Through my work at The Hospital for Sick Children, one organization that I have been exposed to indirectly is the SADS Foundation. SADS stands for Sudden Arrhythmia Death Syndromes, an organization which focuses on the types of rhythm disorders that I am involved with through my work at SickKids.
Sudden cardiac death (which in certain diseases is associated with exercise specifically) is a concern for a number of arrhythmias/other arrhythmogenic diseases. It is quite unfortunate that due to the risk of death, it is not the best clinical symptom to screen for. This is why a number of preventative measures are important, and the emerging use of exercise stress tests in patient diagnosis in addition to preventative treatments such as ICD implant.
For more on SADS check out the following links: