@hpboss84
The ICDs and Pacemakers run of batteries. They are usually good for 8-10 years but depends on usage. If you don't have a pacemaker which paces your heart or keeps will pace it if gets too low. Your ICD will be monitoring your heart beat 24/7 and that takes battery life.

If you have ICD shocks that takes battery power also and will reduce the battery life each time.

I was originally advised to get only a ICD but went to Mayo Jacksonville for second opinion. My EP there said he would recommend doing both and I agreed. The pacemaker will help keep your heart in rymthm and also provide a good electrical signal to your heart. It can correct heart rate if too slow which medications can cause as well a low rate personal heart rymthm. Low heart rates as statisically prone to have arrythmias (per my EP). Many athletes whos heart rates are tremendous low will wind up getting pacemakers after playing.

I assume you have a low EF as why you got the ICD recommendation is that correct?