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Category: Heart Failure

A Review of Why and How We May Use β-Blockers in Congestive Heart Failure: Conclusions

β-blocker used in most of the successful studies, newer nonspecific p-blockers such as bucindolol and carvedilol have advantages over metoprolol partly due to their peripheral vasodilatory properties. canada health and care mall Although several studies have suggested the probability of a decrease in mortality with P-blockers even in addition to the effect of ACE inhibitors, […]

A Review of Why and How We May Use β-Blockers in Congestive Heart Failure: Dose

Although the long-term use of carvedilol may result in tolerance to its a-blockade properties analogous to that produced by prazosin, this does not seem to affect its beneficial long-term effects as shown by Packer et al in their 1996 report on the effect of carvedilol on 1,094 patients with mixed ischemic and idiopathic DCM with […]

A Review of Why and How We May Use β-Blockers in Congestive Heart Failure: β-Blockers and ACE Inhibitors

β-Blockers and ACE Inhibitors Angiotensin II causes an increase in adrenergic neurotransmitter activity, and ACE inhibitors can decrease norepinephrine in venous blood and are therefore said to be antiadrenergic and like β-blockers, can increase β-receptor density. During the acute stages of CHF, an increase in the renin-angiotensin system is necessary to maintain pressure. However, chronically […]

A Review of Why and How We May Use β-Blockers in Congestive Heart Failure: Histologic vs Hemodynamic Criteria for Prognosis With β-Blockers

Conventional hemodynamic criteria cannot predict who will respond to β-blockers. Histologic criteria are more predictive. In 1993, Yamada et al reported that almost all patients with interfascicular fibrosis responded well, while only one third with intercellular fibrosis responded. In 1995, Yamada et al53 reported that the extent of myocardial fibrosis could be estimated by means […]

A Review of Why and How We May Use β-Blockers in Congestive Heart Failure: Ischemic vs Idiopathic DCM and β-Blockers

Two of the negative studies had a duration of only 1 month, during which time there may be temporary deterioration. Although a few patients have immediate improvement, it usually takes 2 months for an increase in ejection fraction, and 6 months to a year for maximum response. After many months, a larger dose may produce […]

A Review of Why and How We May Use β-Blockers in Congestive Heart Failure: Upregulation and Downregulation of β-Receptors

The normal heart has about 80% β1 and 20% β2-receptors. In CHF, it is not surprising that there are about 60% &beta:-receptors and 40% &beta:2-receptors, because theβ2-receptor response is relatively unchanged. However, by β2-stimulation tests in heart failure, there may also be a 30% decrease in their responsiveness. Therefore some downregulation may occur even with […]

A Review of Why and How We May Use β-Blockers in Congestive Heart Failure: Long-term sympathetic stimulation

With long-term sympathetic stimulation, the ability of noradrenergic sympathetic nerve endings of the heart to synthesize norepinephrine is attenuated. In animals, sympathetic blockade can restore the ability to make norepinephrine. Upregulation and Downregulation of β-Receptors Repeated or prolonged exposure to β-agonists causes the β-receptors to become desensitized by chemical uncoupling to binding proteins. Uncoupling makes […]

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