Schwartz published criteria for the diagnosis of the idiopathic long QT syndrome in 1985. The author is from the University of Milan in Italy.
Patient preparation: The patient should not be evaluated while taking any medications associated with prolongation of the QT interval.
Major criteria:
(1) prolonged QT interval (corrected QT interval > 440 msec)
(2) stress-induced syncope
(3) family members diagnosed with long QT syndrome
Minor criteria:
(1) congenital deafness
(2) episodes of T wave alternans
(3) low heart rate (in children)
(4) abnormal ventricular repolarization
Diagnosis of the long QT syndrome requires one of the following:
(1) 2 major criteria
(2) 1 major and >= 2 minor criteria
