Thanks for letting us know, Philip.
Mark - If you do read this.. My best wishes go to you for a speedy and full recovery!
I also had a "near-fatal cardiac event" back in 2011, and have found it real difficult to get back to "normal" - I think it comes down a lot to how much love and support you get from friends and family - If you have this, you have a far better prognosis.
It is only help from a few friends (and a couple of on-line friends, including some at TW) that pulled me through.. A lot changed when I was forced to face the reality of my mortality - Huge shift in my values and motivations.
I hope you get all the support (medical and emotional) that you will need, and will be back on your feet soon!
Fred.