In chest defibrillator

My fahter-in-law just had a in chest defibrillator put in last week.  Just pulled up to the house and an ambulance was there, it shocked him at high voltage 8 times by the time it started and was leaving in the ambulance.  He had a 4-way by-pass several yrs. ago.  I am sitting at home helpless waiting to hear something on his condition and re-searching what I can re: the in-chest de-fib.  One of the issue's I can't seem to find out is, is there a higher risk for him with the in-chestde-fib. since he has already had a by-pass? Any info. on this subject will be appreciated.

[CCF HeartMD6]

There are a number of reasons for why an ICD is placed -- including (but not limited to) a history of cardiac arrest, ventricular arrhythmias, or having a low ejection fraction with symptoms of heart failure. If the ICD went off -- it could indicate an appropriate fire for a ventricular arrhythmia (ventricular tachycardia or ventricular fibrillation), or an inappropriate fire (another fast heart rate that was interpreted as one of the above). The usual process is to have the device interrogated to interpret what was going on at the time of the device discharge.  Having a history of a previous bypass surgery certainly puts him a risk for further ventricular events, especially if there is structural heart damage/weakened heart muscle as a result.