Time to initial control of tachycardia > 24 h (OR 4.89, 95% CI 1.17 ~ 20.41), hyperkalemia (OR 6.55, 95% CI 1.14 ~ 37.75), anemia (OR 5.37, 95% CI 1.15 ~ 25.11), and plasma BNP level (OR 1.001, 95% CI 1.000 ~ 1.001) were significant in univariate analysis (all P < 0.05). Here, NPPB is linked to anemia.