https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 12/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate MODE SELECTION ALGORITHMS A number of guidelines and algorithms are available for determining the appropriate pacing mode for patients with sinus node disease and AV node disease [38]. The indications and contraindications for the various types of pacing modes are listed in the accompanying tables ( table 4) [38]. In this listing, chronotropically competent refers to the ability of a patient to achieve an appropriate heart rate for a given physiologic activity. Several algorithms are also available: General algorithms for all bradycardic indications ( algorithm 1 and figure 1) An algorithm for sick sinus syndrome ( algorithm 2) An algorithm for AV block ( algorithm 3) 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: 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. 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)") Beyond the Basics topic (see "Patient education: Pacemakers (Beyond the Basics)") https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 13/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate SUMMARY AND RECOMMENDATIONS Nomenclature For permanent cardiac pacing, the five position NBG code indicates the chamber(s) paced, the chamber(s) sensed, the response to sensing, presence or absence of rate modulation, and location or absence of multisite pacing ( table 2). (See 'Nomenclature' above.) Selection of pacing mode In selecting a pacing mode, the patient's overall physical condition, associated medical problems, exercise capacity, left ventricular (LV) function, and chronotropic response to exercise must be considered along with the underlying rhythm disturbance. Some commonly used pacing modes are shown in the table ( table 3). (See 'Pacing modes' above.) Most patients with a standard bradycardic indication for pacing can be managed with one of three common pacing modes (with or without rate responsive pacing): AAI(R), VVI(R), or DDD(R). At the time of implantation, one should consider how many leads will be necessary and which additional features, if any, will be of potential value. Choice of single- or dual-chamber pacemaker The most important choice in most patients with a bradycardic indication for pacing is whether to place a single- or dual- chamber pacemaker (see "Permanent cardiac pacing: Overview of devices and indications" and 'Pacing modes' above). The choice varies with the clinical setting: Atrial fibrillation In patients with chronic atrial fibrillation (AF) who require a pacemaker due to slow ventricular response, we recommend a single-chamber ventricular pacemaker (VVI or VVIR) (Grade 1B). (See 'VVI or VVIR pacing' above.) Sinus rhythm In patients in sinus rhythm with conditions that could be managed with either a single- or a dual-chamber pacemaker (eg, atrioventricular [AV] block, sinus node dysfunction [SND]), we suggest a dual-chamber pacemaker (Grade 2B). (See 'Physiologic pacing' above and 'Dual-chamber pacing' above.) Exception for advanced age or difficult two lead implantation A single- chamber pacemaker is a reasonable alternative in patients who are adults with advanced age or whose anatomy and physical condition make the implantation of two leads more difficult than usual. In such cases, the additional costs and risks of a dual-chamber physiologic pacemaker may outweigh the potential benefits of the reduced risk of AF and patient preference. VVI(R) pacing will be effective in all such patients. (See 'VVI or VVIR pacing' above.) https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 14/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate Possible exception for SND with intact AV conduction An AAI(R) pacemaker is a reasonable alternative to VVI(R) pacing in the subset of patients with SND in whom AV conduction is intact and meets intra-implant testing criteria (see "Sinus node dysfunction: Treatment"). However, effective AAIR pacing is more commonly accomplished with a dual-chamber pacemaker with a ventricular pacing avoidance option. (See 'AAI or AAIR pacing' above and 'Modes to minimize ventricular pacing' above.) Additional features The following additional features are appropriate for selected patients: Rate responsiveness This feature can be programmed for patients who are active, but not chronotropically competent. (See 'Rate responsiveness' above.) Mode switching This feature can be programmed for patients with paroxysmal atrial arrhythmias. (See 'Mode switching' above.) Ventricular pacing avoidance Algorithms to avoid ventricular pacing are appropriate for most patients with PR prolongation or type II AV block. Some parameter to minimize ventricular pacing is available in most contemporary devices. (See 'Modes to minimize ventricular pacing' 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. Bernstein AD, Daubert JC, Fletcher RD, et al. The revised NASPE/BPEG generic code for antibradycardia, adaptive-rate, and multisite pacing. North American Society of Pacing and Electrophysiology/British Pacing and Electrophysiology Group. Pacing Clin Electrophysiol 2002; 25:260. 