APEX 1 Question and answers 100%
correct 2026/2027
What is the rate of the SA node? What rhythms will it create on an ECG? - correct answer 60-100 BPM.
It's the pacemaker of the heart and creates sinus rhythms.
What is the rate of the AV node? What rhythms will it create on an ECG? - correct answer 40-60 BPM.
It's the backup pacemaker and creates junctional rhythms.
What is the rate of the purkinje fibers? What rhythms will they create on an ECG? - correct answer 20-
40 BPM. It's the ventricular pacemaker and it creates idioventricular rhythms. These rhythms are lethal!
Ventricular rates are very slow.
Isoelectric Line - correct answer This depicts the resting phase of the myocardium and is a baseline
tracing without electrical activity. Waveforms and intervals are measured at the point of deviation from
the isoelectric line.
P wave - correct answer Represents electrical depolarization of the atria. Normal P waves do not exceed
2.5 mm in amplitude and are usually less than 0.12 seconds wide.
Q wave - correct answer The first portion of the QRS complex is seen as a downward or negative
deflection. It is indicative of the beginning of ventricular depolarization. Sometimes Q waves are absent
and the first deflection is positive.
R wave - correct answer The first upward or positive deflection of the QRS complex after the P wave,
and represents ventricular depolarization.
S wave - correct answer The downward or negative deflection that follows an R wave and denotes the
completion of ventricular depolarization.
correct 2026/2027
What is the rate of the SA node? What rhythms will it create on an ECG? - correct answer 60-100 BPM.
It's the pacemaker of the heart and creates sinus rhythms.
What is the rate of the AV node? What rhythms will it create on an ECG? - correct answer 40-60 BPM.
It's the backup pacemaker and creates junctional rhythms.
What is the rate of the purkinje fibers? What rhythms will they create on an ECG? - correct answer 20-
40 BPM. It's the ventricular pacemaker and it creates idioventricular rhythms. These rhythms are lethal!
Ventricular rates are very slow.
Isoelectric Line - correct answer This depicts the resting phase of the myocardium and is a baseline
tracing without electrical activity. Waveforms and intervals are measured at the point of deviation from
the isoelectric line.
P wave - correct answer Represents electrical depolarization of the atria. Normal P waves do not exceed
2.5 mm in amplitude and are usually less than 0.12 seconds wide.
Q wave - correct answer The first portion of the QRS complex is seen as a downward or negative
deflection. It is indicative of the beginning of ventricular depolarization. Sometimes Q waves are absent
and the first deflection is positive.
R wave - correct answer The first upward or positive deflection of the QRS complex after the P wave,
and represents ventricular depolarization.
S wave - correct answer The downward or negative deflection that follows an R wave and denotes the
completion of ventricular depolarization.
