Arrhythmias in BDMD

Full Title

Defining the prevalence of minimally symptomatic / asymptomatic tachy- and brady- arrhythmias in patients with advanced cardiac dystrophinopathy [Duchenne & Becker muscular dystrophy (BDMD)]

Sponsor: Newcastle upon Tyne Hospitals NHS Foundation Trust
Funder: Duchenne Uk

Conditions:
Cardiac arrhythmias in muscular dystrophy

Purpose
This is an exploratory study to find out whether short lived episodes of abnormally fast or slow heart beating (‘arrhythmia’) occur ‘silently’ (with minimal or no symptoms) in patients whose hearts are affected by either Duchenne or Becker muscular dystrophy. In other conditions, it is known that hearts with reduced pumping function can become ‘irritable’ – meaning that they show increasing numbers of ‘extra beats’ (‘ectopic beats’) and ‘short runs’ of abnormal beats as a sign that the heart is ‘under strain’ (‘not happy’). It is not known whether the same ‘irritability’ occurs in patients with Duchenne or Becker dystrophy.

So the first aim of this research is to find this whether hearts affected by Duchenne or Becker muscular dystrophy show this type of ‘irritability’. This will be examined by implanting a small electronic ‘chip’ (Medtronic LinQ device) under the skin in a small number of patients, who are already taking heart medications because they have some degree of heart pumping weakness. This ‘chip’ allows continuous ’24/7′ surveillance of heart rhythm – recording anything abnormal that it ‘sees’ automatically and transmitting those recordings to a monitoring station at the hospital by means of the home telephone. Monitoring will be for six months and the device can be removed after that time.

The second aim of the study is to correlate any heart ‘irritability’ detected with the degree of heart pumping weakness and with the extent and pattern of scars that form in the heart muscle as part of the Duchenne or Becker condition. To allow this part of the research, patients will undergo a detailed heart scan (magnetic resonance scan; MRI) once. These scans will also be compared in various ways with scans of patients with similar degrees of heart pump weakness, due to old heart attacks or other causes of heart muscle weakness.

Patients with ‘heart irritability’ following heart attacks routinely have specific testing and treatments to decide whether they are at risk of collapse due to longer lasting episodes of abnormally fast or slow heart beating. However, this is not current practice for patients with muscular dystrophy. Ultimately, if the findings of this research show that similar amounts of heart ‘irritability’ occur in patients with muscular dystrophy as, for example, in those after heart attacks, it would mean that patients with Duchenne or Becker muscular dystrophy should receive the same attention to heart arrhythmias as those after heart attacks. This would be on the basis that they would be expected to benefit in the same ways. If, on the other hand, the results show little or no ‘heart irritability’ in patients with muscular dystrophy, then unnecessary testing and treatments can be avoided.

More information via
the HRA Website