Question 12

Created on Wed, 06/03/2015 - 17:29
Last updated on Wed, 11/18/2015 - 06:12
Pass rate: ?
Highest mark: ?

Topic

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What is the role of cardioselective betablockers in the management of severe heart failure in
ICU?

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College Answer

Cardioselective betablockers  (eg. atenolol, metoprolol  & practolol) have less effect on the beta·2 receptors (less vasoconstriction and less bronchoconstriction). No specific benefits of any subgroup of beta·blockers bas been confumed inthe management of severe heart failure.

The candidates should be able to discuss the complex  role of betablockers in heart failure. The role of betablockers in heart failure management is complex enough outside of the !CU. This has been clarified further in the last few years by publication of articles confirming the benefit of addition of betablockers to the conventional  heart failure regimen (ACE inhibitor + diuretics)  in the outpatient setting  (with   decreased   symptoms,   slowing   progression,   improving   LV   function   and   even improving survival). These benefits have been demonstrated  initially with carvedilol (non-selective betablocker) and more recently with metoprolol (cardioselective betablocker). Titration of the medication needs to be slow and judicious. It is unknown whether similar benefits can be obtained in the ICU setting, especially given the beneficial effects of short term administration of inotropic agents in dilated cardiomypoathy.

Betablockers may have some  benefit in the setting  of tachycardia (mcreased  resting  sympathetic tone),  but  many  patients   may  experience  worsening  of  symptoms.  Success  of   treatment  ofarrhythmias  with   betablockade depends  upon   the   magnitude  of   the   coincident  decrease ·in contractility (other  agents  may be preferred  eg. amiodarone). Prevention of sudden  death (malignant ventricular  arrhythmias) may be achieved.

Treatment   of   myocardial  ischaemia  with   betablockers  may   have   beneficial  effects  (oxygen
requirements, improved relaxation, decreased arrhythmias).
Betablockade may  be  beneficial  in the  setting  of  hypertrophic cardiomyopathy  (with  diastolic dysftmction), by decreasing myocardial oxygen  consumption, decreasing ischaemia and  improving
relaxation (lusitropy).

Discussion

How about another table?

 

Advantages of cardioselective betablockers

Disadvantages of cardioselective beta blockers

Mortality

Improve mortality in heart failure patients

Mortality improvement is no different to non-selective beta blockers

Contractility

Decreased contractility; 
Decreased myocardial oxygen consumption and enhanced subendocardial blood flow

Decreased responsiveness to preload

Heart rate

Decreased heart rate = decreased cardiac workload

Fixed stroke volume x decreased heart rate = poor cardiac output

Afterload

No influence on afterload; maintained good diastolic coronary filling

No decrease in afterload = no decrease in cardiac work against afterload

Myocardial oxygen consumption and cardiac workload

Decreased myocardial oxygen consumption  due to decreased heart rate and contractility

Decreased exercise tolerance

Side effects

Fewer beta-2 effects, thus no disadvantage in peripheral vascular disease and asthma

Nightmares, depression, lethargy

References

Al-Gobari, Muaamar, et al. "Beta-blockers for the prevention of sudden cardiac death in heart failure patients: a meta-analysis of randomized controlled trials."BMC cardiovascular disorders 13.1 (2013): 52.

Tuunanen, Helena, and Juhani Knuuti. "Metabolic remodelling in human heart failure." Cardiovascular research 90.2 (2011): 251-257.