Potassium is a mineral in the body that helps maintain fluid balance, nerve function, and muscle contraction, as well as the proper transmission of electrical impulses in the heart. Potatoes and bananas are especially good sources of potassium, which also is found in many meats, milks, fruits, vegetables, and grains.

Both low and high potassium levels can disrupt the normal electrical impulses in the heart, leading to irregular heartbeats (arrhythmias).

By	Healthwise Staff
Primary Medical Reviewer	E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer	Robert A. Kloner, MD, PhD - Cardiology
Last Revised	August 5, 2010