Potassium plays a major role in normal cardiac function, skeletal and smooth muscle contraction and digestion. Hypokalemia is a medical condition that occurs because of a decrease in serum potassium levels. Use of certain diuretics, overuse of laxatives and diarrhea are some causes of potassium loss. The normal range for serum potassium levels is 3.5 to 5 millequivalents per liter or mEq/L. Severe hypokalemia occurs when potassium levels drop below 2.5 mEq/L and is responsible for serious cardiac effects that demand immediate medical attention.
Premature Atrial and Ventricular Contractions
Potassium is an electrolyte. An electrolyte is a substance that dissociates into ions in solution and has the capacity to conduct electricity. Along with sodium, potassium generates muscle contractions and regulates heart rate. Premature atrial and ventricular contractions are cardiac arrhythmias that occur with severe hypokalemia. Premature atrial contractions are extra abnormal beats that originate in the atria or upper chambers of the heart. They can go unnoticed or be perceived as palpitations or a skipped beat or pause in heart rate. Premature ventricular contractions are extra abnormal beats that originate in the ventricles or lower chambers of the heart. They cause the sensation of flip-flopping or a skipped heartbeat in the chest. In most cases, if a person can tolerate the symptoms, treatment is not required.
Atrial and Ventricular Tachycardias
A heart rate of more than 100 beats per minute is called tachycardia. Atrial tachycardia is a rapid heart rate that originates in the atria and can be in the range of 100 to 250 beats per minute. The underlying cause of atrial tachycardia is identified before treatment with either medication or cardio version is administered. Ventricular tachycardia is a rapid heart rate of greater than 100 beats per minute, has at least three irregular heart beats in a row and originates in the ventricles. It is a serious condition because the rapid heart rate stops the chamber from filling with an adequate amount of blood. As a result, output diminishes and less blood circulates through the body. A person with ventricular tachycardia experiences angina, palpitation, dizziness and shortness of breath. In cases of ventricular tachycardia caused by hypokalemia, treatment is aimed at correcting the potassium imbalance.
Ventricular Fibrillation
According to the Merck Manual of Medical Information, severe hypokalemia is one cause of ventricular fibrillation. Ventricular fibrillation is a potentially fatal cardiac arrhythmia. The ventricles contract rapidly but ineffectively and no blood issues from the heart. A person in ventricular fibrillation loses consciousness within seconds. Cardiopulmonary resuscitation must be initiated immediately. This must be followed by defibrillation to restore a normal heart rate. Defibrillation is the process of delivering an electrical shock to the heart.
