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ECG
Level 2
Tutorial: Rhythm Diagnostic Criteria
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Tutorial: Rhythm Diagnostic Criteria
This module will list the basic rhythms, their diagnostic criteria, and their clinical significance .
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Tutorial: Rhythm Diagnostic Criteria
Normal Sinus Rhythm
Lessons
42
Times Practiced
1284
Cases Completed
1h 24m
Total Time spent
1m 24s
Average Time
Progress
Accuracy
Efficiency
Accuracy
Efficiency
1
Normal Sinus Rhythm
Normal Sinus Rhythm
2
Sinus Bradycardia
Sinus Bradycardia
3
Sinus Tachycardia
Sinus Tachycardia
4
Re-entry
Re-entry
5
Atrial Fibrillation
Atrial Fibrillation
6
Atrial Flutter
Atrial Flutter
7
Heart Block - First degree
Heart Block - First degree
8
Heart Block - Second degree Type 1
Heart Block - Second degree Type 1
9
Heart Block - Second degree Type 2
Heart Block - Second degree Type 2
10
Heart Block - Third degree
Heart Block - Third degree
11
Junctional Rhythm
Junctional Rhythm
12
SVT (supraventricular tachycardia)
SVT (supraventricular tachycardia)
13
VT (Ventricular Tachycardia)
VT (Ventricular Tachycardia)
14
Ventricular Fibrillation
Ventricular Fibrillation
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Next Lesson
Normal Sinus Rhythm
Normal Sinus Rhythm
Diagnostic criteria:
Rate: 60-100
Rhythm: regular
P waves: upright, all same size and shape
PR interval: normal (3-5 little squares)
QRS: narrow (< 3 little squares)
Normal sinus rhythm is a rhythm that starts in the sinus node (which is why we have the word "sinus" in the title). If you checked your heart rate right now and it was between 60-100, you are most likely in normal sinus rhythm.
Normal sinus rhythm is frequently "combined" with other diagnoses, such as:
heart blocks (1st, 2nd and 3rd degree)
abnormal axes
bundle branch blocks
chamber enlargement, such as atrial enlargement or left ventricular hypertrophy
myocardial ischemia or infarction
and many others
Electrophysiology:
The sinus node action potential dictates the frequency of firing of the sinus node. The most important component of the action potential is phase 4. Notice that it is upsloping, always moving toward the action potential threshold (the dotted line). The fact that phase 4 is upsloping means that these cells have the ability to create their own heart rate. This is called
automaticity
.
In particular, the slope of phase 4 is the most important component of the action potential for determining the heart rate. A steep phase 4 will shorten the time between action potentials and thus increase the heart rate.
Increased sympathetic
nervous system (SNS) activity or
decreased
para
sympathetic nervous system (PNS) activity increase the slope of phase 4 and increase the sinus heart rate. The opposite is also true: decreased SNS or increased PNS will reduce the heart rate.
Clinical Significance:
Normal sinus rhythm is completely normal.
Examples:
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