cardiology genetics

Long QT Syndrome (Schwartz Score)

Estimates probability of congenital Long QT Syndrome using Schwartz-Moss criteria. Guides genetic testing, beta-blocker therapy, and ICD consideration.

Score interpretation

Low Probability of LQTS (≤ 1 point) 0–1

Schwartz score ≤ 1.

→ LQTS unlikely; check QTc-prolonging medications; genetic testing if clinical suspicion remains; family history review

Intermediate Probability of LQTS (1.5–3 points) 1.5–3

Schwartz score 1.5–3.

→ Electrophysiology and genetics referral; genetic testing (KCNQ1, KCNH2, SCN5A); exercise ECG; avoid QT-prolonging drugs; check crediblemeds.org

High Probability of LQTS (≥ 3.5 points) 3.5–10.5

Schwartz score ≥ 3.5.

→ Beta-blocker (nadolol or propranolol) — first-line; avoid QT-prolonging drugs; electrolyte correction; genetic testing mandatory; family screening; ICD for high-risk patients (prior VF, breakthrough symptoms on beta-blockers)

Interpretation bands for the LQTS Schwartz Score. Apply clinical judgement and local guidance.

References

Schwartz PJ, Moss AJ, Vincent GM, Crampton RS. Diagnostic criteria for the long QT syndrome. An update. Circulation. 1993;88(2):782-784.
Schwartz PJ, Crotti L. QTc behavior during exercise and genetic testing for the long-QT syndrome. Circulation. 2011;124(20):2181-2184.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Brugada Syndrome Diagnostic Criteria (Shanghai Score) · Channelopathy / Sudden Cardiac Death

Drugs

Pathways

Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.

Score interpretation

References

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