Table 1: Diagnostic criteria for LQTS.

ECG findings
 ≥480 msec3 points
 460–470 msec2 points
 450 msec (in males)1 points
Torsade de pointes2 points
T-wave alternans1 points
Notched T wave in 3 derivation1 points
Low heart rate for age0.5 points

Clinical history
 With stress2 points
 Without stress1 points
Congenital deafness0.5 points

Family history
Siblings with LQTS1 points
History of sudden death before 30 years of age0.5 points