Electrolytes are electrically charged minerals such as sodium, potassium, calcium, phosphate and magnesium. Your body uses electrolytes for several purposes. Its cells, especially nerve cells and muscle cells such as those in your heart, maintain an electrical potential that can signal the cell to perform an activity. Electrolytes flow into and out of the cells to produce an electrical current, such as the current that the heart relies on to contract. Imbalances in electrolytes can cause problems with the current and result in abnormal heart rhythms, known as arrhythmias. It is important to consult a healthcare professional for the diagnosis and management of electrolyte imbalances and heart problems.
Electrical and Chemical Signalling
The concentration of positively charged sodium minerals in the blood outside of your heart cells is much higher than that inside. In contrast, potassium levels are much higher inside your cells than outside. At rest, your cells have an overall negative charge inside and positive charge outside. During times of activity, special protein channels open in your cells, letting sodium flow in and making them positive. This change causes nearby cells to open their protein channels as well. The flow of sodium into heart muscle cells causes them to contract and pump blood. The sodium channels promptly close, and potassium channels open, allowing potassium to exit the cell and make it negative again. A pump restores the normal levels of sodium and potassium and the cycle repeats, pumping blood again in a regular rhythm.
Causes
When levels of sodium, potassium and other minerals become abnormal, your heart can become more or less electrically charged, leading to abnormally timed contractions and an irregular heartbeat. Electrolyte imbalances are infrequently due to dietary restriction. Problems with hormone levels, such as those released from your adrenal or pituitary glands, can disrupt electrolyte levels. Kidney problems, genetic diseases and cancers are other possible causes.
Diagnosis
Your doctor can diagnose heart arrhythmias from a history of symptoms such as palpitations, light-headedness, shortness of breath or chest pain, although these symptoms also occur in many other problems such as heart attacks or blood clots to the lungs. A physical examination can reveal an abnormal pulse and laboratory tests such as an electrocardiogram can measure the electrical activity of your heart. An echocardiogram uses sound waves to look at the beating of your heart. The diagnosis of electrolyte imbalances is similar in that a history and physical examination are crucial. Blood tests that measure your levels of electrolytes are also helpful.
Treatment
The treatment of abnormal heart rhythms due to electrolyte imbalances depends on the severity of your abnormal heart rhythm and the nature of the electrolyte imbalance. Some situations may be urgent enough to require an external source of electricity to pace the heart. In other situations you may receive one or more medicines by mouth or intravenously. A doctor can temporarily adjust electrolyte imbalances by giving or restricting fluids and electrolytes, but you may require further intervention such as long-term medications---for example, if you have low hormone levels, you may receive hormone-replacement medication.
References
- "Physiology, 4th Ed."; Linda S.Costanzo; 2008
- "Molecular Biology of the Cell, 4th Ed."; Bruce Alberts et al.; 2002
- "Robbins and Cotran Pathologic Basis of Disease, 8th Ed."; Vinay Kumar, et al.;2009
