"The medical world has heuristic models about how things work. Computer models are more rigorous. Simulation experiments allow us to verify hypothesis in a quantitative way. If the ideas make sense in these computer models, then there's a good reason to go ahead with the medical experiments", stated Dr. Leon, department head of electrical and computer engineering at the University of Calgary.
A typical heart simulation takes a day to run on WestGrid. The same test might take a year or more to perform on a desktop computer. However Dr. Leon added that it is doubtful that a modern desktop could handle the complex computer programming demanded by the heart models. "Our team's heart models are extremely complex; they're built from the sub-cellular level up", stated Dr. Leon. This work entails creating millions of virtual cells, linking them together to build tissue and then layering the tissue to form parts of the heart or a whole heart.
In an NSERC-funded research project, Dr. Leon is using WestGrid-powered simulations to improve implantable defibrillators. An implantable defibrillator is a small device implanted under the skin containing a sophisticated microprocessor and a battery. Thin wire electrodes are threaded from the defibrillator into the heart. The device constantly monitors the hearts rhythm, so when a cardiac patient has an episode of sudden cardiac death, the defibrillator delivers a strong electrical shock to start the heart pumping again.
Dr. Leon is collaborating on this project with researchers across the country and Medtronic, an international biotech company that is developing the devices. "We have a basic hypothesis, based on the dynamics of fibrillation, about improving how the device delivers energy", stated Dr. Leon. "If this works, it will be a fairly major improvement in the safety of the devices. The simulations that allowed us to arrive at this hypothesis, wouldn't have happened without WestGrid."
Dr. Leon and his colleagues are also using WestGrid to simulate potential new drugs for treating atrial fibrillation (AF). AF affects about 10 percent of people over 70 years of age and can lead to life-threatening complications, such as stroke or heart failure. AF causes the upper chambers of the heart to beat irregularly, which interferes with blood flow. To learn more about the mechanisms behind this condition, the University of Calgary researchers build computer models of the electrical activity in the heart's upper chambers and conduct simulations to see if new or existing drugs might work in theory.
Drs. Leon and Vigmond collaborate on AF research with McGill University professor Dr. Stan Nattel, who is the research director of the Montréal Heart Institute and a leading expert on cardiac arrhythmias. "The experiments were done in Montréal and the data analysis was done on WestGrid. The University of Calgary provided the computing support and code for the project."
The simulations would have taken the Québec-based researchers weeks to perform. But thanks to WestGrid, the tests took an hour and the researchers were able to perform hundreds of simulations. Dr. Leon's AF research is supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) and Mathematics of Information Technology and Complex Systems (MITACS), a federally funded Network of Centres of Excellence.
WestGrid is also helping grad students get a leap ahead in the evolution of computers. For example, graduate students are learning complex software programming and problem solving skills that will be needed for the more muscular multiprocessors and ever-faster networks that will be powering our offices and research labs in coming years.
"WestGrid computers are the computers of the future. You're supercomputer today is your desktop three years from now", explained Dr. Leon. "The skills that the graduate students are learning on WestGrid today, may end up being applied to the desktops or small embedded devices of the future." Funding for WestGrid was provided by the provinces of Alberta and British Columbia, the Canada Foundation for Innovation and Hewlett Packard, IBM and SGI.