Question

read the paragraph. then, add the better topic sentence. some people have an arrhythmia, a problem in which the heart beats too fast, too slowly, or unevenly. arrhythmias can be uncomfortable and even dangerous if ignored. a pacemaker is a device with a battery and small wires. when its placed inside the chest, it sends small, timed bursts of electricity through the wires to the heart. the bursts of electricity make the heart beat at the correct speed. a pacemaker has wires connected to a battery. pacemakers help peoples hearts beat at a healthy speed.

Explanation:

The paragraph discusses arrhythmias and how pace - makers correct heart - beat speed. The second option summarizes the overall function of pace - makers better than just stating their physical components.

Answer:

Pacemakers help people's hearts beat at a healthy speed.