I take 100mg in the am and 50mg in the evening. From my last syncope to ICD installation was about a week-- once I decided to do it, I did not delay. No regrets. In fact, because it records everything, the cardiologists have data on which to base decisions.

The time you will miss depends on what you do. I recall having to keep my arm in a sling (which was also bound around my torso) for more than two weeks-- essentially I was told I couldn't move my left arm because it could pull the wires out before they healed in place.