Patient handout

Congenital Long QT Syndrome (chronic — genotype-driven)

PRODUCTION

1. Your condition

This handout is for congenital long qt syndrome (chronic — genotype-driven). Your care team identified this based on: qtc prolongation (≥480 ms; ≥460 ms with symptoms) on 12-lead.

Other reasons your team may use this plan: syncope on exertion/swimming (lqt1), auditory/emotional/postpartum (lqt2), or at rest/sleep (lqt3); aborted scd / family history of lqts or unexplained young scd; known kcnq1/kcnh2/scn5a pathogenic variant.

2. Your medications

Take these medications exactly as prescribed. Do not stop or change a dose without talking to your provider.

Medication	Starting dose	How	When	What it does
nadolol	0.5–1 mg/kg/day (typical adult 40–80 mg)	PO	once–BID	2022 ESC VA — nadolol is the evidence-preferred BB in LQTS (superior event reduction, esp. LQT1/2); long-acting non-selective
propranolol	2–3 mg/kg/day	PO	TID	Propranolol alternative non-selective BB (2017 AHA/ACC/HRS VA)

Plan: LQTS repolarization-protection (2013 HRS/EHRA/APHRS; 2017 AHA/ACC/HRS VA; 2022 ESC VA)

3. When to call your provider

Contact your care team if any of the following happen:

TdP/VF → ED + acute LQTS pathway — 2022 ESC VA
Events on adequate BB → LCSD ± ICD — 2022 ESC VA
New QT-prolonging drug needed → substitute / intensify monitoring — crediblemeds.org

4. When to seek emergency care

Call 911 or go to the nearest emergency room right away if you have:

Aborted SCD / documented sustained VT — secondary-prevention ICD Class I (with continued beta-blocker) — 2017 AHA/ACC/HRS VA(life-threatening)
Cardiac events despite adequate beta-blocker — LCSD (Class IIa) ± ICD — 2022 ESC VA
LQT3 (SCN5A gain-of-function) — rest/sleep events, BB less effective; add mexiletine (late-Na block, QT shortening) — Mazzanti
LQT2, peripartum/postpartum window — highest event risk postpartum; continue/uptitrate beta-blocker, intensified monitoring, K repletion — 2022 ESC VA; ESC 2018 Pregnancy
Patient on / needs a crediblemeds.org QT-prolonging drug — substitute or, if unavoidable, intensified ECG + electrolyte monitoring — crediblemeds.org
Hypokalemia / hypomagnesemia (vomiting, diuretics, eating disorder) — aggressively repleted; high-risk for TdP esp. LQT2 — 2022 ESC VA

5. Follow-up

First-degree family cascade screening; lifelong QT-drug + trigger avoidance; sports re-evaluation

6. Sources

Guideline: 2013 HRS/EHRA/APHRS Inherited Arrhythmia Expert Consensus + 2017 AHA/ACC/HRS VA Guideline + 2022 ESC Ventricular Arrhythmia Guideline