2. Sweeney MO, Prinzen FW. A new paradigm for physiologic ventricular pacing. J Am Coll Cardiol 2006; 47:282. https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 15/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate 3. Sweeney MO, Bank AJ, Nsah E, et al. Minimizing ventricular pacing to reduce atrial fibrillation in sinus-node disease. N Engl J Med 2007; 357:1000. 4. Sweeney MO, Ellenbogen KA, Casavant D, et al. Multicenter, prospective, randomized safety and efficacy study of a new atrial-based managed ventricular pacing mode (MVP) in dual chamber ICDs. J Cardiovasc Electrophysiol 2005; 16:811. 5. Olshansky B, Day JD, Moore S, et al. Is dual-chamber programming inferior to single- chamber programming in an implantable cardioverter-defibrillator? Results of the INTRINSIC RV (Inhibition of Unnecessary RV Pacing With AVSH in ICDs) study. Circulation 2007; 115:9. 6. Ricci RP, Botto GL, B n zet JM, et al. Association between ventricular pacing and persistent atrial fibrillation in patients indicated to elective pacemaker replacement: Results of the Prefer for Elective Replacement MVP (PreFER MVP) randomized study. Heart Rhythm 2015; 12:2239. 7. Stockburger M, Boveda S, Moreno J, et al. Long-term clinical effects of ventricular pacing reduction with a changeover mode to minimize ventricular pacing in a general pacemaker population. Eur Heart J 2015; 36:151. 8. Curtis AB, Worley SJ, Adamson PB, et al. Biventricular pacing for atrioventricular block and systolic dysfunction. N Engl J Med 2013; 368:1585. 9. Curtis AB, Worley SJ, Chung ES, et al. Improvement in Clinical Outcomes With Biventricular Versus Right Ventricular Pacing: The BLOCK HF Study. J Am Coll Cardiol 2016; 67:2148. 10. Hayes DL, Furman S. Stability of AV conduction in sick sinus node syndrome patients with implanted atrial pacemakers. Am Heart J 1984; 107:644. 11. Antonioli, G, Ansani, et al. Single-Lead VDD Pacing. In: New Perspectives in Cardiac Pacing, 3, Barold, S, Mugica, J (Eds), Futura Publishing, Mount Kisco 1993. 12. Rey JL, Tribouilloy C, Elghelbazouri F, Otmani A. Single-lead VDD pacing: long-term experience with four different systems. Am Heart J 1998; 135:1036. 13. Huang M, Krahn AD, Yee R, et al. Optimal pacing for symptomatic AV block: a comparison of VDD and DDD pacing. Pacing Clin Electrophysiol 2004; 27:19. 14. Wiegand UK, Bode F, Schneider R, et al. Development of sinus node disease in patients with AV block: implications for single lead VDD pacing. Heart 1999; 81:580. 15. Morsi A, Lau C, Nishimura S, Goldman BS. The development of sinoatrial dysfunction in pacemaker patients with isolated atrioventricular block. Pacing Clin Electrophysiol 1998; 21:1430. https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 16/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate 16. Lamas GA, Ellenbogen KA. Evidence base for pacemaker mode selection: from physiology to randomized trials. Circulation 2004; 109:443. 17. Healey JS, Toff WD, Lamas GA, et al. Cardiovascular outcomes with atrial-based pacing compared with ventricular pacing: meta-analysis of randomized trials, using individual patient data. Circulation 2006; 114:11. 18. Stewart WJ, Dicola VC, Harthorne JW, et al. Doppler ultrasound measurement of cardiac output in patients with physiologic pacemakers. Effects of left ventricular function and retrograde ventriculoatrial conduction. Am J Cardiol 1984; 54:308. 19. Rediker DE, Eagle KA, Homma S, et al. Clinical and hemodynamic comparison of VVI versus DDD pacing in patients with DDD pacemakers. Am J Cardiol 1988; 61:323. 20. Boon NA, Frew AJ, Johnston JA, Cobbe SM. A comparison of symptoms and intra-arterial ambulatory blood pressure during long term dual chamber atrioventricular synchronous (DDD) and ventricular demand (VVI) pacing. Br Heart J 1987; 58:34. 21. Takeuchi M, Nohtomi Y, Kuroiwa A. Effect of ventricular pacing on coronary blood flow in patients with normal coronary arteries. Pacing Clin Electrophysiol 1997; 20:2463. 22. Nielsen JC, Andersen HR, Thomsen PE, et al. Heart failure and echocardiographic changes during long-term follow-up of patients with sick sinus syndrome randomized to single- chamber atrial or ventricular pacing. Circulation 1998; 97:987. 23. Ausubel K, Furman S. The pacemaker syndrome. Ann Intern Med 1985; 103:420. 24. Lamas GA, Orav EJ, Stambler BS, et al. Quality of life and clinical outcomes in elderly patients treated with ventricular pacing as compared with dual-chamber pacing. Pacemaker Selection in the Elderly Investigators. N Engl J Med 1998; 338:1097. 25. Andersen HR, Thuesen L, Bagger JP, et al. Prospective randomised trial of atrial versus ventricular pacing in sick-sinus syndrome. Lancet 1994; 344:1523. 26. Lamas GA, Lee KL, Sweeney MO, et al. Ventricular pacing or dual-chamber pacing for sinus- node dysfunction. N Engl J Med 2002; 346:1854. 27. Connolly SJ, Kerr CR, Gent M, et al. Effects of physiologic pacing versus ventricular pacing on the risk of stroke and death due to cardiovascular causes. Canadian Trial of Physiologic Pacing Investigators. N Engl J Med 2000; 342:1385. 28. Toff WD, Camm AJ, Skehan JD, United Kingdom Pacing and Cardiovascular Events Trial Investigators. Single-chamber versus dual-chamber pacing for high-grade atrioventricular block. N Engl J Med 2005; 353:145. 29. Kerr CR, Connolly SJ, Abdollah H, et al. Canadian Trial of Physiological Pacing: Effects of physiological pacing during long-term follow-up. Circulation 2004; 109:357. https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 17/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate 30. Andersen HR, Nielsen JC, Thomsen PE, et al. Long-term follow-up of patients from a randomised trial of atrial versus ventricular pacing for sick-sinus syndrome. Lancet 1997; 350:1210. 31. Hellkamp AS, Lee KL, Sweeney MO, et al. Treatment crossovers did not affect randomized treatment comparisons in the Mode Selection Trial (MOST). J Am Coll Cardiol 2006; 47:2260. 32. Skanes AC, Krahn AD, Yee R, et al. Progression to chronic atrial fibrillation after pacing: the Canadian Trial of Physiologic Pacing. CTOPP Investigators. J Am Coll Cardiol 2001; 38:167. 33. Tang AS, Roberts RS, Kerr C, et al. Relationship between pacemaker dependency and the effect of pacing mode on cardiovascular outcomes. Circulation 2001; 103:3081. 34. Ellenbogen KA, Stambler BS, Orav EJ, et al. Clinical characteristics of patients intolerant to VVIR pacing. Am J Cardiol 2000; 86:59. 35. Jahangir A, Shen WK, Neubauer SA, et al. Relation between mode of pacing and long-term survival in the very elderly. J Am Coll Cardiol 1999; 33:1208. 36. Link MS, Hellkamp AS, Estes NA 3rd, et al. High incidence of pacemaker syndrome in patients with sinus node dysfunction treated with ventricular-based pacing in the Mode Selection Trial (MOST). J Am Coll Cardiol 2004; 43:2066. 37. Sulke N, Chambers J, Dritsas A, Sowton E. A randomized double-blind crossover comparison of four rate-responsive pacing modes. J Am Coll Cardiol 1991; 17:696. 38. 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. Topic 950 Version 30.0 https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 18/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate GRAPHICS Guidelines for choice of pacemaker generator in selected indications for pacing Neurally-mediated Type of Sinus node syncope or carotid AV block pacemaker dysfunction sinus hypersensitivity Single-chamber No suspected Not appropriate Not appropriate (unless atrial abnormality of AV AV block systematically conduction and not at increased risk for excluded) future AV block Maintenance of AV synchrony during pacing desired Rate response available if desired Single-chamber ventricular Maintenance of AV synchrony during pacing not necessary Chronic atrial fibrillation or other atrial tachyarrhythmia or maintenance of AV synchrony during pacing not necessary Chronic atrial fibrillation or other atrial tachyarrhythmia Rate response available if desired Rate response available if desired Rate response available if desired Dual-chamber AV synchrony during pacing desired AV synchrony during pacing desired Sinus mechanism present Rate response available if Suspected abnormality of AV conduction or Atrial pacing desired desired increased risk for future AV block Rate response available if desired Rate response available if desired Single-lead, Not appropriate Normal sinus node function Not appropriate atrial-sensing ventricular and no need for atrial pacing https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 19/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate Desire to limit number of pacemaker leads AV: atrioventricular. Data from Gregoratos G, Cheitlin MD, Conill A, et al. Circulation 1998; 97:1325. Graphic 51504 Version 3.0 https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 20/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate Revised NBG code for pacing nomenclature I II III IV V Position Chamber(s) paced Chamber(s) sensed Response to sensing Rate modulation Multisite pacing Category O = None O = None O = None O = None O = None A = Atrium A = Atrium T = R = Rate A = Atrium Triggered modulation V = Ventricle V = Ventricle V = I = Inhibited Ventricle D = Dual (A+V) D = Dual (A+V) D = Dual (T+I) D = Dual (A+V) S = Single (A S = Single (A Manufacturer's or V) or V) designation only: Note: Positions I through III are used exclusively for antibradyarrythmia function. Adapted from Bernstein AD, Daubert JC, Fletcher RD, et al. Pacing Clin Electrophysiol 2002; 25:260. Graphic 68327 Version 3.0 https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 21/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate Types of cardiac pacemakers and NBG codes Code Meaning VOO Asynchronous ventricular pacemaker; no adaptive rate control or antitachyarrhythmia functions VVI Ventricular "demand" pacemaker with electrogram-waveform telemetry; no adaptive rate control or antitachyarrhythmia functions DVI Multiprogrammable atrioventricular-sequential pacemaker; no adaptive rate control DDD Multiprogrammable "physiologic" dual-chamber pacemaker; no adaptive rate control or antitachyarrhythmia functions DDI Multiprogrammable DDI pacemaker (with dual-chamber pacing and sensing but without atrial-synchronous ventricular pacing); no adaptive rate control or antitachycardia functions VVIR Adaptive-rate VVI pacemaker with escape interval controlled adaptively by one or more unspecified variables DDDR Programmable DDD pacemaker with escape interval controlled adaptively by one or more unspecified variables Graphic 79459 Version 1.0 https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 22/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate Rhythms seen with a normal DDD pacemaker The rhythms that occur in a patient with a DDD pacemaker depend upon the underlying heart rate and atrioventricular (AV) nodal conduction. The pacemaker spike is represented in blue. First panel: The pacemaker may be completely inhibited when the sinus rate is greater than the lower rate limit of the pacemaker. Second panel: P- wave synchronous pacing occurs when there is intrinsic AV nodal delay which is greater than the AV delay in the pacemaker. Third panel: Atrial pacing occurs when the sinus rate falls below the lower limit of the pacemaker and AV nodal conduction is intact. Fourth panel: If there is sinus bradycardia and AV nodal conduction delay, the pacemaker paces both atrium and ventricle, known as AV sequential pacing. Graphic 52858 Version 3.0 https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 23/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate Pacing modes indications and contraindications Generally agreed Controversial Mode Contraindications upon indications indications VVI/VVIR Fixed atrial arrhythmias (atrial Symptomatic bradycardia in the Patients with known pacemaker syndrome or fibrillation or flutter) patient with associated hemodynamic with symptomatic bradycardia in the CC patient (VVI) or CI terminal illness or other medical conditions from which deterioration with ventricular pacing at the time of implant patient (VVIR) recovery is not CI patient who will benefit from rate anticipated and pacing is life-sustaining only response Patients with hemodynamic need for dual-chamber pacing AAI/AAIR Symptomatic bradycardia as a result Sinus node dysfunction with associated AV block of sinus node dysfunction; used when AV conduction can be proven normal in the otherwise CC patient (AAI) or CI either demonstrated spontaneously or during pre-implant testing When adequate atrial sensing cannot be patient (AAIR) attained DVI* VDD /VDDR Congenital AV block Sinus node dysfunction AV block when sinus node function can be AV block when accompanied by sinus proven normal in the CC patient (VDD) or CI node dysfunction When adequate atrial patient (VDDR) sensing cannot be attained AV block when accompanied by PSVT DDI/DDIR Need for dual-chamber Sinus node dysfunction CI patient with a pacing in the presence of significant PSVT in in the absence of AV block in the presence demonstrated need or improvement with rate the CC patient (DDI) or CI patient (DDIR) of significant PSVT in the CC patient (DDI) or responsiveness CI patient (DDIR) https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 24/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate DDD/DDDR AV block and sinus For any rhythm Presence of chronic node dysfunction in the CC patient (DDD) or disturbance when atrial sensing and atrial fibrillation, atrial flutter, giant inexcitable CI patient (DDDR) capture is possible for atrium or other the potential purpose of minimizing future frequent PSVTs Need for AV synchrony to maximize cardiac output in CC active When adequate atrial sensing cannot be atrial fibrillation and improved morbidity patients (DDD) attained and survival Previous pacemaker syndrome CC: chronotropically competent (ie, the ability to achieve an appropriate heart rate for a given physiologic activity); CI: chronotropically incompetent (ie, the inability to achieve an appropriate heart rate for a given physiologic activity); AV: atrioventricular; PSVT: paroxysmal supraventricular tachycardia. DVI as a stand-alone pacing mode (ie, a pacemaker capable of DVI as the only dual-chamber mode of operation) is obsolete. All primary uses of this mode should be considered individually. VDD as a stand-alone pacing mode (ie, a pacemaker capable of VDD as the only dual-chamber mode of operation) is currently used primarily as a single-lead VDD system. If a dual-lead system is implanted, then the capability of DDD pacing is desirable. In current single-lead VDDR pacemakers, P-wave tracking occurs as long as the sinus rate is appropriate. However, in the presence of sinus bradycardia or chronotropic incompetence, the pacemaker operates in the VVIR mode. DDIR has been supplanted by DDD or DDDR pacemakers with the capability of mode-switching (ie, the pacemaker automatically reprograms to a mode incapable of tracking the atrial rhythm in the presence of an atrial rhythm that the pacemaker classifies as a pathological rhythm). When the pacemaker recognizes the atrial rhythm as being physiological, the pacemaker reprograms to the previously programmed mode. Graphic 120148 Version 1.0 https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 25/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate Pacemaker algorithm Algorithm for the use of the different types of pacemakers depending upon the need for atrioventricular (AV) sequential pacing, the presence of sinoatrial (SA) node chronotropic competence, the AV conduction rate, and the need for rate-responsiveness. Refer to UpToDate content on modes of cardiac pacing: nomenclature and selection. Courtesy of MD McGoon, MD. Graphic 64626 Version 3.0 https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 26/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate Simplified pacemaker algorithm for use with rate adaptive pacemakers Simplified algorithm for the choice of pacemaker mode assuming that a rate-responsive pacemaker (DDDR or VVIR) will be used. Courtesy of MD McGoon, MD. Graphic 76446 Version 2.0 https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 27/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate Selection of pacemaker systems for patients with sinus node dysfunction Decisions are illustrated by diamonds. Shaded boxes indicate type of pacemaker. AV: atrioventricular. Reproduced with permission from: Epstein AE, DiMarco JP, Ellenbogen KA, et al. ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2008; 51(21):e1-e62. Illustration used with permission of Elsevier Inc. All rights reserved. Copyright 2008 Elsevier Inc. Graphic 77929 Version 5.0 https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 28/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate Selection of pacemaker systems for patients with atrioventricular block Decisions are illustrated by diamonds. Shaded boxes indicate type of pacemaker. AV: atrioventricular. Reproduced with permission from: Epstein AE, DiMarco JP, Ellenbogen KA, et al. ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2008; 51(21):e1-e62. Illustration used with permission of Elsevier Inc. All rights reserved. Copyright 2008 Elsevier Inc. https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 29/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - UpToDate Graphic 71370 Version 4.0 https://www.uptodate.com/contents/modes-of-cardiac-pacing-nomenclature-and-selection/print 30/31 7/6/23, 10:54 AM Modes of cardiac pacing: Nomenclature and selection - 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/modes-of-cardiac-pacing-nomenclature-and-selection/print 31/31