Pharmacology of cardiac muscle

 

Many drugs act on the myocardium and cause it to beat faster or stronger, or the contrary. Adenergic drugs are used to cause increase in rate and strength of contraction. They act either selectively or in combination on α and β receptors. The drugs include catecholamines of which the most important are epinephrine, norepinephrine, isoprenaline, dopamine, dobutamine and dopexamine.

Atropine,  a popular anticholinergic drug can also increase heart rate by blocking cholinergic effect of bradycardia. Vasovagal attack also called primary shock occurs when there is an overwhelming cholinergic action on the heart causing sudden hypotension and bradycardia.