Evolution of Medical Instruments and Devices in Cardiology

Written by: Jisara Wuttikreekiat

Email: jisara.pic@gmail.com

Introduction

Over the centuries, the field of cardiology has witnessed remarkable advancements driven by the continuous evolution of medical instruments and devices. This article provides a comprehensive overview of the historical development and innovations in cardiology instrumentation and evaluates how it has changed the healthcare systems over the years.

Ancient Times

Back in the times of Ancient Egypt, the heart was regarded as the most vital organ in the body, serving as the center of wisdom, emotions, and the soul itself. Although not perfectly, ancient Egyptian physicians had some knowledge of the cardiovascular system as recorded in the Ebers Papyrus––one of the oldest, most important medical papyri of Ancient Egypt dating back to 1550 BCE. The papyrus contains a "treatise on the heart", noting that the heart is the center of blood supply, with vessels attached for every member of the body. The papyrus also contains records of various medical conditions, including some related to the heart in which they demonstrated the correct understanding of its symptoms, leading to somewhat correct treatments. 

Unfortunately, most treatments ended up being influenced by their belief in magic and spirituality, resulting in incorrect treatments. An example of their belief is the afterlife, the process of mummification where they would carefully remove and preserve various organs, but the heart was left intact as they understood its importance. As most of their treatments become intertwined with their religious beliefs, a more detailed study of cardiology and the cardiovascular system would come centuries later, with the advancements in medical knowledge and technology.

19TH CENTURY

Stethoscope

Figure 1. Laennec stethoscope made by Laennec, c.1820

One of the earliest medical devices related to cardiology was the invention of the stethoscope.  The stethoscope allowed physicians to listen to heart and lung sounds, improving diagnosis accuracy of heart conditions. The first version of the stethoscope was invented in 1816 by René Laennec, a French doctor, by rolling up a paper tube and using it as a funnel.  His ideas originated as he was not comfortable placing his ear directly onto a woman's chest to listen to her heart. Later, the stethoscope would become a wooden tube and monaural, meaning it was used with just one ear. 

Sphygmograph

Figure 2. The first machine that could produce a paper record of blood pressure.

In 1847, the first machine that could produce a paper record of blood pressure was introduced. Many other sphygmographs soon followed. In the 1860s, one of the first practical, non-invasive methods for measuring pulse rates and blood pressure was developed by Étienne-Jules Marey. The Marey Sphygmograph became the first instrument of its kind to be widely used in clinical medicine. The Marey Sphygmograph was placed on a patient's forearm with a cloth band, and an ivory plate sat on their wrist's radial artery. When the patient's pulse made the plate move, a pen dipped in ink followed this motion, drawing lines on paper, and creating a record of the patient's pulse.

20TH CENTURY

Pacemaker

Figure 3. 1958 Siemens-Elima Cardiac Pacemaker

A thoracic surgeon, Ake Senning, at the Karolinska Hospital in Stockholm in 1958 inserted myocardial electrodes and a pulse generator with a rechargeable nickel-cadmium battery in a 40-year-old man. Between 1956 and 1958, Senning and his colleague Rune Elmqvist, an engineer at the Swedish company Elema Schönander, designed and tested this pacemaker. The pulse generator lasted roughly six weeks, but it failed in a matter of hours. Nevertheless, the patient lived, had a second pacemaker in 1960, and is still alive today.  

Implantable Cardioverter-Defibrillators (ICDs)=

Figure 4. Early automatic defibrillator (1984); fully programmable dual chamber implantable defibrillator (2009)

The first implantable cardioverter-defibrillator inserted into a patient was done by Dr. Michel Mirowski in the 1980s. An ICD is a device that keeps track of the heart rate by connecting its wires to it. When an ICD detects an abnormality, the device delivers an electric shock to restore the normal heartbeat. At first, ICD therapy was not accepted, considering the therapy unethical; however, as time went on, the data proved that patients who underwent ICD therapy had a higher survival rate. From then on, for patients at risk for life-threatening arrhythmias, ICD therapy is considered as either secondary or primary prevention.

Coronary Stent

Figure 5. The Wonder of the Stent - Ulrich Sigwart and the Stent

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The first stents were implanted in 1986 in Switzerland by Ulrich Sigwart and in France by Jacques Puel. They developed the idea of using stents to treat coronary artery blockages as an alternative to traditional balloon angioplasty. Their method was to use self-expanding metallic stents to help keep coronary arteries open after they were widened with angioplasty balloons. According to clinical trials, stents reduce restenosis and revascularization compared to simple balloon angioplasty. Therefore, it has become a norm to use stents in treating coronary artery blockage ever since.

Cardiac MRI 

Figure 6. First cardiac MRI scan

Unlike other devices, the MRI (magnetic resonance imaging) is developed as a collective effort of several researchers and scientists. The early clinical cardiac MRI scans were performed in the 1980s, primarily focusing on static images and anatomical assessments.  Besides, the MRI can also be used to determine how well the heart is beating, how much blood is coming out with every heartbeat, how the blood flows in the main arteries, as well as to determine the damage within the heart.

21ST CENTURY

Continuous Glucose Monitoring (CGM) in Diabetes Management

Figure 7. CGM- a useful tool for managing diabetes

Although not exclusive to cardiology, CGM technology is essential for controlling cardiovascular risk in diabetic patients. CGM is a device to automatically estimate blood glucose levels in the body, meaning that blood glucose levels can be monitored by the patient at any time. This allows the patient to make more informed decisions about the food and beverages consumed, their physical activities and the effectiveness of medicines they intake.  As technology advances, trends in the patient’s glucose levels can be tracked by computers and AI automatically, providing important information to the patients and doctors.

Transcatheter Aortic Valve Replacement (TAVR)

Figure 8. During TAVR, a doctor accesses the heart using a thin, flexible tube called a catheter.

Unlike open heart surgery (which is relatively risky), TAVR is the replacement of the aortic valve of the heart through blood vessels. Dr. Alain Cribier performed the first successful percutaneous aortic valve replacement on an inoperable patient in 2002. A decade later, in 2012, the FDA approved TAVR in patients at high surgical risk. Patients who undergo TAVR typically have faster recovery times than those who have open-heart surgeries as well as reports that show less pain and trauma. However, TAVR may not always be the best treatment and the decision is solely based on the individual as the treatment is yet to be risk-free. Factors such as the durability of TAVR vary as the valve differs, meaning that some patients may require re-intervention in the future. However, for those with underlying conditions or those who want to avoid risky surgeries, TAVR has now become an option for those patients.

Conclusion

The evolution of medical devices and instruments in cardiology has been a remarkable progress for humanity. From the stethoscope and electrocardiogram to the advanced imaging techniques in current medicine, cardiology has witnessed a transformative journey. However, this evolution has not been without challenges. Several scientists have sacrificed themselves by dedicating years of research throughout their lifetime. Although some succeeded in making new discoveries, many weren't as fortunate. In the future, as humanity continues to learn more about themselves and the universe, we hope for a future where healthcare will advance, helping more of those in need. 

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