Transient decrease in serum potassium level during ischemic attack of acute coronary syndrome: Paradoxical contribution of plasma glucose level and glycohemoglobin

The degree of the potassium dip during ischemic attack (as indicated by ΔK, ΔK？=？K at discharge？？？K on admission) was examined in 311 consecutive patients with ACS who required urgent hospitalization in our institution.Serum potassium level during ischemic attack was significantly decreased compared to that during stable phase (P？<？0.001). Multiple regression analysis revealed that plasma glucose level during attack was the sole factor which was positively correlated with ΔK (P？<？0.01), while HbA1c level was negatively correlated (P？<？0.05). The medication profiles and renal function had no impact on ΔK. A longer hospitalization period, higher incidence of myocardial infarction and higher peak creatine kinase level were observed in patients with a larger ΔK.We have clearly demonstrated that there is a transient decrease in serum potassium level during ischemic attack of ACS compared to stable phase. The degree of the potassium dip was tightly correlated with glucose level, which overwhelmed the diabetic condition, and it also indicates the disease severity. The present study therefore promotes awareness of the significance of monitoring potassium level in parallel with glucose level in patients with ACS.A decrease in serum potassium (K) level has been suggested to be a fairly common observation in patients with acute coronary syndrome (ACS) [1-4], which has been shown to increase the risk of cardiac events, including lethal ventricular arrhythmias [5-7]. In addition, a decrease in K level generally induces vasoconstriction [8], which leads to further ischemia, thereby producing a vicious cycle. The optimal range of K level in ACS has been recently discussed and reviewed [9], and the importance of potassium homeostasis during ischemic attack was thus clarified. However, little is known about the pathophysiological significance of potassium kinetics during ACS attack. Moreover, there have so far been few studies directly demonstrating the transient relative decrease i