The HeartCycle Nitrates Study - to assess the effectiveness of non-invasive devices in measuring responses to hydralazine with and without isosorbide mononitrate in heart failure patients

INTERVENTION: Randomisation will be by blocks using an unequal block size. Control group ? 10 patients with hypertension or coronary artery disease but not heart failure. The control group does not receive pharmacological therapies. There other group is the heart failure group (16). Every patient in this group receives all the therapies in a random sequence (unless if there are side effects). Comparison being made by administering the therapies in random order is to assess the ability of non‐invasive sensors to detect and reliably track cardiovascular physiological changes in response to the administered therapy. The focus of this study is to assess the ability of these devices to detect more subtle changes in congestion and haemodynamics that might be used to guide therapy and thus aid our ability to improve cardiovascular health maintenance rather than just detect and manage crises. In the heart failure group (16 patients), we will investigate the ability of non‐invasive sensors to detect changes in congestion and haemodynamics in response to changes in two vasodilators that are recommended in therapeutic guidelines for the management of heart failure, although not used routinely. Patients in this group will be studied on four occasions at least 72 hours apart. Each study day lasts up to about eight hours. Patients will be asked to avoid large changes in daily diet in the three days before each study period. As part of the consent process, patients will be introduced to the sensors and manoeuvres required in the study. On study days patients will be asked to take their usual morning heart failure medications apart from loop diuretics. Patients will be asked to bring their diuretic with them to be given immediately after being weighed. They will then have a 60 minute investigation period involving the assessment of haemodynamic variables using novel, wearable, non‐invasive monitoring devices, many of which are already commercially available and CE marked. These include de CONDITION: Chronic heart failure ; Circulatory System ; Heart failure PRIMARY OUTCOME: No single primary outcome. This is a pilot study to investigate the ability of novel noninvasive sensors to detect and track the acute haemodynamic effects of medication (hydralazine and/or hydralazine or combination) and a series of physiological manoueuvres. SECONDARY OUTCOME: No secondary outcome measures INCLUSION CRITERIA: 1. Male and female, 18 y.o. plus, legally able to provide written informed consent 2. Clinical diagnosis of Heart Failure 3. Objective evidence of cardiac dysfunction 3.1. NTproBNP >200ng/L and at least one of the following: 3.2. Left ventricular ejection fraction (=45%) 3.3. Left atrial dimension >40mm 4. Treated with at least 40mg/day of furosemide or 1mg/day of bumetanide 5. Receiving other guideline indicated therapy for heart failure 6. Patients should be in sinus rhythm. Atrial fibrillation may reduce accuracy of some signals