What is one effect of beta antagonists on the heart?

Beta antagonists, also known as beta blockers, primarily work by blocking the action of catecholamines like epinephrine and norepinephrine on beta-adrenergic receptors in the heart. One significant effect of this action is a decrease in cardiac contractile force. This occurs because beta-adrenergic stimulation usually increases heart rate and myocardial contractility, which means that blocking these receptors leads to a reduction in the force of contraction of the heart muscle. By decreasing the contractile strength, beta blockers can also lower myocardial oxygen demand, making them useful in managing conditions such as hypertension, angina, and certain arrhythmias. This reduction in contractility helps to alleviate heart strain and can improve outcomes in patients with heart failure in particular. Thus, recognizing the mechanism of action of beta antagonists is key to understanding why they decrease cardiac contractile force.