An abnormally high level of potassium in your blood can lead to a wide range of symptoms, some of which can be fatal according to WebMD. The most life-threatening symptoms that can occur include changes in heart rhythm, which can cause the heart to stop beating in extreme cases.
Since potassium influences the activity of nerve and muscle cells, any slight imbalance can affect one's health. Hyperkalemia, or high blood potassium, affects the body in various ways, and can cause weakness, fatigue, numbness, or even paralysis. Severe hyperkalemia may lead to an irregular heart rhythm that can further cause ventricular fibrillation, an emergency condition that affects the heart's capacity of pumping blood properly, according to WebMD. Without treatment, complications of high blood potassium can result in death.