What all can happen if you have really low patassium?

Low potassium: A small drop in potassium (k) level often does not cause symptoms. Or symptoms may be mild and include: abnormal heart rhythms (dysrhythmias), especially in people with heart disease, constipation , palpitations, fatigue, muscle damage, weakness, tingling or spasms. A small drop in k can make your heart beat slower making you feel weak. A large sudden drop of k can kill you.