[The role of beta-2 stimulators in cardiac insufficiency]

Beta-2 adrenergic stimulators, a class of drugs which has been used for a long time in the treatment of bronchial asthma and in tocolysis, have recently become part of the therapeutic arsenal for congestive heart failure. Their action seems to be essentially vasodilator, although they do have a mild positive inotropic effect. In the short term, they improve the cardiac output and they decrease the peripheral vascular resistance. Their long term haemodynamic effects are still controversial. However, their are some arguments in favour of the persistence of the beneficial effects observed in the short term. They have a contradictory action on the capacity for exercise; one study states that they improve exercise capacity and another study finds that they do not. Their action on the length of survival is still unknown. Some reports suggest that they may aggravate ventricular arrhythmias. At the moment, then, this class of drugs is only used experimentally in congestive heart failure. We need to wait for the results of larger studies on the long-term benefits, the exercise capacity and the survival. Possible side effects also need to be studied in more detail.