A hyperactive cardioinhibitory response to carotid sinus stimulation in the absence of symptoms or in the presence of vague symptoms such as dizziness, lightheadedness, or both. Right bundle branch block with left axis deviation without syncope or other symptoms compatible with intermittent AV block. Reversible AV block, such as those associated with electrolyte abnormalities, Lyme disease, sleep apnea, enhanced vagal tone, and some cases that occur postoperatively. AV block associated with drugs such as beta blockers, diltiazem, or verapamil is not always reversible and can be associated with underlying conduction system disease [32]. (See "Etiology of atrioventricular block", section on 'Medications'.) Long QT syndrome or torsades de pointes due to reversible causes. SOCIETY GUIDELINE LINKS Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Arrhythmias in adults" and "Society guideline links: Cardiac implantable electronic devices".) INFORMATION FOR PATIENTS UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." th th The Basics patient education pieces are written in plain language, at the 5 to 6 grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more th th sophisticated, and more detailed. These articles are written at the 10 to 12 grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon. https://www.uptodate.com/contents/permanent-cardiac-pacing-overview-of-devices-and-indications/print 13/24 7/6/23, 11:01 AM Permanent cardiac pacing: Overview of devices and indications - UpToDate Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.) Basics topic (see "Patient education: Pacemakers (The Basics)" and "Patient education: Bradycardia (The Basics)") Beyond the Basics topic (see "Patient education: Pacemakers (Beyond the Basics)") SUMMARY AND RECOMMENDATIONS General considerations Two general factors guide the vast majority of decisions regarding permanent pacemaker insertion: the association of symptoms with an arrhythmia and the potential for progression of the rhythm disturbance, which is largely dependent on the anatomical location of the conduction abnormality. (See 'General considerations' above.) Association of symptoms with arrhythmia Patients frequently present for consideration of pacemaker placement because of symptoms that may be due to bradyarrhythmias (eg, dizziness, lightheadedness, syncope, fatigue, and poor exercise tolerance). It is critical to attempt to establish a direct correlation between symptoms and bradyarrhythmias, which will increase the likelihood of recommending pacemaker placement. (See 'Symptoms' above.) Risk of progression The location of an atrioventricular (AV) conduction abnormality (ie, within the AV node or below the AV node in the His-Purkinje system) is an important determinant of both the probability and the likely pace of progression of conduction system disease. Disease below the AV node, in the His-Purkinje system, is generally considered to be less stable; as a result, permanent pacemaker placement is more likely to be recommended. (See 'Location of conduction abnormality' above.) Types of pacemaker systems Pacemakers ( picture 1) are most commonly placed in a thoracic pre-pectoral position and connected to one or two transvenous leads, which are positioned endocardially. Epicardial lead placement is still a viable option for patients with limited transvenous access. Leadless pacing systems are now available and hold significant promise for the future. (See 'Types of permanent pacemaker systems' above.) Indications for pacemaker implantation The most common indications for pacemaker implantation are sinus node dysfunction followed by AV block. All other indications are https://www.uptodate.com/contents/permanent-cardiac-pacing-overview-of-devices-and-indications/print 14/24 7/6/23, 11:01 AM Permanent cardiac pacing: Overview of devices and indications - UpToDate much less common and include neurocardiogenic syncope and iatrogenic causes (eg, post- AV node ablation). While patients with a heart rate of less than 40 beats per minute, or pauses of greater than four seconds, are more likely to develop symptoms, there is no definitive threshold for heart rate (or pause length) which determines the absolute need for a permanent pacemaker. (See 'Common indications' above.) When to consider CRT or ICD With the advent of cardiac resynchronization therapy (CRT), it is important to also take into consideration the patient's left ventricular function at the time a pacemaker is considered. If the patient has left ventricular dysfunction and requires frequent pacing, it would be appropriate to consider CRT and/or an implantable cardioverter-defibrillator. Whether His bundle or left bundle pacing will provide benefits similar to CRT is yet to be determined. (See "Cardiac resynchronization therapy in heart failure: Indications and choice of system".) Pacing not indicated Conditions with a lack of adequate evidence of benefit from permanent pacing, in which permanent pacing is generally non indicated, include, among others, syncope of undetermined etiology, asymptomatic sinus bradycardia, asymptomatic first-degree and second-degree Mobitz I (Wenckebach) AV block, reversible AV block, and long QT syndrome or torsades de pointes due to a reversible cause. (See 'Class III: Pacing not indicated' above.) ACKNOWLEDGMENT The UpToDate editorial staff acknowledges David L Hayes, MD, who contributed to earlier versions of this topic review. Use of UpToDate is subject to the Terms of Use. REFERENCES 1. Kusumoto FM, Schoenfeld MH, Barrett C, et al. 2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol 2019; 74:e51. 2. Glikson M, Nielsen JC, Kronborg MB, et al. 2021 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy. Eur Heart J 2021; 42:3427. https://www.uptodate.com/contents/permanent-cardiac-pacing-overview-of-devices-and-indications/print 15/24 7/6/23, 11:01 AM Permanent cardiac pacing: Overview of devices and indications - UpToDate 3. Upadhyay GA, Vijayaraman P, Nayak HM, et al. On-treatment comparison between corrective His bundle pacing and biventricular pacing for cardiac resynchronization: A secondary analysis of the His-SYNC Pilot Trial. Heart Rhythm 2019; 16:1797. 4. Upadhyay GA, Vijayaraman P, Nayak HM, et al. His Corrective Pacing or Biventricular Pacing for Cardiac Resynchronization in Heart Failure. J Am Coll Cardiol 2019; 74:157. 5. Auricchio A, Delnoy PP, Butter C, et al. Feasibility, safety, and short-term outcome of leadless ultrasound-based endocardial left ventricular resynchronization in heart failure patients: results of the wireless stimulation endocardially for CRT (WiSE-CRT) study. Europace 2014; 16:681. 6. Reddy VY, Knops RE, Sperzel J, et al. Permanent leadless cardiac pacing: results of the LEADLESS trial. Circulation 2014; 129:1466. 7. Knops RE, Tjong FV, Neuzil P, et al. Chronic performance of a leadless cardiac pacemaker: 1- year follow-up of the LEADLESS trial. J Am Coll Cardiol 2015; 65:1497. 8. Ritter P, Duray GZ, Steinwender C, et al. Early performance of a miniaturized leadless cardiac pacemaker: the Micra Transcatheter Pacing Study. Eur Heart J 2015; 36:2510. 9. Reddy VY, Exner DV, Cantillon DJ, et al. Percutaneous Implantation of an Entirely Intracardiac Leadless Pacemaker. N Engl J Med 2015; 373:1125. 10. Miller MA, Neuzil P, Dukkipati SR, Reddy VY. Leadless Cardiac Pacemakers: Back to the Future. J Am Coll Cardiol 2015; 66:1179. 11. Reynolds D, Duray GZ, Omar R, et al. A Leadless Intracardiac Transcatheter Pacing System. N Engl J Med 2016; 374:533. 12. Reddy VY, Miller MA, Neuzil P, et al. Cardiac Resynchronization Therapy With Wireless Left Ventricular Endocardial Pacing: The SELECT-LV Study. J Am Coll Cardiol 2017; 69:2119. 13. Sperzel J, Burri H, Gras D, et al. State of the art of leadless pacing. Europace 2015; 17:1508. 14. Tjong FVY, Knops RE, Neuzil P, et al. Midterm Safety and Performance of a Leadless Cardiac Pacemaker: 3-Year Follow-up to the LEADLESS Trial (Nanostim Safety and Performance Trial for a Leadless Cardiac Pacemaker System). Circulation 2018; 137:633. 15. Sperzel J, Defaye P, Delnoy PP, et al. Primary safety results from the LEADLESS Observational Study. Europace 2018; 20:1491. 16. Piccini JP, Stromberg K, Jackson KP, et al. Long-term outcomes in leadless Micra transcatheter pacemakers with elevated thresholds at implantation: Results from the Micra Transcatheter Pacing System Global Clinical Trial. Heart Rhythm 2017; 14:685. 17. Duray GZ, Ritter P, El-Chami M, et al. Long-term performance of a transcatheter pacing system: 12-Month results from the Micra Transcatheter Pacing Study. Heart Rhythm 2017; https://www.uptodate.com/contents/permanent-cardiac-pacing-overview-of-devices-and-indications/print 16/24 7/6/23, 11:01 AM Permanent cardiac pacing: Overview of devices and indications - UpToDate 14:702. 18. http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/DeviceApprovalsandCl earances/Recently-ApprovedDevices/ucm494390.htm (Accessed on April 08, 2016). 19. El-Chami MF, Merchant FM, Leon AR. Leadless Pacemakers. Am J Cardiol 2017; 119:145. 20. Saleem-Talib S, van Driel VJ, Chaldoupi SM, et al. Leadless pacing: Going for the jugular. Pacing Clin Electrophysiol 2019; 42:395. 21. El-Chami MF, Al-Samadi F, Clementy N, et al. Updated performance of the Micra transcatheter pacemaker in the real-world setting: A comparison to the investigational study and a transvenous historical control. Heart Rhythm 2018; 15:1800. 22. Reddy VY, Miller MA, Knops RE, et al. Retrieval of the Leadless Cardiac Pacemaker: A Multicenter Experience. Circ Arrhythm Electrophysiol 2016; 9. 23. Lakkireddy D, Knops R, Atwater B, et al. A worldwide experience of the management of battery failures and chronic device retrieval of the Nanostim leadless pacemaker. Heart Rhythm 2017; 14:1756. 24. Grubman E, Ritter P, Ellis CR, et al. To retrieve, or not to retrieve: System revisions with the Micra transcatheter pacemaker. Heart Rhythm 2017; 14:1801. 25. Gonz lez Villegas E, Al Razzo O, Silvestre Garc a J, Mesa Garc a J. Leadless pacemaker extraction from a single-center perspective. Pacing Clin Electrophysiol 2018; 41:101. 26. El-Chami MF, Clementy N, Garweg C, et al. Leadless Pacemaker Implantation in Hemodialysis Patients: Experience With the Micra Transcatheter Pacemaker. JACC Clin Electrophysiol 2019; 5:162. 27. El-Chami MF, Johansen JB, Zaidi A, et al. Leadless pacemaker implant in patients with pre- existing infections: Results from the Micra postapproval registry. J Cardiovasc Electrophysiol 2019; 30:569. 28. San Antonio R, Chipa-Ccasani F, Apolo J, et al. Management of anticoagulation in patients undergoing leadless pacemaker implantation. Heart Rhythm 2019; 16:1849. 29. Tachibana M, Banba K, Matsumoto K, Ohara M. The feasibility of leadless pacemaker implantation for superelderly patients. Pacing Clin Electrophysiol 2020; 43:374. 30. Steinwender C, Khelae SK, Garweg C, et al. Atrioventricular Synchronous Pacing Using a Leadless Ventricular Pacemaker: Results From the MARVEL 2 Study. JACC Clin Electrophysiol 2020; 6:94. 31. Knops RE, Reddy VY, Ip JE, et al. A Dual-Chamber Leadless Pacemaker. N Engl J Med 2023; 388:2360. https://www.uptodate.com/contents/permanent-cardiac-pacing-overview-of-devices-and-indications/print 17/24 7/6/23, 11:01 AM Permanent cardiac pacing: Overview of devices and indications - UpToDate 32. Zeltser D, Justo D, Halkin A, et al. Drug-induced atrioventricular block: prognosis after discontinuation of the culprit drug. J Am Coll Cardiol 2004; 44:105. 33. American College of Emergency Physicians, Society for Cardiovascular Angiography and Interventions, O'Gara PT, et al. 2013 ACCF/AHA guideline for the management of ST- elevation myocardial infarction: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2013; 61:e78. 34. Al-Khatib SM, Stevenson WG, Ackerman MJ, et al. 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol 2018; 72:e91. 35. Groh WJ. Arrhythmias in the muscular dystrophies. Heart Rhythm 2012; 9:1890. 36. Ommen SR, Mital S, Burke MA, et al. 2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation 2020; 142:e558. Topic 941 Version 43.0 https://www.uptodate.com/contents/permanent-cardiac-pacing-overview-of-devices-and-indications/print 18/24 7/6/23, 11:01 AM Permanent cardiac pacing: Overview of devices and indications - UpToDate GRAPHICS Normal conduction system Schematic representation of the normal intraventricular conduction system (His- Purkinje system). The Bundle of His divides into the left bundle branch and right bundle branch. The left bundle branch divides into anterior, posterior, and, in some cases, median fascicles. AV: atrioventricular; RA: right atrium; LA: left atrium; RV: right ventricle; LV: left ventricle. Graphic 63340 Version 6.0 https://www.uptodate.com/contents/permanent-cardiac-pacing-overview-of-devices-and-indications/print 19/24 7/6/23, 11:01 AM Permanent cardiac pacing: Overview of devices and indications - UpToDate Examples of cardiac pacemaker pulse generators Examples of cardiac pacemaker pulse generators commonly used in practice in 2015. Graphic 104720 Version 1.0 https://www.uptodate.com/contents/permanent-cardiac-pacing-overview-of-devices-and-indications/print 20/24 7/6/23, 11:01 AM Permanent cardiac pacing: Overview of devices and indications - UpToDate A leadless pacing system: The Medtronic Micra This pacing system includes the pulse generator and the electrode within a single unit that is placed into the right ventricle via a transvenous approach. Reproduced with permission of Medtronic, Inc. Copyright 2021. Graphic 130297 Version 1.0 https://www.uptodate.com/contents/permanent-cardiac-pacing-overview-of-devices-and-indications/print 21/24 7/6/23, 11:01 AM Permanent cardiac pacing: Overview of devices and indications - UpToDate Indications for pacing for sinus node dysfunction Pacemaker not Pacemaker necessary Pacemaker probably necessary necessary Symptomatic bradycardia Symptomatic patients with sinus node dysfunction with documented rates of <40 bpm without a clear-cut association between significant symptoms and the Asymptomatic sinus node dysfunction bradycardia Symptomatic sinus bradycardia due to long-term drug therapy of a type and dose for which there is no accepted alternative Graphic 70519 Version 2.0 https://www.uptodate.com/contents/permanent-cardiac-pacing-overview-of-devices-and-indications/print 22/24 7/6/23, 11:01 AM Permanent cardiac pacing: Overview of devices and indications - UpToDate Indications for pacing in multifascicular block Pacemaker probably Pacemaker not Pacemaker necessary necessary necessary Symptomatic patients with fascicular Patients with syncope and Asymptomatic block and significantly prolonged H-V interval by electrophysiologic study bifascicular or trifascicular block with other etiologies of syncope excluded fascicular block without AV block Symptomatic patients with block distal to His at atrial paced rates of less than 100-120 bpm Pacing-induced block distal to His at atrial paced rates of less than 130 bpm Asymptomatic fascicular block and first degree AV block Symptomatic patients with bifascicular block and intermittent type II second Asymptomatic patients with fascicular block and intermittent degree AV block or third degree AV block type II second degree or third degree AV block Graphic 80379 Version 1.0 https://www.uptodate.com/contents/permanent-cardiac-pacing-overview-of-devices-and-indications/print 23/24 7/6/23, 11:01 AM Permanent cardiac pacing: Overview of devices and indications - UpToDate Contributor Disclosures Mark S Link, MD No relevant financial relationship(s) with ineligible companies to disclose. N A Mark Estes, III, MD Consultant/Advisory Boards: Boston Scientific [Arrhythmias]; Medtronic [Arrhythmias]. All of the relevant financial relationships listed have been mitigated. Susan B Yeon, MD, JD, FACC No relevant financial relationship(s) with ineligible companies to disclose. Contributor disclosures are reviewed for conflicts of interest by the editorial group. When found, these are addressed by vetting through a multi-level review process, and through requirements for references to be provided to support the content. Appropriately referenced content is required of all authors and must conform to UpToDate standards of evidence. Conflict of interest policy https://www.uptodate.com/contents/permanent-cardiac-pacing-overview-of-devices-and-indications/print 24/24