Diagnostic criteria for Long QT syndrome (LQTS) the Schwartz score

QTc

>480 ms (+3)

460 - 470 ms (+2)

450 (male) ms (+1)

No (+0)

4-min recovery QTc after exercise test ≥ 480 ms

Yes (+1)

No (+0)

Torsades de pointes

Yes (+2)

No (+0)

T-wave alternans

Yes (+1)

No (+0)

Notched T wave in 3 leads

Yes (+1)

No (+0)

Low heart rate for age

Yes (+0.5)

No (+0)

Syncope

With stress (+2)

Without stress (+1)

No (+0)

Congenital deafness

Yes (+0.5)

No (+0)

Family members with definite LQTS

Yes (+1)

No (+0)

Unexplained sudden cardiac death <age 30 among immediate family members

Yes (+0.5)

No (+0)

References

1) Wilde AAM, Amin AS, Postema PG Diagnosis, management and therapeutic strategies for congenital long QT syndrome

Heart 2022;108:332-338.