Basic Dysrhythmias Part I & II
Basic Dysrhythmias Part I & II Study
Guide Exam Containing 101 Questions
and Answers/ 2024-2025.
Pacemakers of the Heart - Answer: Sinoatrial (SA) node
Atrioventricular (AV) node
Bundle of His
Bundle Branches
, Basic Dysrhythmias Part I & II
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
P wave - Answer: sinoatrial node (SA node) starts an impulse, as the wave of
depolarization spreads through the atria, _______ is inscribed on the ECG
AV node conduction - 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)
AV Valves - Answer: -Prevent ventricle-to-atrium blood backflow
-ELECTRICALLY INSULATE the ventricles from the atria
, Basic Dysrhythmias Part I & II
QRS complex - 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
Ventricular conduction system - 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
P-R interval - Answer: -Period where there is a brief delay impulse in the AV node
SA node to AV node
T-Wave - Answer: Repolarization of ventricles (terminates contraction)
Sympathetic Nervous System: Cardiac Excitability Effect - Answer: activates cardiac
beta-1 adrenergic receptors
-Increases rate of SA node pacing
-Increases rate of conduction
, Basic Dysrhythmias Part I & II
-Increases force of contraction
-Increases irritability of foci
Parasympathetic Nervous System: Cardiac Inhibitory Effect - 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
Normal sinus rhythm (NRS) - 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
Basic Dysrhythmias Part I & II Study
Guide Exam Containing 101 Questions
and Answers/ 2024-2025.
Pacemakers of the Heart - Answer: Sinoatrial (SA) node
Atrioventricular (AV) node
Bundle of His
Bundle Branches
, Basic Dysrhythmias Part I & II
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
P wave - Answer: sinoatrial node (SA node) starts an impulse, as the wave of
depolarization spreads through the atria, _______ is inscribed on the ECG
AV node conduction - 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)
AV Valves - Answer: -Prevent ventricle-to-atrium blood backflow
-ELECTRICALLY INSULATE the ventricles from the atria
, Basic Dysrhythmias Part I & II
QRS complex - 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
Ventricular conduction system - 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
P-R interval - Answer: -Period where there is a brief delay impulse in the AV node
SA node to AV node
T-Wave - Answer: Repolarization of ventricles (terminates contraction)
Sympathetic Nervous System: Cardiac Excitability Effect - Answer: activates cardiac
beta-1 adrenergic receptors
-Increases rate of SA node pacing
-Increases rate of conduction
, Basic Dysrhythmias Part I & II
-Increases force of contraction
-Increases irritability of foci
Parasympathetic Nervous System: Cardiac Inhibitory Effect - 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
Normal sinus rhythm (NRS) - 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
