McLeod Health: New Micra AV - Keeps Heart in Pace, Only Weighs a Penny

McLeod Electrophysiologist Dr. Prabal Guha implants pacemakers like the Micra and the Micra AV in the dedicated Electrophysiology Laboratory at McLeod Regional Medical Center.

THE NEW MICRA AV

Keeps Heart in Pace. Only Weighs a Penny.

story by Dr. Prabal Guha, McLeod Electrophysiologist, McLeod Heart and Vascular Institute

Micra AV is a leadless pacemaker and is 93 percent smaller than modern-day pacemakers.

A pacemaker is a small battery-powered electronic device that sends electrical signals to the heart to help it beat at a proper rate. It is surgically placed under the skin and connected to the heart by one or more wires or leads.

Pacemakers are used for cardiac conditions like bradycardia that disrupt the heart's normal electrical system. Bradycardia is characterized by a slow or irregular heart rhythm. At a low rate, the heart is unable to pump enough oxygen-rich blood to the body during normal activity or exercise causing dizziness, fatigue, shortness of breath or fainting spells. Pacemakers are the most common way to treat bradycardia -- restoring the heart's normal rhythm and relieving symptoms by sending electrical impulses to the heart to increase the heart rate. Pacemakers do not take over the work of the heart but assist in regulating the timing and sequence of the heartbeat. Pacemakers only work when they are needed. These devices are sophisticated enough to decide when support to the heart is required. Over the years, the size of pacemakers has drastically changed. The first wearable pacemaker in the 1950s weighed over half a pound and was worn externally around the neck. Today’s pacemakers are about 2 inches wide and 1.5 inches high. As technology advanced, the devices continued to shrink. In 2017, McLeod began offering a new device, the Micra, that is 93 percent smaller than modern-day pacemakers. Micra weighs about the same as a penny and is the size of a vitamin capsule.

Micra is a leadless pacemaker, which means there are no leads to connect it to the heart. The technology for a leadless pacemaker consists of computer chips and a small battery in a sealed case that resembles a AAA battery. Micra delivers electrical impulses that pace the heart through an electrode located at the end of the device.

Currently, the Micra device is only available for patients with certain medical conditions and a slow heart rate that would require pacing in the lower chamber of the heart.

The original Micra does not cover all the medical problems that require the services of a pacemaker. This system previously did not provide the ability to synchronize the upper and lower chambers of the heart. A new treatment option in dual chamber pacing is the Micra AV. Micra AV is for patients with AV block, a condition in which the electrical signals between the chambers of the heart are impaired. Micra AV has internal sensing to detect activity of the upper chamber of the heart and deliver electrical pulses in the lower chamber maintaining time-based synchronization of the upper and lower chambers. Micra AV is the same size as the original Micra. Both are so small they are delivered via a catheter, similar to the way a heart catheterization is performed. The catheter is inserted through a vein in the leg. X-ray imaging guides the catheter to the right side of the heart. Micra is then implanted directly into the heart muscle. It attaches to the heart with small tines (hooks) that secure the device in place.

The Micra is implanted directly into the heart muscle and attached with small tines that secure the device in place. Image courtesy of Medtronic.

With the leadless device in place inside the heart, there is no lump under the skin that can be felt as with a traditional pacemaker. In addition, patients with a Micra implant will have no chest scar, or visible physical reminder like seen with the traditional pacemakers. With the addition of Micra AV, the benefits of a leadless pacemaker can be extended to even more patients. A cardiologist or electrophysiologist can help determine if a patient may be a candidate for a leadless pacemaker.

Dr. Prabal Guha is a Board Certified Electrophysiologist with McLeod Cardiology Associates who was voted the Best Cardiologist by the readers of the Morning News for the Best of the Pee Dee. Dr. Guha cares for patients at McLeod Cardiology Associates offices located in Florence and Sumter. Appointments can be made by calling 843-667-1891.

For more information, visit McLeodHealth.org.