[Classification and principles of the use of vasodilators in the treatment of left ventricular insufficiency].

Vasodilators have been widely used in recent years for the treatment of severe left ventricular failure (LVF). However, amongst these drugs, not all have the same therapeutic effects, but they differ from one another in molecular structures, cellular mechanisms, haemodynamic actions and modes of administration. A three tier classification is proposed with the single objective of facilitating the therapeutic choice: mechanism of action: this property distinguishes the alpha-blockers from the beta-2 sympathomimetics, calcium antagonists, angiotensin converting enzyme inhibitors and prostacyclin biosynthesis inducers. Some molecules such as hydralazine, whose mechanism of action remains unclear, cannot be classified in this way; haemodynamic effects: these effects can be used to distinguish vasodilators which act mainly on the venous sector from arterial and mixed vasodilators. The knowledge of the preferential site ol action of these molecules helps to adapt the choice of treatment to the initial haemodynamic profile of each patient; pharmacokinetics: these properties distinguish molecules active only by intravenous administration, better adapted for the treatment of acute LVF in the intensive care unit, from those active orally which can be used for long-term ambulatory therapy of chronic cardiac failure. Trinitrin and its derivatives occupy an intermediate position because of their relatively low bioavailability after oral administration: long-term administration is not always easy and may require special modes of administration (i.e. percutaneous). Vasodilators have been widely used in cardiac failure for about 5 years; the results of some medium term controlled therapeutic trials are now available and confirm the efficacy of these drugs but also define their limitations: variable therapeutic efficacy: the number of responders ranges from 30 to 60 p. 100 according to the molecule used.(ABSTRACT TRUNCATED AT 250 WORDS)