PACEMAKERS

In the Heart

By: Juvreen Kaur

What are pacemakers?

A pacemaker, also known as a cardiac pacing device, is a small battery powered device that supports the electrical system in the heart. You would need surgery to get a pacemaker that is normally placed under the skin near the collarbone.

Why would you need pacemakers?

The pacemaker is used to control or increase the heartbeat. The heart’s electrical system typically controls the heartbeat. But, changes in heart signaling may happen if the heart is damaged. These problems can also be caused by changes in genes before birth or by using certain medicines. A pacemaker only works when it senses trouble with the heartbeat.

• John Hopps, an electrical engineer, was recircutied on a part-time basis by National Research Council of Canada & designed the 1st electronic device built as a cardiac pacemaker
• Mains - powered pacemakers were developed in the early 1950’s and were large bulky boxes filled with vacuum tubes that couldn’t be implanted
• The implanted pacemaker in the 1970s was approx the size of an old-fashioned pocket watch and had one or two wires that connected to the heart
• On Oct 8, 1958 the 1st pacemaker implantation was performed in Sweden, which had been developed by the surgeon Ake Senning and physician inventor Rune Elmqvist and implanted on a 43 yr old engineer called Arne Larsson

The History:

Different types of pacemakers

Biventricular pacemakers

Single chamber

It has three leads connected to the right atrium and both ventricles. This is used to treat people with arrhythmias caused by advanced heart failure.

One lead attaches to the upper or lower heart chamber which connects the pulse generator to one chamber of your heart.

Dual—chamber

Connects to both chambers on your right side of your heart (right atrium and ventricle). Programmed to regulate the pace of contractions of both chambers.

DIAGRAM

Leads

Pacemaker generator

Flexible, insulated wires that send the electrical signals needed to correct an irregular heartbeat.

A small metal box consists of a battery and electrical parts. It controls the rate if electrical signals sent to the heart

Risk factors

of

Possible complications or a device or it’s surgery may include:

• infection near the site where the device was placed
• Swelling, bruising or bleeding, especially if you take blood thinners
• Blood clots near where the device was placed
• Damage to blood vessels
• Collapsed lungs
• Blood in the space between the lung and chest wall

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86% of pacemaker patients got about 10 years of survival.

Pacemakers & Electrical Nodes

Connecting this to the cardiology unit & the conversation with electrical nodes, electrical impulses from the heart muscle cause your heart to contract. This electrical signal begins in the SA node, which is at the top of the right atrium. The SA node sends electrical impulses but sometimes it doesn’t work properly, causing complications. But, when an electrical impulse is released from the pacemaker, it causes the atria to contract. Then, the signal passes through the atrioventricular (AV) node. This node checks the signal and sends it through the muscle fibers of the lower chambers causing them to contract.

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Breakthroughs

• One of the biggest advances in pacemaker technology has been shrinking of the devices themselves. Modern pacemakers are now smaller than a deck of cards, and can be implanted through a minimally invasive procedure, reducing the risk of complications.
• With rate - adaptive pacing, the pacemaker can adjust its stimulation rate based on the person’s activity level, providing more support when it’s needed and conserving energy when it’s not
• Today pacemakers can communicate wirelessly with external devices, like remote monitors, which monitor the pacemaker’s performance and adjust it’s settings as needed.
• Before pacemakers were designed to stimulate only one chamber of the heart. However, advances in pacemaker tech allow for multiple - chamber pacing, stimulating both the atria and ventricles

THE NEAR FUTURE

Modern pacemakers will be so much more reliable, and their programmability will provide options for different pacing modes tailored to their specific clinical needs, The advances in device technology will probably include alternative energy sources and dual-chamber leadless pacing. There could be a creation of biological pacemakers that would be generated by somatic gene transfer, cell fusion, provide an alternative to electronic devices. Even as electronic pacemakers become smaller and less invasive, biological pacemakers might expand the therapeutic armamentarium for conduction system disorders.

References

Aquilina, O. “A Brief History of Cardiac Pacing.” Images in Paediatric Cardiology, Apr. 2006, www.ncbi.nlm.nih.gov/pmc/articles/PMC3232561/.

“Cardiac Pacemakers: Single Chamber and Dual Chamber Permanent Cardiac Pacemakers.” CMS.Gov Centers for Medicare & Medicaid Services, www.cms.gov/medicare-coverage-database/view/ncd.aspx?ncdid=357&ncdver=1&chapter=all&sortBy=title&bc=18#:~:text=Single%20chamber%20pacemakers%20typically%20target,requires%20only%20a%20brief%20hospitalization. Accessed 3 Aug. 2023.

Cingolani, Eugenio, et al. “Next-Generation Pacemakers: From Small Devices to Biological Pacemakers.” Nature Reviews. Cardiology, Mar. 2018, www.ncbi.nlm.nih.gov/pmc/articles/PMC6261336/#:~:text=Modern%20pacemakers%20are%20generally%20reliable,not%2Dtoo%2Ddistant%20future.

“History of the Pacemaker.” Understanding Animal Research, www.understandinganimalresearch.org.uk/news/top-ten-medical-inventions-pacemakers#:~:text=1958%3A%20First%20implantable%20pacemaker,old%20engineer%20called%20Arne%20Larsson. Accessed 3 Aug. 2023.

Medical Device News Magazine. “The Latest Advancements in Pacemaker Technology.” Medical Device News Magazine, 3 Feb. 2023, infomeddnews.com/the-latest-advancements-in-pacemaker-technology/?amp=1.

“Pacemaker.” Mayo Clinic, 8 July 2023, www.mayoclinic.org/tests-procedures/pacemaker/about/pac-20384689.

“Pacemakers.” The Texas Heart Institute, 30 Sept. 2020, www.texasheart.org/heart-health/heart-information-center/topics/pacemakers/#:~:text=Electrical%20impulses%20from%20the%20heart,the%20heart’s%20%E2%80%9Cnatural%20pacemaker.%E2%80%9D.

“Types.” Stanford Health Care (SHC) - Stanford Medical Center, 12 Sept. 2017, stanfordhealthcare.org/medical-treatments/p/pacemaker/types.html.