<prompt> True about esmolol is: a It is a cardioselective βblocker b It increases airway resistance c It causes tachycardia d Its t 12 is 4 hrs e It has negative inotropic activitydecdaebc  <response>: Esmolol is an ultrashort acting β-blocker t12 10 min.It is inactivated by esterases in blood.β-blocker decreases heart rate and force of contraction negative inotropic action.Beta blockers can precipitate or aggravate CHF.Selective beta 1 blocker and are less likely to cause bronchoconstriction, thus do not increase airway resistance. 