Cardiac Rhythm Quick Reference Sheet
Rasmussen University 2024 NCLEX
Resting membrane potential of the heart is: - ANSWER: Diastole
What are critical for the rapid change in resting membrane potential of the heart? -
ANSWER: Fast Sodium Channels
What helps to support all or none potentials and a strong uniform contraction of the
heart? - ANSWER: Slow Calcium Channels
Cardiac muscle has a _______ action potential and has a ________ velocity of
depolarization - ANSWER: longer, slower
What does phase 0 action potential correlate to on the EKG? - ANSWER: QRS
Complex
What phase of an action potential consists of fast Na+ channels and slow Ca+
channels opening? - ANSWER: Phase 0
Which phase of an action potential has the fast Na+ channels close? - ANSWER:
Phase 1
What phase of action potential has early rapid repolarization? - ANSWER: Phase 1
What kind of ions influx during phase 1? - ANSWER: Cl
What phase of action potential is the plateau phase? - ANSWER: Phase 2
What remain open in the second phase of an action potential? - ANSWER: Slow
calcium channels
What does phase 2 action potential correlate to on the EKG? - ANSWER: ST Segment
What phase of action potential uses the most oxygen because the ventricles are
contracting? - ANSWER: Phase 2
What is the third phase of action potential of the heart? - ANSWER: Repolarization
What is the fourth phase of action potential of the heart? - ANSWER: Resting state
What does phase 3 action potential correlate to on the EKG? - ANSWER: T wave
What does phase 4 action potential correlate to on the EKG? - ANSWER: T-P segment
, During the third phase of action potential, which ion channels are open? - ANSWER:
K channels
Does potassium efflux or influx during repolarization? - ANSWER: Efflux
P wave is when the: - ANSWER: Atria depolarization
What follows the P wave? - ANSWER: Atrial Contraction
What is the QRS complex? - ANSWER: Ventricle Depolarization
What follows the QRS complex? - ANSWER: Ventricle contraction
Repolarization phase where it cannot be stimulated to depolarize again - ANSWER:
Absolute
Repolarization phase where it can be stimulated to depolarize - ANSWER: Relative
A phenomenon where a contraction occurs during the backhalf of the T wave -
ANSWER: R on T phenomenon
What is the flow of the cardiac conduction system? - ANSWER: SA node, interatrial
tracts, atrium, internodal tracts, AV node, bundle of HIS, bundle branches, purkinje
fibers, ventricle
What happens if the SA node fails to conduct? - ANSWER: Other pacers begin to
control
Primary principle of cardiac pacemakers is that the __________ conducting cells
control electrical activity - ANSWER: fastest
Other portions of conducting system that can pace if necessary - ANSWER: Latent
Pacemakers
Any abnormal site that controls the rhythm - ANSWER: Ectopic Pacemaker
First positive deflection of the cycle - ANSWER: P wave
The P wave is described as __________ and __________ - ANSWER: upright and
uniform
What happens during the PR segment? - ANSWER: Atrial Kick
The entire atrial electrical cycle that lasts from .12 to .20 seconds is the : - ANSWER:
PR interval
Rasmussen University 2024 NCLEX
Resting membrane potential of the heart is: - ANSWER: Diastole
What are critical for the rapid change in resting membrane potential of the heart? -
ANSWER: Fast Sodium Channels
What helps to support all or none potentials and a strong uniform contraction of the
heart? - ANSWER: Slow Calcium Channels
Cardiac muscle has a _______ action potential and has a ________ velocity of
depolarization - ANSWER: longer, slower
What does phase 0 action potential correlate to on the EKG? - ANSWER: QRS
Complex
What phase of an action potential consists of fast Na+ channels and slow Ca+
channels opening? - ANSWER: Phase 0
Which phase of an action potential has the fast Na+ channels close? - ANSWER:
Phase 1
What phase of action potential has early rapid repolarization? - ANSWER: Phase 1
What kind of ions influx during phase 1? - ANSWER: Cl
What phase of action potential is the plateau phase? - ANSWER: Phase 2
What remain open in the second phase of an action potential? - ANSWER: Slow
calcium channels
What does phase 2 action potential correlate to on the EKG? - ANSWER: ST Segment
What phase of action potential uses the most oxygen because the ventricles are
contracting? - ANSWER: Phase 2
What is the third phase of action potential of the heart? - ANSWER: Repolarization
What is the fourth phase of action potential of the heart? - ANSWER: Resting state
What does phase 3 action potential correlate to on the EKG? - ANSWER: T wave
What does phase 4 action potential correlate to on the EKG? - ANSWER: T-P segment
, During the third phase of action potential, which ion channels are open? - ANSWER:
K channels
Does potassium efflux or influx during repolarization? - ANSWER: Efflux
P wave is when the: - ANSWER: Atria depolarization
What follows the P wave? - ANSWER: Atrial Contraction
What is the QRS complex? - ANSWER: Ventricle Depolarization
What follows the QRS complex? - ANSWER: Ventricle contraction
Repolarization phase where it cannot be stimulated to depolarize again - ANSWER:
Absolute
Repolarization phase where it can be stimulated to depolarize - ANSWER: Relative
A phenomenon where a contraction occurs during the backhalf of the T wave -
ANSWER: R on T phenomenon
What is the flow of the cardiac conduction system? - ANSWER: SA node, interatrial
tracts, atrium, internodal tracts, AV node, bundle of HIS, bundle branches, purkinje
fibers, ventricle
What happens if the SA node fails to conduct? - ANSWER: Other pacers begin to
control
Primary principle of cardiac pacemakers is that the __________ conducting cells
control electrical activity - ANSWER: fastest
Other portions of conducting system that can pace if necessary - ANSWER: Latent
Pacemakers
Any abnormal site that controls the rhythm - ANSWER: Ectopic Pacemaker
First positive deflection of the cycle - ANSWER: P wave
The P wave is described as __________ and __________ - ANSWER: upright and
uniform
What happens during the PR segment? - ANSWER: Atrial Kick
The entire atrial electrical cycle that lasts from .12 to .20 seconds is the : - ANSWER:
PR interval
