All of the following drugs can be used for the chronic oral treatment of arrhythmia except:

Esmolol is an ultrasho acting b1 blocker devoid of paial agonistic or membrane stabilizing actions. It is inactivated by esterases in blood. Plasma t 1/2 is < 10 min Action disappears 15-20 min after terminating i.v infusion--degree of b blockade can be titrated by regulating the rate of infusion. It has been used to terminate supraventricular tachycardia, episodic atrial fibrillation or flutter, arrhythmia during anesthesia, to reduce HR and BP during and after cardiac surgery, and in early treatment of MI. Avoided in presence of systolic hea failure or asthma.