Description an antianginal and antiarrhythmic drug. it increases the duration of ventricular and atrial muscle action by inhibiting na,k-activated myocardial adenosine triphosphatase. there is a resulting decrease in heart rate and in vascular resistance.indication :intravenously, for initiation of treatment and prophylaxis of frequently recurring ventricular fibrillation and hemodynamically unstable ventricular tachycardia in patients refractory to other therapy. orally, for the treatment of life-threatening recurrent ventricular arrhythmias such as recurrent ventricular fibrillation and recurrent hemodynamically unstable ventricular tachycardia.contra-indications :1.hypersensitivity to the drug 2.2nd or third degree heart block 3.congestive heart failure 4.cardiogenic shock 5.severe bradycardia 6.severe obstructive pulmonary diseases 7.electrolyte imbalance 8.severe hypotension 9.myasthenia gravis 10.sinus node dysfunction 11.atrial conduction defect