How can an irregular heartbeat cause a stroke?

Atrial fibrillation (AF) is a common medical condition where the upper chambers of the heart don't always beat in a coordinated way with the lower chambers. People can experience palpitations when this happens, and in a certain part of the heart — the left atrial appendage — this can lead to blood becoming stagnant and forming clots. These clots are at risk of dislodging and being pumped into the brain, where they can block vessels to cause a stroke. The clots also risk being pumped into other parts of the body, where they can cause trouble by cutting off the blood supply.

The left atrial appendage can be surgically 'blocked off' (occluded) in several ways to prevent clot formation, theoretically preventing this kind of stroke in patients with AF. However, until recently, there has been no definitive evidence to prove whether this is effective. 

I created this art to help illustrate a news article for the Medical Research Institute of New Zealand to explain the findings of a large study (the LAAOS III trial) that investigated whether a quick 6-minute procedure during heart surgery could prevent stroke in patients with atrial fibrillation. I wanted to make the research findings more accessible for a non-physician audience by giving some visual context with medical comics.

I have been experimenting with medical illustration approaches to make medicine more accessible and enjoyable to explore for almost a decade now. In the past two years, I have been investigating applications for comics in clinical research and care (some of which is already published here). This is slowly culminating into a thesis of work I look forward to sharing in full next year. Stay tuned!