AYCARE EKG TEST 2025-2026 |
B
Solved Questions | Correct Answers |
EKG Rhythm Recognition | Pass
Guaranteed - A+ Graded
[DOMAIN 1: EKG BASICS & WAVEFORM COMPONENTS - 35 Questions]
Question 1.1
What is the standard paper speed for EKG recording?
A) 50 mm/sec
B) 25 mm/sec [CORRECT]
C) 10 mm/sec
D) 100 mm/sec
Rationale: Standard EKG paper speed is 25 mm/second. At this speed, one small box (1 mm)
equals 0.04 seconds (40 ms), and one large box (5 mm) equals 0.20 seconds (200 ms). This
standardization allows consistent interpretation of intervals and rates. Some EKG machines can
record at 50 mm/sec for detailed analysis, but 25 mm/sec is the clinical standard.
Question 1.2
One small box on EKG paper represents how much time?
A) 0.01 seconds
B) 0.04 seconds [CORRECT]
C) 0.20 seconds
D) 1.00 second
Rationale: At standard 25 mm/sec paper speed, each 1 mm small box represents 0.04 seconds
(40 milliseconds). Five small boxes (one large box) equal 0.20 seconds. This measurement is
crucial for calculating intervals (PR, QRS, QT) and determining rate (300 method uses large
boxes).
Question 1.3
The standard calibration for EKG amplitude is:
A) 5 mm = 1 mV
B) 10 mm = 1 mV [CORRECT]
C) 20 mm = 1 mV
D) 1 mm = 1 mV
Rationale: Standard calibration is 10 mm (10 small boxes) vertical deflection equals 1 millivolt
(mV). This allows measurement of wave amplitudes (P wave <2.5 mm, QRS amplitude varies).
If QRS complexes are too large, half-standard (5 mm/mV) may be used; if too small,
double-standard (20 mm/mV) may be used, but this must be noted on the tracing.
, uestion 1.4
Q
The P wave represents:
A) Ventricular depolarization
B) Atrial depolarization [CORRECT]
C) Ventricular repolarization
D) Atrial repolarization
Rationale: The P wave represents depolarization (electrical activation) of the atria, initiated by
the SA node and spreading through atrial muscle. Atrial repolarization is usually hidden within
the QRS complex and not visible. Ventricular depolarization creates the QRS complex;
ventricular repolarization creates the T wave.
Question 1.5
Normal P wave duration is:
A) <0.20 seconds
B) <0.12 seconds [CORRECT]
C) 0.12-0.20 seconds
D) >0.20 seconds
Rationale: Normal P wave duration is <0.12 seconds (3 small boxes). Prolonged P wave (>0.12
sec) suggests left atrial enlargement (P mitrale), often seen in mitral valve disease. P wave
amplitude should be <2.5 mm in limb leads. Right atrial enlargement causes tall, peaked P
waves (P pulmonale).
Question 1.6
The PR interval represents:
A) Time from ventricular depolarization to repolarization
B) Time from atrial depolarization to ventricular depolarization [CORRECT]
C) Time of ventricular contraction only
D) Time of atrial relaxation only
Rationale: The PR interval measures from the beginning of the P wave (atrial depolarization) to
the beginning of the QRS complex (ventricular depolarization), representing conduction through
the AV node, bundle of His, and bundle branches. Normal is 0.12-0.20 seconds (3-5 small
boxes). It assesses AV conduction integrity.
Question 1.7
Normal PR interval duration is:
A) 0.06-0.10 seconds
B) 0.12-0.20 seconds [CORRECT]
C) 0.20-0.40 seconds
D) 0.44-0.52 seconds
Rationale: Normal PR interval is 0.12-0.20 seconds (3-5 small boxes). <0.12 seconds suggests
pre-excitation (WPW) or junctional rhythm. >0.20 seconds indicates first-degree AV block. The
PR interval varies slightly with heart rate (shorter at faster rates) but should remain within
normal range.
Question 1.8
The QRS complex represents:
A) Atrial depolarization
B) Ventricular depolarization [CORRECT]
, ) Atrial repolarization
C
D) Ventricular repolarization
Rationale: The QRS complex represents ventricular depolarization, the electrical activation of
the ventricles via the His-Purkinje system. Despite being called a "complex," it is a single
electrical event lasting <0.12 seconds in normal conduction. Ventricular repolarization is
represented by the T wave (and U wave).
