April 01, 2019

Implanted heart devices

Advances in technology

Pacemakers perform two main functions — to monitor your heart rate and to send electrical impulses to ¬≠restore a normal heart rate should it slow or become uncoordinated. Virtually all newer pacemakers also can sense increased exertion and adjust your heart rate to match your physical activity level.

Pacemaker

Your heart has its own electrical system that generates electrical signals and, when healthy, sends a precise impulse through the heart. This causes coordinated contractions of muscles in the heart's upper and lower chambers. The result is a steady heartbeat — usually at around 60 to 100 beats a minute at rest — that pumps blood efficiently throughout the body.

However, many factors can disrupt the heart's electrical system. In older adults, disruptions commonly lead to an unnaturally slowed heartbeat (bradycardia). When this happens, an important therapy choice is an implantable pacemaker that provides electrical signals to pace the heart.

Today's pacemakers are incredibly high-tech and are continually evolving and improving. Among the recent developments is the increasing use of tiny wireless (leadless) pacemakers that can be implanted inside the heart with no other leads or parts required.

Bradycardia — slowed heart rate

A heartbeat begins with an electrical signal from the heart's natural pacemaker, the sinoatrial (SA) node. The SA node is located in the right, upper chamber (atrium) of the heart. The signal from the SA node passes through the right and left atria, causing both to contract. This squeezes blood into the heart's two lower chambers (ventricles).

The electrical signals next converge at a grouping of cells called the atrioventricular (AV) node. This is the heart's junction box, and it stalls the signal for a split second, which allows the ventricles to fill with blood. The signal then follows electrical pathways to the right...