Cardiac Implantable Electronic Devices (CIEDs)

Original Editor - Lucinda hampton

Top Contributors - Lucinda hampton, Justin Bryan and Kim Jackson  

Introduction[edit | edit source]

Cardiac implantable electronic devices (CIED), or Cardiac Rhythm Management Devices (CRMD), are a very common medical device. The number of implanted cardiovascular devices has dramatically increased in recent years. Many people utilize "Pacemaker" as a general term for these devices, but in actuality, a pacemaker is a specific type of CIED. Additionally, there is a variety of other devices that fall under this general umbrella.[1]

There are several major types of CEIDs:

  1. Pacemakers
  2. Defibrillators - Including automatic implantable cardioverter-defibrillators (AICD/ICD) (may be co-implanted as an ICD-pacemaker combination)
  3. Loop Recorders

Leadless cardiac pacemakers are a recently introduced type of CEID. These pacemakers are self-contained right ventricular, single-chamber, pacemakers.[2] Outcomes have generally been positive for cases where leadless pacemakers have been utilized and initially, the safety and efficacy appear promising. For this reason, their use has been on the rise, resulting in a shift that now marks a new era of cardiac pacing. [3]

Why Cardiac Implantable Electronic Devices are Used[edit | edit source]

Pacemakers: Used primarily to control the rhythm or pace of a beating heart, they are generally indicated for cases where the concern is symptomatic bradycardia due to medication, heart block, heart failure, or abnormal cardiac rhythms/arrhythmia. Pacemakers help control the inherent beating of the heart, or in some cases, may be solely responsible for generating and maintaining rhythm in a heart that does not produce any inherent beating.[1]

There are many different variations of pacemakers, each of which can be used to address a specific condition or symptom. Pacing requirements can fall on a spectrum from entirely dependent pacing, where the heart does not produce any beats itself, to intermittent pacing, where the CIED senses rhythm changes or deficiencies and "assists" only when needed.[1]

Types of therapies pacemakers can provide include those that address bradycardia originating in either the atria or ventricle, this is one of the more basic forms of pacing. Another therapy, cardiac resynchronization therapy (CRT), is used in the treatment of heart failure. CRT utilizes a biventricular pacemaker to address a common situation seen in patients with HF where the two ventricles do not pump in a normal manner (i.e. ventricular desynchrony). When this happens, less blood is pumped by the heart. A biventricular pacemaker paces both ventricles at the same time, increasing the amount of blood pumped by the heart. Additional therapies include anti-tachycardia pacing (ATP), which is a treatment used for those with arrhythmia that increases the rate that a chamber beats (i.e. ventricular tachycardia or atrial fibrillation). These pacemakers may disrupt the arrhythmia by inducing the heart to temporarily beat at a rate greater than that created by the arrhythmia. Pacemakers may also be set up to monitor for certain rhythm changes, such as missed beats, and provide pacing as appropriate.[1][4]

Defibrillators: These devices are utilized in patients diagnosed with life-threatening arrhythmia or other conditions that may result in sudden cardiac death. This includes such situations as reduced ventricular function or ventricular arrhythmia such as ventricular tachycardia. Defibrillators may also be used in those with a history of cardiac arrest. One to three leads may be utilized to monitor different chambers (similar to pacemakers), or monitoring may be performed directly from the pulse generator. When a life-threatening condition is sensed, the defibrillator will provide an electric shock intended to restore the heart's normal rhythm. Automatic Implantable Cardioverter Defibrillators (AICD/ICD) are a type of defibrillator device.[1]

Loop Recorders: These devices are purely monitoring devices and are not utilized to provide any therapy. They are used as part of the diagnostic process in cases where the cause of a specific cardiac event is unable to be determined. Loop recorders can then provide information regarding heart rhythm that can be used to provide insight into potential underlying causes of such events. Common events that may warrant a loop recorder include syncope or palpitations that occur without an obvious cause.[1]

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Major components[edit | edit source]

There are many variations of Cardiac Implantable Electronic Devices depending on their application and manufacturer. Generally though, the two main components of these devices are a pulse generator and leads (except in leadless pacemakers).

