Neurohumoral changes in patients with left ventricular dysfunction following acute myocardial infarction and the effect of nitrate therapy: a randomized, double-blind, placebo-controlled long-term study.

BACKGROUND

Several neurohumoral mechanisms involved in cardiovascular regulation are activated in the failing heart, but only limited information is available regarding the influence of long-term nitrate therapy.

METHODS

This was a double-blind, randomized comparison of isosorbide-5-mononitrate (IS-5-MN), 60 mg given orally, once daily for 11 months to patients (n = 47) with left ventricular (LV) dysfunction following acute myocardial infarction (AMI). Forty-five patients received placebo. All patients received ramipril.Plasma natriuretic peptides (atrial [ANP] and brain [BNP] natriuretic peptide), epinephrine, norepinephrine (NEPI), antidiuretic hormone, aldosterone (Aldo), renin activity (PRA), substance P, neuropeptide Y-like immunoreactivity, calcitonin gene-related peptide, and vasoactive intestinal peptide were measured at baseline and at the end of the treatment period. Clinical, echocardiographic, and hemodynamic data were also obtained.

CONCLUSIONS

Chronic nitrate therapy does not significantly affect the neurohumoral status in patients with LV dysfunction after AMI, apart from a decrease in ANP. Some hormones are more closely associated with diastolic dysfunction/increased volume load (ANP and BNP) and others are more closely associated with systolic dysfunction (PRA, NEPI, Aldo). There is a temporal dissociation of these 2 groups of hormones 1 year post infarction: ANP and BNP decrease, whereas NEPI and Aldo show a slight increase. BNP levels do not reflect all important pathophysiologic mechanisms in heart failure. Consequently, the use of other neurohormonal factors than BNP for monitoring of heart failure therapy should be explored.