Digoxin is generally contraindicated in patients with hypertrophic obstructive cardiomyopathy unless there is severe cardiac failure, since the outflow obstruction may be worsened. It is also contraindicated in patients with the Wolff-Parkinson-White syndrome or other evidence of an accessory pathway, especially if it is accompanied by atrial fibrillation, since ventricular tachycardia or fibrillation may be precipitated.