lb46 was 8 times more active than racemic propranolol in blocking the effects of isoprenaline on isolated cardiac muscle , and since its direct action on the cardiac membrane was only 0.1 times that of propranolol , there was a net gain of 80 times in the specificity of lb46 for class 2 ( antisympathetic ) over class 1 ( depression of mrd ) antidysrhythmic actions.5 .
C0027061
cardiac muscle
C0018787
cardiac