct Answer: B
Rationale: The RCA supplies the SA node in ~60% of individuals;
the LCx supplies it in ~40%. This is clinically relevant in RCA
occlusions causing bradyarrhythmias.
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,2. The left main coronary artery typically bifurcates into which
two branches?
A. LAD and diagonal
B. LAD and LCx
C. RCA and PDA
D. LCx and obtuse marginal
Correct Answer: B
Rationale: The left main divides into the left anterior descending
(LAD) and left circumflex (LCx). The LAD gives off diagonals and
septals; the LCx gives off obtuse marginals.
3. Which coronary vessel is most commonly responsible for
inferior wall myocardial infarction?
A. LAD
B. RCA
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,C. LCx
D. Left main
Correct Answer: B
Rationale: The RCA supplies the inferior wall via the PDA. Inferior
STEMI often involves RCA occlusion.
4. The vein that courses with the LAD and is used as a conduit
for coronary artery bypass grafting (CABG) is the:
A. Great cardiac vein
B. Middle cardiac vein
C. Small cardiac vein
D. Coronary sinus
Correct Answer: A
Rationale: The great cardiac vein runs in the anterior
interventricular groove with the LAD. It is not used as a bypass
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, conduit (saphenous vein, internal mammary, radial artery are
used).
5. Which structure is the primary pacemaker of the heart?
A. AV node
B. Purkinje fibers
C. SA node
D. Bundle of His
Correct Answer: C
Rationale: The SA node (60–100 bpm) is the normal pacemaker.
The AV node (40–60 bpm) and Purkinje fibers (15–40 bpm) are
secondary/tertiary.
6. The right coronary artery gives rise to which branch that
supplies the inferior wall?
A. Acute marginal
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