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Module title = Tutorial: Origins of Activity
Lesson title = Wavy Baselines
This is lesson 4 of 8 in this module
Wavy Baselines!
When the heart is in between heartbeats (diastole), there should be no electrical activity (blue and yellow ovals). The tracing should show a nice flat "isoelectric" line that is doing nothing:
Sometimes this nice flat line is replaced by some
random wavy garbage.
There are 2 things that cause wavy garbage:
fibrillation
muscle tremors (or patient movement)
Fibrillation is chaotic electrical activity.
Fibrillation can occur in the atria or in the ventricles. If fibrillation is occuring in the atria, there will be no P waves. If fibrillation occurs in the ventricles, there will be no QRS complexes. The reverse is also true: the presence of
regular consistent
P waves rules out atrial fibrillation and the presence of QRS complexes rules out ventricular fibrillation.
Rule #1: Wavy baseline + regular P waves + QRS complexes = no fibrillation.
Below we see P waves + QRS complexes + wavy garbage. This is muscle tremor (or movement). Can you see the P waves? Can you see the T waves? They are all present.
Rule #2:
Wavy baseline +
no P waves
+ QRS complexes = atrial fibrillation (probably) = atrial origin
Here are 2 examples of wavy garbage that is caused by atrial fibrillation. There are QRS complexes and T waves, but no P waves. Sometimes the wavy garbage can mimic P waves.
Rule #3: Wavy baseline with
no QRS complexes
= ventricular fibrillation = ventricular origin
There are no QRS complexes in the ECG below. The ventricular rate is zero. This is one form of cardiac arrest. This patient will have no pulse and will require CPR and defibrillation.
For more details on atrial fibrillation and ventricular fibrillation, see our helpful videos in the
Rhythm Diagnostic Criteria tutorial
.
Summary of the wavy garbage:
P waves + QRS + wavy garbage = movement artifact
No P waves
+ QRS + wavy garbage = atrial fibrillation = atrial origin
No QRS
+ wavy garbage = ventricular fibrillation = ventricular origin
Lesson 4 of 8
That was the last lesson!
