Submitted by Dr T on July 14, 2011 – 9:49am
The source hasn’t been treated yet according to what you have told me. It is most likely either his heart or his carotid arteries. An arrhythmia such as A fib can cause blood clots to develop in the heart, a piece of which may brake off and get stuck in a brain artery. This is best evaluated with a Cardiac ECHO or MRI for the heart or an ECHO of the carotids:
Talk to his doctors about checking these things out!
Hope this helps,