Question 1.9
Normal QRS duration is:
A) <0.06 seconds
B) 0.06-0.10 seconds [CORRECT]
C) 0.12-0.20 seconds
D) >0.12 seconds
Rationale: Normal QRS duration is 0.06-0.10 seconds (1.5-2.5 small boxes). Narrow QRS
(<0.12 sec) indicates supraventricular origin with normal conduction. Wide QRS (>0.12 sec)
indicates ventricular origin, bundle branch block, or aberrant conduction. QRS duration is
measured from Q wave onset to S wave end.
Question 1.10
The QT interval represents:
A) Atrial activity only
B) Total ventricular activity (depolarization and repolarization) [CORRECT]
C) AV node conduction time only
D) Atrial repolarization only
Rationale: The QT interval measures from the beginning of the QRS (ventricular depolarization)
to the end of the T wave (ventricular repolarization), representing total ventricular electrical
activity. It is rate-dependent and must be corrected (QTc) for heart rate. Prolonged QT increases
risk of torsades de pointes.
Question 1.11
Normal corrected QT interval (QTc) should be:
A) <0.30 seconds
B) <0.44 seconds [CORRECT]
C) >0.50 seconds
D) 0.20-0.30 seconds
Rationale: QTc (corrected for heart rate using Bazett's formula: QT/√RR) should be <0.44
seconds in men and <0.46 seconds in women. QTc >0.50 seconds significantly increases risk of
torsades de pointes. Causes of prolonged QT include medications (antiarrhythmics, antibiotics),
electrolyte abnormalities (hypokalemia, hypomagnesemia), and congenital long QT syndrome.
Question 1.12
The ST segment represents:
A) Atrial depolarization
B) Early ventricular repolarization [CORRECT]
C) Late ventricular depolarization
D) Atrial repolarization
Rationale: The ST segment is the isoelectric period between the end of the QRS complex (S
wave) and the beginning of the T wave, representing early ventricular repolarization when the
, entricles are fully depolarized. ST elevation (>1 mm in limb leads, >2 mm in precordial leads)
v
indicates acute injury (MI, pericarditis). ST depression indicates ischemia or reciprocal changes.
Question 1.13
The T wave represents:
A) Atrial depolarization
B) Ventricular repolarization [CORRECT]
C) AV node conduction
D) SA node firing
Rationale: The T wave represents ventricular repolarization (electrical recovery). Normally
upright in leads with positive QRS complexes (I, II, aVF, V3-V6) and inverted in aVR. T wave
inversion can indicate ischemia, electrolyte abnormalities, or be normal in aVR and V1. T wave
peaking occurs in hyperkalemia; flattening in hypokalemia.
Question 1.14
The U wave, when prominent, is most commonly associated with:
A) Hyperkalemia
B) Hypokalemia [CORRECT]
C) Hypercalcemia
D) Normal variant only
Rationale: Prominent U waves (following the T wave) are classically associated with
hypokalemia (low potassium), though they can be normal variants. They represent
repolarization of the Purkinje fibers. Hypokalemia also causes ST depression and flattened T
waves. Hyperkalemia causes peaked T waves, not prominent U waves.
Question 1.15
The absolute refractory period in the cardiac cycle corresponds to:
A) The PR interval
B) The QRS complex to the peak of the T wave [CORRECT]
C) The ST segment only
D) The P wave only
Rationale: The absolute refractory period (no stimulus can trigger another action potential)
extends from the beginning of the QRS through most of the T wave (roughly to the peak).
During this time, the myocardium cannot be restimulated, preventing tetanic contraction. The
relative refractory period extends from peak T to end of T wave.
Question 1.16
The vulnerable period of the cardiac cycle, when a stimulus may trigger ventricular fibrillation, is:
A) During the P wave
B) At the peak of the T wave (R-on-T phenomenon) [CORRECT]
C) During the PR interval
D) During the QRS complex
Rationale: The vulnerable period corresponds to the relative refractory period at the peak of the
T wave. An electrical stimulus (PVC, pacemaker, defibrillation) occurring at this time (R-on-T)
can cause ventricular fibrillation because some cells are repolarized (excitable) while others are
still refractory, creating re-entry circuits.
