When are pacemakers necessary?

HeartRhythm or block. Pacemakers are most commonly necessary for patients with bradycardia- slow heart rate, tachycardia - fast heart rate, and heart block - when the heart stops beating for several seconds.
Heart blocks. Pacemakers are used for symptomatic bradycardia (slow heart beat), syncope (passing out due to slow heart beat or heart block) and heart block.

Related Questions

Can you explain how the heart beats? When is pacemaker necessary?

Electrical Impulses . The heart is a muscle that will contract or beat when an electrical impulse is sent to it by the controlling sinus or av node located within the heart. The impulse is transmitted to the heart muscle by the conduction system. If there is a "failure" of the impulse originating node or a "short circuit" in the conduction system, the heart rate slows down and a pacemaker is needed to correct this. Read more...
SA node; slow heart. The sino-atrial (sa) node near the top of your right atrium is the natural pacemaker of the heart. A pacemaker is necessary if the native heart beat is so slow that you cannot maintain a normal blood pressure. Generally, a pulse of 60 or greater is needed to maintain a normal blood pressure, although some athletes can have lower heart rates. Read more...