非ST段抬高型心肌梗死或不稳定型心绞痛后的血清钾水平、心律失常及死亡率：来自MERLIN-TIMI 36研究的见解
Serum potassium levels, cardiac arrhythmias, and mortality following non-ST-elevation myocardial infarction or unstable angina: insights from MERLIN-TIMI 36.
作者信息
Patel Ravi B, Tannenbaum Sara, Viana-Tejedor Ana, Guo Jianping, Im KyungAh, Morrow David A, Scirica Benjamin M
机构信息
1 TIMI Study Group, Division of Cardiology, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, USA.
2 Hospital Clinico San Carlos, Spain.
出版信息
Eur Heart J Acute Cardiovasc Care. 2017 Feb;6(1):18-25. doi: 10.1177/2048872615624241. Epub 2016 Sep 20.
BACKGROUND
In acute coronary syndrome (ACS), potassium levels <3.5 mEq/L are associated with ventricular arrhythmias. Current guidelines therefore recommend a potassium target >4.0 mEq/L in ACS. Our study evaluated the association between potassium levels, cardiac arrhythmias, and cardiovascular death in patients with non-ST-segment elevation myocardial infarction or unstable angina.
METHODS
Potassium levels were measured in 6515 patients prior to randomization to receive either ranolazine or a placebo in the MERLIN-TIMI 36 trial. A seven-day continuous electrocardiographic assessment was obtained to determine the incidence of non-sustained ventricular tachycardia (NSVT) and ventricular pauses. The association between potassium levels and cardiovascular death was evaluated using a Cox proportional hazards regression model with multivariable adjustment.
RESULTS
NSVT lasting for at least eight consecutive beats occurred more frequently at potassium levels <3.5 mEq/L than at potassium levels ⩾5 mEq/L (10.1 vs. 4.5%, p=0.03 for trend), whereas the inverse pattern was observed for ventricular pauses >3 s, which occurred more frequently at potassium levels ⩾5 mEq/L than at potassium levels <3.5 mEq/L (5.9 vs. 2.0%, p=0.03 for trend). There was a U-shaped relationship between the potassium level at admission and both early and late risk of cardiovascular death. Compared with patients with potassium levels of 3.5 to <4 mEq/L, a potassium level <3.5 mEq/L was associated with an increased risk of cardiovascular death at day 14 (2.4 vs. 0.8%, HR 3.1, p=0.02) and at one year (6.4 vs. 3.0%, HR 2.2, p=0.01). The risk of cardiovascular death at one year was also significantly increased at potassium levels ⩾4.5 mEq/L and a similar trend was noted at potassium levels ⩾5 mEq/L.
CONCLUSIONS
The lowest risk of cardiovascular death was observed in patients with admission potassium levels between 3.5 and 4.5 mEq/L. Both lower and higher levels of potassium were associated with tachyarrhythmias and bradyarrhythmias, suggesting a potential mechanistic explanation for the increased risk of cardiovascular death at the extremes of potassium homeostasis.
背景
在急性冠状动脉综合征（ACS）中，血钾水平<3.5 mEq/L与室性心律失常相关。因此，当前指南推荐ACS患者的血钾目标值>4.0 mEq/L。我们的研究评估了非ST段抬高型心肌梗死或不稳定型心绞痛患者的血钾水平、心律失常和心血管死亡之间的关联。
方法
在MERLIN-TIMI 36试验中，对6515例患者在随机接受雷诺嗪或安慰剂治疗前测量血钾水平。进行为期7天的连续心电图评估，以确定非持续性室性心动过速（NSVT）和心室停搏的发生率。使用多变量调整的Cox比例风险回归模型评估血钾水平与心血管死亡之间的关联。
结果
血钾水平<3.5 mEq/L时，持续至少8个连续心搏的NSVT发生率高于血钾水平≥5 mEq/L时（10.1%对4.5%，趋势p=0.03），而对于>3 s的心室停搏则观察到相反的模式，血钾水平≥5 mEq/L时比血钾水平<3.5 mEq/L时更频繁发生（5.9%对2.0%，趋势p=0.03）。入院时血钾水平与心血管死亡的早期和晚期风险之间呈U形关系。与血钾水平为3.5至<4 mEq/L的患者相比，血钾水平<3.5 mEq/L与第14天（2.4%对0.8%，HR 3.1，p=0.02）和1年时（6.4%对3.
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