Beta Blocker use in Resuscitation of Cardiac Arrests due to Ventricular Fibrillations

The mortality figures associated with cardiac arrest continue to remain high and have bothered the physicians for a long time. At present, epinephrine is recommended as the choice of drug to be used during cardio-pulmonary resuscitation because it causes peripheral vasoconstriction due to its alpha adrenergic effect. This, in turn, increases the coronary blood flow and the coronary perfusion pressure making defibrillation a possibility. However, it may increase the oxygen consumption by the cardiac tissue and can cause post resuscitation cardiac dysfunction because of its beta adrenergic actions.

Now a new study, led by researchers from Brazil, has found that beta blockers may play a role in treating cardiac arrest arising due to ventricular fibrillation. The researchers analyzed 12 animal studies, 10 case reports, and 2 clinical studies in which beta blockers had been used to treat cardiac arrests. It was seen that in the studies involving the animal models, use of beta blockers lowered the oxygen demands of the myocardium, thereby reducing the number of shocks required during defibrillation. This resulted in better myocardial function in the post resuscitation phase and improved chances of survival. The chances of recurrence of the cardiac arrhythmias were also found to be reduced.

In studies involving humans, use of propranolol during cardio-pulmonary resuscitation increased the rate of recovery of the inotropic function of the cardiac muscles to pre-arrest levels, as the damage to myocardium was considerably reduced. The researchers have suggested that using esmolol instead of propranolol would yield even better results as it has a faster onset of action and shorter half-life. The results of the analysis have been published in the latest issue of the journal Resuscitation.

lthough the results of the study point to a definitive role of beta blockers in the treatment of cardiac arrest, the researchers have stated that the number of studies investigating this topic are alarmingly low. Considerable research is still required to test the safety and efficacy of beta blockers before they can be put into use for treating cardiac arrests.

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Date: 
Thursday, March 15, 2012
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