8. MECHANISM OF BETA BLOCKERS
IN HEART FAILURE
Upregulation of β receptors and improved β
adrenergic signaling.
Reducing the hyperphosphorylation of calcium
release channels of sarcoplasmic reticulum and
normalizing their function
Bradycardia (↑ coronary blood flow and
decreased myocardial oxygen demand).
Protection from catecholamine myocyte toxicity.
Suppression of ventricular arrhythmias.
Anti-apoptosis. β2 receptors, which are relatively
increased, are coupled to inhibitory G protein & block
apoptosis.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20. Mechanism of β-blocker benefits
in ischemic heart disease
• Reduction in myocardial oxygen
requirements via a decrease in
heart rate, blood pressure and
ventricular contractility.
• Slowing of the heart rate
prolongs coronary diastolic
filling period.
• Redistribution of coronary
21. Mechanism of β-blocker benefits
in ischemic heart disease
• Increases threshold to
ventricular fibrillation.
• Reduction in infarct size and
reduction in the risk of cardiac
rupture.
• Reduction in the rate of
reinfarction.
• Regression of the atheromatous
22. Summary of Trials of Beta-Blocker Therapy
Phase of
Treatment
Total No.
Patients
RR (95% CI)
Acute
treatment
28,970
0.87 (0.77-0.98)
Secondary
prevention
24,298
0.77 (0.70-0.84)
Overall
53,268
0.81 (0.75-0.87)
2
1
0.5
Relative risk (RR) of death
Placebo
Beta blocker
better
better
Antman E, Braunwald E. Acute Myocardial Infarction. In:
Braunwald E, Zipes DP, Libby P, eds. Heart Disease: A
textbook of Cardiovascular Medicine, 6th ed.,
Philadelphia, PA: W.B. Sanders, 2001, 1168.
23. MAINTATE
Usefulness of beta-blocker therapy in patients with
diabetes mellitus and CAD (BIP)
1.00
0.90
0.85
Mortality
42%
Withß-blockers
Withoutß-blockers
0.80
P = 0.0001
0.75
1
14.417 pts
2
3
Year
4
5
Jonas et al. Am J Cardiol 1996; 77: 1273 et seqq.
Survival rate
0.95
29. This is how braunwald’s textbook
summarizes the use of betablockers in
hypertension
“Beta blockers are specifically recommended for
hypertensive patients with concomitant coronary
disease, particularly after a myocardial infarction,
congestive heart failure, or tachyarrhythmias.”
“If a beta blocker is chosen, the agents that are more
cardioselective offer the likelihood of fewer
perturbations of lipid and carbohydrate metabolism
and, because of fewer side effects (except for
bradycardia), better adherence to therapy.”
“Long-acting formulations are better for once-daily
dosing.”
Page 945 braunwald’s
textbook of medicine 9th edition
32. Bisoprolol in hypertension
Objectives:
This study was aimed to evaluate the
efficacy and tolerability of
bisoprolol, in Indian patients
diagnosed with stage I essential
hypertension as first line drug.
Primary and secondary outcomes measures:
The primary outcome measure was
percentage of patients achieving
blood pressure (BP) <140/90 mm Hg
at the end of 12 weeks, while
Channaraya V, Marya RK, Somasundaram M, et al. BMJ Open 2012;2:e000683
multiple secondary outcome