Effects of Ranolazine on Coronary Microvascular Dysfunction in Patients With Hypertrophic Cardiomyopathy

Inclusion Criteria: * Male and female gender (females of childbearing potential must be using highly effective contraceptive precautions such as implants, injectables, combined oral contraceptives, intrauterine devices, sexual abstinence or vasectomised partner); * Females of childbearing potential or within two years from the menopause must have a negative urine pregnancy test; * Patients which fulfill conventional echocardiographic criteria for the diagnosis of HCM: maximum LV wall thickness ≥ 15 mm; * Patients aged \> 18 years and \< 80 years; * Sinus rhythm accepted isolated Supraventricular and Ventricular Premature Beats (VPB); * Absence of severe resting LV outflow tract obstruction (peak gradient ≤ 50 mmHg); * Written informed consent prior to enrolment into the study; Exclusion Criteria: * Females of childbearing potential not using highly effective contraceptive precautions; * Presence of known coronary artery disease (CAD); * Presence of Chronic Obstructive Airways Disease; * Asthma; * Other causes of microvascular dysfunction including long-standing history of arterial hypertension, diabetes, uncontrolled dyslipidemia; * Body mass index \>32 kg/m2; \< 17 kg/m2 * Overt LV systolic dysfunction with end-stage progression (LV-EF \<50%); * Concomitant administration of potent CYP3A4 inhibitors (e.g. itraconazole, ketoconazole, voriconazol, posaconazol, HIV protease inhibitors, clarithromycin, telithromycin, nefazodone); * Patients treated with sotalol, dronedarone, class I antiarrhythmics (see appendix 4) or other QT-prolonging drugs; stable treatment with amiodarone is permitted; * Patients with QTc (Bazett's formula) at baseline ≥ 450 ms males; ≥470 msec females; * Any clinically relevant haematological or biochemical abnormality on routine screening, according to Investigator's judgment; * Severe concurrent pathology, including terminal illness (cancer, AIDS, etc.); * Severe renal impairment defined as GFR \< 29 mL/min/1.73m2 or creatinine level \> 2.5 mg/dL or BUN \>60 mg/dL; * Moderate or severe hepatic impairment or hepatic insufficiency defined as SGOT or SGPT \> 2 times greater than normal upper limit of the local laboratory or total serum bilirubin \> 1.5 times greater than normal upper limit of the local laboratory; * Dementia, psychosis, alcoholism (\>350 g ethanol/week) or chronic abuse of medicaments, drugs or psychoactive substances; * Claustrophobia; * Females who are pregnant or lactating; * Conditions that in the Investigator's opinion may interfere with the study's execution or due to which the patient should not participate for safety reasons; * Risk of poor patient cooperation; * Participation in a clinical study ≤ 2 months before enrolment; * Inability or unwillingness to issue the informed consent; * Concomitant use of \> 20 mg daily dose of Simvastatin during the study (in case of patients taking simvastatin \> 20 mg daily, the switch to other statins not metabolized by the CYP3A4 could be considered); * Concomitant use of Atorvastatin (\> 80 mg daily) * Concomitant use of \> 1000 mg daily dose of metformin during the study