Effect of moderate potassium-elevating treatment in long QT syndrome: The TriQarr Potassium Study
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Effect of moderate potassium-elevating treatment in long QT syndrome : The TriQarr Potassium Study. / Marstrand, Peter; Almatlouh, Kasim; Kanters, Jørgen K.; Graff, Claus; Christensen, Alex Hørby; Bundgaard, Henning; Theilade, Juliane.
I: Open Heart, Bind 8, Nr. 2, e001670, 2021.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Effect of moderate potassium-elevating treatment in long QT syndrome
T2 - The TriQarr Potassium Study
AU - Marstrand, Peter
AU - Almatlouh, Kasim
AU - Kanters, Jørgen K.
AU - Graff, Claus
AU - Christensen, Alex Hørby
AU - Bundgaard, Henning
AU - Theilade, Juliane
N1 - Publisher Copyright: © Author(s) (or their employer(s)) 2021.
PY - 2021
Y1 - 2021
N2 - Background In long QT syndrome (LQTS), beta blockers prevent arrhythmias. As a supplement, means to increase potassium has been suggested. We set to investigate the effect of moderate potassium elevation on cardiac repolarisation. Methods Patients with LQTS with a disease-causing KCNQ1 or KCNH2 variant were included. In addition to usual beta-blocker treatment, patients were prescribed (1) 50 mg spironolactone (low dose) or (2) 100 mg spironolactone and 3 g potassium chloride per day (high dose+). Electrocardiographic measures were obtained at baseline and after 7 days of treatment. Results Twenty patients were enrolled (10 low dose and 10 high dose+). One patient was excluded due to severe influenza-like symptoms, and 5 of 19 patients completing the study had mild side effects. Plasma potassium in low dose did not increase in response to treatment (4.26±0.22 to 4.05±0.19 mmol/L, p=0.07). Also, no change was observed in resting QTcF (QT interval corrected using Fridericia's formula) before versus after treatment (478±7 vs 479±7 ms, p=0.9). In high dose+, potassium increased significantly from 4.08±0.29 to 4.48±0.54 mmol/L (p=0.001). However, no difference in QTcF was observed comparing before (472±8 ms) versus after (469±8 ms) (p=0.66) high dose+ treatment. No patients developed hyperkalaemia. Conclusion In patients with LQTS, high dose+ treatment increased plasma potassium by 0.4 mmol/L without cases of hyperkalaemia. However, the potassium increase did not shorten the QT interval and several patients had side effects. Considering the QT interval as a proxy for arrhythmic risk, our data do not support that potassium-elevating treatment has a role as antiarrhythmic prophylaxis in patients with LQTS with normal-range potassium levels. Trial registration number NCT03291145.
AB - Background In long QT syndrome (LQTS), beta blockers prevent arrhythmias. As a supplement, means to increase potassium has been suggested. We set to investigate the effect of moderate potassium elevation on cardiac repolarisation. Methods Patients with LQTS with a disease-causing KCNQ1 or KCNH2 variant were included. In addition to usual beta-blocker treatment, patients were prescribed (1) 50 mg spironolactone (low dose) or (2) 100 mg spironolactone and 3 g potassium chloride per day (high dose+). Electrocardiographic measures were obtained at baseline and after 7 days of treatment. Results Twenty patients were enrolled (10 low dose and 10 high dose+). One patient was excluded due to severe influenza-like symptoms, and 5 of 19 patients completing the study had mild side effects. Plasma potassium in low dose did not increase in response to treatment (4.26±0.22 to 4.05±0.19 mmol/L, p=0.07). Also, no change was observed in resting QTcF (QT interval corrected using Fridericia's formula) before versus after treatment (478±7 vs 479±7 ms, p=0.9). In high dose+, potassium increased significantly from 4.08±0.29 to 4.48±0.54 mmol/L (p=0.001). However, no difference in QTcF was observed comparing before (472±8 ms) versus after (469±8 ms) (p=0.66) high dose+ treatment. No patients developed hyperkalaemia. Conclusion In patients with LQTS, high dose+ treatment increased plasma potassium by 0.4 mmol/L without cases of hyperkalaemia. However, the potassium increase did not shorten the QT interval and several patients had side effects. Considering the QT interval as a proxy for arrhythmic risk, our data do not support that potassium-elevating treatment has a role as antiarrhythmic prophylaxis in patients with LQTS with normal-range potassium levels. Trial registration number NCT03291145.
KW - arrhythmias
KW - cardiac
KW - clinical
KW - electrophysiology
KW - genetics
KW - pharmacology
KW - ventricular fibrillation
UR - http://www.scopus.com/inward/record.url?scp=85115301770&partnerID=8YFLogxK
U2 - 10.1136/openhrt-2021-001670
DO - 10.1136/openhrt-2021-001670
M3 - Journal article
C2 - 34531279
AN - SCOPUS:85115301770
VL - 8
JO - Open Heart
JF - Open Heart
SN - 2398-595X
IS - 2
M1 - e001670
ER -
ID: 281602072