心力衰竭患者血钾水平与室性心律失常及住院死亡的关系

Association Between Serum Potassium Level on Admission and Ventricular Arrhythmias as Well as In-hospital Mortality in Hospitalized Patients With Heart Failure

目的:观察住院心力衰竭患者入院时血钾水平与室性心律失常及住院死亡的关系。方法:入选2014年6月至2017年12月在我院住院的NYHA心功能分级Ⅲ~Ⅳ级、非重度以上肾功能不全且完成动态心电图检查的心力衰竭患者1 007例。根据患者入院时血钾水平将患者分为低钾血症组(血钾<3.5 mmol/L)、高钾血症组(血钾>5.5 mmol/L)及正常血钾组(血钾3.5~5.5 mmol/L);应用Lown分级(Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ级)评估室性心律失常的严重程度;又根据患者住院期间是否发生死亡将患者分为死亡组与非死亡组。分析住院心力衰竭患者入院时血钾水平与室性心律失常及住院死亡的关系。结果:1 007例患者中,低钾血症患者38例(3.8%),高钾血症患者9例(0.9%)。随着患者血钾水平降低,Lown分级级别呈升高趋势(P<0.001)。Lown分级Ⅳ级患者中,同时出现Lown分级Ⅲ级及Ⅳ级患者的血钾水平明显低于单纯表现为Lown分级Ⅳ级患者(P=0.048)。Spearman相关分析显示,住院心力衰竭患者入院时血钾水平与室性心律失常Lown分级呈负相关(r=-0.226,P<0.001)。1 007例患者中发生住院死亡63例(6.3%);死亡组患者血钾水平明显低于非死亡组(P=0.006)。多因素Logistic回归模型分析显示,血钾水平是心力衰竭患者住院死亡的独立预测因素(P=0.044),血钾每升高0.5 mmol/L,患者住院死亡风险降低26.8%。ROC曲线及限制性立方样条图均证实住院心力衰竭患者血钾控制的最佳切点为4.18 mmol/L。结论:住院心力衰竭患者入院时血钾水平与Lown分级呈负相关,可作为患者住院死亡的独立预测因素。

Objectives: This study aimed to explore the association between serum potassium level on admission and ventricular arrhythmias as well as in-hospital death in patients hospitalized with heart failure(HF). Methods: One thousand and seven hospitalized HF patients with NYHA functional class Ⅰ-Ⅰ and Holter ECG monitoring, without moderate and severe renal dysfunction were enrolled for analysis. Patients were divided into three groups: hypokalemia group(potassium level <3.5 mmol/L), hyperkaliemia group(potassium level >5.5 mmol/L), and normokalemia group(3.5 mmol/L ≤ potassium level ≤ 5.5 mmol/L). Lown’s classification(grade I, II, III, IV, and V) was used to evaluate the severity of ventricular arrhythmia. Patients were also grouped according to the occurrence of death during hospitalization: dead group and survival group. The association between potassium levels and ventricular arrhythmias as well as in-hospital death was assessed in this study.Results: There were 38(3.8%) patients with hypokalemia and 9(0.9%) patients with hyperkalemia. Low potassium levels was associated with increased Lown’s classification(P<0.001). Patients with both Lown’s III and IV had a significant lower potassium levels than those with Lown’s IV(P=0.048). In this study, 63 patients died during hospitalization. Patients died during hospitalization had a lower potassium levels compared with patients free of in-hospital death(P=0.006). Multivariable logistic regression analyses showed that potassium level was independently associated with in-hospital mortality(P=0.044). The risk of in-hospital death was reduced by 26.8% with every 0.5 mmol/L increase in serum potassium. The ROC analysis and restricted cubic spline regression analysis suggested an optimal threshold of potassium 4.18 mmol/L on predicting in-hospital death. Conclusions: Potassium levels on admission is negatively correlated with Lown’s classification, and lower potassium level is independently associated with in-hospital mortality in patients hospitalized with HF and without significant renal dysfunction.