A pacemaker is a small medical device that helps regulate the heartbeat. It is typically implanted under the skin of the chest and connected to the heart with thin wires. The device sends electrical signals to the heart to ensure it beats at a normal rate, which is especially important for people with irregular heart rhythms, known as arrhythmias. Pacemakers can be temporary or permanent, depending on the patient's needs. They are often used in cases where the heart beats too slowly, a condition called bradycardia. Modern pacemakers can also adjust their pacing based on the body's activity level, providing more effective heart rate management for patients.