Cite this article as:
Anders, M. Prolonged QT syndrome, Don't Forget the Bubbles, 2013. Available at: http://doi.org/10.31440/DFTB.3681
Definition: prolonged QTc interval, calculated by Bazett’s formula: QTc = QT : sqr (previous RR interval). normal <440 ms (460 ms in women and children).
Congenital causes:
Jervell and Lange-Nielsen syndrome, Romano-Ward syndrome, idiopathic
[1] American Heart Journal, 1957, 54, 59 – 68: Jervell et all: Congenital deaf-mutism, functional heart disease with prolongation of the Q-Y interval and sudden death
[2] Circulation, 2000, 102, 782 – 784: Splawski et all: Spectrum of mutations in long QT syndrome genes: KVLQT1, HERG, SCN5A, KCNE1, and KCNE2
All Marc’s PICU cardiology FOAM can be found on PICU Doctor and can be downloaded as a handy app for free on iPhone or Android. A list of contributors can be seen here.
Prolonged QT syndrome
Tags: long QT
Anders, M. Prolonged QT syndrome, Don't Forget the Bubbles, 2013. Available at:
http://doi.org/10.31440/DFTB.3681
Definition: prolonged QTc interval, calculated by Bazett’s formula: QTc = QT : sqr (previous RR interval). normal <440 ms (460 ms in women and children).
Congenital causes:
Jervell and Lange-Nielsen syndrome, Romano-Ward syndrome, idiopathic
Acquired causes:
metabolic – hypokalemia, hypomagnesemia, hypocalcacemia; drugs – quinidine, procaine, amiodarone, sotalol, erythromycin, terfenadine, haloperidol, TCA, risperidone, methadone, droperidol, organophosphates, or myocardial ischaemia, HIV, hypothermia
Diagnosis:
pQTS measured via Bazett’s formula, Torsades de pointes, T-wave alternans, syncope, family history
Treatment:
1. acute: haemodynamically unstable patient: DC 2 J/kg, MgSO4 (0.2 mmol/kg), lignocaine (1 mg/kg over 2 min), isoprenaline infusion (0.05-1 mcg/kg/min), overdrive pacing
2. chronic: β-Blocker, pacemaker, ICD, sympathectomy
References:
[1] American Heart Journal, 1957, 54, 59 – 68: Jervell et all: Congenital deaf-mutism, functional heart disease with prolongation of the Q-Y interval and sudden death [2] Circulation, 2000, 102, 782 – 784: Splawski et all: Spectrum of mutations in long QT syndrome genes: KVLQT1, HERG, SCN5A, KCNE1, and KCNE2[3] JAMA, 2003, 23, 2041 – 2044: Moss: Long QT Syndrome
All Marc’s PICU cardiology FOAM can be found on PICU Doctor and can be downloaded as a handy app for free on iPhone or Android. A list of contributors can be seen here.
About Marc Anders
Marc Anders is a paediatric intensivist.