Sinus Rhythms
Sinus rhythms are characterized by electrical flow through the normal conduction pathways of the heart. The natural pacemaker, the SA node, is represented by a P wave with a normal PR-interval.
Normal Sinus Rhythm
ECG Characteristics:
Rate 60 to 100 bpmRhythm Regularly Regular
P wave Upright & Rounded, a P wave exists for every QRS complex
PR-Interval 0.12 to 0.20 seconds (120 - 200 ms)
QRS Complex 0.06 to 0.12 seconds (60 - 120 ms)
T wave Upright & Rounded
QT-Interval 0.36 to 0.44 seconds (360 - 440 ms) may be longer for females
Sinus Bradycardia
ECG Characteristics:
Rate less than 60 bpmRhythm Regularly Regular
P wave Upright & Rounded, a P wave exists for every QRS complex
PR-Interval 0.12 to 0.20 seconds (120 - 200 ms)
QRS Complex 0.06 to 0.12 seconds (60 - 120 ms)T wave Upright & RoundedQT-Interval 0.36 to 0.44 seconds (360 - 440 ms) may be longer for females
Sinus Tachycardia
ECG Characteristics:
Rate greater than 100 bpm (usually between 100 - 160 bpm)Rhythm Regularly RegularP wave Upright & Rounded, a P wave exists for every QRS complexPR-Interval 0.12 to 0.20 seconds (120 - 200 ms)QRS Complex 0.06 to 0.12 seconds (60 - 120 ms)T wave Upright & Rounded
QT-Interval 0.36 to 0.44 seconds (360 - 440 ms) may be shortened
Sinus Arrhythmia
ECG Characteristics:
Rate 60 to 100 bpm, varies with respiration (faster with inspiration, slower with expiration)Rhythm Irregularly Irregular, the R-R interval is shorter during inspiration and longer with expiration.
P wave Upright & Rounded, a P wave exists for every QRS complex
PR-Interval May vary slightly within normal limits
QRS Complex 0.06 to 0.12 seconds (60 - 120 ms)
T wave Upright & Rounded
QT-Interval Usually within normal limits
Possible Causes:
- Reflex vagal tone inhibition related to the normal respiratory cycle.
- Underlying conditions that increase vagal tone, digitalis toxicity, increased ICP, and inferior wall MI
Sinus Arrest
ECG Characteristics:
Rate 60 to 100 bpm, varies with the pauseRhythm Regularly Regular, except where there is dropped beats
P wave Exists for every QRS complex, absent during pause
PR-Interval Within normal limits when present
QRS Complex 0.06 to 0.12 seconds (60 - 120 ms), absent during pause
T wave Upright & Rounded, absent during pause
QT-Interval Within normal limits when present
Possible Causes:
- Acute infection
- Inferior wall AMI
- Digitalis, quinidine, salicylate toxicity
- Carotid sinus massage
- Contrast dye
- Coronary artery disease
- Vagal stimulation
- Pesticide poisoning
- Degenerative heart disease
The tutorial:
2 comments:
I am a nursing student, and this tutorial has really helped me out. Do you go into A-Fib, flutter, V-tach etc. on this site?
I haven't yet. I took a break with the tutorial, but I will get back to it soon. Premature complexes are next, then atrial rhythms.
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