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][1]. No data are available. All data relevant to the study are included in the article or uploaded as supplementary information. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT03291145&atom=%2Fopenhrt%2F8%2F2%2Fe001670.atom

中文翻译：

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适度升钾治疗对长 QT 综合征的效果：TriQarr 钾研究


背景 在长 QT 综合征 (LQTS) 中，β 受体阻滞剂可预防心律失常。作为补充，有人建议采取增加钾的方法。我们着手研究中度钾升高对心脏复极的影响。方法 纳入具有致病 KCNQ1 或 KCNH2 变异的 LQTS 患者。除了常规的β受体阻滞剂治疗外，还给患者开了（1）50毫克螺内酯（低剂量）或（2）每天100毫克螺内酯和3克氯化钾（高剂量+）。在基线和治疗 7 天后进行心电图测量。结果 20 名患者入组（10 名低剂量患者和 10 名高剂量+患者）。一名患者因严重流感样症状而被排除，完成研究的 19 名患者中有 5 名出现轻微副作用。低剂量的血浆钾并未因治疗而增加（4.26±0.22至4.05±0.19 mmol/L，p=0.07）。此外，治疗前与治疗后静息 QTcF（使用 Fridericia 公式校正的 QT 间期）没有观察到变化（478±7 vs 479±7 ms，p=0.9）。在高剂量+中，钾含量从 4.08±0.29 显着增加至 4.48±0.54 mmol/L (p=0.001)。然而，与高剂量+治疗之前（472±8 ms）和之后（469±8 ms）（p=0.66）相比，QTcF 没有观察到差异。没有患者出现高钾血症。结论 在LQTS患者中，大剂量+治疗可使血浆钾升高0.4 mmol/L，且无高钾血症病例。然而，钾的增加并没有缩短 QT 间期，并且一些患者出现了副作用。考虑到 QT 间期作为心律失常风险的代表，我们的数据并不支持钾水平正常的 LQTS 患者中钾升高治疗具有抗心律失常预防作用。 试用注册号[NCT03291145][1]。无可用数据。与研究相关的所有数据都包含在文章中或作为补充信息上传。 [1]：/lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT03291145&atom=%2Fopenhrt%2F8%2F2%2Fe001670。原子