in contrast , isoproterenol exerted dose-dependent positive chronotropic effects in either condition ( hr : 189 +/- 7 and 332 +/- 5 beats/min ) and propranolol exerted dose-dependent negative chronotropic effects in either condition ( hr : 209 +/- 5 and 344 +/- 19 beats/min ) .
C0022245
isoproterenol
C1372804
positive chronotropic