Cardiovascular research
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Cardiovascular research · Mar 1998
Efficacy of a beta-adrenergic receptor antagonist, propranolol, in preventing ischaemic ventricular fibrillation: dependence on heart rate and ischaemia duration.
To investigate the prevention of ventricular fibrillation with a beta-adrenergic receptor (beta-AR) antagonist in anaesthetized, open-chest pigs in a model of ischaemia, intended to reproduce what happens either in anginal attack or in the first hour of infarction. ⋯ The prevention of ischaemic ventricular fibrillation by a beta-AR antagonist, judged from VFT, is easily checked experimentally when ischaemia is only transitory, especially if sympathetic activity is high. The maintenance of VFT at a relatively high level is essentially related to the depressant effect on the sinus rate. The same animal model does not give support to an effective protection in the first hour of infarction. However, the control of heart rate may also be beneficial in these circumstances by attenuating systemic haemodynamic disorders.
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Cardiovascular research · Mar 1998
Efficacy of myocardial initial reperfusion with 2,3 butanedione monoxime after cardioplegic arrest is time-dependent.
In a previous study, initial reperfusion of isolated hearts after cardioplegic arrest with 2,3 butanedione monoxime (BDM) for 5 min was markedly superior to warm hyperkalemic reperfusion in improving the initial oxygen balance and reducing reperfusion arrhythmias. However, left ventricular contractility was only marginally enhanced. The goal of the present study was to test, wether the efficacy of BDM reperfusion can be enhanced by prolonging the application period. ⋯ 20 min of initial BDM reperfusion were clearly superior to immediate Krebs reperfusion or a shorter (5 min) or longer (40 min) BDM treatment period in attenuating reperfusion damage. Thus, contraction uncoupling during initial reperfusion by BDM or similarly acting drugs may prove a viable technique to reduce myocardial reperfusion damage in patients undergoing open heart surgery.