BASIC DYSRHYTHMIAS P ART I & II
STUDY GUIDE EXAM CON TAINING 101
QUESTIONS AND ANSWER S/ .
Question : Sinoatrial (SA) node
Correct answer: p wave
Question : Atrioventricular (AV) node
Correct answer: PR segment
Question : Bundle of His
Correct answer: QRS complex
Question : Bundle Branches
Correct answer: QRS complex
Question : Purkinje Fibers
Correct answer: QRS complex
Question : sinoatrial node (SA node) starts an impulse, as the
wave of depolarization spreads through the atria, _______ is inscribed on the ECG
Correct answer: P wave
Question : AV node conduction
Correct answer: Is the ONLY electrical conduction pathway
between the atria and ventricles.-Depolarization is SLOWED to allow fill time -It is carried by SLOW Ca++ ions = slower conduction (Na+ produces fast depolarization)
Question : AV Valves
Correct answer: -Prevent ventricle-to-atrium blood backflow
-ELECTRICALLY INSULATE the ventricles from the atria
Question : QRS complex
Correct answer: 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 depolarization
Question : Ventricular conduction system
Correct answer: -Bundle of HIS (penetrates the AV valves)
-Then splits into Left & Right bundle branches -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
Question : P-R interval
Correct answer: -Period where there is a brief delay impulse
in the AV node SA node to AV node
Question : T-Wave
Correct answer: Repolarization of ventricles (terminates
contraction)
Question : Sympathetic Nervous System: Cardiac Excitability Effect
Correct answer: activates cardiac beta-1 adrenergic receptors
-Increases rate of SA node pacing -Increases rate of conduction -Increases force of contraction -Increases irritability of foci
Question : Parasympathetic Nervous System: Cardiac Inhibitory Effect
Correct answer: Activates cholinergic receptors
-Decreases rate of SA node pacing -Decreases rate of conduction -Decreases force of contraction -Decreases irritability of atrial and junctional foci
Question : Normal sinus rhythm (NRS)
Correct answer: -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 0.06 to 0.10 (half of PR interval) Any deviation from above is sinus tachycardia, sinus bradycardia or an arrhythmia But is still originating from the SA node if the above criteria is met with rate variance.