Hea rate is decreased by

ref; KD Tripathi Pharmacology 6th edition (page no;136) Propranolol is a beta blocker which decreases hea rate, force of contraction (at relatively higher doses) and cardiac output (c.o.). beta blocker inhibits adrenergic responses mediated through the beta receptors. Isoprenaline,Dobutamine,Dopamine are adrenergic drugs , which are cardiac stimulators so increases hea rate