Possible mechanism for improved myocardial function with higher potassium levels
myocardial Na, heart failure, hypokalemic
HEART FAILURE, DEPOLARIZATION
Changes in potassium concentrations in- and around the cardiomyocyte affect several aspects of myocardial electrophysiology which could result in altered mechanical function. P-K determines the resting membrane potential of the myocyte and significantly impacts depolarization velocity. Additionally, cardiac repolarization is mainly driven by an outward potassium flux and a low p-K lengthens the repolarization time and increases QT dispersion and active relaxation of the myocardium as well as the action potential- and refractory period durations [The effects of variations in potassium levels are likely to be more pronounced in patients with heart failure as the remodeling of the myocardium during deterioration of left ventricular function and increased hemodynamic load, even in early stages of heart failure, includes downregulation of potassium ion channels as well as of myocardial Na,K- ATPase concentration [Patients in the present study were increased from mid-normal to high-normal levels of p-K and there could be a greater improvement by increasing patients from low or even hypokalemic levels to high-normal levels. These considerations are left for future studies. Studies with hard endpoints are needed to elucidate if the present findings improve clinical patient outcomes.