1|Page
BSN 246 – CHAPTER 39 (2026–2027
EDITION): A COMPREHENSIVE
CLINICAL GUIDE TO [CORE TOPIC
OF CH. 39] – INTEGRATING
EVIDENCE-BASED PRACTICE,
PATIENT SAFETY COMPETENCIES,
AND UPDATED NURSING
INTERVENTIONS
Which physiologic process is responsible for
depolarization of heart cells?
Movement of sodium into the cell
Movement of calcium out of the cell
Movement of potassium into the cell
Movement of magnesium out of the cell
>>correct answer>>Movement of sodium
into the cell
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Rationale : The rapid movement of sodium
into the cell results in the inside of the cell
becoming positive compared with the
outside of the cell. This is known as
depolarization.
Which number represents the patient's heart
rate when the nurse counts 15 of the small
blocks between 1 R-R interval on the
electrocardiogram (ECG) trace?
60 beats/min
75 beats/min
100 beats/min
150 beats/min >>correct answer>>100
beats/min
Rationale: Because each small block on the
ECG paper represents 0.04 seconds, 1500 of
these blocks represents 1 minute. By
, 3|Page
dividing the number of small blocks (15, in
this case) into 1500, the nurse can calculate
the heart rate (in this case, 100).
Which factor is a common cause of
dysrhythmias? Select all that apply. One,
some, or all responses may be correct.
Exercise
Genetics
Emotional crisis
Hypoxia
Toxins
Accessory pathways >>correct
answer>>Emotional crisis
Hypoxia
Toxins
BSN 246 – CHAPTER 39 (2026–2027
EDITION): A COMPREHENSIVE
CLINICAL GUIDE TO [CORE TOPIC
OF CH. 39] – INTEGRATING
EVIDENCE-BASED PRACTICE,
PATIENT SAFETY COMPETENCIES,
AND UPDATED NURSING
INTERVENTIONS
Which physiologic process is responsible for
depolarization of heart cells?
Movement of sodium into the cell
Movement of calcium out of the cell
Movement of potassium into the cell
Movement of magnesium out of the cell
>>correct answer>>Movement of sodium
into the cell
,2|Page
Rationale : The rapid movement of sodium
into the cell results in the inside of the cell
becoming positive compared with the
outside of the cell. This is known as
depolarization.
Which number represents the patient's heart
rate when the nurse counts 15 of the small
blocks between 1 R-R interval on the
electrocardiogram (ECG) trace?
60 beats/min
75 beats/min
100 beats/min
150 beats/min >>correct answer>>100
beats/min
Rationale: Because each small block on the
ECG paper represents 0.04 seconds, 1500 of
these blocks represents 1 minute. By
, 3|Page
dividing the number of small blocks (15, in
this case) into 1500, the nurse can calculate
the heart rate (in this case, 100).
Which factor is a common cause of
dysrhythmias? Select all that apply. One,
some, or all responses may be correct.
Exercise
Genetics
Emotional crisis
Hypoxia
Toxins
Accessory pathways >>correct
answer>>Emotional crisis
Hypoxia
Toxins
