Fluid and electrolyte imbalance in the patient with cardiovascular dysfunction is a common complication of cardiac disease. Cardiovascular diseases remain the number one cause of death in the United States today. Recovery from these diseases requires careful attention to the factors that influence heart status. Fluid and electrolyte imbalance in the cardiac patient often is both life-threatening and preventable. Maintaining a homeostatic environment in terms of fluid and electrolyte balance is critical to achieving optimal cardiac function in all heart patients.