What Effects Does Low Potassium Have on the Heart?

An average man has about 270 milligrams or 9 ounces of potassium in the body. Most of this potassium is found inside the cells, since it is the major cat-ion of the intracellular fluids (155 milliequivalent/liter). The rest of the potassium, even though small in amount (3.5 to 5 milliequivalent/liter in serum), has an extremely important role in muscular activity, especially that of the heart. Even minute changes in serum potassium concentrations are reflected in electrocardiographic (ECG) readings, which determine the rhythm and strength of the heart.

Function of Potassium

• Potassium, along with sodium and calcium, regulates neuromuscular activity, transmits electrochemical impulses and contracts muscle fibers. Its concentration is especially significant for the heart muscle since it continuously contracts and expands. Apart from this, potassium plays a pivotal role in the electrolyte-fluid and acid-base balance of the body.

Low-Serum Potassium

• A low serum level of potassium (less than 3.5 milliequivalent/liter) is known as hypokalemia. Hypokalemia may cause an irregular heart rhythm and tachycardia, or exceedingly fast heartbeat. This could result in the failure of the heart to contract and circulate blood, a condition known as cardiac arrest.

Reasons for Potassium Deficiency

• Potassium deficiency may occur due to prolonged malnutrition, excessive vomiting and diarrhea, and gastric suction. Continuous use of some diuretic drugs and metabolic disturbances like diabetic acidosis also cause potassium depletion. Hence, additional potassium medications are often prescribed with diuretics to avoid potassium deficiency. Chronic renal diseases affect potassium levels, too.

Food Sources of Potassium

• Bananas are a rich source of potassium.

  The recommended dietary allowances for potassium in adults is 4.7 grams per day. The richest sources of potassium in the diet are fresh fruits like bananas (451 micrograms), dried figs (666 micrograms per five figs), dates and cantaloupes (413 microgram per quarter). Fresh vegetables like artichokes (425 microgram), asparagus (279 microgram) and spinach (420 microgram) are high in potassium, too. Potatoes baked with skin contain as high as 844 micrograms of potassium per potato. Fresh orange juice and prune juice are good sources of potassium, as well as meats and skimmed milk.

Excess of Potassium

• Renal failure, severe dehydration and shock can cause hyperkalemia or excess of potassium in the body. The heart rate slows down to such an extent that it fails to transmit electrochemical impulses needed to mediate the heartbeat. This can eventually lead to death.