I.1 Use of Helmholtz coils to design less painful transcutaneous pacemaker

Acute bradycardia (slow heart rate) that causes symptoms is a serious emergency.  Patients can present to the hospital with dizziness, passing out (syncope) or myriad of other symptoms.  Definitive treatment, in absence of reversible causes is usually implantable permanent cardiac pacemaker3.  However, often patients are initially stabilized with either external temporary transcutaneous pacemaker or external temporary transvenous pacemaker2.  This is done till additional medical workup is done and any reversible causes of bradycardia (use of certain medications like beta-blockers, abnormal thyroid levels, infections like Lyme’s disease etc.) are ruled out.  Transcutaneous pacemaker involves stimulating myocardium (heart muscle) externally by placing patches on chest and back. It is non-invasive but painful for patient as it also stimulates other tissues like skin, muscle in addition to myocardium.  Transvenous pacemaker is an invasive procedure that involves placing electrodes inside the heart (right ventricle) but is not painful since it only stimulates the myocardium. 

This purpose of this project is to design a contraption for non-invasive external pacemaker. It involves use of Helmholtz coils placed on chest and back.  Electrical current is applied to the coils to generate a magnetic current. It this magnetic current is varied, it can then induce an electric field which could stimulate the myocardium in less painful manner (please see figure 1). Use of Helmholtz coils to stimulate bone tissue to promote healing has been described before1. 

 Since the entire project may take a long time, the project that I am proposing will be a small subset of this idea. It could be finished in one semester and would include designing a device using Helmholtz coils that would be used to induce an electric field (as mentioned above) of low frequency at a distance that mimics the distance from skin to myocardium for an average person. The calculations for the distance, electric field required, size of the coils etc. will be done as part of the project. Since this is a small subset of the idea, it can potentially be finished in one semester.  This project can then be passed off to a different student group in next semester, if there is continued interest.   Students can start the project by setting reasonable goals that could be accomplished in the time allotted to them. 

Figure 1

References:

1. Bassett CA. The development and application of pulsed electromagnetic fields (PEMFs) for ununited fractures and arthrodeses. Orthop Clin North Am. 1984 Jan;15(1):61-87. PMID: 6607442

1. Crofoot M, Sarwar A, Weir AJ. External Pacemaker. 2022 Sep 12. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan–. PMID: 30137851

1. Biffi M, Capobianco C, Spadotto A, Bartoli L, Sorrentino S, Minguzzi A, Piemontese GP, Angeletti A, Toniolo S, Statuto G. Pacing devices to treat bradycardia: current status and future perspectives. Expert Rev Med Devices. 2021 Feb;18(2):161-177. doi: 10.1080/17434440.2021.1866543. Epub 2020 Dec 31. PMID: 33336616.