Question 1.17
Five large boxes on EKG paper represent:
B
Solved Questions | Correct Answers |
EKG Rhythm Recognition | Pass
Guaranteed - A+ Graded
[DOMAIN 1: EKG BASICS & WAVEFORM COMPONENTS - 35 Questions]
Question 1.1
What is the standard paper speed for EKG recording?
A) 50 mm/sec
B) 25 mm/sec [CORRECT]
C) 10 mm/sec
D) 100 mm/sec
Rationale: Standard EKG paper speed is 25 mm/second. At this speed, one small box (1 mm)
equals 0.04 seconds (40 ms), and one large box (5 mm) equals 0.20 seconds (200 ms). This
standardization allows consistent interpretation of intervals and rates. Some EKG machines can
record at 50 mm/sec for detailed analysis, but 25 mm/sec is the clinical standard.
Question 1.2
One small box on EKG paper represents how much time?
A) 0.01 seconds
B) 0.04 seconds [CORRECT]
C) 0.20 seconds
D) 1.00 second
Rationale: At standard 25 mm/sec paper speed, each 1 mm small box represents 0.04 seconds
(40 milliseconds). Five small boxes (one large box) equal 0.20 seconds. This measurement is
crucial for calculating intervals (PR, QRS, QT) and determining rate (300 method uses large
boxes).
Question 1.3
The standard calibration for EKG amplitude is:
A) 5 mm = 1 mV
B) 10 mm = 1 mV [CORRECT]
C) 20 mm = 1 mV
D) 1 mm = 1 mV
Rationale: Standard calibration is 10 mm (10 small boxes) vertical deflection equals 1 millivolt
(mV). This allows measurement of wave amplitudes (P wave <2.5 mm, QRS amplitude varies).
If QRS complexes are too large, half-standard (5 mm/mV) may be used; if too small,
double-standard (20 mm/mV) may be used, but this must be noted on the tracing.
, uestion 1.4
Q
The P wave represents:
A) Ventricular depolarization
B) Atrial depolarization [CORRECT]
C) Ventricular repolarization
D) Atrial repolarization
Rationale: The P wave represents depolarization (electrical activation) of the atria, initiated by
the SA node and spreading through atrial muscle. Atrial repolarization is usually hidden within
the QRS complex and not visible. Ventricular depolarization creates the QRS complex;
ventricular repolarization creates the T wave.
Question 1.5
Normal P wave duration is:
A) <0.20 seconds
B) <0.12 seconds [CORRECT]
C) 0.12-0.20 seconds
D) >0.20 seconds
Rationale: Normal P wave duration is <0.12 seconds (3 small boxes). Prolonged P wave (>0.12
sec) suggests left atrial enlargement (P mitrale), often seen in mitral valve disease. P wave
amplitude should be <2.5 mm in limb leads. Right atrial enlargement causes tall, peaked P
waves (P pulmonale).
Question 1.6
The PR interval represents:
A) Time from ventricular depolarization to repolarization
B) Time from atrial depolarization to ventricular depolarization [CORRECT]
C) Time of ventricular contraction only
D) Time of atrial relaxation only
Rationale: The PR interval measures from the beginning of the P wave (atrial depolarization) to
the beginning of the QRS complex (ventricular depolarization), representing conduction through
the AV node, bundle of His, and bundle branches. Normal is 0.12-0.20 seconds (3-5 small
boxes). It assesses AV conduction integrity.
Question 1.7
Normal PR interval duration is:
A) 0.06-0.10 seconds
B) 0.12-0.20 seconds [CORRECT]
C) 0.20-0.40 seconds
D) 0.44-0.52 seconds
Rationale: Normal PR interval is 0.12-0.20 seconds (3-5 small boxes). <0.12 seconds suggests
pre-excitation (WPW) or junctional rhythm. >0.20 seconds indicates first-degree AV block. The
PR interval varies slightly with heart rate (shorter at faster rates) but should remain within
normal range.
Question 1.8
The QRS complex represents:
A) Atrial depolarization
B) Ventricular depolarization [CORRECT]
, ) Atrial repolarization
C
D) Ventricular repolarization
Rationale: The QRS complex represents ventricular depolarization, the electrical activation of
the ventricles via the His-Purkinje system. Despite being called a "complex," it is a single
electrical event lasting <0.12 seconds in normal conduction. Ventricular repolarization is
represented by the T wave (and U wave).
