Vasodilators are commonly used in the management of congestive heart failure. They can be divided into three categories:

(1) Venodilators - increase the venous capacitance, thus reduce the blood volume returning to the heart (reduces the filling pressures, i.e. the preload) and the pulmonary circuit. Indicated for the treatment of 'backward' heart failure, especially pulmonary oedema.
(2) Arterial vasodilators - reduce impedance (resistance) to left ventricular ejection, thus improving stroke volume (and cardiac output), i.e. they reduce the afterload on the heart. Therefore indicated for the treatment of 'forward' heart failure (except due to obstructive valvular disease or restricted diastolic filling states). This will also tend to reduce the workload and oxygen consumption by the myocardium. If mitral regurgitation is present, the improved forward flow will produce a resultant reduction in the regurgitant fraction.
  1. Mixed vasodilators - reduce preload and afterload (dilate arteries and veins).

Venodilators
nitrates: glyceryl trinitrate
Arterial vasodilators
hydralazine
Mixed vasodilators
sodium nitroprusside and prazosin
Angiotensin converting enzyme (ACE) inhibitor vasodilators

enalapril and benazepril

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