Effects of the recombinant form of the natural human B-type natriuretic peptide and levosimendan on pulmonary hyperventilation and chemosensivity in heart failure.

ABSTRACT

BACKGROUND: The origin of dyspnea in chronic heart failure (HF) is multifactorial, and excessive ventilation is thought to play a role in inducing this symptom. Chemosensivity is augmented in HF, correlates with increased pulmonary ventilation (VE), and is an adverse prognostic marker. Despite increased blood levels of natriuretic peptides in clinical conditions associated with dyspnea, their effect on pulmonary VE and chemoreceptor activity remains unexplored. METHODS: We tested in a prospective, placebo-controlled, three-way cross-over, double-blind randomized study the effects of the recombinant form of the natural human B-type natriuretic peptide (R-BNP) in comparison with placebo and levosimendan on chemoreflex sensitivity at rest, as well as their effects on pulmonary VE, systemic blood pressure, heart rate and sympathetic serum activity both at rest and during exercise. RESULTS: Eleven stable chronic HF patients were randomized to sessions of 6-min treadmill-walking tests during placebo, or levosimendan or R-BNP intravenous infusion in the following conditions room air, hypoxia, and hypercapnia. R-BNP administration determined higher pulmonary ventilatory response at rest and during exercise (P < 0.001) consequent to a boost of respiratory rate (P < 0.001) under room air and hypoxia conditions. Norepinephrine blood levels increased from rest to exercise in all conditions without differences among placebo, levosimendan, and R-BNP effects. BNP blood levels remained unchanged. CONCLUSIONS: The novelty of the present findings is that R-BNP infusion in HF patients can boost pulmonary ventilatory response at rest and during exercise.