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Long‐Term (Subacute) Potassium Treatment in Congenital HERG‐Related Long QT Syndrome (LQTS2)
Author(s) -
TAN HANNO L.,
ALINGS MARCO,
OLDEN RUDOLF W.,
WILDE ARTHUR A.M.
Publication year - 1999
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/j.1540-8167.1999.tb00665.x
Subject(s) - herg , potassium , medicine , torsades de pointes , potassium channel , hypokalemia , homeostasis , potassium channel blocker , endocrinology , long qt syndrome , repolarization , short qt syndrome , qt interval , cardiology , pharmacology , chemistry , electrophysiology , organic chemistry
Potassium Treatment in LQTS2. Introduction : Congenital long QT syndrome (LQTS) is subdivided according to the underlying gene defect. In LQTS2, an aberrant HERG gene that encodes the potassium channel I Kr leads to insufficient I Kr activity and delayed repolarization, causing ECG abnormalities and torsades de pointes (TdP). Increasing serum potassium levels by potassium infusion normalizes the ECG in LQTS2 because I Kr activity varies with serum potassium levels. Methods and Results : In an LQTS2 patient who presented with TdP, we attempted to achieve a long‐term (subacute) elevation of serum potassium by increased potassium intake and potassium‐sparing drugs. However, due to renal potassium homeostasis, it was impossible to achieve a long‐lasting rise of serum potassium above 4.0 mmol/L. Conclusion : Although raising serum potassium reverses the ECG abnormalities in LQTS2, a long‐lasting rise of serum potassium is only partially achievable because in the presence of normal renal function, potassium homeostasis limits the amount of serum potassium increase.