Cardiac Drugs

Questions and Answers

Which of the following is a primary mechanism by which beta-blockers reduce the incidence of angina?

Decreasing heart rate (correct)

Increasing afterload

Increasing blood pressure

Increasing myocardial contractility

What effect do beta-blockers have on myocardial contractility?

Decrease contractility (correct)

Increase contractility

Increase contractility, but only in specific cases

No effect on contractility

How do beta-blockers help reduce oxygen demand in the heart?

By decreasing afterload (correct)

By increasing heart rate

By increasing contractility

By increasing afterload

Which of the following is NOT a mechanism by which beta-blockers reduce the incidence of angina?

Increasing contractility Signup and view all the answers

What is the primary reason beta-blockers are considered antihypertensive?

They decrease afterload, leading to lower blood pressure Signup and view all the answers

How do beta-blockers affect oxygen supply to the heart?

They increase oxygen supply by decreasing heart rate Signup and view all the answers

Which of the following is a primary benefit of beta-blockers in the treatment of angina?

Decrease in oxygen demand Signup and view all the answers

What is the relationship between beta-blockers and afterload in angina treatment?

Beta-blockers decrease afterload, helping to reduce angina Signup and view all the answers

Which of the following is a major beta-1 selective antagonist commonly used in the UK for treating angina?

Bisoprolol Signup and view all the answers

What is the primary mechanism of action of beta-blockers in treating angina?

Reducing heart contractility and oxygen demand Signup and view all the answers

Which of the following statements is TRUE regarding the use of beta-blockers in angina?

Beta-blockers can be used to prevent both angina attacks and heart failure. Signup and view all the answers

Which of the following is a primary mechanism of action for calcium channel blockers in the treatment of angina?

Dilating coronary arteries by inhibiting calcium entry Signup and view all the answers

Which of the following statements accurately describes the use of calcium channel blockers in angina?

Calcium channel blockers are more effective than beta-blockers in treating angina caused by coronary artery vasospasm. Signup and view all the answers

Which of the following is NOT a typical effect of beta-blockers on the cardiovascular system?

Increased myocardial contractility Signup and view all the answers

Which type of angina is primarily associated with coronary artery vasospasm?

Variant angina Signup and view all the answers

What is the main reason beta-blockers are considered effective in the management of angina?

They reduce oxygen demand by decreasing heart contractility. Signup and view all the answers

What is the primary benefit of beta blockers in treating angina pain?

They relieve symptoms caused by atheroma. Signup and view all the answers

How do beta blockers achieve a negative chronotropic effect?

By antagonizing sympathetic nervous system effects. Signup and view all the answers

What happens to myocardial contractility when beta blockers are administered?

Myocardial contractility decreases. Signup and view all the answers

Which mechanism do beta blockers use to lower heart rate during each heartbeat?

They decrease calcium levels. Signup and view all the answers

In the context of heart failure management, what effect do beta blockers have on cardiac conduction?

They slow cardiac conduction. Signup and view all the answers

What physiological change occurs in the myocardium when the heart rate is slowed by beta blockers?

Improved oxygen supply to the inner myocardium Signup and view all the answers

Study Notes

Beta Blockers in Angina

Beta blockers improve oxygen supply to the inner myocardium by slowing the heart rate (negative chronotropic effect) and increasing time for blood perfusion within each heartbeat.
The major benefit of beta blockers is in relieving angina pain caused by atheroma rather than coronary vasospasm.

Beta-Adrenoceptor Antagonism

Beta blockers antagonize the effect of the sympathetic nervous system and circulating adrenaline.
This reduces the activation of cell membrane adenylate cyclase, decreasing cAMP and calcium entry into the cell.
As a result, heart rate slows, cardiac conduction decreases, and myocardial contractility reduces.

Mechanisms of Beta Blockers in Angina

Beta blockers reduce oxygen demand by inhibiting myocardial contractility (negative inotrope).
They reduce oxygen demand by decreasing the afterload on the heart by lowering systemic blood pressure (antihypertensive effect).
Beta blockers increase oxygen supply to the heart by reducing heart rate, allowing for better distribution of oxygen supply.

Other Beta Blockers

Propranolol and atenolol are still in common use today.
Bisoprolol is a major beta1-selective antagonist in use in the UK, with about a 75-fold selectivity for the beta-1 adrenoceptor.

Variant Angina

Calcium channel blockers are effective in treating variant angina.
They work by blocking calcium entry into the cell, reducing vasospasm and angina pectoris.

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Description

This quiz explores the effects of beta blockers on heart rate, blood perfusion, and relief of angina pain caused by atheroma.