Hemodynamic resistance to intravenous nitroglycerin in severe congestive heart failure and restored response after diuresis

A wide variety of organic nitrate preparations are often used in the management of congestive heart failure (CHF). This class of drugs exerts a vasodilatory action, predominantly on the venous capacitance vessels, that leads to a reduced ventricular filling pressure and usually without an increase in cardiac output. 1,2 Two major problems exist that deter its widespread acceptance as an effective drug in CHF: the development of tolerance and hemodynamic resistance or primary drug failure. Tolerance is responsible for the loss of hemodynamic and clinical benefits after nitrate therapy has been initiated. 3–5 An absent or feeble hemodynamic response to nitrates, a relatively common occurrence, has been reported to occur in approximately ≥50% of treated patients. 6,7 However, nitrate resistance is not always apparent when intravenous nitroglycerin is used without hemodynamic monitoring. This study was designed for 2 purposes: (1) to substantiate previously described hemodynamic and clinical correlates of CHF predictive of resistance to intravenous nitroglycerin, 6,7 and (2) to determine whether hemodynamic modification using alternate drug therapy might restore responsiveness to nitroglycerin.