Atrial fibrillation recognition on ECG for new nurses and students
In atrial fibrillation, the atria may initiate ~300–600 beats/min! These are disorganized quivers, creating a favorable environment for blood pooling and clot formation in the upper chambers (particularly the left atrial appendage; LAA).
The AV node protects the ventricles from an onslaught of impulses, conducting atrial impulses sporadically to the His-purkinje system below. The result is the irregular ventricular pattern shown above. With atrial impulses passing through the AV to the ventricles, a narrow QRS is typically seen (excluding aberrant conduction).
On our rhythm strip, two of the most important characteristics in recognizing atrial fibrillation are:
A rhythm that is irregularly irregular
No discrete P waves present - Compare this to MAT in which the rhythm is irregular, but discrete P waves are present with alternating appearances.
Ventricular response is a special concern in atrial fibrillation. With cardiac output already potentially impaired due to the underperforming atria, very rapid heart rates may further decrease cardiac output due to decreases in diastolic ventricular filling times and irregularly occurring ventricular beats. At high heart rates particularly, patients may be prone to symptoms of chest discomfort, fatigue, dizziness, imbalance, and more.
Atrial fibrillation is the most common arrhythmia in the general population with an estimated 1/3 of arrhythmia related hospitalizations being attributed to A-fib. Expect to encounter it at some point. Additionally, the “atrial kick” that sends blood forward to the ventricles is responsible for ~10-30% of total cardiac output. Therefore, patients with atrial fibrillation may potentially experience meaningful decreases in total cardiac output which may worsen with very rapid heart rates.
Treatment goals for atrial fibrillation include stroke prevention, rate control, and rhythm control.
Hope this helps!
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