  1. A pulse generator: A small metal container or box commonly implanted in an area of the chest wall just below the clavicle. The generator contains a battery used to produce the electrical current that controls rhythm, as well as power the small computer chip that interprets inherent rhythms and controls the activation and production of impulses used for various therapies.[4][6]
  2. The lead(s) are wires used for both sensing of inherent rhythm and conduction of impulses from the pulse generator to the heart. The lead(s) of most modern pacemakers are routed transvenously, traveling typically through the subclavian vein from a point near the pulse generator and ending up inside the heart chambers. The tip of each lead is embedded in the tissue of the corresponding chamber that it controls or monitors.[4][6]

Pacemakers[edit | edit source]

Pakemaker leads.png

Pacemakers are often categorized depending on the number of electrodes and location of pacing:

  • Single chamber (single lead) pacemakers utilize one lead that terminates in either the right atria or right ventricle, providing sensing and/or pacing to that chamber only.[1]
  • Dual chamber (dual lead) pacemakers require two leads traveling to two separate chambers of the heart. Typically this is for sensing/pacing of the right atrium and right ventricle, but in the case of CRT, leads would go to both ventricles instead. In these cases, sensing and pacing is separate for each chamber, and can also be set up to both increase and decrease the rate depending on the rhythm sensed.[7]
  • Three lead pacemakers can sense and/or pace three chambers, typically the right atria, and both ventricles.[1]
  • Leadless pacemakers are used to pace a single chamber without the need for leads or a pulse generator outside the heart. Leadless devices are implanted directly into the tissue inside of the target chamber. Currently, these devices are generally approved only for single chamber pacing to address conditions such as bradycardia.[8]

Automatic Implantable Cardioverter Defibrillators (AICD)[edit | edit source]

AICD.jpeg

AICDs are common cardiac devices designed for both patient monitoring and therapy in cases of ventricular tachycardia or fibrillation. AICDs consist of various combinations of sensing and shocking electrodes/leads. They are frequently combined with a pacemaker, treating both the patient’s established arrhythmia and also acting as a fail-safe system should ventricular fibrillation or ventricular tachycardia occur.[1]


Activation of Pacemakers and AICDs[edit | edit source]

If the heart's rate is slower than the programmed limit, an electrical impulse is sent through the lead(s) to the electrode, causing the heart to beat at a faster rate.

When the heart beats at a rate faster than the programmed limit, the pacemaker generally monitors the heart rate and will not typically pace. In instances where an anti-tachycardia device is used, a rate above the programmed limit will trigger a response such as a temporary higher pacing rate (higher than the sensed rate) which can disrupt the abnormality and return the heart to a more normal pace. Modern pacemakers are programmed to work on demand only, so they do not compete with natural heartbeats. Generally, no electrical impulses will be sent to the heart unless the heart's natural rate falls below the pacemaker's lower limit, or the device is set up specifically to address tachycardia events.[1][4]

Landmark Innovations[edit | edit source]

In 2020, news was released that cardiologists working for Monash Health reached a breakthrough in the treatment of cardiomyopathies, a group of conditions that reduce the heart's ability to function and can often result in heart failure. This breakthrough was the implementation of a leadless pacemaker, the first of its kind, which utilized two devices to help synchronise the pumping action of the heart and improve overall function. Where traditional pacemakers devices utilize leads to deliver pulses from a generator located away from the heart, these leadless devices are affixed directly to the myocardial tissue within the ventricles. Both devices, an ultrasonically activated left ventricular pacer the size of a grain of rice, and a slightly larger right ventricular pacer, were delivered tranvenously via a small access point. The pacing used by the devices was also innovative, known as physiologic pacing, whereby the healthy rhythm produced by the right atria is sensed by the system and used as the driver to synchronise the beating of the ventricles.[9]

Heart location.jpg

In 2019, a study published in the Journal of Physiology described a new treatment for heart failure known as a bionic pacemaker. This bionic pacemaker has the ability to pace the heart at a more natural, variable, rhythm that mimics the normal variation in heart rate that occurs with natural processes of the body. One such variation is respiratory sinus arrhythmia, a normal process whereby the heart rate actually increases and then decreases with the normal inhale and exhale of breathing, respectfully. Traditional pacemakers deliver a rhythm at a constant interval, meaning that under normal resting conditions, there is no change in rate with respect to physiologic processes that would normally impact rate.[10]

Physiotherapy[edit | edit source]

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There are no specific international policies regarding the administration of physiotherapy modalities in patients with CRMDs, thus, there are no specific guidelines to be implemented at the local level. Review of the literature and of recommendations from CRMD manufacturers suggests that TENS, Diathermy, and Interferential Electrical Current Therapy are best avoided in patients with CRMDs. Additionally, it is recommended that therapies such as ultrasound, e-stim, deep heating, and superficial heating not be applied directly over the pulse generator.[11]

Precautions after Implantation[edit | edit source]

Following the placement of a pacemaker, there are some restrictions that are often advised to allow for proper healing. PLEASE NOTE: This an example of suggested guidelines, patients and practitioners should always refer to the provider who performed the placement for specific limitations and the duration they should be followed.

Here is an example of recommendations and precautions that may be suggested following the procedure:[12]

  • Movement of the arm on the SAME side the pacemaker was inserted should be avoided for several weeks, including raising the arm above shoulder height.
  • Do not lift heavy weights (i.e. shopping bags) for approx 6 weeks
  • Strenuous activity, work, or sports should be avoided for several weeks
  • The arm on the same side of the pacemaker should be periodically moved through a gentle pain-free range to avoid a loss of range of motion
  • Driving may be restricted for a period by local or federal regulations, the patient is generally notified of restriction following placement
  • Your pacemaker card should be kept with you at all times
  • Consult your medical provider and the manufacturer of your device for specific restrictions and guidelines for procedures such as MRIs or situations like airport security

Reuse of Devices - Ethical, Logistical, and Legal Considerations[edit | edit source]

Refugee camp.jpg

A British charity wants to remove pacemakers from people who have died in the UK and send the devices to developing countries for re-use. Pace4Life says thousands of the life-saving devices, which cost thousands of pounds, are typically thrown away or buried with patients each year in the UK[13].

A 2013 study by Nava et al. supported the idea that the reuse of pacemakers that have been sterilized and properly prepared is not only safe, but no less effective in treatment the of bradyarrhythmia than the use of a new device. Risk of infection, malfunction, and other complications is generally low. One major drawback is shorter battery life, which can increase the risk of changes in pacer functioning.

However, the reuse of pacemakers and defibrillators in developing countries raises some logistical, legal, and ethical questions and challenges. Logistical barriers include the collection and transportation of used devices, sterilization and testing, and training and support for healthcare professionals. Legal barriers encompass regulatory approval and liability concerns, while ethical barriers involve consent, health equity, and quality of care. To address these issues, establishing partnerships with hospitals and NGOs, developing standardized protocols for sterilization and testing, and providing education and training programs for healthcare professionals can be beneficial. Advocacy for the development of appropriate regulations and guidelines, implementing a robust informed consent process, and developing transparent and objective criteria for patient selection can further help mitigate these challenges[14][15] [16]

Ongoing monitoring, evaluation, and quality improvement initiatives can ensure that the care provided to patients receiving reused devices meets appropriate standards. While reusing pacemakers and defibrillators in developing countries presents significant challenges, the implementation of these solutions can help improve access to life-saving treatments for patients who would otherwise be unable to afford them. [15][17]

Nevertheless, the reuse of pacemakers does present a viable option for those in developing countries and regions where access to new devices is limited by cost or other barriers.[18]

References[edit | edit source]

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 Stevenson I, Voskoboinik A. Cardiac rhythm management devices. Australian Journal of General Practice 2018; 47(5): n.p. Availible from: https://www1.racgp.org.au/ajgp/2018/may/cardiac-rhythm-management-devices
  2. Radswiki T, Chieng R, Yap J, et al. Cardiac conduction devices [Internet]. Radiopaedia. 2022 [accessed 29.4.2021]. Availible from: https://doi.org/10.53347/rID-12188
  3. Curnis A, Salghetti F, Cerini M, Fabbricatore D, Ghizzoni G, Arrigoni L, et al. Leadless pacemaker: State of the art and incoming developments to broaden indications. Pacing and Clinical Electrophysiology: 2020; 22. Available from: https://onlinelibrary.wiley.com/doi/10.1111/pace.14097 (accessed 29.4.2021)
  4. 4.0 4.1 4.2 4.3 John Hopkins Medicine. Pacemaker Insertion. Available from: https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/pacemaker-insertion (accessed 30.4.2021)
  5. Zero to Finals. Understanding Pacemakers. Available from: https://www.youtube.com/watch?v=53_jyoA47Fk [last accessed 11/26/2018]
  6. 6.0 6.1 Lak HM, Goyal A. Pacemaker Types and Selection. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023. Available from: https://www.ncbi.nlm.nih.gov/books/NBK556011/
  7. Goldberger AL, Goldberger ZD, Shvilkin A. Clinical electrocardiography: a simplified approach e-book. Elsevier Health Sciences; 2017 Mar 19. Available from: https://www.sciencedirect.com/topics/nursing-and-health-professions/dual-chamber-pacemaker(accessed 30.4.2021)
  8. Cleveland Clinic. Leadless Pacemakers. Available from: https://my.clevelandclinic.org/health/treatments/17166-pacemakers-leadless-pacemaker (accessed 30.4.2021)
  9. Monash Health. Monash Health implants world-first leadless pacemaker treatment for heart failure. Available: https://monashhealth.org/latest-news/2020/10/15/monash-health-implants-world-first-leadless-pacemaker-treatment-for-heart-failure/ (accessed 30.4.2021)
  10. Thomas L. New type of boinic pacemaker [Internet]. News Medical New type of bionic pacemaker. 2019 [cited 4/30/2021] Available: https://www.news-medical.net/news/20191114/New-type-of-bionic-pacemaker.aspx
  11. Digby GC, Daubney ME, Baggs J, Campbell D, Simpson CS, Redfearn DP, et al. Physiotherapy and cardiac rhythm devices: a review of the current scope of practice. Europace. 2009; 11(7): 850-9. Available from:https://academic.oup.com/europace/article/11/7/850/498953 (accessed 30.4.2021)
  12. Practice Development Nurse et al. Discharge advice after your Permanent Pacemaker (PPM) procedure: Information for patients. Oxford: Oxford University Hospitals NHS Foundation Trust, 2017.
  13. Mazumdar T. British Charity Calls for Reuse of Pacemakers Abroad. BBB News Health. Available: https://www.bbc.com/news/health-24828244 (accessed 30.4.2021)
  14. VanArtsdalen J, Goold SD, Kirkpatrick JN, Goldman E, Eagle K, Crawford T. Pacemaker reuse for patients in resource poor countries: is something always better than nothing?. Progress in cardiovascular diseases. 2012 Nov 1;55(3):300-6.
  15. 15.0 15.1 Kirkpatrick JN, Papini C, Baman TS, Khota K, Eagle KA, Verdino RJ, Caplan AL. Reuse of pacemakers and defibrillators in developing countries: logistical, legal, and ethical barriers and solutions. Heart Rhythm. 2010 Nov 1;7(11):1623-7.
  16. Hughey AB, Baman TS, Eagle KA, Crawford TC. Pacemaker reuse: an initiative to help those in underserved nations in need of life-saving device therapy. Expert Review of Medical Devices. 2013 Sep 1;10(5):577-9.
  17. Baman TS, Meier P, Romero J, Gakenheimer L, Kirkpatrick JN, Sovitch P, Oral H, Eagle KA. Safety of pacemaker reuse: a meta-analysis with implications for underserved nations. Circulation: Arrhythmia and Electrophysiology. 2011 Jun;4(3):318-23.
  18. Nava S, Morales JL, Márquez MF, Barrera F, Gómez J, Colín L. Reuse of pacemakers: comparison of short and long-term performance. Circulation. 2013; 127(11): 1177-83. Available:https://www.ahajournals.org/doi/full/10.1161/CIRCULATIONAHA.113.001584