Final answer:
Beta-blockers, or β-blockers, are used to treat tachycardia and are effective in improving heart function by blocking β-receptors that affect heart rate and blood vessel dilation. They are not used to treat low blood pressure or bronchospasm.
Step-by-step explanation:
Beta-blockers, also known as β-blockers, are a class of drugs that are commonly used to manage cardiac conditions. They can be used to treat tachycardia (a fast heart rate), help manage symptoms of chest pain (angina), and control cardiac arrhythmias (abnormal heart rhythms). Additionally, they have a role in the treatment of congestive heart failure and in patients who have suffered heart attacks. Β-blockers work by blocking β-receptors, which are associated with the effects of adrenaline such as vasoconstriction and cardioacceleration. By blocking these receptors, beta-blockers prevent increases in heart rate and allow blood vessels to dilate, improving heart function. However, they are not typically used to treat low blood pressure or bronchospasm. In fact, they can potentially worsen these conditions. Therefore, the correct answer to the question is A) Tachycardia.