Long‐term (subacute) potassium treatment in congenital HERG‐related long QT syndrome (LQTS2)
HL Tan, M Alings, RW Van Olden… - Journal of …, 1999 - Wiley Online Library
HL Tan, M Alings, RW Van Olden, AAM Wilde
Journal of cardiovascular electrophysiology, 1999•Wiley Online LibraryPotassium 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 IKr leads to insufficient IKr 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 IKr activity
varies with serum potassium levels. Methods and Results: In an LQTS2 patient who …
subdivided according to the underlying gene defect. In LQTS2, an aberrant HERG gene that
encodes the potassium channel IKr leads to insufficient IKr 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 IKr activity
varies with serum potassium levels. Methods and Results: In an LQTS2 patient who …
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 IKr leads to insufficient IKr 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 IKr 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.
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