That looks familiar; are you using observeChanges? It has a memory leak, see: Meteor perfomance issues with collection observeChanges
If you’re using that, you have no choice than to rewrite your code to polling methods. Alternatively, you can subscribe to collection changes only, and then within the autorun fetch collection data using methods.
You’ll find that your app performs much better, and CPU will stay down forever.
Edit: also check this Memory Leak - App crash every day