The study is designed to evaluate the effects of L-arginine on myocardial structure and function and circulating microRNAs in patients with arterial hypertension.

The study will analyze the impact of 4 weeks treatment randomized to L-arginine or placebo, on mechanical-energy efficiency (MEE) and longitudinal strain in patients with arterial hypertension. The investigators will also assess whether the changes in MEE and strain induced by L-arginine treatment is associated with changes in circulating micro RNAs.

The patients and controls will be recruited at the Hypertension research center of Federico II university hospital.

The overall duration of the study will be 4 weeks for each participant. Blood pressure, heart rate, echocardiogram and blood sample will be collected for each patients at randomization and after 4 weeks of treatment.

Patients or controls will be randomized to receive bioarginine (up to 2 vials per os of 1.66 g every 12 hours) or placebo (up to 2 vials per os without active substance every 12 hours). Before the start of treatment, patients will receive a peripheral venous blood sample (10-12 ml), which will be identified through the use of an alphanumeric code (PRE-XXXYYY). In addition, patients will undergo full echocardiographic examination (the parameters will be reported in a password-protected database, using the same identification codes used for blood sampling). The duration of the treatment will be 4 weeks. At the end of the treatment, the patients will receive a peripheral venous blood sample (10-12 ml) which will be identified through the use of an alphanumeric code (POST-XXXYYY) and full echocardiographic examination.

In some controls, we will run an explorative study to verify the eventual impact of Bioarginine on standardized physical exercise. Healthy controls will undergo a physical exercise according to their preference, at baseline and after 4 weeks of treatment or placebo. Ear lobe blood samples are taken before and after the effort and analyzed for serum lactate content using the reflectance photometric enzymatic reaction method. All L-arginine and placebo, made up of the L-arginine vehicle without the active substance, will be offered free of charge by the Farmaceutici DAMOR company.

Inclusion Criteria:

• Low values of mechanical-energy efficiency
• Sinus rhytm

Exclusion Criteria:

• Atrial fibrillation
• Taking Beta blockers
• Pregnancy
• Cancer