Increased heart rate when running

My husband has been. Running approx four miles every other day.  Occassionally his heart rate increases dramatically to the point where he passes out.  It is also taking increasingly longer for his heart rate to reduce.  This is about one in every four runs.  He is 40 and has had two previous heart attacks and has three stents in place. His last stenting was done december 2008.  Recent ECG was ok and consultant said carry on with running but these episodes are scarry. No stress tests have been done so he and I are the only ones who have witnessed it (I have had to go and pick him of the street recently!). He says it helps if he coughs or punches his chest.

[Cleveland Clinic]

He should not run anymore and should be seen by an elctrophysiologist who given the past history of a heart attack should order an EP study and some form of monitoring.  This may be a serious condition, but it could also be just a simple arrhythmia.  Either way, it needs to be sorted out.