Clinical Resources

VT Origin Predictor

Outflow Tract vs Fascicular vs Scar-Mediated VT

Section 1 — QRS Morphology

QRS duration < 130 ms

Yes

No

QRS axis

Normal

Superior (left axis deviation)

Rightward / Inferior

QRS morphology in V1

LBBB-like

RBBB-like

Other / Indeterminate

Section 2 — Precordial Transition

R/S transition zone

V3 or earlier

V4

V5 or later

V1 morphology detail

QS

rS

Rs

R

RBBB-like

Section 3 — Clinical History

Known prior MI or structural heart disease

Young patient (<40) with normal echo

Induced by exercise or emotional stress

Adenosine-sensitive (terminates with adenosine)

Occurs at rest, not exercise-related

Results

Predicted Origin —

Select ECG and clinical features above.

Reference

Lerman BB. Mechanism, clinical significance, and treatment of idiopathic ventricular arrhythmias. Heart Rhythm. 2023. Coggins DL et al. Heart Rhythm 2014.