Beta - blockers, Biology

Assignment Help:

Beta-blockers have traditionally been considered contraindicated in patients with heart failure because they may block the compensatory actions of the sympathetic nervous system with potential to worsening of symptoms. However, chronically failing heart is adrenergically activated and persistent elevations of catecholamines and sympathetic nervous system activity cause progressive myocardial damage, leading to worsening left ventricular function and dilation. Several large clinical trials have demonstrated that beta-blockers decrease mortality in patients who are already receiving standard heart failure therapy (i.e., angiotensin-converting enzyme [ACE] inhibitors and diuretics with or without digoxin). Hence the role of beta blockade in heart failure management.

Beneficial effects of beta-blockers in heart failure include improvement in LV ejection fraction over a period of 3-6 months decrease in LV end-systolic and end-diastolic volumes and mass in 4 to 12 months ('reversed remodeling').

Large randomized trials have shown mortality reduction to the tune of 35 per cent with beta-blocker therapy.

Current guidelines recommend that beta-blockers be used in patients with systolic dysfunction, ejection fraction less than 40 per cent, and mild to moderate heart failure as judged by New York Heart Association (NYHA) (10) class II or III symptoms. Beta-blockers should be started at low doses and gradually increased to the target goals. Effective beta blockade can be reached progressively by increasing doses of beta-blocker agents every 2 to 3 weeks.

Agents found useful in heart failure are second generation selective B 1 agents or third generation agents with vasodilatory action. There is evidence for the usefulness of metoprolol, bisoprolol, and cardvedilol in heart failure.


Related Discussions:- Beta - blockers

Define nutritional management of neurological disorders, Define Nutritional...

Define Nutritional Management of Neurological Disorders Your friend's aged father, over a period of time has become very confused, forgetful and is unable to do many things he

Explain the term- latent squint, Explain the term- Latent Squint (Anisophor...

Explain the term- Latent Squint (Anisophoria or Heterophoria) This eye condition occurs when the balance of extra-ocular muscles is altered. There is a tendency of the eye to

Eretmochelys imbricata, Ivory was much in demand for production of a variet...

Ivory was much in demand for production of a variety of jewellery and artifacts in the past. Reptile leather from crocodiles, lizards and snakes has quite a high demand for manufac

Define nutritional requirements for young and older children, Define Nutrit...

Define Nutritional requirements for Young and Older Children? Young children need 3 en%, which would be easily met from 8-10 g of oil. However, more visible oil is needed to im

Ethylene production - responses to infection, Ethylene production - Res...

Ethylene production - Responses to Infection Ethylene is also induced in response to infection. It is also known to be produced under other stress conditions like wounding

Preparation of cardiac surgery, Preparation on the Previous Day of Operatio...

Preparation on the Previous Day of Operation Remove all the jewellery, nail polish, cut nails.  The patient's body is cleaned - shaving from chin to toe, inclu

The signals for parturition originate from, The signals for parturition ori...

The signals for parturition originate from: 1. placenta only 2. placenta as well as fully developed foetus 3. oxytocin released from maternal pituitary 4. fully develop

How are secondary cell walls different from primary cell, How are secondary...

How are secondary cell walls different from primary cell walls? Primary cell walls are assembled on the surface of the plasma membrane whereas the cell is growing. They can gro

Respiratory system, 1. Considering the nature of negative-feedback control ...

1. Considering the nature of negative-feedback control and the function of the respiratory system, what effect do you predict that a decrease in CO2 in the internal environment wou

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd