Super Safi’s Monday Morning Musings 12 – Pacemaker

Morning Musically-Minded, Medically-Minded, Masticators!

(Today’s post is sponsored by the letter “M”)

Over the past 600+ episodes, The Simpsons has taken us on an amazing journey involving music, science, and food to name a few concepts.

And what better way to start your week, then by discussing some of these concepts Monday morning?

So let’s get started this week by talking about an important medical device from the twelfth episode of our favourite family, the pacemaker.

In the twelfth episode of The Simpsons, Krusty Gets Busted (Season 01, Episode 12), Homer witnesses a robbery at the Kwik-E-Mart, and he identifies Krusty the Clown as the culprit. Krusty is arrested, tried, imprisoned, and replaced on his show by Sideshow Bob. Lisa and Bart are adamant that Krusty is innocent, so they examine all the evidence available.

During their investigation, Lisa recalls that the robber used the microwave oven at the Kwik-e-Mart checkout counter to heat a burrito (which has a sign warning that it is unsafe for pacemaker users). Lisa mentions that as per Kent Brockman’s report, a few years ago Krusty suffered a heart attack and had a pacemaker implanted.

But have you ever actually wondered what a pacemaker is and how it works:

Pacemakers

A pacemaker is an implantable cardiac device that is used to regulate the hearts rate and rhythm. A pacemaker is useful particularly if a patient has not responded well to drug therapy and is still suffering from abnormal heart rates (bradycardias or tachycardias) or abnormal heart rhythms (arrhythmias).

The pacemaker generates electrical impulses that are sent to the hear via pacemaker leads. As per the Heart and Stroke Canada website, there are several ways of implanting the leads of a pacemaker:

• Transvenous approach: Transvenous means through a vein. In this method, a small incision is made near your collarbone and the leads are maneuvered through a vein into the heart. The tip of each lead is positioned next to the inside wall of the heart (the endocardium).
• Thoracotomy: In this approach, your chest is opened and thin oval patches made of rubber and wire mesh are sewn onto the outside of the heart (epicardium). These patches are connected to the leads.
• Sternotomy: This approach is similar to a thoracotomy in that the chest is opened. The difference is that the incision is made over the breastbone (the sternum) and the leads are advanced into the heart. A sternotomy may be combined with coronary artery bypass surgery or heart valve surgery.
• Subxiphoid approach: This approach is also similar to a thoracotomy, but the incision is made slightly to the left of the breastbone (sternum).

Once the leads are in place and tested, they will be connected to the pacemaker. The pacemaker is then placed under the skin, either near the collarbone or somewhere above or at the waistline.

In 1889, Scottish physiologist John Alexander MacWilliam reported his experiments to the British Medical Journal in which he used an electrical impulse to a human heart in asystole to evoke ventricular contraction and briefly maintain a heart rhythm of 60–70 beats per minute by applying impulses at spacings equal to 60–70/minute.

John Alexander MacWilliam

In 1950, Canadian electrical engineer John Hopps designed and built the first external pacemaker based upon observations by Canadian cardio-thoracic surgeons Wilfred Gordon Bigelow and John Callaghan at Toronto General Hospital, although the device was first tested at the University of Toronto’s Banting Institute on a dog.

The first clinical implantation of a fully implantable pacemaker into a human was in 1958 at the Karolinska Institute in Solna, Sweden, using a pacemaker designed by Rune Elmqvist and surgeon Åke Senning, connected to electrodes attached to the myocardium of the heart by thoracotomy. The device failed after three hours. A second device was then implanted which lasted for two days. The world’s first implantable pacemaker patient, Arne Larsson, went on to receive 26 different pacemakers during his lifetime. He died in 2001, at the age of 86, outliving the inventor as well as the surgeon.

Arne Larsson

Now that we’ve learned more about pacemakers, be sure to come back next week when we continue our Monday morning musings with the next episode of The Simpsons.

What’s your favourite Simpsons medical device reference? What about your favourite Simpsons heart-related episode? Do you know anyone who has a pacemaker? Sound off in the comments below. You know we love hearing from you.