23-33: Ventricular Tachycardia

ECG Findings

• Wide, regular tachycardia (usually > 120 bpm).

• Evidence of AV dissociation may be found: P waves may appear periodically in the T wave or baseline.

• “Capture” beats may occur if atrial depolarization occurs prior to the intrinsic firing of the ventricle.

• “Fusion” beats may occur if atrial depolarization passes through the AV node at the same time as the intrinsic ventricle depolarization, producing a QRS that appears to be different or narrower than the other QRS complexes.

Pearls

1. It can be difficult to distinguish VT from SVT with aberrancy. When in doubt, treat as VT.

2. Patient factors that make VT more likely include history of coronary artery disease, congestive heart failure, and advanced age.

3. ECG features that increase likelihood of VT include absence of typical RBBB or LBBB morphology, extreme axis deviation, AV dissociation, presence of capture beats, presence of fusion beats, Brugada sign (distance of onset of the QRS complex to the nadir of the S wave is > 100 ms), positive or negative concordance in the chest leads, Josephson’s sign (notching near the nadir of the S wave), or R-wave peak time > 50 ms in lead II.