What is the effect of beta-blockers on cardiac output?

Beta-blockers primarily work by blocking the effects of the hormone epinephrine (also known as adrenaline) on beta-adrenergic receptors in the heart. This leads to a reduction in heart rate and myocardial contractility, ultimately resulting in a decrease in cardiac output.

When beta-blockers are administered, the heart beats more slowly and with less forceful contractions, which translates to a reduced volume of blood being pumped out with each heartbeat. This decrease in heart rate (negative chronotropic effect) and reduction in the strength of heart contractions (negative inotropic effect) contribute to the overall decline in cardiac output.

The role of beta-blockers in managing conditions such as hypertension and heart failure hinges on their ability to reduce cardiac workload and lower oxygen demand, thereby alleviating stress on the cardiovascular system. This is why the correct answer indicates that beta-blockers decrease cardiac output.