in the presence of isoproterenol ( 5 x 10 ( -7 ) m ) , 1-verapamil ( 1 microgram/ml ) depressed the vmax and decreased the conduction velocity to 16.9 +/- 4.2 cm/sec , just before development of the conduction block , while lidocaine was without effect .
C0022245
isoproterenol
C0018794
conduction