rhythms UPDATED Exam Questions and
CORRECT Answers
Normal sinus rhythm (NSR) - CORRECT ANSWER -Rate: 60-100 bpm
-Rhythm: regular
-P waves (lead II): Positive; one precedes each QRS
-PR interval: 0.12-0.20 seconds
-QRS: 0.10 seconds or less unless abnormally conducted.
Sinus bradycardia - CORRECT ANSWER -Rate: <60 bpm
-Rhythm: regular
-P waves (lead II): Positive, one precedes each QRS. Look alike.
-PR interval: 0.12-0.20 seconds
-QRS: 0.10 seconds or less unless abnormalls conducted.
Causes of sinus bradycardia - CORRECT ANSWER -Inferior myocardial infarction (IMI)
-Posterior mycocardial infraction (PMI)
-Disease of SA node
-Vagal stimulation
-Hypoxia
-Hypothermia
-Increased intracranial pressure
-Hypothyroidism
-Hypokalemia/ Hyperkalemia
-Post heart transplant
-Obstructive sleep apnea
-Medications such as: calcium channel blockers, digitalis, Beta-blockers, amiodarone, and sotalol
,Sinus tachycardia - CORRECT ANSWER -Rate: 101-180 bpm
-Rhythm: P-P regular, R-R regular
-P waves (Lead II): Positive, one precedes each QRS. Look alike. At first fast rates, may be hard
to tell difference between P and T.
-PR interval: 0.12-0.20 (may shorten with faster rates) and constant from best to beat.
-QRS complex: 0.10 seconds or less unless an intraventricular conduction delay exists.
Causes of sinus tachycardia - CORRECT ANSWER -Exercise
-Fever
-Pain
-Fear and anxiety
-Hypoxia
-CHF
-Acute Myocardial Infarction (AMI)
-Infection
-Sympathetic stimulation
-Shock
-Dehydration, hypervolemia
-PE
-Hyperthyroidism
-Medications such as epinephrine, atropine, and dopamine
-Caffeine-containing beverages
-Nicotine
-Drugs such as cocaine, amphetamines, "ecstasy," cannabis
Sinus arrhythmia - CORRECT ANSWER -Rate: 60-100 bpm, but may be slower or faster
-Rhythm: irregular, phasic with respiration; heart rates increases gradually with inhalation (R-R
shorten) and decreases with exhalation(R-R widens)
, P waves (Lead II): Positive, one precedes before each QRS, look alike.
-PR interval: 0.12-0.20 seconds and constant from beat to beat.
-QRS: 0.10 seconds or less unless an intraventricular conduction delay exists.
What causes sinus arrhythmia - CORRECT ANSWER -Age
-Heart disease
-Post acute inferior wall MI
-Increased intracranial pressure.
-Medications such as digitalis and morphine
-Carotid sinus pressure
Sinoatrial (SA) block - CORRECT ANSWER -Rate: usually normal but varies because of the
pause
-Rhythm: irregular due to pause(s) caused by the SA block-- the pause is the same as (or an exact
multiple of) the distance between two other P-P
-P waves (Lead II): Positive, look alike. when present, one precedes each QRS
-PR interval: 0.12-0.20 seconds and constant from beat to beat.
-QRS: 0.10 seconds or less unless an intraventricular conduction delay exists
Causes of SA block - CORRECT ANSWER -Acute MI
-Medications such as digitalis, quindine, procainamide, or salicylates
-CAD
-Myocarditis
-CHF
-Carotid sinus sensitivity
-Increased vagal tone
Sinus arrest - CORRECT ANSWER -Rate: usually normal but varies because of the pause