AS A result of their ability to unload the heart, drugs that reduce vasomotor tone in the periphery have been used in the treatment of a variety of cardiac disorders. In patients with left ventricular dysfunction, vasodilators improve cardiac performance and relieve symptoms of congestion and low output. They have also been used to treat patients who are symptomatic from severe valvular regurgitation. We review the recently published information describing the effects of vasodilators in patients with mitral and aortic regurgitation, and suggest some of the directions that future research is likely to take.
A convenient and useful way of classifying vasodilators is according to their major site of action, since the hemodynamic effects of a particular drug depend on whether it reduces tone in peripheral arteries, in veins, or, in the case of dual-acting agents, in both. Nitroglycerin and isosorbide dinitrate (Isordil) are predominantly venodilators. By decreasing tone in