Patients with heart failure and a preserved left ventricular ejection fraction (HFpEF) almost invariably complain of exertional breathlessness. Abnormal cardiac hemodynamics with pulmonary congestion are believed to trigger dyspnea in this patients. However, some patients may complain of exertional breathlessness which seems to be out of proportion as compared with hemodynamic abnormalities.

Chemoreflex sensitivity accounts for the ventilatory responses to a variety of chemical stimuli, including carbon dioxide produced by the organism during exercise. Chemoreflex sensitivity can be augmented in heart failure with reduced left ventricular ejection fraction, and an increased chemoreflex sensitivity has been linked to symptoms, neurohumoral activation, breathing disturbances, and adverse prognosis.

However, the clinical correlates and implications of chemoreflex sensitivity in HFpEF have not been accurately studied.

We aim to characterize chemoreflex sensitivity in patients with a diagnosis of HFpEF, and to correlate chemoreflex sensitivity with clinical and hemodynamic characteristics.

Inclusion Criteria:

• diagnosis of symptomatic HFpEF (group 1)
• diagnosis of asymptomatic left ventricular diastolic dysfunction with echocardiographic signs of PH (group 2)
• healthy volunteers (group 3)

Exclusion Criteria:

• breastfeeding or childbearing

we will include

• symptomatic patients with a diagnosis of HFpEF
• asymptomatic individuals with echocardiographic signs of PH attributable to left ventricular diastolic dysfynction
• healthy controls