Atrial fibrillation.

Although most cases of sustained atrial fibrillation are associated with mitral valve disease, hypertension, cardiac failure and atherosclerotic heart disease, some cases occur in the absence of any identifiable organic pathology. The consequences of atrial fibrillation include reduction in cardiac output, systemic emboli and an exaggerated ventricular response to exercise. In most clinical situations, digoxin is the drug of choice for controlling the ventricular response. Cardioversion should be undertaken in appropriately selected patients.