Question 1.9
Normal QRS duration is:
A) <0.06 seconds
B) 0.06-0.10 seconds [CORRECT]
C) 0.12-0.20 seconds
D) >0.12 seconds
Rationale: Normal QRS duration is 0.06-0.10 seconds (1.5-2.5 small boxes). Narrow QRS
(<0.12 sec) indicates supraventricular origin with normal conduction. Wide QRS (>0.12 sec)
indicates ventricular origin, bundle branch block, or aberrant conduction. QRS duration is
measured from Q wave onset to S wave end.
Question 1.10
The QT interval represents:
A) Atrial activity only
B) Total ventricular activity (depolarization and repolarization) [CORRECT]
C) AV node conduction time only
D) Atrial repolarization only
Rationale: The QT interval measures from the beginning of the QRS (ventricular depolarization)
to the end of the T wave (ventricular repolarization), representing total ventricular electrical
activity. It is rate-dependent and must be corrected (QTc) for heart rate. Prolonged QT increases
risk of torsades de pointes.
Question 1.11
Normal corrected QT interval (QTc) should be:
A) <0.30 seconds
B) <0.44 seconds [CORRECT]
C) >0.50 seconds
D) 0.20-0.30 seconds
Rationale: QTc (corrected for heart rate using Bazett's formula: QT/√RR) should be <0.44
seconds in men and <0.46 seconds in women. QTc >0.50 seconds significantly increases risk of
torsades de pointes. Causes of prolonged QT include medications (antiarrhythmics, antibiotics),
electrolyte abnormalities (hypokalemia, hypomagnesemia), and congenital long QT syndrome.
Question 1.12
The ST segment represents:
A) Atrial depolarization
B) Early ventricular repolarization [CORRECT]
C) Late ventricular depolarization
D) Atrial repolarization
Rationale: The ST segment is the isoelectric period between the end of the QRS complex (S
wave) and the beginning of the T wave, representing early ventricular repolarization when the
, entricles are fully depolarized. ST elevation (>1 mm in limb leads, >2 mm in precordial leads)
v
indicates acute injury (MI, pericarditis). ST depression indicates ischemia or reciprocal changes.
Question 1.13
The T wave represents:
A) Atrial depolarization
B) Ventricular repolarization [CORRECT]
C) AV node conduction
D) SA node firing
Rationale: The T wave represents ventricular repolarization (electrical recovery). Normally
upright in leads with positive QRS complexes (I, II, aVF, V3-V6) and inverted in aVR. T wave
inversion can indicate ischemia, electrolyte abnormalities, or be normal in aVR and V1. T wave
peaking occurs in hyperkalemia; flattening in hypokalemia.
Question 1.14
The U wave, when prominent, is most commonly associated with:
A) Hyperkalemia
B) Hypokalemia [CORRECT]
C) Hypercalcemia
D) Normal variant only
Rationale: Prominent U waves (following the T wave) are classically associated with
hypokalemia (low potassium), though they can be normal variants. They represent
repolarization of the Purkinje fibers. Hypokalemia also causes ST depression and flattened T
waves. Hyperkalemia causes peaked T waves, not prominent U waves.
Question 1.15
The absolute refractory period in the cardiac cycle corresponds to:
A) The PR interval
B) The QRS complex to the peak of the T wave [CORRECT]
C) The ST segment only
D) The P wave only
Rationale: The absolute refractory period (no stimulus can trigger another action potential)
extends from the beginning of the QRS through most of the T wave (roughly to the peak).
During this time, the myocardium cannot be restimulated, preventing tetanic contraction. The
relative refractory period extends from peak T to end of T wave.
Question 1.16
The vulnerable period of the cardiac cycle, when a stimulus may trigger ventricular fibrillation, is:
A) During the P wave
B) At the peak of the T wave (R-on-T phenomenon) [CORRECT]
C) During the PR interval
D) During the QRS complex
Rationale: The vulnerable period corresponds to the relative refractory period at the peak of the
T wave. An electrical stimulus (PVC, pacemaker, defibrillation) occurring at this time (R-on-T)
can cause ventricular fibrillation because some cells are repolarized (excitable) while others are
still refractory, creating re-entry circuits.
Question 1.17
Five large boxes on EKG paper represent:
