Electrolytes are required to keep all cells alive. Normally, the kidneys regulate blood electrolyte levels by making fine adjustments according to the body's needs. Under some conditions an electrolyte imbalance can occur, as when potassium is depleted by dehydration. This can result in irregularities of the heart's rhythm such as palpitations and fibrillations, which can be serious consequences of electrolyte imbalance.
Cardiac Rhythm
The heart is a blood pump powered by cardiac muscle cells. Cardiac muscle cells are electrically excited to contract in synchrony by nervous tissues within the heart muscle. This synchronous movement opens and closes compartments within the heart, which forces blood through the heart and to the rest of the body. The rhythmic control is maintained by a number of physiological checks and balances to ensure the heart beats remain relatively constant, and increase or decrease as the body's demands dictate.
Heart Palpitations
Normally, whether the heart beats slowly or quickly, its rhythm is mostly regular from beat to beat. Neural control of heart muscles, such as that provided by the heart's natural pacemaker, ensures this regularity. Even under a variety of conditions such as physical stress, the regularity of the beats changes gradually. However, sometimes you can sense irregular beats, where there is an abrupt change in rhythm that can last for one or more beats and then change again. This abnormal condition is known as heart palpitations.
Electrolyte Function
Electrolytes are minerals that dissolve in water and are then capable of carrying an electric charge. Electrolytes are normally obtained from the diet and include sodium, potassium, chloride, magnesium and calcium. The kidneys control the amount of each electrolyte in the blood by retaining those in demand and excreting, in the urine, those in excess. The kidneys are capable of sensing the ratio of one electrolyte to another and make appropriate adjustments to keep a constant balance between electrolytes. This is important because the total amount each electrolyte and their relative ratios influence all cell functions in the body.
Electrolyte Imbalance and the Heart
An imbalance of electrolytes occurs when there is a disproportionate amount of one or more electrolytes in the blood. Imbalance can occur with various conditions such as diarrhea, dehydration and some diseases. Electrolyte imbalance upsets the normal equilibrium around cells, which affects how they function. Electrically active cells, like cardiac cells, are particularly vulnerable to a shift in electrolyte equilibrium. In particular, cardiac cells are very sensitive to changes in potassium and sodium levels. For example, low serum potassium levels, called hypokalemia, can cause the heart's electrical rhythm to change, resulting in palpitations. Usually, replacing the electrolytes by food or drink can bring the heart's rhythm back to normal.
