Bearing in mind that the plural of anecdotes isn't evidence, I did want to relate one extremely personal experience - my dad went down, with ventricular fibrilation, one very hot day when he was out for a jog on the golf course near his home. Two lawyers (yeah, cue the jokes) were finishing their round of golf, saw him go, and started CPR. 911 was called, he got to the county hospital in good time, had the bypass, and 23 years later he's still with us, and still jogging.
Super-glad somebody took CPR!
Jane