ECG WORKOUT
EXERCISES IN ARRHYTHMIA
INTERPRETATION
8TH EDITION
• AUTHOR(S)JANE HUFF
TEST BANK
1️⃣ Reference
Ch. 1 — Description and Location of the Heart
Question (stem)
A 62-year-old patient lies supine for a telemetry check after an
uncomplicated elective procedure. The monitor shows
unexpected low-amplitude QRS complexes across all leads with
normal rhythm and rate. Considering the heart’s anatomical
position and surrounding structures, which anatomical
,explanation best accounts for diffusely low QRS voltages on
surface ECG monitoring?
A. Left ventricular hypertrophy increasing myocardial mass and
attenuating surface voltages
B. Distant placement of monitoring leads due to anatomic
variability of the heart in the thorax
C. Increased electrical insulation from fluid in the pericardial sac
(e.g., pericardial effusion)
D. Focal anterior myocardial infarction causing localized loss of
depolarization forces
Correct answer
C
Rationale — Correct (C)
Pericardial fluid increases the distance and electrical insulation
between the myocardium and surface electrodes, leading to
globally low QRS voltages. This is an anatomy-based explanation
tied to the heart’s location within the pericardial sac.
Rationales — Incorrect
A. LV hypertrophy typically increases QRS amplitude rather than
causing diffuse low voltage.
B. Lead placement errors cause variable voltages but not a
consistent diffuse low-voltage pattern across all standard leads.
D. A focal anterior infarct produces regional changes (loss of
forces in anterior leads), not diffuse low voltages in all leads.
,Teaching point
Pericardial effusion attenuates QRS voltage by electrically
insulating the heart.
Citation
Huff, J. (2022). ECG Workout: Exercises in Arrhythmia
Interpretation (8th ed.). Ch. 1.
2️⃣ Reference
Ch. 1 — Function of the Heart
Question (stem)
A patient with progressive left ventricular failure becomes
symptomatic with pulmonary edema. On telemetry the nurse
notes episodes of abrupt sinus tachycardia during exertion.
Which physiologic mechanism linking heart function to ECG
best explains the sudden tachycardic response?
A. Increased sympathetic drive from decreased cardiac output
triggering sinus node acceleration
B. Loss of atrial contraction causing automatic ventricular
tachycardia
C. Pericardial constriction causing electrical dissociation and
compensatory tachycardia
D. Coronary artery occlusion producing bradyarrhythmia and
reflex tachycardia
Correct answer
A
, Rationale — Correct (A)
Reduced cardiac output from LV failure stimulates sympathetic
activation to maintain perfusion, which increases sinus node
firing rate, producing sinus tachycardia on ECG.
Rationales — Incorrect
B. Loss of effective atrial contraction does not directly produce
ventricular tachycardia; it affects filling, not sinus automaticity.
C. Pericardial constriction is a mechanical issue; electrical
dissociation is not the primary driver of sinus tachycardia.
D. Coronary occlusion more commonly produces ischemic
arrhythmias; bradyarrhythmia causing reflex tachycardia is
physiologically inconsistent.
Teaching point
Sinus tachycardia often reflects adrenergic compensation for
reduced cardiac output.
Citation
Huff, J. (2022). ECG Workout (8th ed.). Ch. 1.
3️⃣ Reference
Ch. 1 — Heart Surfaces
Question (stem)
A nurse is interpreting an ECG after chest trauma. The monitor
shows prominent Q waves in precordial leads V1–V4 and
reduced R-wave progression. Which structural surface of the
EXERCISES IN ARRHYTHMIA
INTERPRETATION
8TH EDITION
• AUTHOR(S)JANE HUFF
TEST BANK
1️⃣ Reference
Ch. 1 — Description and Location of the Heart
Question (stem)
A 62-year-old patient lies supine for a telemetry check after an
uncomplicated elective procedure. The monitor shows
unexpected low-amplitude QRS complexes across all leads with
normal rhythm and rate. Considering the heart’s anatomical
position and surrounding structures, which anatomical
,explanation best accounts for diffusely low QRS voltages on
surface ECG monitoring?
A. Left ventricular hypertrophy increasing myocardial mass and
attenuating surface voltages
B. Distant placement of monitoring leads due to anatomic
variability of the heart in the thorax
C. Increased electrical insulation from fluid in the pericardial sac
(e.g., pericardial effusion)
D. Focal anterior myocardial infarction causing localized loss of
depolarization forces
Correct answer
C
Rationale — Correct (C)
Pericardial fluid increases the distance and electrical insulation
between the myocardium and surface electrodes, leading to
globally low QRS voltages. This is an anatomy-based explanation
tied to the heart’s location within the pericardial sac.
Rationales — Incorrect
A. LV hypertrophy typically increases QRS amplitude rather than
causing diffuse low voltage.
B. Lead placement errors cause variable voltages but not a
consistent diffuse low-voltage pattern across all standard leads.
D. A focal anterior infarct produces regional changes (loss of
forces in anterior leads), not diffuse low voltages in all leads.
,Teaching point
Pericardial effusion attenuates QRS voltage by electrically
insulating the heart.
Citation
Huff, J. (2022). ECG Workout: Exercises in Arrhythmia
Interpretation (8th ed.). Ch. 1.
2️⃣ Reference
Ch. 1 — Function of the Heart
Question (stem)
A patient with progressive left ventricular failure becomes
symptomatic with pulmonary edema. On telemetry the nurse
notes episodes of abrupt sinus tachycardia during exertion.
Which physiologic mechanism linking heart function to ECG
best explains the sudden tachycardic response?
A. Increased sympathetic drive from decreased cardiac output
triggering sinus node acceleration
B. Loss of atrial contraction causing automatic ventricular
tachycardia
C. Pericardial constriction causing electrical dissociation and
compensatory tachycardia
D. Coronary artery occlusion producing bradyarrhythmia and
reflex tachycardia
Correct answer
A
, Rationale — Correct (A)
Reduced cardiac output from LV failure stimulates sympathetic
activation to maintain perfusion, which increases sinus node
firing rate, producing sinus tachycardia on ECG.
Rationales — Incorrect
B. Loss of effective atrial contraction does not directly produce
ventricular tachycardia; it affects filling, not sinus automaticity.
C. Pericardial constriction is a mechanical issue; electrical
dissociation is not the primary driver of sinus tachycardia.
D. Coronary occlusion more commonly produces ischemic
arrhythmias; bradyarrhythmia causing reflex tachycardia is
physiologically inconsistent.
Teaching point
Sinus tachycardia often reflects adrenergic compensation for
reduced cardiac output.
Citation
Huff, J. (2022). ECG Workout (8th ed.). Ch. 1.
3️⃣ Reference
Ch. 1 — Heart Surfaces
Question (stem)
A nurse is interpreting an ECG after chest trauma. The monitor
shows prominent Q waves in precordial leads V1–V4 and
reduced R-wave progression. Which structural surface of the
