Novel mechanisms of autonomic dysfunction in heart failure

- effects of iron status on skeletal muscle function and sympathetic

nerve activity

Summary

Heart failure affects approximately one million people in Britain. Many of these people have low iron levels. Iron tablets don't help but replacing iron by a drip into the vein improves breathing and reduces admissions to hospital. However, we don't understand how iron does this. We think that low iron makes muscles less efficient as iron is used by muscle cells to create energy. This triggers a series of effects, controlled by the nervous system, making people breathless and less able to exercise.

We will compare 24 patients with heart failure and low iron and 24 patients with heart failure and normal iron levels. We will assess the activity of the nervous system that controls heart rate and blood pressure, and measure muscle performance in both groups. We will treat the participants with low iron with an iron injection as part of normal care and look for changes in nervous system activity and muscle performance after iron treatment.

We will recruit participants from the Bristol Heart Institute Heart Failure Clinics.

We have used participant feedback from previous studies to decide which tests to use. Patients have emphasised the importance of door-to-door transport for this group of very breathless people. After speaking to potential participants and following previous feedback we have simplified the study and reduced the number of visits.

We will use this pilot study to see if iron does improve muscle function and will use the information to write a NIHR grant to understand the mechanisms involved.