Non-Invasive Identification of Mechanisms of Atrial Flutter; Investigating the Long-Term Outcomes of Patients with Legg-Calve-Perthes: How Treatment is Influenced by Surgeon Bias

Powell, Reid, School of Engineering and Applied Science, University of Virginia
Mangrum, James, MD-INMD CV Medicine UPG-MD-INMD CV Medicine, University of Virginia
Baritaud, Catherine, EN-Engineering and Society PV-Summer & Spec Acad Progs, University of Virginia
Seabrook, Bryn, EN-Engineering and Society PV-Summer & Spec Acad Progs, University of Virginia

As technology improves within the healthcare industry, new diagnosis and treatment methods provide an opportunity to enhance the patient experience. The technical project focuses on new diagnostic methods such as the Medtronic CardioInsight Vest can be used on patients to diagnose the second most common atrial arrhythmia, otherwise known as atrial flutter. The vest provides a noninvasive way of diagnosing arrhythmias, leading to a more comfortable and less risky way of identifying electrical abnormalities in the heart. The STS topic focuses on improving the treatment method of patients, especially for patients who have rare diseases like Legg-Calve-Perthes disease (LCPD). LCPD is a rare orthopedic disease that presents in young children, and presents much controversy when deciding what surgical or nonsurgical methods to employ when treating the patient. While these topics are loosely coupled, both emphasize the importance of improving overall care for a patient.
When diagnosing a heart arrhythmia, most patients must undergo an electrophysiology study. This study requires catheters to be intravenously placed into the heart, where pacing maneuvers will be performed to capture the arrhythmia. The Medtronic CardioInsight Vest used for the technical project provides an optimal, noninvasive technique to diagnose heart arrhythmias without the use of intracardiac catheters. This method has proven useful in diagnosing arrhythmias such as atrial fibrillation and premature ventricular complexes, and has the potential to diagnose atrial flutter as well. Through 252 electrodes sending signals to the vest, 3-dimensional atrial maps are created that display the electrical activity of the heart. From these maps, conclusions can be drawn about types of atrial flutter and where they are located.
Two types of maps were used for the project, propagation maps and phase maps. Propagation maps provide information on the directionality of the electrical circuit and how signal conducts across the atria. These maps were used to compare the directionalities between different types of flutter to determine if the vest accurately captured the conduction signals. Phase maps were then used to display false hinge points, which can be used as pattern identifiers for certain types of flutter. Both of these maps appeared to have patterns that allow the electrophysiologist to approximate what type of flutter is present and where it originates from.
The STS project focuses on the variables that affect what treatment options are presented to pediatric patients. The research question pertaining to the topic concerns what is the best treatment option for children diagnosed with LCPD. This question is examined using Callon and Law’s Actor Network Theory, where factors such as long-term outcomes from treatment methods, what classification system was used to diagnose the hip, and why surgeons are more likely to promote certain treatment options over others. All of these factors are crucial when treating Perthes patients, especially when considering most of them will need a hip replacement much earlier in life. To closely examine the options available to Perthes patients, research was completed with papers that detailed long-term outcomes for eight of the most common treatment methods. The outcomes were evaluated to determine the lifespan of the hip joint post treatment, and whether the patient still experienced significant pain. In addition, surgeon bias was examined to determine why orthopedic surgeons may be more or less likely to perform complex osteotomies on pediatric patients.
After close examination of the treatment options, one option presented itself as the optimal one for treating Perthes disease. While it is beneficial to have one option that stands out, it appears as though surgeons are less likely to offer complex surgeries to young children. This can be attributed to age, especially since the patients have not reached skeletal maturity, as well as location. Hospitals located in rural areas are less likely to have surgeons capable of performing difficult procedures on small patients, and are therefore less likely to offer the surgery as a treatment option. In addition, surgeons are more comfortable with some procedures than others, and prefer to not deviate from typical surgical procedures that they perform. From these points, it can be concluded that Perthes is a complicated disease to treat, and may not result in an optimal outcome due to the ambiguity of treatment.
These projects aim to provide patients additional information about devices that diagnose common heart arrhythmias, as well as treatments available for patients with a rare hip disease. Doctors should aim to provide the best care possible for their patients through the integration of new diagnosis and treatment methods available to them.

BS (Bachelor of Science)
Atrial Flutter, Legg-Calve-Perthes Disease (LCPD), Actor Network Theory (ANT)

School of Engineering and Applied Science
Bachelor of Science in Biomedical Engineering
Technical Advisor: J. Michael Mangrum MD
STS Advisor: Catherine Baritaud

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