biostudies-literatureMarstrand Pthe FUKAP foundationfondsbørsvekselerer Henry Hansen og hustrus legatHjerteforeningenKøbmand Sven Hansen og Hustru Ina Hansens FondFonden til Lægevidenskabens FremmeLundbeckfondenNovo Nordisk FondenLundbeck Foundatione001670https://www.ebi.ac.uk/biostudies/studies/S-EPMC8449979biostudies-literatureUnknown8(2)<h4>Background</h4>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.<h4>Methods</h4>Patients with LQTS with a disease-causing <i>KCNQ1</i> or <i>KCNH2</i> variant were included. In addition to usual beta-blocker treatment, patients were prescribed (1) 50 mg spironolactone (<i>low dose</i>) or (2) 100 mg spironolactone and 3 g potassium chloride per day (<i>high dose+</i>). Electrocardiographic measures were obtained at baseline and after 7 days of treatment.<h4>Results</h4>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 compOpen heartEffect of moderate potassium-elevating treatment in long QT syndrome: the TriQarr Potassium Study.PMC8449979NNF20OC0065799Grant 17-R115-A7532-22065R358-2020-2343Graff CBundgaard HChristensen AHTheilade JAlmatlouh KMarstrand PKanters JKfalseEffect of moderate potassium-elevating treatment in long QT syndrome: the TriQarr Potassium Study.<h4>Background</h4>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.<h4>Methods</h4>Patients with LQTS with a disease-causing <i>KCNQ1</i> or <i>KCNH2</i> variant were included. In addition to usual beta-blocker treatment, patients were prescribed (1) 50 mg spironolactone (<i>low dose</i>) or (2) 100 mg spironolactone and 3 g potassium chloride per day (<i>high dose+</i>). Electrocardiographic measures were obtained at baseline and after 7 days of treatment.<h4>Results</h4>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 comp2021-01-01T00:00:00Z2021 Sep2026-06-15T06:09:03.088Z2026-06-15T03:08:29.979ZS-EPMC84499793453127910.1136/openhrt-2021-001670