Fundamentals of EKG and Basic Dysrhythmias Study
Guide
, •
Basic Electrophysiology
I. Cardiac Conduction System
A. Components
Pacemakers:
-SA node (intrinsic rate 60-100)
-AV node (Intrinsic rate 40-60)
-Bundle branches (Intrinsic rate (20-40)
Notes:
B. Electrical Impulse Pathway
Normal conduction impulse originates in the SA Node
Impulse travels from SA Node → AV Node causing
atrial depolarization (contraction)
AV Node slightly delays impulse then sends → Bundle of HIS → Bundle Branches
Impulse continues down Bundle Branches → Purkinje
Fibers causing ventricular depolarization (contraction)
Notes:
1
The printed copy is for temporary use only. Always refer to FH Intranet for the current document.
Review Date: 02/04/2019
, Basic Electrophysiology cont.
II. Cardiac Cycle
A. Components
B. Isoelectric line- (absence of electrical activity/base line)
Positive Deflection- above the line
Negative Deflection- below the
line
C. Depolarization- Repolarization cycle
Atrial Depolarization (atrial contraction)
Represented by the P wave on the EKG complex
Ventricular Depolarization (ventricular contraction)
Represented by the QRS complex
Ventricular Repolarization (resting phase)
Represented by the ST segment and T wave on
the EKG Complex
D. Refractory
Periods Absolute Refractory
• Cardiac cells will not respond
to further stimulation
• Myocardial cells will not contract
Relative Refractory
• Vulnerable period
• Cardiac cells can be
stimulated to contract
Notes:
, Basic Electrophysiology
cont. Notes:
III. Waveforms, segments,
Intervals
A. P wave
Variations
P waves can appear normal, notched, peaked, or inverted.
2. P-R interval
B. Q-R-S
1. waves
C. ST Segment
1. Normal Presentation
2. Deviations
D. T wave
1. Presentations
NormalTall Inverted Hyperacute
E. QT Interval
Ventricular depolarization and repolarization
Inversely related to the heart rate
Normally less than half of the length of the R-R interval
4
The printed copy is for temporary use only. Always refer to FH Intranet for the current document.
Review Date: 02/04/2019
Guide
, •
Basic Electrophysiology
I. Cardiac Conduction System
A. Components
Pacemakers:
-SA node (intrinsic rate 60-100)
-AV node (Intrinsic rate 40-60)
-Bundle branches (Intrinsic rate (20-40)
Notes:
B. Electrical Impulse Pathway
Normal conduction impulse originates in the SA Node
Impulse travels from SA Node → AV Node causing
atrial depolarization (contraction)
AV Node slightly delays impulse then sends → Bundle of HIS → Bundle Branches
Impulse continues down Bundle Branches → Purkinje
Fibers causing ventricular depolarization (contraction)
Notes:
1
The printed copy is for temporary use only. Always refer to FH Intranet for the current document.
Review Date: 02/04/2019
, Basic Electrophysiology cont.
II. Cardiac Cycle
A. Components
B. Isoelectric line- (absence of electrical activity/base line)
Positive Deflection- above the line
Negative Deflection- below the
line
C. Depolarization- Repolarization cycle
Atrial Depolarization (atrial contraction)
Represented by the P wave on the EKG complex
Ventricular Depolarization (ventricular contraction)
Represented by the QRS complex
Ventricular Repolarization (resting phase)
Represented by the ST segment and T wave on
the EKG Complex
D. Refractory
Periods Absolute Refractory
• Cardiac cells will not respond
to further stimulation
• Myocardial cells will not contract
Relative Refractory
• Vulnerable period
• Cardiac cells can be
stimulated to contract
Notes:
, Basic Electrophysiology
cont. Notes:
III. Waveforms, segments,
Intervals
A. P wave
Variations
P waves can appear normal, notched, peaked, or inverted.
2. P-R interval
B. Q-R-S
1. waves
C. ST Segment
1. Normal Presentation
2. Deviations
D. T wave
1. Presentations
NormalTall Inverted Hyperacute
E. QT Interval
Ventricular depolarization and repolarization
Inversely related to the heart rate
Normally less than half of the length of the R-R interval
4
The printed copy is for temporary use only. Always refer to FH Intranet for the current document.
Review Date: 02/04/2019
