QUESTIONS & DETAILED COMPLETE
SOLUTIONS RATED 100% CORRECT
1. Pacemakers Sinoatrial (SA) node
of the Heart Atrioventricular (AV)
node Bundle of His
Bundle Branches
Purkinje Fibers
-SA node: p wave
-SA node to AV node: PR segment
-Impulse travels from Bundle of His to Bundle branches and then to
Purkinje fibers: QRS complex
-Repolarization of ventricles: T wave
2. P wave sinoatrial node (SA node) starts an impulse, as the wave of
depolarization spreads through the atria, is inscribed on
the ECG
3. AV node Is the ONLY electrical conduction pathway between the atria and
conduc- tion ventricles.
-Depolarization is SLOWED to allow fill time
-It is carried by SLOW Ca++ ions = slower
conduction (Na+ produces fast depolarization)
4. AV Valves -Prevent ventricle-to-atrium blood backflow
-ELECTRICALLY INSULATE the ventricles from the atria
5. QRS complex After leaving the AV node, the wave of depolarization (impulse) spread
rapidly
through the Bundle of His to the Bundle branches and then to Purkinje
fibers; which cause ventricular depolarization, contraction immediately
follows depolar- ization
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,BASIC DYSRHYTHMIAS PART I & II EXAM
QUESTIONS & DETAILED COMPLETE
SOLUTIONS RATED 100% CORRECT
6. Ventricular -Bundle of HIS (penetrates the AV valves)
con- duction -Then splits into Left & Right bundle branches
system -BOTH THE BUNDLE OF HIS & BUNDLE BRANCHES ARE BUNDLES of
rapidly
conducting Purkinje fibers
-Purkinje fibers use FAST MOVING Na+ ions for conduction of
depolarization
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,BASIC DYSRHYTHMIAS PART I & II EXAM
QUESTIONS & DETAILED COMPLETE
SOLUTIONS RATED 100% CORRECT
7. P-R interval -Period where there is a brief delay impulse in the AV node
SA node to AV node
8. T-Wave Repolarization of ventricles (terminates contraction)
9. Sympathetic Ner- activates cardiac beta-1 adrenergic receptors
vous System: -Increases rate of SA node pacing
Cardiac Excitabili- -Increases rate of conduction
ty Effect
10. Parasympathe
tic Nervous
System: 12. Sinus Arrhythmia
Cardiac
Inhibitory
Effect
11. Normal
sinus
rhythm
(NRS)
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, BASIC DYSRHYTHMIAS PART I & II EXAM
QUESTIONS & DETAILED COMPLETE
SOLUTIONS RATED 100% CORRECT
-Increases force of contraction 0.06 to 0.10 (half of PR interval)
-Increases irritability of foci Any deviation from above is sinus tachycardia, sinus bradycardia or an
arrhythmia But is still originating from the SA node if the above
Activates cholinergic criteria is met with rate variance.
receptors
-Decreases rate of SA node
pacing
-Decreases rate of conduction
-Decreases force of
contraction
-Decreases irritability of atrial
and junctional foci
-Impulses originate from S-A
node at normal rate; all
complexes are normal and
evenly spaced
(1) Rate: 60 to 100
beats/min
(2) Rhythm: regular
(evenly space) +/- 10%
(3) P wave: must be
present, and only one
must precede every QRS
complex
(4) P-R interval: presents
delay in AV node; should
be 0.12 to .20 seconds
(5) QRS complex: size
and shape do not matter,
but ALL QRS pattern must
look alike; duration of
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