Congenital Long QT Syndrome (LQTS) may occur with (Jervell and Lange-Nielsen syndrome) or without (Romano-Ward syndrome) deafness. Presents as lightheadedness, syncope, torsades, and cardiac arrest. May be triggered by adrenergic stimulation or even auditory stimulation (LQT1 and 2). Three ion channel abnormalities have been identified – LQT1 and LQT2 (K+), and LQT3 (Na+). Female gender (or males with QT3), deafness, QT > 500 msec, and widened T waves are associated with a high risk of sudden death
Long QT Syndrome can also be acquired, with multiple pharmacologic (quinidine, procainamide, sotalol, amiodarone, macrolide antibiotics, TMP-SMX, imidazoles, TCAs, haloperidol, phenothiazines, milrinone) and metabolic (hypokalemia, hypomagnesemia, hypocalcemia) causes. In these acquired cases, EKG is more notable for unusual T wave appearance, not for prolonged QT interval.
Acute management is based on intravenous magnesium, replacement of potassium and calcium if indicated. Avoid amiodarone in these patients as it may worsen the disease.
Long term therapy is usually based on beta blockade, although sometimes permanent pacing is indicated (especially in LQT3). Left stellate sympathectomy has been attempted in refractory cases.
Editing Congenital Long QT: Management
- Acute: magnesium, replacement of potassium and calcium
- Long term: beta blockade and possibly pacing