Schwartz's diagnostic criteria for congenital long QT syndrome

The Schwartz's diagnostic criteria for congenital long QT syndrome is a clinical scoring system used to diagnose congenital long QT syndrome (LQTS), a genetic disorder of the heart's electrical system. This calculator is applicable to patients of all ages who present with unexplained syncope, seizures, or cardiac arrest, or have a family history of sudden cardiac death at a young age. The Schwartz's criteria uses a combination of clinical and electrocardiographic features, including the QT interval, T-wave alternans, notched T waves in three leads, low heart rate for age, clinical history, and family history. The score ranges from 1 to 6, with a score of 3.5 or higher being indicative of a high probability of LQTS. The Schwartz's criteria should not be used in patients with secondary causes of QT prolongation such as medications, electrolyte imbalances, or other medical conditions. It is also less accurate in neonates and very young children due to the physiological shortening of the QT interval in this age group.

Reference

P J Schwartz, A J Moss, G M Vincent et al. Diagnostic criteria for the long QT syndrome. An update. Circulation. 1993 Aug;88(2):782-4.