Q. My brother-in-law is getting a defibrillator. How is that different from a pacemaker?
An implantable cardioverter-defibrillator (ICD) and a pacemaker are battery-powered devices installed in the chest to deliver electrical impulses to the heart. In general, a pacemaker is used when the heart beats too slowly; an ICD is used when the heart beats too quickly.
Pacemakers jog the heart with mild reminders that patients usually can’t feel. Pacemakers are small; some are only as big as a quarter.
The electrical impulses from an ICD can feel like being whacked in the chest. These devices are about the size of a stack of three silver dollars.
If you’ve ever watched shows like “Grey’s Anatomy” or “ER,” you’ve probably seen a cliché scene in which a doctor uses electrified paddles to shock a troubled heart. An ICD works inside the chest like those paddles.
ICDs monitor for abnormal rhythms and try to correct them. An ICD is considered effective in fighting cardiac arrest more than 9 times out of 10.