I had a heart attack when I was 48 and had a couple episodes of v-tachycardia and my ejection fraction severely reduced as a result of my heart attack. As a 'precaution' my cardiologist suggested an ICD. I decided to go ahead with it. The device clinic checks the data it sends and also in person at the clinic to make sure things are functioning correctly. For over five years, it was there 'just in case' it would be needed like automobile air bags. Last fall, the device clinic called me and asked me if I recalled having any issues. They told me the device had shocked my heart and when they told me the time, I said I was sound asleep and didn't remember anything. Then about 4 months later, I was shoveling some heavy wet snow and apparently my heart rate was higher than I realized and then it hit me with its shock. It scared me because this was the first time I actually felt it, and it took me by surprise. The way I describe the feeling to my family is that someone put their fist around my heart and gave it a tight squeeze. Had I not had it ready on standby to go into action when needed, I know I wouldn't be here responding to this thread. So yes, it is uncomfortable, but it happens so quickly it's over by the time you realize what's just happened. The harder part is actually processing what has just happened…my life was spared yet again. After an EKG to double check things, we discovered my heart was in a-fib so I had a procedure done under sedation where they shocked my heart back into normal rhythm. I've learned there are different types of ICD units and they can have multiple wire leads from them to the heart depending on different conditions. Because I only had V-tach at the time of implant, they only felt the need for a single wire lead to my ventricle. When the device battery runs out and will need to be replaced, I'm sure they will look at recent history and determine if more leads are needed or other therapy is warranted. In the meantime, I've still got 4-5 years of batter left (provided it doesn't fire too frequently). Would I do it again, in a heartbeat. Am I scared of it firing again, of course, but now when I'm doing strenuous exercise, I take it slower. Going to be 55 in a couple months and shortly after that we are anxious to welcome our first grandbaby into our family! I have no regrets having had it implanted, it is through that machine and my faith I'm still here. When I go to public buildings and see the external defibulator units hanging on walls, I smile knowing that I've got my own unit to protect me and I won't have to rely on someone knowing what to do to bring my rhythm back to normal.