ECG WORKOUT
EXERCISES IN ARRHYTHMIA
INTERPRETATION
8TH EDITION
• AUTHOR(S)JANE HUFF
TEST BANK
1
Reference
Ch. — Description and Location of the Heart
Question Stem
A telemetry monitor shows progressive ST elevation in leads II,
III, and aVF during a patient’s chest pain episode. Based on the
typical anatomical location of the heart, which coronary artery
territory is most likely responsible for these ECG changes?
,Describe the anatomical relationship that explains the lead
distribution.
Options
A. Left anterior descending (LAD) artery — anterior wall
involvement
B. Right coronary artery (RCA) — inferior wall involvement
C. Left circumflex (LCx) artery — lateral wall involvement
D. Posterior descending artery (from LAD) — posterior wall
involvement
Correct Answer
B
Rationales
Correct (B): Leads II, III, and aVF view the inferior surface of the
heart, which is most commonly supplied by the RCA in right-
dominant circulation; infarction in the RCA territory produces
inferior ST elevation.
Incorrect (A): LAD supplies the anterior wall and septum (V1–
V4); ST changes there would appear in precordial leads, not
II/III/aVF.
Incorrect (C): LCx supplies lateral leads (I, aVL, V5–V6); inferior
lead ST elevation is not consistent.
Incorrect (D): A posterior infarct produces reciprocal ST
depression in V1–V2 and tall R waves there; isolated II/III/aVF
ST elevation points to inferior RCA territory.
,Teaching Point
Inferior leads (II, III, aVF) reflect the heart’s diaphragmatic
(inferior) surface—usually RCA.
Citation
Huff, J. (2022). ECG Workout: Exercises in Arrhythmia
Interpretation (8th ed.). Ch. — Description and Location of the
Heart.
2
Reference
Ch. — Function of the Heart
Question Stem
A patient on telemetry has sinus rhythm with a prolonged PR
interval of 320 ms but otherwise narrow QRS complexes and
stable vitals. Considering atrioventricular conduction
physiology, which physiological location is most likely
responsible for the PR prolongation? Explain why.
Options
A. SA node conduction delay
B. AV node conduction delay
C. His–Purkinje system delay
D. Ventricular myocardial delay
Correct Answer
B
, Rationales
Correct (B): The PR interval primarily reflects conduction from
atria through the AV node to the His bundle; prolonged PR
(>200 ms) most commonly indicates AV nodal delay (first-
degree AV block).
Incorrect (A): SA node dysfunction affects P-wave
generation/pauses rather than PR duration.
Incorrect (C): His–Purkinje delays more commonly widen the
QRS or produce infra-nodal block, not isolated PR prolongation
with narrow QRS.
Incorrect (D): Ventricular myocardial delay would widen QRS
and alter ventricular depolarization, not prolong PR alone.
Teaching Point
PR interval reflects AV nodal conduction time; isolated
prolongation suggests AV nodal delay.
Citation
Huff, J. (2022). ECG Workout: Exercises in Arrhythmia
Interpretation (8th ed.). Ch. — Function of the Heart.
3
Reference
Ch. — Heart Surfaces
Question Stem
A monitor technician notes tall R waves and right-axis deviation
on a 12-lead ECG in a young adult with chronic lung disease.
EXERCISES IN ARRHYTHMIA
INTERPRETATION
8TH EDITION
• AUTHOR(S)JANE HUFF
TEST BANK
1
Reference
Ch. — Description and Location of the Heart
Question Stem
A telemetry monitor shows progressive ST elevation in leads II,
III, and aVF during a patient’s chest pain episode. Based on the
typical anatomical location of the heart, which coronary artery
territory is most likely responsible for these ECG changes?
,Describe the anatomical relationship that explains the lead
distribution.
Options
A. Left anterior descending (LAD) artery — anterior wall
involvement
B. Right coronary artery (RCA) — inferior wall involvement
C. Left circumflex (LCx) artery — lateral wall involvement
D. Posterior descending artery (from LAD) — posterior wall
involvement
Correct Answer
B
Rationales
Correct (B): Leads II, III, and aVF view the inferior surface of the
heart, which is most commonly supplied by the RCA in right-
dominant circulation; infarction in the RCA territory produces
inferior ST elevation.
Incorrect (A): LAD supplies the anterior wall and septum (V1–
V4); ST changes there would appear in precordial leads, not
II/III/aVF.
Incorrect (C): LCx supplies lateral leads (I, aVL, V5–V6); inferior
lead ST elevation is not consistent.
Incorrect (D): A posterior infarct produces reciprocal ST
depression in V1–V2 and tall R waves there; isolated II/III/aVF
ST elevation points to inferior RCA territory.
,Teaching Point
Inferior leads (II, III, aVF) reflect the heart’s diaphragmatic
(inferior) surface—usually RCA.
Citation
Huff, J. (2022). ECG Workout: Exercises in Arrhythmia
Interpretation (8th ed.). Ch. — Description and Location of the
Heart.
2
Reference
Ch. — Function of the Heart
Question Stem
A patient on telemetry has sinus rhythm with a prolonged PR
interval of 320 ms but otherwise narrow QRS complexes and
stable vitals. Considering atrioventricular conduction
physiology, which physiological location is most likely
responsible for the PR prolongation? Explain why.
Options
A. SA node conduction delay
B. AV node conduction delay
C. His–Purkinje system delay
D. Ventricular myocardial delay
Correct Answer
B
, Rationales
Correct (B): The PR interval primarily reflects conduction from
atria through the AV node to the His bundle; prolonged PR
(>200 ms) most commonly indicates AV nodal delay (first-
degree AV block).
Incorrect (A): SA node dysfunction affects P-wave
generation/pauses rather than PR duration.
Incorrect (C): His–Purkinje delays more commonly widen the
QRS or produce infra-nodal block, not isolated PR prolongation
with narrow QRS.
Incorrect (D): Ventricular myocardial delay would widen QRS
and alter ventricular depolarization, not prolong PR alone.
Teaching Point
PR interval reflects AV nodal conduction time; isolated
prolongation suggests AV nodal delay.
Citation
Huff, J. (2022). ECG Workout: Exercises in Arrhythmia
Interpretation (8th ed.). Ch. — Function of the Heart.
3
Reference
Ch. — Heart Surfaces
Question Stem
A monitor technician notes tall R waves and right-axis deviation
on a 12-lead ECG in a young adult with chronic lung disease.
