What’s a brief summary of your research?

I’m a muscle physiologist. My focus is on cardiac and skeletal muscle physiology. In cardiac muscle, I'm interested in sudden cardiac death, and in particular the causes of fatal arrhythmias (irregular heart rhythms) in genetic disorders such as Brugada Syndrome and CPVT (catecholaminergic polymorphic ventricular tachycardia), in which hearts are often structurally normal. In skeletal muscle, I’m currently looking at myotonia. In both cases, magnesium and calcium affect the function of the muscles.

What is Myotonia?

It is a disease of skeletal muscle hyper-excitability. Normally, skeletal muscle only contracts when told to by a nerve, and otherwise sits there doing nothing. In myotonia, muscle contracts when told to by a nerve, but it may not stop contracting when the nerve impulses stop. People become rigidly paralysed in the muscles they were using. It can be quite debilitating, and sufferers struggle with things like walking up stairs.

Myotonia is quite famous in goats, why is this?

YouTube! Search for myotonic goats on YouTube (but not somewhere that laughing will embarrass you). They used to be bred to protect flocks of sheep. When a wolf came along, the sheep would all run and the myotonic goat would go rigid, fall to the ground, and be eaten by the wolf in their place. Now, they are kept as pets, as they learn to be fairly docile.

What got you interested in myotonia?

It is well recognised that myotonia congenita is caused by a lack of chloride channels in skeletal muscle, but big questions remain. For example, why do different people with the same abnormality have very different severities of symptoms? Even more puzzling is why people who have this condition will have weeks or months being fairly unaffected by it and then will have periods where they are very much affected by it. My group is starting to understand that at least some of this phenotypic variability is probably due to variation in the concentrations of calcium and magnesium ions in the blood. We hope this research will lead to a simple treatment, allowing sufferers  to stay more active, possibly by simple dietary changes.

What causes CPVT?

It’s been known for a while that people with CPVT have lots of extra “ectopic” heartbeats, and these sometimes trigger fatal arrhythmias. But everyone gets ectopic beats (you might feel them as “skipped beats”, especially after drinking lots of coffee), and in normal people they essentially never cause fatal arrhythmias. So although most previous work in CPVT has focused on the causes of ectopic heartbeats, I wanted to explore whether there was also something that made ectopic beats more dangerous. Quite surprisingly, we found that the conduction velocity is slow in CPVT hearts. This is important because, normally, if an electric signal travels in a circle in the heart, it gets back to its starting point too soon to initiate more electrical activity: the starting point is said to be refractory. But if conduction is slowed, circular activity can re-excite the starting area, producing a continuous and uncontrolled spiral of excitation. This quickly degenerates into ventricular fibrillation and, unless someone can give you a big electric shock, that means death. My hope is that by finding this new mechanism for the increased risk of cardiac death in CPVT, we have discovered a new area to focus research into treatments.

How did you get into research?

I’m medically qualified, but I don’t practice medicine anymore, I focus on research. It was quite a gradual change. I did a PhD, which is quite common amongst doctors, and I wanted to carry on the work I started as a Part II student in physiology. At end of my PhD, I realised that I was really enjoying research and teaching undergraduate medicine, so I applied for a Research Fellowship at Caius. I was fortunate enough to get it, giving me another four years of research. It wasn’t until then, and perhaps the realisation that I would be junior to the people I had supervised as undergraduates, that I started thinking that I would stay in full time research. I’m not regretting that decision.