Wide complex tachycardias examples

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Shown below are examples of wide complex tachycardias and their diagnosis:

---

VT with right bundle branch block morphology:

---

Shown below is a patient with sinus tachycardia and WPW which mimics VT:

ECG pedia suggests the 7 + 2 method to interpret the above EKG:

Rhythm

• This is a regular rhythm and every QRS complex is preceded by a p wave. The p wave is positive in II,III, and AVF and thus originates from the sinus node. Conclusion: sinus rhythm.

Rate

• Use the 'count the squares' method (a bit less than 3 large squares ~> 300-150-100), thus about 110 bpm and thus sinustachycardia.

Conduction (PQ,QRS,QT)

• PQ-interval=0.10sec (2.5 small squares), QRS duration=0.10sec, QT interval=320ms

Axis

• Positive in I, II, negative in III and AVF. Thus a horizontal (normal) heart axis.

P wave morphology

• The p wave is rather large in II, but does not fulfill the criteria for right atrial dilatation.

QRS morphology

• The QRS shows a slurred upstroke or delta wave.

ST morphology

• Negative T wave in I and AVF. Flat ST in V3-V5.

Compare with the old ECG (not available, so skip this step)

---

Shown below is a wide complex tachycardia:

A broad complex tachycardia at a rate of 160/min with a RBBB configuration. The following favor VT as a diagnosis:

• Extreme right axis deviation. Both I and avF are downward.
• AV dissociaiton

7.5 mg verapamil was administered, which slowed the VT and ultimately converted the patient to sinus rhythm: