Tachycardia - Differential Diagnosis and Management - Narrow vs Wide, Regular vs Irregular

Narrow - Regular:

Use P waves. Positive deflection not AVRT/AVNRT. Absent p try adenosine. If see flutter p = AFIutter.

 • Sinus Tachy. 220-Age, resp variability.

 • SVT. 140-280, very regular.

 • Atrial Flutter. 150+/-20, 2:1.

Narrow - Irregular:

Use P waves. If can't see Afib. If see P, either Flutter or MAT. If not Flutter P waves, is MAT.

 • AFib.

 • AFIutter.

 • MAT. 3 types of Ps.

Wide - Regular:

Assume VT until proven otherwise.

 • Monomorphic VTach. Each beat identical. Rate > 120, QRS > 120. 

 • DDx: SVT + Aberrancy, HyperK, NaChBlocker.

Wide - Irregular:

 • Polymorphic VTach.

 • AFib + BBB. Rate rarely >200.

 • AFib + Pre-excitation. Rate can be 300! Variable QRS morphology.

 • Hyperkalemia



- Dr. Sarah Foohey @SarahFoohey



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