Autonomic nervous system dysfunction is known to be associated with an increased risk of heart rhythm abnormalities and sudden cardiac death (SCD) in patients with chronic heart failure - a condition affecting millions of people worldwide. The nitric oxide pathway has been identified as being involved in mediating the effects of the autonomic nervous system on the heart. Recent studies have shown that dietary nitrates can increase the availability of nitric oxide in the body. This study hopes to find out if dietary nitrate supplementation can help to improve cardiac and autonomic function in patients with heart failure and autonomic dysfunction and reduce the risk of arrhythmias.
20 participants enrolled at the University Hospitals of Leicester NHS Trust will be invited to take a beetroot juice supplement, which naturally contains a high concentration of nitrates, and a nitrate-free (placebo) beetroot supplement. In a double blind way, participants will be randomised to the order in which they receive the 2 treatments with crossover of the treatments. There will be a washout period between the two treatments. In order to assess cardiac and autonomic function, and risk of heart rhythm abnormalities, tests will be carried out before and after each treatment period Hypotheses: * Nitrate supplementation reverses the autonomic dysfunction seen in Chronic Heart Failure (CHF) * Markers of prognostic significance for predicting SCD, including QT variability index and cardiac restitution properties (R2I2, PERS), are normalised by nitrate supplementation in patients with CHF. * Nitrate supplementation results in functional improvement in CHF patients.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
20
70mls of concentrated beetroot juice containing approximately 5-6 mmol of inorganic nitrate
70mls of concentrated beetroot juice that has been nitrate-depleted
Glenfield Hospital, University Hospitals of Leicester NHS Trust
Leicester, Leicestershire, United Kingdom
Change in heart rate variability (HRV) from baseline
Measure of autonomic function
Time frame: 4 weeks and 8 weeks
Change in QT variability index (QTVI) from baseline
Marker of arrhythmia risk
Time frame: 4 weeks and 8 weeks
Change in Regional Restitution Instability Index (R2I2) from baseline
Marker of ventricular arrhythmia and sudden cardiac death risk
Time frame: 4 weeks and 8 weeks
Change in Peak Electrocardiogram Restitution Slope (PERS) from baseline
Marker of ventricular arrhythmia and sudden cardiac death risk
Time frame: 4 weeks and 8 weeks
Change in left ventricular function from baseline
LVEF, volumes and filling pressure (E/e ratio)
Time frame: 4 weeks and 8 weeks
Change in peak oxygen uptake (VO2max) on cardiopulmonary exercise test from baseline
Maximum oxygen uptake
Time frame: 4 weeks and 8 weeks
Change in total exercise time on cardiopulmonary exercise test from baseline
Time to exhaustion on exercise test
Time frame: 4 weeks and 8 weeks
Change in the total score on the Minnesota Living With Heart Failure Quality of Life Questionnaire from baseline
Measured using Minnesota Living With Heart Failure Quality of Life Questionnaire, with total score ranging from 0 to 105
Time frame: 4 weeks and 8 weeks
Participant compliance with dietary supplement
Compliance as measured using supplement and food diary
Time frame: 4 weeks and 8 weeks
Correlation between Non-Invasive Programmed Stimulation (NIPS) derived and exercise ECG derived R2I2 and PERS values
Assessment of the correlation between R2I2 and PERS values recorded using NIPS and exercise ECG
Time frame: 4 weeks
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